1 · Our treatise proposes to find a line of inquiry whereby we shall be able to reason from reputable opinions about any subject presented to us, and also shall ourselves, when putting forward an argument, avoid saying anything contrary to it. First, then, we must say what deduction is, and what its varieties are, in order to grasp dialectical deduction; for this is the object of our search in the treatise before us.
Now a deduction is an argument in which, certain things being laid down, [25] something other than these necessarily comes about through them. It is a demonstration, when the premisses from which the deduction starts are true and primitive, or are such that our knowledge of them has originally come through premisses which are primitive and true; and it is a dialectical deduction, if it reasons from reputable opinions. Things are true and primitive which are convincing on the [30] strength not of anything else but of themselves; for in regard to the first principles of science it is improper to ask any further for the why and wherefore of them; each of the first principles should command belief in and by itself. On the other hand, those [100b20] opinions are reputable which are accepted by everyone or by the majority or by the wise—i.e. by all, or by the majority, or by the most notable and reputable of them. Again, a deduction is contentious if it starts from opinions that seem to be reputable, but are not really such, or again if it merely seems to reason from opinions that are or seem to be reputable. For not every opinion that seems to be [25] reputable actually is reputable. For none of the opinions which we call reputable show their character entirely on the surface, as happens in the case of the principles of contentious arguments; for the nature of the falsity in these is obvious immediately, and for the most part even to persons with little power of comprehension. So then, of the contentious deductions mentioned, the former really deserves to [101a1] be called deduction, but the other should be called contentious deduction, but not deduction, since it appears to deduce, but does not really do so.
Further, besides all the deductions we have mentioned there are the fallacies [5] that start from the premisses peculiar to the special sciences, as happens (for example) in the case of geometry and its sister sciences. For this form of reasoning appears to differ from the deductions mentioned above; the man who draws a false [10] figure reasons from things that are neither true and primitive, nor yet reputable. For he does not fall within the definition: he does not assume opinions that are received either by everyone or by the majority or by the wise—that is to say, by all, or by most, or by the most reputable of them—but he conducts his deduction upon assumptions which, though appropriate to the science in question, are not true; for [15] he effects his fallacy either by describing the semicircles wrongly or by drawing certain lines in a way in which they should not be drawn.
The foregoing must stand for an outline survey of the species of deduction. In general, in regard both to all that we have already discussed and to those which we [20] shall discuss later, we may remark that that amount of distinction between them may serve, because it is not our purpose to give a precise definition of any of them; we merely want to describe them in outline: we consider it quite enough from the point of view of the line of inquiry before us to be able to recognize each of them in some sort of way.
[25] 2 · Next in order after the foregoing, we must say for how many and for what purposes the treatise is useful. They are three—intellectual training, casual encounters, and the philosophical sciences. That it is useful as a training is obvious on the face of it. The possession of a plan of inquiry will enable us more easily to [30] argue about the subject proposed. For purposes of casual encounters, it is useful because when we have counted up the opinions held by most people, we shall meet them on the ground not of other people’s convictions but of their own, shifting the ground of any argument that they appear to us to state unsoundly. For the study of [35] the philosophical sciences it is useful, because the ability to puzzle on both sides of a subject will make us detect more easily the truth and error about the several points that arise. It has a further use in relation to the principles used in the several sciences. For it is impossible to discuss them at all from the principles proper to the particular science in hand, seeing that the principles are primitive in relation to [101b1] everything else: it is through reputable opinions about them that these have to be discussed, and this task belongs properly, or most appropriately, to dialectic; for dialectic is a process of criticism wherein lies the path to the principles of all inquiries.
[5] 3 · We shall be in perfect possession of the way to proceed when we are in a position like that which we occupy in regard to rhetoric and medicine and faculties of that kind; [this means the doing of that which we choose with the materials that are available.]1 for it is not every method that the rhetorician will employ to persuade, or the doctor to heal: still, if he omits none of the available means, we [10] shall say that his grasp of the science is adequate.
4 · First, then, we must see of what parts our inquiry consists. Now if we were to grasp with reference to how many, and what kind of, things arguments take place, and with what materials they start, and how we are to become well supplied with these, we should have sufficiently won our goal. Now the materials with which arguments start are equal in number, and are identical, with the subjects on which deductions take place. For arguments start with propositions, while the subjects on [15] which deductions take place are problems. Now every proposition and every problem indicates either a genus or a property or an accident—for the differentia too, being generic, should be ranked together with the genus. Since, however, of what is proper to anything part signifies its essence, while part does not, let us divide [20] the proper into both the aforesaid parts, and call that part which indicates the essence a definition, while of the remainder let us adopt the terminology which is generally current about these things, and speak of it as a property. What we have said, then, makes it clear that according to our present division, the elements turn out to be four, all told, namely either property or definition or genus or accident. Do [25] not let any one suppose us to mean that each of these enunciated by itself constitutes a proposition or problem, but only that it is from these that both problems and propositions are formed. The difference between a problem and a proposition is a difference in the turn of the phrase. For if it be put in this way, ‘Is two-footed terrestrial animal the definition of man?’ or ‘Is animal the genus of man?’ the result [30] is a proposition; but if thus, ‘Is two-footed terrestrial animal the definition of man or not?’ and ‘Is animal the genus of man or not?’ the result is a problem. Similarly too in other cases. Naturally, then, problems and propositions are equal in number; for out of every proposition you will make a problem if you change the turn of phrase.
5 · We must now say what are definition, property, genus, and accident. A definition is a phrase signifying a thing’s essence. It is rendered in the form either of a phrase in lieu of a name, or of a phrase in lieu of another phrase; for it is [102a1] sometimes possible to define the meaning of a phrase as well. People whose rendering consists of a term only, try it as they may, clearly do not render the definition of the thing in question, because a definition is always a phrase of a [5] certain kind. One may, however, call definitory such a remark as that the beautiful is the becoming, and likewise also of the question, ‘Are perception and knowledge the same or different?’—for argument about definitions is mostly concerned with questions of sameness and difference. In a word we may call definitory everything that falls under the same branch of inquiry as definitions; and that all the [10] above-mentioned examples are of this character is clear on the face of them. For if we are able to argue that two things are the same or are different, we shall be well supplied by the same turn of argument with lines of attack upon their definitions as well; for when we have shown that they are not the same we shall have demolished the definition. But the converse of this last statement does not hold; for to show that they are the same is not enough to establish a definition. To show, however, that [15] they are not the same is enough of itself to overthrow it.
A property is something which does not indicate the essence of a thing, but yet belongs to that thing alone, and is predicated convertibly of it. Thus it is a property [20] of man to be capable of learning grammar; for if he is a man, then he is capable of learning grammar, and if he is capable of learning grammar, he is a man. For no one calls anything a property which may possibly belong to something else, e.g. sleep in the case of man, even though at a certain time it may happen to belong to him alone. [25] That is to say, if any such thing were actually to be called a property, it will be called not a property absolutely, but a temporary or a relative property; for being on the right hand side is a temporary property, while two-footed is a relative property; e.g. it is a property of man relatively to a horse and a dog. That nothing which may belong to anything else is a convertible predicate is clear; for it does not necessarily [30] follow that if something is asleep it is a man.
A genus is what is predicated in what a thing is of a number of things exhibiting differences in kind. We should treat as predicates in what a thing is all such things as it would be appropriate to mention in reply to the question, ‘What is the object in question?’; as, for example, in the case of man, if asked that question, it [35] is appropriate to say ‘He is an animal’. The question, ‘Is one thing in the same genus as another or in a different one?’ is also a generic question; for a question of that kind as well falls under the same branch of inquiry as the genus; for having argued that animal is the genus of man, and likewise also of ox, we shall have argued that [102b1] they are in the same genus; whereas if we show that it is the genus of the one but not of the other, we shall have argued that these things are not in the same genus.
An accident is something which, though it is none of the foregoing—i.e. [5] neither a definition nor a property nor a genus—yet belongs to the thing; and something which may either belong or not belong to any one and the self-same thing, as (e.g.) being seated may belong or not belong to some self-same thing. Likewise also whiteness; for there is nothing to prevent the same thing being at one [10] time white and at another not white. Of the definitions of accident the second is the better; for in the case of the first, any one is bound, if he is to understand it, to know already what definition and genus and property are, whereas the second is sufficient of itself to tell us the essential nature of the thing in question. To accident are to be [15] attached also all comparisons of things together, when expressed in language that is derived in any kind of way from accident; such as, for example, the question, ‘Is the honourable or the expedient preferable?’ and ‘Is the life of virtue or the life of self-indulgence the pleasanter?’, and any other problem which may happen to be phrased in terms like these. For in all such cases the question is ‘of which of the two [20] is the predicate more properly an accident?’ It is clear on the face of it that there is nothing to prevent an accident from becoming a temporary or a relative property. Thus being seated is an accident, but will be a temporary property, whenever a man is the only person sitting, while if he is not the only one sitting, it is still a property relatively to those who are not sitting. So then, there is nothing to prevent an [25] accident from becoming both a relative and a temporary property; but a property absolutely it will never be.
6 · We must not fail to observe that everything applicable to property and genus and accident will be applicable to definition as well. For when we have shown that the content of the definition fails to belong to the subject alone, as we do in the case of a property, or that the genus rendered in the definition is not the true genus, [30] or that any of the things mentioned in the phrase used does not belong, as would be remarked in the case of an accident, we shall have demolished the definition; so that, in the sense previously described, all the points we have enumerated might in a way be called definitory. But we must not on this account expect to find a single line [35] of inquiry which will apply universally to them all; for this is not an easy thing to find, and, even were one found, it would be very obscure indeed, and of little service for the treatise before us. Rather, a special plan of inquiry must be laid down for each of the classes we have distinguished, and then, starting from what is appropriate in each case, it will be easier to make our way right through the task [103a1] before us. So then, as was said before, we must outline a division of our subject, and other questions we must relegate each to the particular branch to which it most naturally belongs, speaking of them as definitory and generic questions. The questions I mean have practically been already assigned to their several branches. [5]
7 · First of all we must determine the number of ways we talk of sameness. Sameness would be generally regarded as falling, roughly speaking, into three divisions. We generally apply the term numerically or specifically or generically—numerically in cases where there is more than one name but only one thing, e.g. doublet and cloak; specifically, where there is more than one thing, but they present [10] no differences in respect of their species, as one man and another, or one horse and another; for things like this that fall under the same species are said to be specifically the same. Similarly, too, those things are called generically the same which fall under the same genus, such as a horse and a man. It might appear that the sense in which water from the same spring is called the same water is somehow [15] different and unlike the senses mentioned above; but really such a case as this ought to be ranked in the same class with the things that in one way or another are called the same in view of unity of species. For all such things seem to be of one family and to resemble one another. For the reason why all water is said to be specifically the same as all other water is because of a certain likeness it bears to it, and the only [20] difference in the case of water drawn from the same spring is this, that the likeness is more emphatic: that is why we do not distinguish it from the things that in one way or another are called the same in view of unity of species. It seems that things numerically one are called the same by everyone with the greatest degree of agreement. But this too is apt to be rendered in more than one sense; its most literal [25] and primary use is found whenever the sameness is rendered by a name or definition, as when a cloak is said to be the same as a doublet, or a two-footed terrestrial animal is said to be the same as a man; a second sense is when it is rendered by a property, as when what can acquire knowledge is called the same as a man, and what naturally travels upward the same as fire; while a third use is found when it is rendered in reference to some accident, as when the creature who is [30] sitting, or who is musical, is called the same as Socrates. For all these are meant to signify numerical unity. That what I have just said is true may be best seen where one form of appellation is substituted for another. For often when we give the order to call one of the people who are sitting down, indicating him by name, we change [35] our description, whenever the person to whom we give the order happens not to understand us; he will, we think, understand better from some accidental feature; so we bid him call to us the man who is sitting or who is conversing—clearly supposing ourselves to be indicating the same object by its name and by its accident.
[103b1] 8 · Of sameness then, as has been said, three types are to be distinguished. Now one way to confirm that the elements mentioned above are those out of which and through which and to which arguments proceed, is by induction; for if any one were to survey propositions and problems one by one, it would be seen that each was [5] formed either from the definition of something or from its property or from its genus or from its accident. Another way to confirm it is through deduction. For every predicate of a subject must of necessity be either convertible with its subject or not: and if it is convertible, it would be its definition or property, for if it signifies [10] the essence, it is the definition; if not, it is a property—for this was what a property is, viz. what is predicated convertibly, but does not signify the essence. If, on the other hand, it is not predicated convertibly of the thing, it either is or is not one of the terms contained in the definition of the subject; and if it is one of those terms, then it will be the genus or the differentia, inasmuch as the definition consists of [15] genus and differentiae; whereas, if it is not one of those terms, clearly it would be an accident, for accident was said to be what belongs to a subject without being either its definition or its genus or a property.
[20] 9 · Next, then, we must distinguish between the categories of predication in which the four above-mentioned are found. These are ten in number: What a thing is, Quantity, Quality, Relation, Place, Time, Position, State, Activity, Passivity. For the accident and genus and property and definition of anything will always be in one [25] of these predications; for all the propositions found through these signify either what something is or its quality or quantity or some one of the other types of predicate. It is clear, too, on the face of it that the man who signifies what something is signifies sometimes a substance, sometimes a quality, sometimes some one of the other types of predicate. For when a man is set before him and he says [30] that what is set there is a man or an animal, he states what it is and signifies a substance; but when a white colour is set before him and he says that what is set there is white or is a colour, he states what it is and signifies a quality. Likewise, also, if a magnitude of a cubit be set before him and he says that what is set there is a cubit or a magnitude, he will be describing what it is and signifying a quantity. [35] Likewise, also, in the other cases; for each of these kinds of predicate, if either it be asserted of itself, or its genus be asserted of it, signifies what something is; if, on the other hand, one kind of predicate is asserted of another kind, it does not signify what something is, but a quantity or a quality or one of the other kinds of predicate. Such, then, and so many, are the subjects on which arguments take place, and the materials with which they start. How we are to acquire them, and by what means [104a1] we are to become well supplied with them, falls next to be told.
10 · First, then, a definition must be given of a dialectical proposition and a dialectical problem. For it is not every proposition nor yet every problem that is to [5] be set down as dialectical; for no one in his senses would make a proposition of what no one holds, nor yet make a problem of what is obvious to everybody; for the latter admits of no doubt, while to the former no one would assent.
Now a dialectical proposition consists in asking something that is reputable to all men or to most men or to the wise, i.e. either to all, or to most, or to the most [10] notable of these, provided it is not paradoxical; for a man would probably assent to the view of the wise, if it be not contrary to the opinions of most men. Dialectical propositions also include views which are like those which are reputable; also propositions which contradict the contraries of opinions that are taken to be reputable, and also all opinions that are in accordance with the recognized arts. [15] Thus, supposing it to be reputable that the knowledge of contraries is the same, it might probably pass for reputable also that the perception of contraries is the same; also, supposing it to be a reputable opinion that there is but one single science of grammar, it might pass for a reputable opinion that there is but one science of flute-playing as well—and if more than one science of grammar, more than one science of flute-playing as well; for all these seem to be alike and akin. Likewise, [20] also, propositions contradicting the contraries of reputable opinions will pass as reputable; for if it is a reputable opinion that one ought to do good to one’s friends, it will also be a reputable opinion that one ought not to do them harm. Here, that one ought to do harm to one’s friends is the contrary, and that one ought not to do them harm is the contradictory of that contrary. Likewise also, if one ought to do good to [25] one’s friends, one ought not to do good to one’s enemies: this too is the contradictory of the contrary—the contrary being that one ought to do good to one’s enemies. Likewise, also, in other cases. Also, on comparison, it will look like a reputable opinion that the contrary predicate belongs to the contrary subject: e.g. if one ought to do good to one’s friends, one ought also to do evil to one’s enemies. (It might appear as if doing good to one’s friends were a contrary to doing evil to one’s [30] enemies; but whether this actually is or is not so in reality will be stated in the course of the discussion of contraries.)2 Clearly also, all opinions that are in accordance with the arts are dialectical propositions; for people are likely to assent to the views held by those who have made a study of these things, e.g. on a question of medicine [35] they will agree with the doctor, and on a question of geometry with the geometrician; and likewise also in other cases.
11 · A dialectical problem is a subject of inquiry that contributes either to [104b1] choice and avoidance, or to truth and knowledge, and does that either by itself, or as a help to the solution of some other such problem. It must, moreover, be something on which either people hold no opinion either way, or most people hold a contrary [5] opinion to the wise, or the wise to most people, or each of them among themselves. For some problems it is useful to know only with a view to choice or avoidance, e.g. whether pleasure is to be chosen or not, while some it is useful to know merely with a view to knowledge, e.g. whether the universe is eternal or not; others, again, are not useful in themselves for either of these purposes, but yet help us in regard to some [10] such problems; for there are many things which we do not wish to know in themselves, but for the sake of other things, in order that through them we may come to know something else. Problems also include questions in regard to which deductions conflict (the difficulty then being whether so-and-so is so or not, there being convincing arguments for both views); others also in regard to which we have [15] no argument because they are so vast, and we find it difficult to give our reasons, e.g. the question whether the universe is eternal or no; for into questions of that kind too it is possible to inquire.
Problems, then, and propositions are to be defined as aforesaid. A thesis is a [20] paradoxical belief of some eminent philosopher; e.g. the view that contradiction is impossible, as Antisthenes said; or the view of Heraclitus that all things are in motion; or that what exists is one, as Melissus says; for to take notice when any ordinary person expresses views contrary to men’s usual opinions would be silly. Or it may be a view contrary to men’s usual opinions about which we have an argument, e.g. the view maintained by the sophists that what is need not in every [25] case either have come to be or be eternal; for a musician who is a grammarian is so without ever having come to be so, or being so eternally. For even if some do not accept this view, a man might do so on the ground that it has an argument in its favour.
Now a thesis also is a problem, though a problem is not always a thesis, [30] inasmuch as some problems are such that we have no opinion about them either way. That a thesis is a problem, is clear; for it follows of necessity from what has been said that either the mass of men disagree with the wise about the thesis, or that the one or the other class disagree among themselves, seeing that the thesis is a [35] paradoxical belief. Practically all dialectical problems indeed are now called theses. But it should make no difference whichever description is used; for our object in thus distinguishing them has not been to create a terminology, but to recognize [105a1] what differences actually exist between them.
Not every problem, nor every thesis, should be examined, but only one which might puzzle one of those who need argument, not punishment or perception. For [5] people who are puzzled to know whether one ought to honour the gods and love one’s parents or not need punishment, while those who are puzzled to know whether snow is white or not need perception. The subjects should not border too closely upon the sphere of demonstration, nor yet be too far removed from it; for the former cases admit of no doubt, while the latter involve difficulties too great for the art of the trainer.
[10] 12 · Having made these distinctions, we must distinguish how many species there are of dialectical arguments. There are induction and deduction. Now what deduction is has been said before; induction is a passage from particulars to universals, e.g. the argument that supposing the skilled pilot is the most effective, and likewise the skilled charioteer, then in general the skilled man is the best at his [15] particular task. Induction is more convincing and clear: it is more readily learnt by the use of the senses, and is applicable generally to the mass of men; but deduction is more forcible and more effective against contradictious people.
13 · The classes, then, of things about which, and of things out of which, [20] arguments are constructed, are to be distinguished in the way we have said before. The instruments whereby we are to become well supplied with deductions are four: one, the securing of propositions; second, the power to distinguish in how many ways an expression is used; third, the discovery of the differences of things; fourth, the investigation of likeness. The last three, as well, are in a certain sense propositions; [25] for it is possible to make a proposition corresponding to each of them, e.g. that the desirable is either the honourable or the pleasant or the expedient; and that sensation differs from knowledge in that the latter may be recovered again after it has been lost, while the former cannot; and that the relation of the healthy to health [30] is like that of the vigorous to vigour. The first proposition depends upon the use of one term in several ways, the second upon the differences of things, the third upon their likenesses.
14 · Propositions should be selected in as many ways as we drew distinctions in regard to the proposition: thus one may choose the opinions held by all or by most [35] men or by the wise, i.e. by all, or most, or the most notable of them—if they are not contrary to those that seem to be generally held; and, again, all opinions that are in accordance with the arts. We must make propositions also of the contradictories of [105b1] opinions contrary to those that seem to be generally held, as was laid down before. It is useful also to make them by selecting not only those opinions that actually are reputable, but also those that are like these, e.g. that the perception of contraries is the same—the knowledge of them being so—and that we see by admission of [5] something into ourselves, not by an emission; for so it is, too, in the case of the other senses; for in hearing we admit something into ourselves; we do not emit; and we taste in the same way. Likewise also in the other cases. Moreover, all statements [10] that seem to be true in all or in most cases, should be taken as a principle or accepted thesis; for they are posited by those who do not also see what exception there may be. We should select also from the written handbooks of argument, and should draw up sketch-lists of them upon each several kind of subject, putting them down under separate headings, e.g. ‘On Good’, or ‘On Life’—and that ‘On Good’ should deal with every form of good, beginning with the essence. In the margin, too, one should [15] indicate also the opinions of individual thinkers, e.g. that Empedocles said that the elements of bodies were four; for any one might assent to the saying of some reputable authority.
Of propositions and problems there are—to comprehend the matter in outline—three divisions; for some are ethical propositions, some are on natural [20] science, while some are logical. Propositions such as the following are ethical, e.g. ‘Ought one rather to obey one’s parents or the laws, if they disagree?’; such as this are logical, e.g. ‘Is the knowledge of opposites the same or not?’; while such as this [25] are on natural science, e.g. ‘Is the universe eternal or not?’ Likewise also with problems. The nature of each of the aforesaid kinds of proposition is not easily rendered in a definition, but we have to try to recognize each of them by means of the familiarity attained through induction, examining them in the light of the illustrations given above.
[30] For purposes of philosophy we must treat of these things according to their truth, but for dialectic only with an eye to opinion.
All propositions should be taken in their most universal form; then, the one should be made into many. E.g. ‘The knowledge of opposites is the same’; next, ‘The knowledge of contraries is the same’, and ‘of relative terms’. In the same way these [35] should again be divided, as long as division is possible, e.g. the knowledge of good and evil, of white and black, of cold and hot. Likewise also in other cases.
[106a1] 15 · On the subject of propositions, the above remarks are enough. As regards the number of ways in which a term is used, we must not only treat of those terms which are used in different ways, but we must also try to render their definitions; e.g. we must not merely say that justice and courage are called good in [5] one way, and that what conduces to vigour and what conduces to health are called so in another, but also that the former are so called because of a certain intrinsic quality they themselves have, the latter because they are productive of a certain result and not because of any intrinsic quality in themselves. Similarly also in other cases.
Whether a term is used in many ways or in one only, may be considered by the [10] following means. First, look and see if its contrary is used in many ways, whether the discrepancy between them be one of kind or one of names. For in some cases a difference is at once displayed even in the names; e.g. the contrary of sharp in the case of a sound is flat, while in the case of a body it is dull. Clearly, then, the [15] contrary of sharp is used in many ways, and if so, so also is sharp; for corresponding to each of the former terms the contrary will be different. For sharp will not be the same when contrary to dull and to flat, though sharp is the contrary of each. Again that in the case of a sound has sharp as its contrary, but in the case of a body raised,3 so that that is used in many ways, inasmuch as its contrary also is so used. Likewise, [20] also, fine as applied to an animal has ugly as its contrary, but, as applied to a house, mean; so that fine is homonymous.
In some cases there is no discrepancy of any sort in the names used, but a [25] difference of kind is at once obvious: e.g. in the case of clear and obscure;4 for sound is called clear and obscure, just as colour is too. As regards the names, then, there is no discrepancy, but the difference in kind is at once obvious; for colour is not called clear in a like way to sound. This is plain also through sensation; for of things that are the same in kind we have the same sense, whereas we do not judge clearness by [30] the same sense in the case of sound and of colour, but in the latter case we judge by sight, in the former by hearing. Likewise also with sharp and dull in regard to flavours and bodies: here in the latter case we judge by touch, but in the former by taste. For here again there is no discrepancy in the names used, in the case either of the original terms or of their contraries; for the contrary of sharp in either case is dull. [35]
Moreover, see if one use of a term has a contrary, while another has absolutely none; e.g. the pleasure of drinking has a contrary in the pain of thirst, whereas the pleasure of seeing that the diagonal is incommensurate with the side has none, so that pleasure is used in more than one way. To love also, used of the frame of mind, [106b1] has to hate as its contrary, while as used of the physical activity it has none; clearly, therefore, to love is homonymous.
Further, see in regard to their intermediates, if one use has an intermediate, while another has none, or if both have one but not the same one, as e.g. clear and [5] obscure in the case of colours have grey as an intermediate, whereas in the case of sound they have none, or, if they have, it is muffled, as some people say that a muffled sound is intermediate. Clear, then, is homonymous, and likewise also obscure.
See, moreover, if some of them have more than one intermediate, while others have but one, as is the case with clear and obscure; for in the case of colours there [10] are numbers of intermediates, whereas in regard to sound there is but one, viz. muffled.
Again, in the case of the contradictory opposite, look and see if it is used in more than one way. For if it is, then the opposite of it also will be used in more than [15] one way; e.g. to fail to see is used in more than one way, viz. to fail to possess the power of sight, and to fail to put that power to active use. But if this is used in more than one way, it follows necessarily that to see also is used in more than one way; for there will be an opposite to each way of failing to see; e.g. the opposite of failing to possess the power of sight is to possess it, while of failing to put the power of sight to active use, the opposite is to put it to active use. [20]
Moreover, examine the case of terms that are opposed as privation and possession; for if the one term is used in more than one way, then so will the remaining term: e.g. if to perceive is used in more than one way, as applied to the soul and to the body, then to be imperceptive too will be used in more than one way, as applied to the soul and to the body. That the opposition between the terms now in [25] question depends upon privation and possession is clear, since animals naturally possess each kind of perception, both as applied to the soul and as applied to the body.
Moreover, examine the inflected forms. For if ‘justly’ is used in more than one way, the ‘just’, also, will be used in more than one way; for there will be a ‘just’ [30] corresponding to each ‘justly’; e.g. if ‘justly’ is used of judging according to one’s own opinion, and also of judging as one ought, then ‘just’ also will be used in like manner. In the same way also, if ‘healthy’ is used in more than one way, then [35] ‘healthily’ also will be used in more than one way: e.g. if healthy is what produces health and what preserves health and what betokens health, then ‘healthily’ also will be used to mean ‘in such a way as to produce’ or ‘preserve’ or ‘betoken’ health. Likewise also in other cases, whenever the original term is used in more than one [107a1] way, the inflexion also that is formed from it will be used in more than one way, and vice versa.
Look also at the classes of the predicates signified by the term, and see if they are the same in all cases. For if they are not the same, then clearly the term is [5] homonymous: e.g. good in the case of food is what is productive of pleasure, and in the case of medicine what is productive of health, whereas as applied to the soul it is to be of a certain quality, e.g. temperate or courageous or just; and likewise also, as applied to a man. Sometimes it signifies what happens at a certain time, as (e.g.) what happens at the right time; for what happens at the right time is called good. [10] Often it signifies what is of a certain quantity, e.g. as applied to the proper amount; for the proper amount too is called good. So then good is homonymous. In the same way also clear, as applied to a body, signifies a colour, but in regard to a sound it denotes what is easy to hear. Sharp, too, is in a closely similar case; for the same [15] term does not have the same use in all its applications; for a sharp note is a swift note, as the mathematical theorists of harmony tell us, whereas a sharp angle is one that is less than a right angle, while a sharp dagger is one cut at a sharp angle.
Look also at the genera of the objects denoted by the same name, and see if they are different without the one falling under the other, as (e.g.) donkey is both [20] the animal and the engine. For the account of them that corresponds to the name is different; for the one will be declared to be an animal of a certain kind, and the other to be an engine of a certain kind. If, however, the genera are subordinate one to the other, there is no necessity for the accounts to be different. Thus (e.g.) animal is the genus of raven, and so is bird. Whenever therefore we say that the raven is a bird, we [25] also say that it is a certain kind of animal, so that both the genera are predicated of it. Likewise also whenever we call the raven a winged two-footed animal, we declare it to be a bird; in this way, then, as well, both the genera are predicated of raven. But in the case of genera that are not subordinate one to the other this does not happen; [30] for whenever we call a thing an engine, we do not call it an animal, nor vice versa.
Look also and see not only if the genera of the term before you are different without being subordinate one to the other, but also in the case of its contrary; for if [35] its contrary is used in many ways, clearly the term before you is as well.
It is useful also to look at the definition that arises from the use of the term in combination, e.g. of a clear body and of a clear sound. For then if what is proper to each case be abstracted, the same phrase ought to remain over. This does not happen in the case of homonyms, e.g. in the cases just mentioned. For the former [107b1] will be a body possessing such and such a colour, while the latter will be a sound easy to hear. Abstract, then, ‘a body’ and ‘a sound’, and the remainder in each case is not the same. It should, however, have been, had clear in each case been [5] synonymous.
Often in the actual accounts as well homonymy creeps in without being noticed, and for this reason the accounts also should be examined. If (e.g.) any one describes what betokens and produces health as being in a balanced state, we must not desist but go on to examine in what sense he has used the term ‘balanced’ in each [10] case, e.g. if in the latter case it means that it is of the right amount to produce health, whereas in the former it means that it is such as to betoken what kind of state prevails.
Moreover, see if the terms cannot be compared as more or less or as in like degree, as is the case (e.g.) with a clear sound and a clear argument,5 and a sharp flavour and a sharp sound. For neither are these things said to be clear or sharp in a [15] like degree, nor yet is the one said to be clearer or sharper than the other. Clear, then, and sharp are homonymous. For synonyms are always comparable; for they will always hold either in like manner, or else in a greater degree in one case.
Now since of genera that are different without being subordinate one to the other the differentiae also are different in kind, e.g. those of animal and knowledge [20] (for the differentiae of these are different), look and see if the items falling under the same term are differentiae of genera that are different without being subordinate one to the other, as e.g. sharp is of a sound and a body. For being sharp differentiates sound from sound, and likewise also one body from another. Sharp, then, is homonymous; for it forms differentiae of genera that are different without [25] being subordinate one to the other.
Again, see if the items falling under the same term themselves have different differentiae, e.g. colour in bodies and colour in tunes; for the differentiae of colour in bodies are dispersing the eye and compressing the eye, whereas colour in melodies [30] has not the same differentiae. Colour, then, is homonymous; for things that are the same have the same differentiae.
Moreover, since the species is never the differentia of anything, look and see if one of the items falling under the same term is a species and another a differentia, as (e.g.) clear as applied to a body is a species of colour, whereas in the case of a [35] sound it is a differentia; for one sound is differentiated from another by being clear.
16 · Thus when a term is used in many ways, it may be investigated by these and like means. The differences which things present to each other should be [108a1] examined both in the genera themselves (e.g. ‘Wherein does justice differ from courage, and wisdom from temperance?’—for all these belong to the same genus); and also from one genus to another, provided they are not too far apart (e.g. ‘Wherein does perception differ from knowledge?’); for in the case of genera that [5] are very far apart, the differences are entirely obvious.
17 · Likeness should be studied, first, in the case of things belonging to different genera, the formula being: as one is to one thing, so is another to another (e.g. as knowledge stands to the object of knowledge, so is perception related to the [10] object of perception), or: as one is in one thing, so is another in another (e.g. as sight is in the eye, so is intellect in the soul, and as is a calm in the sea, so is windlessness in the air). Practice is more especially needed in regard to terms that are far apart; for in the case of the rest, we shall be more easily able to see the points of likeness. We should also look at things which belong to the same genus, to see if any identical [15] attribute belongs to them all, e.g. to a man and a horse and a dog; for in so far as they have any identical attribute, in so far they are alike.
18 · It is useful to have examined the number of uses of a term both for clearness’ sake (for a man is more likely to know what it is he asserts, if it has been [20] made clear to him how many uses it may have), and also with a view to ensuring that our deductions shall be in accordance with the actual facts and not addressed merely to the word used. For as long as it is not clear in how many ways a term is used, it is possible that the answerer and the questioner are not directing their minds upon the same thing; whereas when once it has been made clear how many uses there are, and also upon which of them the former directs his mind when he makes [25] his assertion, the questioner would then look ridiculous if he failed to address his argument to this. It helps us also both to avoid being misled and to mislead by fallacies; for if we know the number of uses of a term, we shall certainly never be misled by fallacy, but shall know if the questioner fails to address his argument to the same point; and when we ourselves put the questions we shall be able to mislead [30] him, if our answerer happens not to know the number of uses of our terms. This, however, is not possible in all cases, but only when of the many uses some are true and others are false. This manner of argument, however, does not belong properly to dialectic; dialecticians should therefore by all means beware of this kind of verbal [35] discussion, unless any one is absolutely unable to discuss the subject before him in any other way.
The discovery of differences helps us both in deductions about sameness and difference, and also in recognizing what any particular thing is. That it helps us in [108b1] deductions about sameness and difference is clear; for when we have discovered a difference of any kind whatever between the objects before us, we shall already have proved that they are not the same; while it helps us in recognizing what a thing is, [5] because we usually distinguish the account that is proper to the substance of each particular thing by means of the differentiae that are appropriate to it.
The examination of likeness is useful with a view both to inductive arguments and to hypothetical deductions, and also with a view to the rendering of definitions. [10] It is useful for inductive arguments, because it is by means of an induction of particulars in cases that are alike that we claim to induce the universal; for it is not easy to do this if we do not know the points of likeness. It is useful for hypothetical deductions because it is a reputable opinion that among similars what is true of one is true also of the rest. If, then, with regard to any of them we are well supplied with [15] matter for a discussion, we shall secure a preliminary admission that however it is in these cases, so it is also in the case before us; then when we have proved the former we shall have proved, on the strength of the hypothesis, the matter before us as well; for we have first made the hypothesis that however it is in these cases, so it is also in the case before us, and have then produced the demonstration. It is useful for the rendering of definitions because, if we are able to see what is the same in each [20] individual case of it, we shall be at no loss when we define it; for of the common predicates that which is most definitely predicated in what the thing is is likely to be the genus. Likewise, also, in the case of objects widely divergent, the examination of likeness is useful for purposes of definition, e.g. the sameness of a calm at sea, and [25] windlessness in the air (each being a form of rest), and of a point on a line and the unit in number (each being a principle). If, then, we render as the genus what is common to all the cases, we shall get the credit of defining not inappropriately. Definition-mongers too nearly always render them in this way; for they declare the unit to be the principle of number, and the point the principle of a line. It is clear, [30] then, that they place them in that which is common to both as their genus.
The instruments, then, whereby deductions are effected, are these; the commonplace rules, for the observance of which the aforesaid instruments are useful, are as follows.
1 · Of problems some are universal, others particular. Universal problems are such as ‘Every pleasure is good’ and ‘No pleasure is good’; particular problems [35] are such as ‘Some pleasure is good’ and ‘Some pleasure is not good.’ The methods of establishing and overthrowing a view universally are common to both kinds of [109a1] problems; for when we have proved that a predicate belongs in every case, we shall also have proved that it belongs in some cases. Likewise, also, if we prove that it does [5] not belong in any case, we shall also have proved that it does not belong in every case. First, then, we must speak of the methods of overthrowing a view universally, because such are common to both universal and particular problems, and because people more usually introduce theses asserting a predicate than denying it, while those who argue with them overthrow it.
The conversion of an appropriate name which is derived from an accident is an extremely precarious thing; for in the case of accidents and in no other it is possible [10] for something to be true in a certain respect and not universally. Names derived from definition and property and genus are bound to be convertible; e.g. if being a two-footed terrestrial animal belongs to something, then it will be true by conversion to say that it is a two-footed terrestrial animal. Likewise, also, if derived [15] from the genus; for if being an animal belongs to something, then it is an animal. The same is true also in the case of a property; for if being capable of learning grammar belongs to something, then it will be capable of learning grammar. For none of these attributes can possibly belong or not belong in part; they must either belong or not belong absolutely. In the case of accidents, on the other hand, there is [20] nothing to prevent an attribute (e.g. whiteness or justice) belonging in part, so that it is not enough to show that whiteness or justice belongs to a man in order to show [25] that he is white or just; for it is open to dispute it and say that he is white or just in part only. Conversion, then, is not a necessary process in the case of accidents.
We must also define the errors that occur in problems. They are of two kinds, caused either by false statement or by transgression of the established use of language. For those who make false statements, and say that something belongs to a [30] thing which does not belong to it, commit error; and those who call objects by the names of other objects (e.g. calling a plane-tree a man) transgress the established terminology.
2 · Now one commonplace rule is to look and see if a man has ascribed as an [35] accident what belongs in some other way. This mistake is most commonly made in regard to the genera of things, e.g. if one were to say that being a colour is an accident of white—for being a colour does not happen by accident to white, but colour is its genus. The assertor may of course make the mistake in so many words, [109b1] saying (e.g.) that it is an accident of justice to be a virtue; but often even without such explicitness it is obvious that he has rendered the genus as an accident; e.g. suppose that one were to say that whiteness is coloured or that walking is in motion. For a predicate drawn from the genus is never ascribed to the species in a derived [5] form, but always the genera are predicated of their species synonymously; for the species take on both the name and the account of their genera. A man therefore who says that white is coloured has not rendered it as its genus, seeing that he has used a derived form, nor yet as its property or as its definition; for the definition and [10] property of a thing belong to it and to nothing else, whereas many things besides white are coloured, e.g. a log, a stone, a man, a horse. Clearly then he renders it as an accident.
Another rule is to examine all cases where a predicate has been said to belong to all or none of something. Look at them species by species, and not in their infinite [15] multitude; for then the inquiry will proceed more directly and in fewer steps. You should look and begin with the primitives, and then proceed in order down to those that are not further divisible: e.g. if a man has said that the knowledge of opposites is the same, you should look and see whether it be so of relative opposites and of contraries and of terms opposed as privation and possession, and of contradictory [20] terms. Then, if no clear result is reached so far in these cases, you should again divide these until you come to those that are not further divisible, and see (e.g.) whether it is so of just deeds and unjust, or of the double and the half, or of blindness and sight, or of being and not-being; for if in any case it is proved that the knowledge of them is not the same we shall have demolished the problem. Likewise, also, if the [25] predicate belongs in no case. This rule is convertible for both destructive and constructive purposes; for if, as we proceed with the division, the predicate appears to hold in all or in a large number of cases, we may then claim that the other should actually assert it universally, or else bring an objection to show in what case it is not so; for if he does neither of these things, a refusal to assert it will make him look absurd.
[30] Another rule is to make accounts both of an accident and of its subject, either of both separately or else of one of them, and then look and see if anything untrue has been assumed as true in the accounts. Thus (e.g) to see if it is possible to wrong a god, ask what is to wrong? For if it be to injure deliberately, clearly it is not possible for a god to be wronged; for it is impossible that God should be injured. Again, to see if the good man is jealous, ask who is the jealous man and what is jealousy. For if [35] jealousy is pain at the apparent success of some honest person, clearly the good man is not jealous; for then he would be bad. Again, to see if the indignant man is jealous, ask who each of them is; for then it will be obvious whether the statement is true or false; e.g. if he is jealous who grieves at the successes of the good, and he is indignant [110a1] who grieves at the successes of the evil, then clearly the indignant man would not be jealous. A man should substitute accounts also for the words contained in his [5] account, and not stop until he comes to something familiar; for often when the account is given as a whole, the point at issue is not cleared up, whereas if for one of the words used in the account an account be stated, it becomes obvious.
Moreover, a man should make the problem into a proposition for himself, and [10] then bring an objection against it; for the objection will be a ground of attack upon the thesis. This rule is very nearly the same as the rule to look into cases where a predicate has been said to belong to all or none of something; but it differs in the turn of the argument.
Moreover, you should determine what kind of things should be called as most men call them, and what should not. For this is useful both for establishing and for [15] overthrowing a view: e.g. you should say that we ought to use our words to mean the same things as most people mean by them, but when we ask what kinds of things are or are not of such and such a kind, we should not here go with the multitude: e.g. it is right to call healthy whatever tends to produce health, as do most men; but in saying whether the object before us tends to produce health or not, we should adopt the [20] language no longer of the multitude but of the doctor.
3 · Moreover, if a term be used in several ways, and it has been laid down that it belongs or that it does not belong to something, you should prove your case of one of its several uses, if you cannot prove it of both. This rule is to be observed in [25] cases where the difference of use is undetected; for supposing this to be obvious, then the other man will object that the point which he himself questioned has not been discussed, but only the other point. This commonplace rule is convertible for purposes both of establishing and of overthrowing a view. For if we want to establish a statement, we shall prove that in one use the attribute belongs, if we cannot show [30] it of both; whereas if we are overthrowing a statement, we shall prove that in one use the attribute does not belong, if we cannot prove it of both. Of course, in overthrowing a statement there is no need to start the discussion by securing any admission, whether the attribute is said to belong to all or to none of something; for if we prove that in any case whatever the attribute does not belong, we shall have demolished the universal assertion of it, and likewise if we prove that it belongs even [35] in a single case, we shall demolish the universal denial of it. Whereas in establishing a statement we ought to secure a preliminary admission that if it belongs in any case whatever, it belongs universally, supposing this claim to be a plausible one. For it is not enough to argue for a single instance in order to prove that an attribute belongs [110b1] universally; e.g. to argue that if the soul of man is immortal, then every soul is immortal, so that a previous admission must be secured that if any soul whatever is immortal, then every soul is immortal. This is not to be done in every case, but only [5] whenever we are not easily able to quote any single argument applying to all cases in common, as (e.g.) the geometrician can argue that the triangle has its angles equal to two right angles.
If, again, the multiplicity of uses of a term is obvious, distinguish how many uses it has before proceeding either to demolish or to establish: e.g. supposing the [10] right thing to do to be the expedient or the honourable, you should try either to establish or to demolish both of the subject in question; e.g. by showing that it is honourable and expedient, or that it is neither honourable nor expedient. Supposing, however, that it is impossible to show both, you should prove the one, adding an indication that it is true in the one sense and not in the other. The same rule applies [15] also when the number of uses into which it is divided is more than two.
Again, consider those terms whose uses are many, but differ not by way of homonymy, but in some other way: e.g. The science of many things is one: here many things may be the end and the means to that end, as (e.g.) medicine is the science both of producing health and of dieting; or they may be both of them ends, [20] as the science of contraries is said to be the same (for of contraries the one is no more an end than the other); or again they may be an essential and an accidental attribute, as (e.g.) the essential fact that the triangle has its angles equal to two right angles, and the accidental fact that the equilateral figure has them so—for it [25] is because of the accident of the equilateral triangle happening to be a triangle that we know that it has its angles equal to two right angles. If, then, it is not possible in any way that the science of many things should be the same, it clearly is altogether impossible that it should be so; or, if it is possible in some way, then clearly it is [30] possible. Distinguish as many uses as are required: e.g. if we want to establish a view, we should bring forward such uses as admit that view, and should divide them only into those which also are required for the establishment of our case; whereas if we want to overthrow a view, we should bring forward all that do not admit that view, and leave the rest aside. We must proceed thus in this case too when the multiplicity of uses goes unnoticed. Further, that one thing is, or is not, of or for another should be established by means of the same commonplace rules; e.g. that a [35] particular science is of a particular thing, treated either as an end or as a means to its end, or as accidentally connected with it; or again that it is not of or for it in any of the aforesaid ways. The same rule holds true also of desire and all other terms [111a1] that have more than one object. For the desire for something may be the desire for it as an end (e.g. the desire for health) or as a means to an end (e.g. the desire for being doctored), or as a thing desired accidentally, as, in the case of wine, the sweet-toothed person desires it not because it is wine but because it is sweet. For he [5] desires the sweet for itself, and the wine only accidentally; for if it is dry, he no longer desires it. His desire for it is therefore accidental. This rule is useful in dealing with relative terms; for cases of this kind are generally cases of relative terms.
4 · Moreover, it is well to alter a word into one more familiar, e.g. to substitute ‘clear’ for ‘precise’ in describing a conception, and ‘meddling’ for ‘officious’; for when the expression is made more familiar, the thesis becomes easier [10] to attack. This commonplace rule also is available for both purposes alike, both for establishing and for overthrowing a view.
In order to prove that contrary attributes belong to the same thing, look at its genus; e.g. if we want to prove that rightness and wrongness are possible in regard to [15] perception: to perceive is to judge, and it is possible to judge rightly or wrongly; thus in regard to perception as well rightness and wrongness must be possible. In the present instance the demonstration proceeds from the genus and relates to the species; for judging is the genus of perceiving; for the man who perceives judges in a certain way. Again, it may proceed from the species to the genus; for all the [20] attributes that belong to the species belong to the genus as well; e.g. if there is a bad and a good knowledge there is also a bad and a good disposition; for disposition is the genus of knowledge. Now the former commonplace argument is false for purposes of establishing a view, while the second is true. For there is no necessity [25] that all the attributes that belong to the genus should belong also to the species; for animal is winged and quadruped, but not so man. All the attributes, on the other hand, that belong to the species must of necessity belong also to the genus; for if man is good, then animal also is good. On the other hand, for purposes of overthrowing a view, the former argument is true while the latter is false; for all the [30] attributes which do not belong to the genus do not belong to the species either; whereas all those that are wanting to the species are not of necessity wanting to the genus.
Since those things of which the genus is predicated must also of necessity have one of its species predicated of them, and since those things that are possessed of the genus in question, or are described by terms derived from that genus, must also of [35] necessity be possessed of one of its species or be described by terms derived from one of its species (e.g. if knowledge is predicated of something, then so too will be grammatical or musical knowledge, or knowledge of one of the other sciences; and if any one possesses knowledge or is described by a term derived from knowledge, then [111b1] he will also possess grammatical or musical knowledge or knowledge of one of the other sciences, or will be described by a term derived from one of them, e.g. as a grammarian or a musician)—therefore if any expression be asserted that is in any way derived from the genus (e.g. that the soul is in motion), look and see whether it [5] is possible for the soul to be moved with any of the species of motion; whether (e.g.) it can grow or be destroyed or come to be, and so forth with all the other species of motion. For if it cannot be moved in any of these ways, clearly it does not move at all. This commonplace rule is common for both purposes, both for overthrowing and for establishing a view; for if the soul moves with one of the species of motion, [10] clearly it does move; while if it does not move with any of the species of motion, clearly it does not move.
If you are not well equipped with an argument against the thesis, look among the definitions, real or apparent, of the thing before you, and if one is not enough, draw upon several. For it will be easier to attack people when committed to a [15] definition. [For an attack is always more easily made on definitions.]6
Moreover, look and see in regard to the thing in question, what is such that if it is the case the thing in question is the case, or what is necessarily the case if the thing in question is the case: if you wish to establish a view inquire what there is such that if it is the case the thing in question will be the case (for if the former be [20] proved to hold, then the thing in question will also have been proved to hold); while if you want to overthrow a view, ask what it is that is the case if the thing in question is the case (for if we show that what follows from the thing in question is not the case, we shall have demolished the thing in question).
Moreover, look at the time involved, to see if there is any discrepancy [25] anywhere: e.g. suppose a man to have stated that what is being nourished of necessity grows; for animals are always being nourished, but they do not always grow. Likewise, also, if he has said that knowing is remembering; for the one is concerned with past time, whereas the other has to do also with the present and the future. For we are said to know things present and future (e.g. that there will be an [30] eclipse), whereas it is impossible to remember anything save what is past.
5 · Moreover, there is the sophistic turn of argument, whereby we draw our opponent into the kind of statement against which we shall be well supplied with lines of argument. This process is sometimes a real necessity, sometimes an apparent necessity, sometimes neither an apparent nor a real necessity. It is really [35] necessary whenever the answerer has denied any view that would be useful in attacking the thesis, and the questioner thereupon addresses his arguments to the support of this view, and when moreover the view in question happens to be one of a kind on which he has a good stock of lines of argument. Likewise, also, it is really necessary whenever starting from the view laid down, he reduces it to something [112a1] else and then tries to demolish that statement; for when this has been demolished, the view originally laid down is demolished as well. It is an apparent necessity, when the point to which the arguments come to be directed appears to be useful, and relevant to the thesis, without being really so; whether it be that the man who is undertaking the argument has refused to concede something, or whether the [5] questioner has reached it by a reputable reduction based upon the thesis and then tries to demolish it. The remaining case is when the point to which the argument comes to be directed is neither really nor apparently necessary, and it turns out that the answer is refuted on an irrelevant issue. You should beware of the last of the [10] aforesaid methods; for it appears to be wholly disconnected from, and foreign to, the art of dialectic. For this reason, moreover, the answerer should not lose his temper, but assent to those statements that are of no use in attacking the thesis, adding an indication whenever he assents although he does not agree with the view. For, for the most part, it increases the confusion of questioners if, after all propositions of [15] this kind have been granted them, they can then draw no conclusion.
Moreover, any one who has made any statement whatever has in a certain sense made several statements, inasmuch as each statement has a number of necessary consequences: e.g. anyone who said that something is a man has also said that it is an animal and that it is animate and a biped and capable of acquiring reason and knowledge, so that by the demolition of any single one of these [20] consequences, of whatever kind, the original statement is demolished as well. But you should beware here of making a change to a more difficult subject; for sometimes the consequence, and sometimes the original thesis, is the easier to demolish.
6 · In regard to subjects which must have one and one only of two predicates, as (e.g.) a man must have either illness or health, supposing we are well supplied as [25] regards the one for arguing its presence or absence, we shall be well equipped as regards the remaining one as well. This rule is convertible for both purposes; for when we have proved that the one attribute belongs, we shall have proved that the remaining one does not belong; while if we prove that the one does not belong, we shall have proved that the remaining one does belong. Clearly then the rule is useful [30] for both purposes.
Moreover, you may attack by reinterpreting a word in respect of its account, with the implication that it is most fitting so to take it rather than in its established meaning: e.g. it is not, as established use has it, the courageous man who is strong-hearted, but rather the man the state of whose heart is strong—just as the man whose arms are strong is strong-armed.7 Likewise also the man whose star is [35] good is well-starred—as Xenocrates says, he who has a noble soul is well-starred. For a man’s star is his soul.
Some things occur of necessity, others for the most part, others however it may [112a1] chance; if therefore what is necessary has been asserted to hold for the most part, or if what holds for the most part (either itself or its contrary) has been stated to hold of necessity, it always gives an opportunity for attack. For if what is necessary has [5] been asserted to hold for the most part, clearly the speaker has denied an attribute to be universal which is universal, and so has made a mistake; and so he has if he has declared what holds for the most part to be necessary; for then he declares it to belong universally when it does not so belong. Likewise also if he has declared the contrary of what holds for the most part to be necessary. For the contrary of what [10] holds for the most part is always a comparatively rare attribute: e.g. if men are for the most part bad, they are comparatively seldom good, so that his mistake is even worse if he has declared them to be good of necessity. The same is true also if he has declared a matter of chance to hold of necessity or for the most part; for a matter of chance holds neither of necessity nor for the most part. If the thing holds for the [15] most part, then even supposing his statement does not distinguish whether he meant that it holds for the most part or that it holds necessarily, it is open to you to discuss it on the assumption that he meant that it holds necessarily: e.g. if he has stated without any distinction that disinherited persons are bad, you may assume in discussing it that he means that they are so necessarily. [20]
Moreover, look and see also if he has stated a thing to be an accident of itself, taking it to be a different thing because it has a different name, as Prodicus used to divide pleasures into joy and delight and good cheer; for all these are names of the same thing, to wit, pleasure. If then any one says that joyfulness is an accidental [25] attribute of cheerfulness, he would be declaring it to be an accidental attribute of itself.
7 · Inasmuch as contraries can be conjoined with each other in six ways, and four of these conjunctions constitute a contrariety, we must take hold of contraries in whatever way they may be of use both in demolishing and in establishing a view. [30] Well then, that the modes of conjunction are six is clear; for either each of the one pair of contraries will be conjoined to each of the other; and this gives two modes, e.g. to do good to friends and to do evil to enemies, or per contra to do evil to friends and to do good to enemies. Or else both of the first pair may be attached to one of [35] the second; and this too gives two modes, e.g. to do good to friends and to do evil to friends, or to do good to enemies and to do evil to enemies. Or one of the first pair may be attached to both of the second; and this also gives two modes, e.g. to do good to friends and to do good to enemies, or to do evil to friends and evil to enemies.
[113a1] The first two then of the aforesaid conjunctions do not constitute any contrariety; for the doing of good to friends is not contrary to the doing of evil to enemies; for both courses are desirable and belong to the same disposition. Nor is the doing of evil to friends contrary to the doing of good to enemies; for both of these [5] are objectionable and belong to the same disposition; and one objectionable thing is not thought to be the contrary of another, unless the one refers to an excess, and the other to a defect—for an excess is thought to belong to the class of objectionable things, and likewise also a defect. But the other four all constitute a contrariety. For [10] to do good to friends is contrary to the doing of evil to friends; for it proceeds from the contrary disposition, and the one is desirable, and the other objectionable. The case is the same also in regard to the other conjunctions; for in each combination the one course is desirable, and the other objectionable, and the one belongs to an honourable disposition and the other to a bad. Clearly, then, from what has been [15] said, the same thing has more than one contrary. For the doing of good to friends has as its contrary both the doing of good to enemies and the doing of evil to friends. Likewise, if we examine them in the same way, we shall find that the contraries of each of the others also are two in number. Select therefore whichever of the two contraries is useful in attacking the thesis.
[20] Moreover, if the accident of a thing has a contrary, see whether it belongs to the subject to which the accident in question has been declared to belong; for if the latter belongs the former could not belong; for it is impossible that contrary predicates should belong at the same time to the same thing.
Or again, look and see if anything has been said about something, of such a [25] kind that if it is true, contrary predicates must necessarily belong to the thing; e.g. if he has said that the Ideas exist in us. For then the result will be that they are both in motion and at rest, and moreover that they are objects both of sensation and of thought. For according to those who posit the existence of Ideas, those Ideas are at rest and are objects of thought; while if they exist in us, it is impossible that they should be unmoved; for when we move, it follows necessarily that all that is in us [30] moves with us as well. Clearly also they are objects of sensation, if they exist in us; for it is through the sensation of sight that we recognize the form present in each individual.
Again, if there be posited an accident which has a contrary, look and see if that which admits of the accident will admit of its contrary as well; for the same thing admits of contraries. Thus (e.g.) if he has asserted that hatred follows anger, hatred [35] would in that case be in the spirited faculty; for that is where anger is. You should therefore look and see if its contrary is also in the spirited faculty; for if not—if [113b1] friendship is in the faculty of desire—then hatred will not follow anger. Likewise also if he has asserted that the faculty of desire is ignorant. For if it were capable of ignorance, it would be capable of knowledge as well: and this does not seem to be [5] so—I mean that the faculty of desire is capable of knowledge. For purposes, then, of overthrowing a view you should proceed as we have said; but for purposes of establishing one, though the rule will not help you to assert that the accident actually belongs, it will help you to assert that it may possibly belong. For having proved that the thing in question will not admit of the contrary, we shall have [10] proved that the accident neither belongs nor can possibly belong; while on the other hand, if we prove that the contrary belongs, or that the thing is capable of the contrary, we shall not indeed as yet have proved that the accident asserted does belong as well; our proof will merely have gone to this point, that it is possible for it to belong.
8 · Seeing that the modes of opposition are four in number, you should look [15] among the contradictories of your terms, reversing the order of their sequence, both when demolishing and when establishing a view; and you should grasp this by means of induction. E.g. if man is an animal, what is not an animal is not a man; and likewise also in other instances of contradictories. For here the sequence is reversed; for animal follows upon man, but not-animal does not follow upon not-man, but the [20] reverse—not-man upon not-animal. In all cases, therefore, a claim of this sort should be made, (e.g.) that if the honourable is pleasant, what is not pleasant is not honourable, while if the latter is not so, neither is the former. Likewise, also, if what is not pleasant is not honourable, then what is honourable is pleasant. Clearly, then, reversing the sequence in the case of contradictories is a method convertible for both [25] purposes.
Then look also at the case of the contraries, and see if the contrary of the one follows upon the contrary of the other, either directly or conversely, both when you are demolishing and when you are establishing a view; and grasp this too by means of induction. Now the sequence is direct in a case such as that of courage and [30] cowardice; for upon the one of them virtue follows, and vice upon the other; and upon the one it follows that it is desirable, while upon the other it follows that it is objectionable. The sequence in the latter case also is direct; for the desirable is the contrary of the objectionable. Likewise also in other cases. The sequence is converse in such a case as this: health follows upon vigour, but disease does not follow upon [114a1] debility; rather debility follows upon disease. In this case, then, clearly the sequence is converse. Converse sequence is, however, rare in the case of contraries; usually the sequence is direct. If, therefore, the contrary of the one term does not follow upon the contrary of the other either directly or conversely, clearly neither does the [5] one term follow upon the other in the statement made; whereas if the one follows the other in the case of the contraries, it must of necessity do so as well in the original statement.
You should look also into cases of privation and possession in like manner to the case of contraries. Only, in the case of privations the converse sequence does not [10] occur: the sequence is always bound to be direct; e.g. as perception follows sight, while absence of perception follows blindness. For perception is opposed to absence of perception as possession and privation; for the one of them is a possession, and the other privation.
The case of relative terms should also be studied in like manner to privation; [15] for the sequence of these as well is direct; e.g. if thrice is a multiple, then a third is a fraction; for thrice is relative to a third, and so is a multiple to a fraction. Again, if knowledge is a belief, then also the object of knowledge is an object of belief; and if sight is a perception, then also the object of sight is an object of perception. An [20] objection may be made that there is no necessity for the sequence to take place, in the case of relative terms, in the way described; for an object of perception is an object of knowledge, whereas perception is not knowledge. The objection, however, does not seem to be true; for many people deny that there is knowledge of objects of perception. Moreover, the principle stated is just as useful for the contrary purpose, [25] e.g. to show that the object of perception is not an object of knowledge, on the ground that neither is perception knowledge.
9 · Again look at the co-ordinates and the inflexions, both in demolishing and in establishing. By co-ordinates are meant things such as the following: just deeds and the just man are co-ordinates of justice, and courageous deeds and the courageous man are co-ordinates of courage. Likewise also things that tend to [30] produce and to preserve anything are co-ordinates of that which they tend to produce and to preserve, as e.g. healthy habits are co-ordinates of health and vigorous habits of vigour—and so forth also in other cases. Such things, then, are usually called co-ordinates. Inflexions are such as the following: ‘justly’, ‘courageously’, ‘healthily’, and such as are formed in this way. It is usually held that [35] inflected forms as well are co-ordinates, as (e.g.) ‘justly’ in relation to justice, and ‘courageously’ to courage; and then all the members of the same series are co-ordinates, e.g. justice, just man, just deed, justly. Clearly, then, when any one [114b1] member, whatever its kind, of the same series is proved to be good or praiseworthy, then all the rest as well come to be proved to be so: e.g. if justice is something praiseworthy, then so will a just man, and a just deed, and ‘justly’ connote something praiseworthy. Then ‘justly’ will be rendered also ‘praiseworthily’, derived by the same inflexion from the praiseworthy as ‘justly’ is derived from justice. [5]
Look not only in the case of the subject mentioned, but also in the case of its contrary, for the contrary predicate: e.g. argue that good is not necessarily pleasant; for neither is evil painful; or that, if the latter is the case, so is the former. Also, if justice is knowledge, then injustice is ignorance: and if ‘justly’ means ‘knowingly’ and ‘skilfully’, then ‘unjustly’ means ‘ignorantly’ and ‘unskilfully’; whereas if the [10] latter is not true, neither is the former, as in the instance given just now—for ‘unjustly’ is more likely to seem equivalent to ‘skilfully’ than to ‘unskilfully’. This commonplace rule has been stated before in dealing with the sequence of contraries; for all we are claiming now is that the contrary follows the contrary [15].
Moreover, look at the modes of generation and destruction of a thing, and at the things which tend to produce or to destroy it, both in demolishing and in establishing a view. For those things whose modes of generation rank among good things, are themselves also good; and if they themselves are good, so also are their modes of generation. If, on the other hand, their modes of generation are evil, then they themselves also are evil. In regard to modes of destruction the converse is true; [20] for if the modes of destruction rank as good things, then they themselves rank as evil things; whereas if the modes of destruction count as evil, they themselves count as good. The same argument applies also to things tending to produce and destroy; for things whose productive causes are good, themselves also rank as good; whereas if causes destructive of them are good, they themselves rank as evil.
10 · Again, look at things which are like the subject in question, and see if [25] they are in like case; e.g. if one branch of knowledge has more than one object, so also will one opinion; and if to possess sight is to see, then also to possess hearing will be to hear. Likewise also in the case of other things, both those which are and those which are held to be like. The rule in question is useful for both purposes; for if it is as stated in the case of some one like thing, it is so with the other like things as well, [30] whereas if it is not so in the case of some one of them, neither is it so in the case of the others. Look and see also whether the cases are alike as regards a single thing and a number of things; for sometimes there is a discrepancy. Thus, if to know a thing is to think of it, then also to know many things is to be thinking of many things; whereas this is not true; for it is possible to know many things but not to be thinking of them. If, then, the latter is not true, neither was the former that dealt [35] with a single thing, viz. that to know a thing is to think of it.
Moreover, argue from greater and less degrees. There are four commonplace rules. One is: see whether a greater degree of the predicate follows a greater degree of the subject: e.g. if pleasure is good, see whether also a greater pleasure is a greater good; and if to do a wrong is evil, see whether also to do a greater wrong is a [115a1] greater evil. Now this rule is of use for both purposes; for if an increase of the accident follows an increase of the subject, as we have said, clearly the accident belongs; while if it does not follow, the accident does not belong. You should [5] establish this by induction. Another rule is: if one predicate is attributed to two subjects, then supposing it does not belong to the subject to which it is the more likely to belong, neither does it belong where it is less likely to belong; while if it does belong where it is less likely to belong, then it belongs as well where it is more likely. Again: if two predicates are attributed to one subject, then if the one which is more generally thought to belong does not belong, neither does the one that is less [10] generally thought to belong; or, if the one that is less generally thought to belong does belong, so also does the other. Moreover: if two predicates are attributed to two subjects, then if the one which is more usually thought to belong to the one subject does not belong, neither does the remaining predicate belong to the remaining subject; or, if the one which is less usually thought to belong to the one subject does belong, so too does the remaining predicate to the remaining subject.
[15] Moreover, you can argue from the fact that an attribute belongs, or is thought to belong, in a like degree, in three ways, viz. those described in the last three rules given in regard to a greater degree. For supposing that one predicate belongs, or is thought to belong, to two subjects in a like degree, then if it does not belong to the one, neither does it belong to the other; while if it belongs to the one, it belongs to the remaining one as well. Or, supposing two predicates to belong in a like degree to the [20] same subject, then, if the one does not belong, neither does the remaining one; while if the one does belong, the remaining one belongs as well. The case is the same also if two predicates belong in a like degree to two subjects; for if the one predicate does not belong to the one subject, neither does the remaining predicate belong to the remaining subject, while if the one predicate does belong to the one subject, the remaining predicate belongs to the remaining subject as well.
[25] 11 · You can argue, then, from greater or less or like degrees in the aforesaid manner of ways. Moreover, you should argue from the addition of one thing to another. If the addition of one thing to another makes that other good or white, whereas formerly it was not white or good, then the thing added will be white or good—it will possess the character it imparts to the whole as well. Moreover, if an [30] addition of something to a given object intensifies the character which it had, then the thing added will itself as well be of that character. Likewise, also, in the case of other attributes. The rule is not applicable in all cases, but only in those in which an increased intensity is found to take place. The above rule is, however, not convertible for overthrowing a view. For if the thing added does not make the other good, it is not thereby made clear whether in itself it may not be good; for the [115b1] addition of good to evil does not necessarily make the whole good, any more than the addition of white to black makes the whole white.
Again, any predicate of which we can speak of greater or less degrees belongs also without qualification; for greater or less degrees of good or of white will not be [5] attributed to what is not good or white; for a bad thing will never be said to have a greater or less degree of goodness, but always of badness. This rule is not convertible, either, for the purpose of overthrowing; for several predicates of which we cannot speak of a greater degree belong without qualification; for the term man [10] is not attributed in greater and less degrees, but a man is a man for all that.
You should examine in the same way predicates attributed in a given respect, and at a given time and place; for if the predicate is possible in some respect, it is possible also without qualification. Likewise, also, what is predicated at a given time or place; for what is without qualification impossible is not possible either in any respect or at any place or time. An objection may be raised that in a given [15] respect people may be good by nature, e.g. they may be generous or temperately inclined, while they are not good by nature without qualification. Likewise, also, it is possible for a destructible thing to escape destruction at a given time, whereas it is not possible for it to escape without qualification. In the same way also it is a good thing at certain places to follow such and such a diet, e.g. in infected areas, though it [20] is not a good thing without qualification. Moreover, in certain places it is possible for there to be just one man, but without qualification it is not possible for there to be just one man. In the same way also it is in certain places honourable to sacrifice one’s father, e.g. among the Triballi, whereas, without qualification, it is not [25] honourable. Or possibly this may indicate a relativity not to places but to persons; for it makes no difference wherever they may be; for everywhere it will be honourable for them. Again, at certain times it is a good thing to take medicines, e.g. when one is ill, but it is not so without qualification. Or possibly this again may indicate a relativity not to a certain time, but to a certain state of health; for it makes no difference when it occurs, if only one is in that state. A thing is without qualification so which without any addition you are prepared to say is honourable or [30] the contrary. Thus (e.g.) you will deny that to sacrifice one’s father is honourable: it is honourable only to certain persons; it is not therefore honourable without qualification. On the other hand, to honour the gods you will declare to be honourable without adding anything; hence that is honourable without qualification. So that whatever without any addition is thought to be honourable or dishonourable or anything else of that kind, will be said to be so without [35] qualification.
1 · The question which is the more desirable, or the better, of two or more [116a1] things, should be examined upon the following lines; only first of all it must be clearly laid down that the inquiry we are making concerns not things that are widely divergent and that exhibit great differences from one another (for nobody raises any [5] doubt whether happiness or wealth is more desirable), but things that are nearly related and about which we discuss for which of the two we ought rather to vote, because we do not see any advantage on either side as compared with the other. Clearly, then, in such cases if we can prove a single advantage, or more than one [10], our judgement will record our assent that whichever side happens to have the advantage is the more desirable.
First, then, that which is more lasting or secure is more desirable than that which is less so; and so is that which is more likely to be chosen by the prudent or by [15] the good man or by the right law, or by men who are good in any particular line, when they make their choice as such; i.e. either whatever most of them or what all of them would choose; e.g. in medicine (or in carpentry) those things are more desirable which most, or all, doctors would choose; or, in general, whatever most men or all men or all things would choose, e.g. the good; for everything aims at the good. You should direct the argument to whatever purpose you require. What is [20] absolutely better or more desirable is determined by the better science; what is relatively better, by the appropriate science.
In the second place, that which is essentially so is more desirable than that which does not come within the genus—e.g. justice than a just man; for the former falls within the genus, whereas the other does not, and the former is essentially [25] good, whereas the latter is not; for nothing which does not happen to belong to the genus is essentially the genus; e.g. a white man is not essentially a colour. Likewise also in other cases.
Also, that which is desired for itself is more desirable than that which is desired [30] for something else; e.g. health is more desirable than gymnastics; for the former is desired for itself, the latter for something else. Also, that which is desirable in itself is more desirable than what is desirable per accidens; e.g. justice in our friends than justice in our enemies; for the former is desirable in itself, the latter per accidens; for we desire that our enemies should be just per accidens, in order that they may do [35] us no harm. This last principle is the same as the one that precedes it, with, however, a different turn of expression. For we desire justice in our friends for itself, even though it will make no difference to us, and even though they be in India; whereas in our enemies we desire it for something else, in order that they may do us no harm.
[116b1] Also, that which is in itself the cause of good is more desirable than what is so per accidens, e.g. virtue than luck (for the former is in itself, and the latter per accidens, the cause of good things), and so in other cases of the same kind. Likewise also in the case of the contrary; for what is in itself the cause of evil is more [5] objectionable than what is so per accidens, e.g. vice and chance; for the one is so in itself, whereas chance is so per accidens.
Also, what is good absolutely is more desirable than what is good for a particular person, e.g. recovery of health than a surgical operation; for the former is good absolutely, the latter only for a particular person, viz. the man who needs an [10] operation. So too what is good by nature is more desirable than the good that is not so by nature, e.g. justice than the just man; for the one is good by nature, whereas in the other case the goodness is acquired. Also the attribute is more desirable which belongs to the better and more honourable subject, e.g. to a god rather than to a man, and to the soul rather than to the body. So too the property of the better thing is better than the property of the worse, e.g. the property of God than the property [15] of man; for whereas in respect of what is common in both of them they do not differ at all from each other, in respect of their properties the one surpasses the other. Also that is better which is inherent in things better or prior or more honourable: thus (e.g.) health is better than strength and beauty; for the former is inherent in the moist and the dry, and the hot and the cold, in short in all the primary constituents [20] of an animal, whereas the others are inherent in what is posterior, strength being a feature of the sinews and bones, while beauty is thought to consist in a certain symmetry of the limbs. Also the end is generally supposed to be more desirable than the means, and of two means, that which lies nearer the end. In general, too, a means directed towards the end of life is more desirable than a means to anything else, e.g. that which contributes to happiness than that which contributes to [25] prudence. Also the possible is more desirable than the impossible. Moreover, of two productive agents that one is more desirable whose end is better; while between a productive agent and an end we can decide by a proportional sum: whenever the excess of the one end over the other is greater than that of the latter over its own productive means—e.g. supposing the excess of happiness over health to be greater than that of health over what produces health—then what produces happiness is [30] better than health. For what produces happiness exceeds what produces health just as much as happiness exceeds health. But health exceeds what produces health by a smaller amount; hence, the excess of what produces happiness over what produces health is greater than that of health over what produces health. Clearly, therefore, what produces happiness is more desirable than health; for it exceeds the same [35] standard by a greater amount.
Moreover, what is in itself nobler and more precious and praiseworthy is more desirable, e.g. friendship than wealth, and justice than strength. For the former belong in themselves to the class of things precious and praiseworthy, while the latter do so not in themselves but for something else; for no one prizes wealth for [117a1] itself but always for something else, whereas we prize friendship for itself, even though nothing else is likely to come to us from it.
2 · Moreover, whenever two things are very much like one another, and we [5] cannot see any superiority in the one over the other of them, we should look at them from the standpoint of their consequences. For the one which is followed by the greater good is the more desirable; or, if the consequences be evil, that is more desirable which is followed by the less evil. For though both may be desirable, yet there may still be some unpleasant consequence. Our survey from the point of view [10] of consequences lies in two directions, for there are prior consequences and later consequences: e.g. if a man learns, it follows that he was ignorant before and knows afterwards. For the most part, the later consequence is the better. You should take, therefore, whichever of the consequences suits your purpose [15].
Moreover, a greater number of good things is more desirable than a smaller, either absolutely or when the one is included in the other, viz. the smaller number in the greater. An objection may be raised if in some particular case the one is for the sake of the other; for then the two together are not more desirable than the one; e.g. recovery of health and health, than health alone, inasmuch as we desire recovery of [20] health for the sake of health. Also it is quite possible for what are not good things to be more desirable than a number of good things, e.g. the combination of happiness and something else which is not good may be more desirable than the combination of justice and courage. Also, the same things are more valuable if accompanied than if unaccompanied by pleasure, and likewise when free from pain than when attended with pain.
[25] Also, everything is more desirable at the season when it is of greater consequence; e.g. freedom from pain in old age more than in youth; for it is of greater consequence in old age. On the same principle also, prudence is more desirable in old age; for no man chooses the young as leaders, because he does not expect them to be prudent. With courage, the converse is the case, for it is in youth [30] that the active exercise of courage is more imperatively required. Likewise also with temperance; for the young are more troubled by their passions than are their elders.
Also, that is more desirable which is more useful at every season or at most [35] seasons, e.g. justice and temperance rather than courage; for they are always useful, while courage is only useful at times. Also, that one of two things which if all possess, we do not need the other thing, is more desirable than that which all may possess and still we want the other one as well. Take the case of justice and courage: [117b1] if everybody were just, there would be no use for courage, whereas all might be courageous, and still justice would be of use.
Moreover, judge by the destructions and losses and generations and acquisitions and contraries of things; for things whose destruction is more objectionable are [5] themselves more desirable. Likewise also with the losses and contraries of things; for a thing whose loss or whose contrary is more objectionable is itself more desirable. With the generations or acquisitions of things the opposite is the case; for things whose acquisition or generation is more desirable are themselves also more desirable.
[10] Another commonplace rule is that what is nearer to the good is better and more desirable; and also what more nearly resembles the good: thus justice is better than a just man. Also, the one which is more like something better than them both, as e.g. some say that Ajax was a better man than Odysseus because he was more like Achilles. (An objection may be raised to this that it is not true; for it is quite possible [15] that Ajax did not resemble Achilles more nearly in the points which made Achilles the best of them, and that Odysseus was a good man, though unlike Achilles. Look also to see whether the resemblance tends to the ridiculous, like the resemblance of a monkey to a man, whereas a horse bears none; for the monkey is not the more handsome creature, despite its nearer resemblance to a man.) Again, in the case of [20] two things, if one is more like the better thing while another is more like the worse, then that will be better which is more like the better. (This too, however, admits of an objection; for quite possibly the one only slightly resembles the better, while the other strongly resembles the worse, e.g. supposing the resemblance of Ajax to [25] Achilles to be slight, while that of Odysseus to Nestor is strong.) Also it may be that the one which is like the better resembles it for the worse, whereas the one which is like the worse resembles it for the better: witness the likeness of a horse to a donkey, and that of a monkey to a man.
Another rule is that the more conspicuous good is more desirable than the less conspicuous, and the more difficult than the easier; for we appreciate better the possession of things that cannot be easily acquired. Also the more personal [30] possession is more desirable than the more widely shared. Also, that which we share less in common with evil men; [for what is not attended by any unpleasantness is more desirable than what is so attended.]8
Moreover, if one thing is without qualification better than another, then also the best of the members of the former is better than the best of the members of the latter; e.g. if man is better than horse, then also the best man is better than the best [35] horse. Also, if the best is better than the best, then also the former is better than the latter without qualification; e.g. if the best man is better than the best horse, then also man is better than horse without qualification.
Moreover, things which our friends can share are more desirable than those [118a1] they cannot. Also, things which we like rather to do to a friend are more desirable than those we like to do to anyone, e.g. just dealing and the doing of good rather than the semblance of them; for we would rather really do good to our friends than seem to do so, whereas towards anyone the converse is the case. [5]
Also, superfluities are better than necessities, and are sometimes more desirable as well; for the good life is better than mere life, and good life is a superfluity, whereas mere life itself is a necessity. Sometimes, though, what is better is not also more desirable; for there is no necessity that because it is better it should also be more desirable: at least to be a philosopher is better than to make [10] money, but it is not more desirable for a man who lacks the necessities of life. There is superfluity whenever a man possesses the necessities of life and sets to work to secure as well other noble acquisitions. Roughly speaking, perhaps, necessities are more desirable, while superfluities are better. [15]
Also, what cannot be got from another is more desirable than what can be got from another as well, as (e.g.) is the case of justice compared with courage. Also, a thing is more desirable if it is desirable without the other, but not the other without it: power (e.g.) is not desirable without prudence, but prudence is desirable without power. Also, if of two things we repudiate the one in order to be thought to possess [20] the other, then that one is more desirable which we wish to be thought to possess; thus (e.g.) we repudiate hard work in order that people may think us naturally gifted.
Moreover, that is more desirable in whose absence it is less blameworthy for people to be vexed; and that is more desirable in whose absence it is more [25] blameworthy for a man not to be vexed.
3 · Moreover, of things that belong to the same species one which possesses the virtue appropriate to the species is more desirable than one which does not. If both possess it, then the one which possesses it in a greater degree is more desirable.
Moreover, if one thing makes good whatever it affects, while another does not, [30] the former is more desirable, just as also what makes things warm is warmer than what does not. If both do so, then that one is more desirable which does so in a greater degree, or if it renders good the better and more important object—if (e.g.) the one affects the soul, and the other the body.
Moreover, judge things by their inflexions and uses and actions and effects, [35] and judge these by them; for they go with each other: e.g. if ‘justly’ is more desirable than ‘courageously’, then also justice is more desirable than courage; and if justice is more desirable than courage, then also ‘justly’ is more desirable than ‘courageously’. Similarly also in the other cases.
[118b1] Moreover, if one thing exceeds while the other falls short of the same standard of good, the one which exceeds is the more desirable; or if the one exceeds an even higher standard. Again, if there are two things both more desirable than something, the one which is more desirable to a greater degree is more desirable than the one more desirable to a less degree. Moreover, when the excess of a thing is more [5] desirable than the excess of something else, that thing is itself also more desirable than the other, as (e.g.) friendship than money; for an excess of friendship is more desirable than an excess of money. So also that of which a man would rather that it were his by his own doing is more desirable than what he would rather get by another’s doing, e.g. friends than money.
[10] Moreover, judge by means of an addition, and see which when added to the same thing makes the whole more desirable. You must, however, beware of adducing a case in which the common term uses, or in some other way helps the case of, one of the things added to it, but not the other, as (e.g.) if you took a saw and a [15] sickle in combination with the art of carpentry; for in the combination the saw is a more desirable thing, but it is not a more desirable thing without qualification. Again, a thing is more desirable if, when added to a lesser good, it makes the whole a greater good. Likewise, also, you should judge by means of subtraction; for the thing upon whose subtraction the remainder is a lesser good may be taken to be a greater good, whichever it be whose subtraction makes the remainder a lesser good.
[20] Also, if one thing is desirable for itself, and the other because of opinion, the former is more desirable, as (e.g.) health than beauty. A thing is defined as being desired because of opinion if, supposing no one knew of it, you would not care to have it. Also, it is more desirable if it is desirable both for itself and because of opinion, while the other thing is desirable on the one ground alone. Also, whichever is the more precious in itself, is also better and more desirable. A thing may be taken [25] to be more precious in itself which we choose rather for itself, without anything else being likely to come of it.
Moreover, you should distinguish in how many ways things are called desirable, and with a view to what ends, e.g. expediency or honour or pleasure. For what is useful for all or most of them is more desirable, if they belong to the same [30] degree. If the same characters belong to both things you should look and see which possesses them more markedly, i.e. which of the two is the more pleasant or more honourable or more expedient. Again, that is more desirable which serves the better purpose, e.g. that which serves to promote virtue more than that which serves to promote pleasure. Likewise also in the case of objectionable things; for that is more objectionable which stands more in the way of what is desirable, e.g. disease more [35] than ugliness; for disease is a greater hindrance both to pleasure and to being good.
Moreover, argue by proving that the thing in question is in like measure objectionable and desirable; for a thing of such a character that a man might well desire and object to it alike is less desirable than the other which is desirable only.
4 · Comparisons of things with one another should be conducted in the [119a1] manner prescribed. The same commonplace rules are useful also for showing that anything is desirable or objectionable; for we have only to subtract the excess of one thing over another. For if what is more precious is more desirable, then also what is precious is desirable; and if what is more useful is more desirable, then also what is [5] useful is desirable. Likewise, also, in the case of other things which admit of comparisons of that kind. For in some cases in the very course of comparing the things together we at once assert also that each of them, or the one of them, is desirable, e.g. whenever we call the one good by nature and the other not by nature; [10] for clearly what is good by nature is desirable.
5 · The commonplace rules relating to comparative degrees and amounts ought to be taken in the most general possible form; for when so taken they are likely to be useful in a large number of instances. It is possible to render some of the actual rules given above more universal by a slight alteration of the expression, e.g. [15] that what by nature exhibits such and such a quality exhibits that quality in a greater degree than what exhibits it not by nature. Also, if one thing does, and another does not, impart such and such a quality to that which possesses it, then whichever does impart it is of that quality in greater degree than the one which does not impart it; and if both impart it, then that one exhibits it in a greater degree which imparts it in a greater degree.
Moreover, if in any character one thing exceeds and another falls short of the [20] same standard; also, if the one exceeds something which possesses the character, while the other exceeds something which does not, then clearly the first thing exhibits that character in a greater degree. Moreover, you should judge by means of addition, and see if when added to the same thing it imparts to the whole such and such a character in a more marked degree, or if, when added to a thing which exhibits that character in a less degree, it imparts that character to the whole in a greater degree. Likewise, also, you may judge by means of subtraction; for a thing [25] upon whose subtraction the remainder exhibits such and such a character in a less degree, itself exhibits that character in a greater degree. Also, things exhibit such and such a character in a greater degree if more free from admixture with their contraries; e.g. that is whiter which is more free from admixture with black. Moreover, apart from the rules given above, that has such and such a character in greater degree which admits in a greater degree of the account proper to the given [30] character; e.g. if the account of ‘white’ is a colour which disperses the vision, then that is whiter which is in a greater degree a colour that disperses the vision.
6 · If the problem is put in a particular and not in a universal form, in the first place9 the universal constructive or destructive commonplace rules that have been given may all be brought into use. For in demolishing or establishing a thing [35] universally we also prove it in particular; for if it belongs to all, it belongs also to some, and if to none, not to some. Especially handy and of general application are the commonplace rules that are drawn from the opposites and co-ordinates and inflexions; for it is equally reputable to claim that if all pleasure is good, then also all [119b1] pain is evil, and that if some pleasure is good, then also some pain is evil. Moreover, if some form of perception is not a capacity, then also some form of failure of perception is not a failure of capacity. Also, if some objects of belief are objects of knowledge, then also some form of belief is knowledge. Again, if what happens [5] unjustly is in some cases good, then some unjust things are good. Also, if what is done with pleasure is in some cases objectionable, then pleasure is in some cases an objectionable thing. On the same principle, also, if what is pleasant is in some cases beneficial, then pleasure is in some cases good. The case is the same also as regards the things that destroy, and the processes of generation and destruction. For if some [10] things that destroy pleasure or knowledge are good, then pleasure or knowledge is in some cases an evil thing. Likewise, also, if the destruction of knowledge is in some cases a good thing or its production an evil thing, then knowledge will be in some cases an evil thing; e.g. if for a man to forget his disgraceful conduct is a good thing, or to remember it an evil thing, then the knowledge of his disgraceful conduct is an [15] evil thing. The same holds also in other cases; for all are equally reputable.
Moreover you should judge by means of greater or less or like degree; for if some member of another genus exhibits such and such a character in a more marked degree, while no member of that genus exhibits that character at all, then the object in question will not exhibit it; e.g. if some form of knowledge is good in a [20] greater degree than pleasure, while no form of knowledge is good, then pleasure is not good either. Also, you should judge by a less or like degree in the same way; for so you will find it possible both to demolish and to establish a view, except that whereas both are possible by means of like degrees, by means of a less degree it is possible only to establish, not to overthrow. For if a certain capacity is good in a like [25] degree to knowledge, and a certain capacity is good, then also is knowledge; while if no capacity is good, then neither is knowledge. If, too, a certain capacity is good in a less degree than knowledge, and a certain capacity is good, then so also is knowledge; but if no capacity is good, there is no necessity that no form of knowledge either should be good. Clearly, then, it is only possible to establish a view [30] by means of a less degree.
Not only by means of another genus can you overthrow a view, but also by means of the same, if you take the most marked instance of the character in question; e.g. if it is maintained that some form of knowledge is good, then, suppose it to be proved that prudence is not good, neither will any other kind be good, seeing that not even the kind upon which there is most general agreement is so. Moreover, you should argue from an hypothesis: you should claim that the attribute, if it [35] belongs or does not belong in one case, does so in a like degree in all, e.g. that if the soul of man is immortal, so are other souls as well, while if this one is not so, neither are the others. If, then, it is maintained that in some instance the attribute belongs, you must prove that in some instance it does not belong; for then it will follow, by [120a1] reason of the hypothesis, that it does not belong in any instance. If, on the other hand, it is maintained that it does not belong in some instance, you must prove that it does belong in some instance, for in this way it will follow that it belongs in all instances. It is clear that the maker of the hypothesis universalizes the problem, whereas it was stated in a particular form; for he claims that anyone who agrees to the particular should agree to the universal, inasmuch as he claims that if the attribute belongs in one instance, it belongs also in all instances alike [5].
If the problem is indefinite, it is possible to overthrow it in only one way; e.g. if a man has asserted that some pleasure is good or is not good, without any further definition. For if he has asserted that some pleasure is good, you must prove universally that no pleasure is good, if the proposition in question is to be [10] demolished. And likewise, also, if he has asserted that some pleasure is not good you must prove universally that all pleasure is good: it is impossible to demolish it in any other way. For if we prove that some pleasure is not good or is good, the proposition in question is not yet demolished. It is clear, then, that it is possible to demolish an indefinite statement in one way, whereas it can be established in two ways; for whether we prove universally that all pleasure is good, or that some pleasure is good, [15] the proposition in question will have been proved. Likewise, also, supposing we are required to argue that some pleasure is not good, if we prove that no pleasure is good or that some pleasure is not good, we shall have produced an argument in both ways, both universally and in particular, to show that some pleasure is not good. If, on the [20] other hand, the thesis is definite, it will be possible to demolish it in two ways; e.g. if it is maintained that it is an attribute of some pleasure to be good, while of some it is not; for whether it is proved that all pleasure, or that no pleasure, is good, the proposition in question will have been demolished. If, however, he has stated that only one single pleasure is good, it is possible to demolish it in three ways; for by [25] proving that all pleasure, or that no pleasure, or that more than one pleasure, is good, we shall have demolished the statement in question. If the thesis is still more definite, e.g. that prudence alone of the virtues is knowledge, there are four ways of demolishing it; for if it is proved that all virtue is knowledge, or that no virtue is, or that some other virtue (e.g. justice) is, or that prudence itself is not knowledge, the [30] proposition in question will have been demolished.
It is useful also to take a look at individual instances, in cases where some attribute has been said to belong or not to belong, as in the case of universal problems. Moreover, you should take a look among genera, dividing them by their [35] species until you come to those that are not further divisible, as has been said before; for whether the attribute is found to belong in all cases or in none, you should, after adducing many instances, claim that he should either admit your point universally, or else bring an objection showing in what case it does not hold. Moreover, in cases where it is possible to divide the accident either specifically or numerically, you should look and see whether none of them belongs, showing e.g. that time is not [120b1] moved, nor yet is a movement, by enumerating all the species of movement; for if none of these belongs to time, clearly it does not move, nor yet is a movement. Likewise, also, you can show that the soul is not a number, by dividing all numbers [5] into either odd or even; for if the soul is neither odd nor even, clearly it is not a number.
In regard then to accident, you should set to work by means like these, and in this manner.
1 · Next we must go on to examine questions relating to genus and property. These are elements in the questions that relate to definitions, but dialecticians seldom address their inquiries to these by themselves.
[15] If, then, a genus is suggested for something that is, first take a look at all objects which belong to the same genus as the thing mentioned, and see whether the genus suggested is not predicated of some of them, as in the case of accident: e.g. if good is laid down as the genus of pleasure, see whether some pleasure is not good; [20] for, if so, clearly good is not the genus of pleasure; for the genus is predicated of all the members of the same species. Secondly, see whether it is predicated not in what it is, but as an accident, as white is predicated of snow, or self-moved of the soul. For snow is not just what is white, and therefore white is not the genus of snow, nor is the soul just what is moving—its motion is an accident of it, as it often is of an animal to [25] walk or to be walking. Moreover, moving does not seem to indicate what something is, but rather a state of doing or of undergoing. Likewise, also, white; for it indicates not what snow is, but a certain quality of it. So that neither of them is predicated in what it is.
[30] Especially you should take a look at the definition of accident, and see whether it fits the genus mentioned, as (e.g.) is the case in the instances just given. For it is possible for a thing to be and not to be self-moved, and likewise, also, for it to be and not to be white. So that neither of these is the genus but an accident, since we said [35] that an accident is an attribute which can belong to a thing and also not belong.
Moreover, see whether the genus and the species are not found in the same division, but the one is a substance while the other is a quality, or the one is a relative while the other is a quality, as (e.g.) snow and swan are each a substance, while white is not a substance but a quality, so that white is not a genus either of [121a1] snow or of swan. Again, knowledge is a relative, while good and noble are each a quality, so that good, or noble, is not the genus of knowledge. For the genera of relatives ought themselves also to be relatives, as is the case with double; for multiple, which is the genus of double, is itself also a relative. To speak generally, [5] the genus ought to fall under the same division as the species; for if the species is a substance, so too should be the genus, and if the species is a quality, so too the genus should be a quality; e.g. if white is a quality, so too should colour be. Likewise, also, in other cases.
Again, see whether it is necessary or possible for the genus to partake of the [10] object which has been placed in the genus. Partaking is defined as admitting the account of that which is partaken. Clearly, therefore, the species partake of the genera, but not the genera of the species; for the species admits the account of the genus, whereas the genus does not admit that of the species. You must look, therefore, and see whether the alleged genus partakes or can partake of the species, [15] e.g. if any one were to render anything as genus of being or of one; for then the result will be that the genus partakes of the species; for of everything that is, being and one are predicated, and therefore their account as well.
Moreover, see if there is anything of which the alleged species is true, while the [20] genus is not, e.g. supposing being or object of knowledge were stated to be the genus of object of opinion. For object of opinion will be a predicate of what does not exist; for many things which do not exist are objects of opinion; whereas that being or object of knowledge is not predicated of what does not exist is clear. So that neither being nor object of knowledge is the genus of object of opinion; for of the objects of [25] which the species is predicated, the genus ought to be predicated as well.
Again, see whether the object placed in the genus cannot partake of any of its species; for it is impossible that it should partake of the genus if it does not partake of any of its species, unless it is one of the species reached by the first division—these partake of the genus alone. If, therefore, motion is stated as the genus of [30] pleasure, you should look and see if pleasure is neither locomotion nor alteration, nor any of the rest of the given modes of motion; for clearly it will not partake of any of the species, and therefore not of the genus either, since what partakes of the genus must necessarily partake of one of the species as well; so that pleasure could [35] not be a species of motion, nor yet be one of the individual phenomena falling under a species of motion.10 For individuals as well partake in the genus and the species, as (e.g.) an individual man partakes of both man and animal.
Moreover, see if the term placed in the genus has a wider denotation than the [121b1] genus, as (e.g.) object of opinion has, as compared with being; for both what is and what is not are objects of opinion, so that object of opinion could not be a species of being; for the genus is always of wider denotation than the species. Again, see if the species and its genus have an equal denotation; suppose, for instance, that of the [5] attributes which go with everything, one were to be stated as a species and the other as its genus, as for example being and one; for everything has being and one, so that neither is the genus of the other, since their denotation is equal. Likewise, also, if primitives and principles were to be placed one under the other; for a principle is a [10] primitive and a primitive a principle, so that either the two are identical or neither is the genus of the other. The elementary principle in regard to all such cases is that the genus has a wider denotation than the species and its differentia; for the differentia too has a narrower denotation than the genus.
[15] See also whether the genus mentioned fails, or might be thought to fail, to apply to some object which is not specifically different from the thing in question; or, if your argument is constructive, whether it does so apply. For all things that are not specifically different have the same genus. If, therefore, it is proved to apply to one, then clearly it applies to all, and if it fails to apply to one, clearly it fails to apply to any; e.g. if any one who assumes that there are indivisible lines were to say that [20] the indivisible is their genus. For the aforesaid term is not the genus of divisible lines, and these do not differ as regards their species—for straight lines are never different from each other as regards their species.
2 · Look and see, also, if there is any other genus of the given species which [25] neither embraces the given genus nor falls under it, e.g. suppose any one were to lay down that knowledge is the genus of justice. For virtue is its genus as well, and neither of these genera embraces the remaining one, so that knowledge could not be the genus of justice; for it seems that whenever one species falls under two genera, [30] the one is embraced by the other. Yet a principle of this kind gives rise to a difficulty in some cases. For some people hold that prudence is both virtue and knowledge, and that neither of its genera is embraced by the other—although certainly not everybody admits that prudence is knowledge. If, however, any one were to admit the truth of this assertion, yet it would still be thought to be necessary that the [35] genera of the same object must at any rate be subordinate either the one to the other or both to the same thing as actually is the case with virtue and knowledge. For both fall under the same genus; for each of them is a state and a disposition. You should look, therefore, and see whether neither of these things is true of the given genus; for [122a1] if the genera are subordinate neither the one to the other nor both to the same thing, then what is given could not be the genus.
Look, also, at the genus of the given genus, and so continually at the next higher genus, and see whether all are predicated of the species, and predicated in [5] what it is; for the higher genus should be predicated of the species in what it is. If, then, there is anywhere a discrepancy, clearly what is given is not the genus. Again, see whether either the genus itself, or one of its higher genera, partakes of the species; for the higher genus does not partake of any of the lower. If, then, you are [10] overthrowing a view, follow the rule as given; if establishing one, then—suppose that what has been named as genus is admitted to belong to the species, only it is disputed whether it belongs as genus—it is enough to prove that one of its higher genera is predicated of the species in what it is. For if one of them is predicated in [15] what it is, all of them, both higher and lower than this one, if predicated at all of the species, will be predicated of it in what it is; so that what has been given as genus is also predicated in what it is. The proposition that when one genus is predicated in what it is, all the rest, if predicated at all, will be predicated in what it is, should be secured by induction. Supposing, however, that it is disputed whether the given genus belongs at all, it is not enough to prove that one of the higher genera is [20] predicated of the species in what it is: e.g. if any one has given locomotion as the genus of walking, it is not enough to prove that walking is motion in order to prove that it is locomotion, seeing that there are other forms of motion as well; but one must prove in addition that walking does not partake of any of the species of motion [25] produced by the same division as locomotion. For of necessity what partakes of the genus partakes also of one of the species produced by the first division. If, therefore, walking does not partake either of increase or decrease or of the other kinds of motion, clearly it will partake of locomotion, so that locomotion will be the genus of [30] walking.
Again, look among the things of which the given species is predicated as genus, and see if what is given as its genus is also predicated in what it is of the very things of which the species is so predicated, and likewise if all the genera higher than this genus are so predicated as well. For if there is anywhere a discrepancy, clearly what has been given is not the genus; for had it been the genus, then both the genera [35] higher than it, and it itself, would all have been predicated in what it is of those objects of which the species too is predicated in what it is. If, then, you are overthrowing a view, it is useful to see whether the genus fails to be predicated in what it is of those things of which the species is predicated. If establishing a view, it is useful to see whether it is predicated in what it is; for if so, the result will be that [122b1] the genus and the species will be predicated of the same object in what it is, so that the same object falls under two genera; the genera must therefore of necessity be subordinate one to the other, and therefore if it is proved that the one we wish to establish as genus is not subordinate to the species, clearly the species will be [5] subordinate to it, so that it is proved that it is the genus.
Look, also, at the accounts of the genera, and see whether they apply both to the given species and to the objects which partake of the species. For of necessity the accounts of its genera must be predicated of the species and of the objects which partake of the species; if, then, there is anywhere a discrepancy, clearly what has [10] been given is not the genus.
Again, see if he has given the differentia as the genus, e.g. immortal as the genus of God. For immortal is a differentia of living being, seeing that of living beings some are mortal and others immortal. Clearly, then, a mistake has been made; for the differentia of a thing is never its genus. And that this is true is clear; [15] for a thing’s differentia never signifies what it is, but rather some quality, as do walking and biped.
Also, see whether he has placed the differentia inside the genus, e.g. saying that the odd is essentially a number. For odd is a differentia of number, not a species. Nor is the differentia thought to partake of the genus; for what partakes of [20] the genus is always either a species or an individual, whereas the differentia is neither a species nor an individual. Clearly, therefore, the differentia does not partake of the genus, so that odd too is no species, seeing that it does not partake of the genus.
[25] Moreover, see whether he has placed the genus inside the species, e.g. by taking contact to be essentially continuity, or mixture essentially fusion, or, as in Plato’s definition,11 change of place to be locomotion. For there is no necessity that contact should be continuity: rather, conversely, continuity must be contact; for what is in contact is not always continuous, though what is continuous is always in [30] contact. Likewise, also, in the remaining instances; for mixture is not always a fusion (for to mix dry things does not fuse them), nor is change of place always locomotion. For walking is not thought to be locomotion; for it is mostly used of things that change one place for another involuntarily, as happens in the case of [35] inanimate things. Clearly, also, the species, in the instances given, has a wider denotation than the genus, whereas it ought to be vice versa.
Again, see whether he has placed the differentia inside the species, by taking (e.g.) immortal to be essentially a god. For the result will be that the species has an equal or wider denotation; for always the differentia has an equal or a wider [123a1] denotation than the species. Moreover, see whether he has placed the genus inside the differentia, by making colour (e.g.) to be essentially dispersive, or number essentially odd. Also, see if he has mentioned the genus as differentia; for it is possible for a man to bring forward a thesis of this kind as well, e.g. that mixture is a [5] differentia of fusion, or that change of place is a differentia of locomotion. All such cases should be examined by means of the same principles; for they depend upon common rules; for the genus should have a wider denotation than its differentia, and also should not partake of its differentia; whereas, if it is given in this manner, neither of the aforesaid requirements can be satisfied; for the genus will both have a [10] narrower denotation than its differentia, and will partake of it.
Again, if no differentia belonging to the genus is predicated of the given species, neither will the genus be predicated of it; e.g. of soul neither odd nor even is predicated; neither therefore is number. Moreover, see whether the species is naturally prior and abolishes the genus along with itself; for the contrary seems to [15] be the case. Moreover, if it is possible for the genus stated, or for its differentia, to be absent, e.g. for movement to be absent from the soul, or truth and falsehood from opinion, then neither of the terms stated can be its genus or its differentia; for it seems that the genus and the differentia accompany the species, as long as it exists.
[20] 3 · Look and see, also, if what is placed in the genus partakes or could partake of any contrary of the genus; for in that case the same thing will at the same time partake of contrary things, seeing that the genus is never absent from it, while it partakes, or can partake, of the contrary as well. Moreover, see whether the species shares in any character which it is utterly impossible for any member of the [25] genus to have. Thus (e.g.) if the soul has a share in life, while it is impossible for any number to live, then the soul will not be a species of number.
You should look and see, also, if the species is a homonym of the genus, and employ as your elementary principles those already stated for dealing with homonyms;12 for the genus and the species are synonymous.
Seeing that of every genus there is more than one species, look and see if it is [30] impossible that there should be another species belonging to the genus stated, for if there is none, then clearly what has been stated will not be a genus at all.
Look and see, also, if he has given as genus something spoken of metaphorically, describing (e.g.) temperance as a harmony; for a genus is always predicated of its species in its literal sense, whereas harmony is predicated of temperance not in a [35] literal sense but metaphorically; for a harmony always consists in notes.
Moreover, if there is any contrary of the species, examine it. The examination [123b1] may take different forms; first of all see if the contrary as well is found in the same genus, supposing the genus to have no contrary; for contraries ought to be found in the same genus, if there is no contrary to the genus. Supposing, on the other hand, that there is a contrary to the genus, see if the contrary of the species is found in the [5] contrary genus; for of necessity the contrary must be in the contrary, if there is any contrary to the genus. Each of these points is made plain by means of induction. Again, see whether the contrary of the species is not found in any genus at all, but is itself a genus, e.g. the good; for if this is not found in any genus, neither will its contrary be found in any genus, but will itself be a genus, as happens in the case of [10] good and evil; for neither of these is found in a genus, but each of them is a genus. Moreover, see if both genus and species are contrary to something, and one pair of contraries has an intermediary, but not the other. For if the genera have an intermediary, so should their species as well, and if the species have, so should their [15] genera as well, as is the case with virtue and vice, and with justice and injustice; for each pair has an intermediary. (An objection to this is that there is no intermediary between health and disease, although there is one between evil and good.) Or see whether, though there is an intermediary between both, i.e. both between the species and between the genera, yet it is not similarly related, but in one case negatively, but in the other case as a subject. For it is a reputable opinion that the [20] relation should be similar in both cases, as it is in the cases of virtue and vice and of justice and injustice; for the intermediaries between both are purely negative. Moreover, whenever the genus has no contrary, look and see not merely whether the contrary is found in the same genus, but the intermediate as well; for the genus containing the extremes contains the intermediates as well, as (e.g.) in the case of [25] white and black; for colour is the genus both of these and of all the intermediate colours. (An objection may be raised that defect and excess are found in the same genus (for both are in the genus evil), whereas moderate amount, an intermediate between them, is found not in evil but in good.) Look and see also whether, while the genus has a contrary, the species has none; for if the genus is contrary to anything, [30] so too is the species, as virtue and vice, and justice and injustice. Likewise, also, if one were to look at other instances, one would come to see this clearly. (An objection may be raised in the case of health and disease; for health without qualification is [35] the contrary of disease, whereas a particular disease, e.g. fever and ophthalmia and any other particular disease, has no contrary.)
[124a1] If, therefore, you are demolishing a view, there are all these ways in which you should make your examination; for if the aforesaid characters do not belong to it, clearly what has been given is not the genus. If, on the other hand, you are establishing a view, there are three ways: in the first place, see whether the contrary is found in the genus stated, supposing the genus to have no contrary; for if the [5] contrary is found in it, clearly the species in question is found in it as well. Moreover, see if the intermediate species is found in the genus stated; for whatever genus contains the intermediate contains the extremes as well. Again, if the genus has a contrary, look and see whether the contrary species is found in the contrary genus; for if so, clearly also the species in question is found in the genus in question.
[10] Again, consider in the case of the inflexions and the co-ordinates, and see whether they follow in the same way, both in demolishing and in establishing a view. For whatever attribute belongs or does not belong to one belongs or does not belong at the same time to all; e.g. if justice is a particular form of knowledge, then also justly is knowingly and the just man is a man of knowledge; whereas if any of these things is not so, then neither is any of the rest of them.
[15] 4 · Again, consider the case of things that bear a like relation to one another. Thus (e.g.) the relation of the pleasant to pleasure is like that of the useful to the good; for in each case the one produces the other. If therefore pleasure is essentially good, then also the pleasant will be essentially useful; for clearly it will be productive of good, seeing that pleasure is good. In the same way also consider the [20] processes of generation and destruction; if (e.g.) to build is to be active, then to have built is to have been active, and if to learn is to recollect, then also to have learnt is to have recollected, and if to be decomposed is to be destroyed, then to have been decomposed is to have been destroyed, and decomposition is a kind of destruction. Consider also in the same way the case of things that generate or destroy, and of the [25] capacities and uses of things; and in general, both in demolishing and in establishing, you should examine things in the light of any resemblance of whatever description, as we were saying in the case of generation and destruction. For if what tends to destroy tends to decompose, then also to be destroyed is to be decomposed; [30] and if what tends to generate tends to produce, then to be generated is to be produced, and generation is production. Likewise, also, in the case of the capacities and uses of things; for if a capacity is a disposition, then also to be capable is to be disposed, and if the use of anything is an activity, then to use it is to be active, and to have used it is to have been active.
[35] If the opposite of the species is a privation, there are two ways of demolishing an argument. First of all by looking to see if the opposite is found in the given genus; for either the privation is never absolutely in the same genus, or at least not in the same ultimate genus: e.g. if the ultimate genus containing sight is perception, then blindness will not be a perception. Secondly, if there is a privation opposed to both genus and species, but the opposite of the species is not found in the opposite of the [124b1] genus, then neither will the given species be in the given genus. If, then, you are demolishing a view, you should follow the rule as stated; but if establishing one there is but one way; for if the opposite species is found in the opposite genus, then also the species in question will be found in the genus in question: e.g. if blindness is [5] a form of lack of perception, then sight is a form of perception.
Again, look at the negations in reverse order, according to the method described in the case of accident:13 e.g. if the pleasant is essentially good, what is not good is not pleasant. [For were this not so, something not good would then be pleasant.]14 For it is impossible, if good is the genus of pleasant, that anything not [10] good should be pleasant; for of things of which the genus is not predicated, none of the species is predicated either. Also, in establishing a view, you should adopt the same method of examination; for if what is not good is not pleasant, then what is pleasant is good, so that good is the genus of pleasant.
If the species is a relative, see whether the genus is a relative as well; for if the [15] species is a relative, so too is the genus, as is the case with double and multiple; for each is a relative. If, on the other hand, the genus is a relative, there is no necessity that the species should be so as well; for knowledge is a relative, but not so grammar. (Or possibly not even the first statement would seem true; for virtue is essentially [25] noble and essentially good, and yet, while virtue is a relative, good and noble are not relatives but qualities.)
Again, see whether the species fails to be related to the same thing in its own right, and in respect of its genus: e.g. if double is the double of a half, then it ought also to be multiple of a half. Otherwise multiple will not be the genus of double.[25]
Moreover, see whether it fails to be related to the same thing both in respect of its genus and in respect of all the genera of its genus. For if the double is a multiple of a half, then it will also be in excess of a half; and, in general, in respect of all the [30] higher genera it will be related to a half. (An objection may be raised that there is no necessity for a term to be related to the same thing in its own right and in respect of its genus; for knowledge is called knowledge of an object of knowledge, whereas it is called a state and disposition not of an object of knowledge but of the soul.)
Again, see whether the genus and the species are used in the same way in [35] respect of the inflexions they take, e.g. datives and genitives and all the rest.15 For as the species is used, so should the genus be as well, as in the case of double and its higher genera; for both double and multiple take a genitive. Likewise, also, in the case of knowledge; for both knowledge itself and its genera, e.g. disposition and state, take a genitive. (An objection may be raised that in some cases it is not so; for [125a1] different and contrary take a dative, whereas other, which is the genus of these terms, takes a genitive—for we talk of being other than something.)
[5] Again, see whether terms used in like manner in respect of inflexions fail to yield a like construction when converted, as do double and multiple. For each of these terms takes a genitive both in itself and in its converted form; for both a half and a fraction take the genitive. The case is the same also as regards both [10] knowledge and belief; for they take a genitive themselves, and likewise after conversion; for object of knowledge and object of belief both take a dative. If, then, in any cases the constructions after conversion are not alike, clearly the one term is not the genus of the other.
Again, see whether the species and the genus fail to be used in relation to an [15] equal number of things; for it seems that the uses of both are alike and equal in number, as is the case with transfers and gifts. For a transfer is of something and to someone, and also a gift is of something and to someone; and transfer is the genus of gift, for a gift is a transfer that need not be returned. In some cases, however, it turns out that they are not related to an equal number of things; for while double is [20] double of something, in excess and greater are in something, as well as of something; for what is in excess or greater is always in excess in something, as well as in excess of something.16 Hence the terms in question are not the genera of double, inasmuch as they are not used in relation to an equal number of things with the species. Or perhaps it is not universally true that species and genus are used in relation to an equal number of things.
[25] See, also, if the opposite of the species has the opposite of the genus as its genus, e.g. whether, if multiple is the genus of double, fraction is of half. For the opposite of the genus should always be the genus of the opposite. If, then, anyone were to assert that knowledge is essentially perception, then also the object of knowledge will have to be essentially an object of perception, whereas it is not; for an object of knowledge is not always an object of perception; for objects of [30] knowledge include some of the objects of the intellect as well. Hence object of perception is not the genus of object of knowledge; and if it is not, neither is perception the genus of knowledge.
Seeing that of relatives some are of necessity found in, or about, the things in relation to which they happen at any time to be used (e.g. composition and state and [35] balance; for in nothing else can the aforesaid terms possibly be found except in the things in relation to which they are used), while others need not be found in the things in relation to which they are used at any time, though they still may be (e.g. if the soul is an object of knowledge, for it is quite possible that the soul should possess knowledge of itself, but it is not necessary—for knowledge may just as well be found [125b1] in something different), while for others, again, it is absolutely impossible that they should be found in the things in relation to which they happen at any time to be used (as e.g. that a contrary should be found in its contrary or knowledge in the object of knowledge unless the object of knowledge happens to be a soul or a man)—you [5] should look, therefore, and see whether he places a term of one kind inside a genus that is not of that kind, e.g. suppose he has said that memory is a persisting of knowledge. For a persisting is always found in that which persists, and is about it, so that the persisting of knowledge also will be found in knowledge. Memory, then, is found in knowledge, seeing that it is a persisting of knowledge. But this is impossible; for memory is always found in the soul. The aforesaid commonplace [10] rule is common to the subject of accident as well; for it makes no difference whether you say that persisting is the genus of memory, or allege that it is an accident of it. For if in any way whatever memory is a persisting of knowledge, the same argument in regard to it will apply.
5 · Again, see if he has placed what is a state inside the genus activity, or an [15] activity inside the genus state, e.g. by calling perception a movement communicated through the body; for perception is a state, whereas movement is an activity. Likewise, also, if he has said that memory is a state that is retentive of a belief; for memory is never a state, but rather an activity.
They also make a mistake who rank a state within the capacity that attends it, [20] e.g. by calling good temper mastery of anger, and courage and justice mastery of fears and of gains; for courage and good temper belong to the man who is immune from passion, whereas mastery is exhibited by the man who is exposed to passion and not led by it. Quite possibly, indeed, each of the former is attended by a capacity such that, if he were exposed to passion, he would control it and not be led [25] by it; but, for all that, this is not what is meant by being courageous in the one case, and good-tempered in the other; what is meant is an absolute immunity from any passions of that kind at all.
Sometimes, also, people state any kind of attendant feature as the genus, e.g. pain as the genus of anger and belief as that of conviction. For both of the things in [30] question follow in a certain sense upon the given species, but neither of them is genus to it. For when the angry man feels pain, the pain has appeared in him earlier than the anger; for his anger is not the cause of his pain, but his pain of his anger, so that anger simply is not pain. By the same reasoning, neither is conviction belief; for it is possible to have the same belief even without being convinced of it, whereas this [35] is impossible if conviction is a species of belief; for it is impossible for a thing still to remain the same if it is entirely transferred out of its species, just as the same animal could not at one time be, and at another not be, a man. If, on the other hand, anyone says that a man who has a belief must of necessity be also convinced of it, then belief and conviction will be used with an equal denotation, so that not even so [126a1] could the former be the genus of the latter—for the denotation of the genus should be wider.
See, also, whether both naturally come to be in the same thing; for what contains the species contains the genus as well: e.g. what contains white contains colour as well, and what contains knowledge of grammar contains knowledge as [5] well. If, therefore, any one says that shame is fear, or that anger is pain, the result will be that genus and species are not found in the same thing; for shame is found in the reasoning faculty, whereas fear is in the spirited faculty; and pain is found in the [10] faculty of desire (for in this pleasure also is found), whereas anger is found in the spirited faculty. Hence the terms given are not the genera, seeing that they do not naturally come to be in the same thing as the species. Likewise, also, if friendship is found in the faculty of desire, it is not a form of wishing; for wishing is always found in the reasoning faculty. This commonplace rule is useful also in dealing with accident; for the accident and that of which it is an accident are both found in the [15] same thing, so that if they do not appear in the same thing, clearly it is not an accident.
Again, see if the species partakes of the alleged genus only in some particular respect; for it seems that the genus is not partaken in only in some particular respect; for a man is not an animal in a particular respect, nor is grammar [20] knowledge. Likewise also in other instances. Look, therefore, and see if in certain cases the genus is partaken in only in a certain respect; e.g. if animal has been described as essentially an object of perception or of sight. For an animal is an object of perception or of sight in a particular respect only; for it is in respect of its body that it is perceived and seen, not in respect of its soul; so that object of sight [25] and object of perception will not be the genus of animal.
Sometimes also people unawares place the whole inside the part, calling (e.g) animal an animate body; whereas the part is not predicated in any sense of the whole, so that body could not be the genus of animal, seeing that it is a part.
[30] See also if he has put anything that is blameworthy or objectionable into capacity or the capable, e.g. by calling a sophist or a slanderer or a thief one who is capable of secretly thieving other people’s property. For none of the aforesaid characters is so called because he is capable in one of these respects; for even God [35] and the good man are capable of doing bad things, but that is not their character; for it is always in respect of their choice that bad men are so called. Moreover, a capacity is always a desirable thing; for even the capacities for doing bad things are desirable, and that is why we say that even God and the good man possess them; for [126b1] they are capable (we say) of doing evil. So then capacity can never be the genus of anything blameworthy. Otherwise, the result will be that some blameworthy thing is desirable; for there will be a capacity that is blameworthy.
Also, see if he has put anything that is precious or desirable for its own sake [5] into capacity or the capable or the productive. For capacity, and what is capable or productive of anything, is always desirable for the sake of something else.
Or see if he has put anything that is in two genera or more into one of them only. For some things it is impossible to place in a single genus, e.g. the cheat and the slanderer; for neither he who has the intention without the capacity, nor he who [10] has the capacity without the intention, is a slanderer or cheat, but he who has both of them. Hence he must be put not into one genus, but into both the aforesaid genera.
Moreover, people sometimes give things the wrong way about, genus as differentia, and differentia as genus, calling (e.g.) astonishment an excess of [15] wonderment and conviction strength of belief. For neither excess nor strength is the genus, but the differentia; for astonishment seems to be an excessive wonderment, and conviction to be a strong belief, [so that wonderment and belief are the genus, while excess and strength are the differentia.]17 Moreover, if any one gives excess and strength as genera, then inanimate things will be convinced and astonished. For [20] the strength and excess of a thing are found in that thing of which they are. If, therefore, astonishment is an excess of wonderment the astonishment will be found in the wonderment, so that wonderment will be astonished. Likewise, also, conviction will be found in belief, if it is strength of belief, so that the belief will be [25] convinced. Moreover, a man who argues in this style will in consequence find himself calling strength strong and excess excessive; for there is such a thing as a strong conviction; if then conviction is strength there will be a strong strength. [30] Likewise, also, there is such a thing as excessive astonishment; if then astonishment is an excess, there will be an excessive excess. But neither of these things seems to be the case any more than that knowledge is an object of knowledge or motion a moving thing.
Sometimes, too, people make the mistake of putting an affection into that [35] which is affected, as its genus, e.g. those who say that immortality is everlasting life; for immortality seems to be a certain affection or accidental feature of life. That this is true would appear clear if anyone were to admit that a man can pass from being mortal and become immortal; for no one will assert that he takes another life, but that a certain accidental feature or affection enters into this one as it is. So then [127a1] life is not the genus of immortality.
Again, see if they say that an affection is that of which it is an affection, calling (e.g.) wind air in motion; [Rather, wind is a movement of air]18 for the same air [5] persists both when it is in motion and when it is still. Hence wind is not air at all; for then there would also have been wind when the air was not in motion, seeing that the same air which formed the wind persists. Likewise, also, in other cases of the kind. Even, then, if we ought in this instance to admit that wind is air in motion, yet we [10] should not accept this sort of thing in all those things of which the genus is not true, but only in cases where the given genus is truly predicated. For in some cases, e.g. mud or snow, it does not seem to be true. For people say that snow is frozen water and mud is earth mixed with moisture, whereas snow is not water, nor mud earth, so [15] that neither of the given terms could be the genus; for the genus should be true of all its species. Likewise neither is wine fermented water, as Empedocles speaks of ‘water fermented in wood’19—for it simply is not water at all.
6 · Moreover, see whether the given term fails to be the genus of anything at [20] all; for then clearly it also fails to be the genus of the species mentioned. Examine the point by seeing whether the objects that partake of the genus fail to be specifically different from one another, e.g. white objects; for these do not differ specifically from one another, whereas of a genus the species are always different, so that white will not be the genus of anything. [25]
Again, see whether he has named as genus or differentia some feature that goes with everything; for there are several attributes that follow everything: thus (e.g.) being and one are among the attributes that follow everything. If, therefore, he has rendered being as a genus, clearly it will be the genus of everything, seeing [30] that it is predicated of everything; for the genus is never predicated of anything except of its species. Hence one will be a species of being. The result, therefore, is that of all things of which the genus is predicated, the species is predicated as well, seeing that being and one are predicates of absolutely everything, whereas the predication of the species ought to be of narrower range. If, on the other hand, he [35] has named as differentia some attribute that follows everything, clearly the denotation of the differentia will be equal to, or wider than, that of the genus. For if the genus, too, is an attribute that follows everything, the denotation of the differentia will be equal to its denotation, while if the genus does not follow everything, it will be wider.
[127b1] Moreover, see if the given genus is said to be in the species as subject, as white in the case of snow, thus showing clearly that it will not be the genus; for the genus is only said of the species as subject.
[5] Look and see also if the genus fails to be synonymous with its species. For the genus is always predicated of its species synonymously.
Moreover, beware, whenever both species and genus have a contrary, and he places the better of the contraries inside the worse genus; for the result will be that [10] the remaining species will be found in the remaining genus, seeing that contraries are found in contrary genera, so that the better species will be found in the worse genus and the worse in the better; but it seems that of the better species the genus too is better. Also see if he has placed something inside the worse and not inside the better genus, when it is related in like manner to both, as (e.g.) if he has called the [15] soul essentially a form of motion or a moving thing. For the same soul seems to be a principle alike of rest and of motion, so that, if rest is the better of the two, this is the genus into which the soul should have been put.
Moreover, judge by means of greater and less degrees: if overthrowing a view, see whether the genus admits of a greater degree, whereas neither the species itself [20] nor anything that is called after it does so; e.g. if virtue admits of a greater degree, so too does justice and the just man; for one man is called more just than another. If, therefore, the given genus admits of a greater degree, whereas neither the species itself nor anything called after it does so, then what has been given will not be the [25] genus.
Again, if what is more generally, or as generally, thought to be the genus is not so, clearly neither is the given genus. The commonplace rule in question is useful especially in cases where the species appears to have several predicates in what it is, and where it has not been determined and we cannot say which of them is genus; e.g. [30] both pain and belief seem to be predicated of anger in what it is; for the angry man is both in pain and also believes that he is slighted. The same mode of inquiry may be applied also to the case of the species, by comparing it with some other species; for if the one which is more generally, or as generally, thought to be found in the [35] given genus is not found herein, then clearly neither will the given species be found therein.
In demolishing a view, therefore, you should follow the rule as stated. In establishing one, on the other hand, the commonplace rule that you should see if both the given genus and the species admit of a greater degree will not serve; for [128a1] even though both admit it, it is still possible for one not to be the genus of the other. For both beautiful and white admit of a greater degree, and neither is the genus of the other. On the other hand, the comparison of the genera and of the species one with another is of use: e.g. supposing this and that to have a like claim to be genus, [5] then if one is a genus, so also is the other. Likewise also, if what has less claim is a genus, so also is what has more claim: e.g. if capacity has more claim than virtue to be a genus of self-control, and virtue is a genus, so also is capacity. The same observations will apply also in the case of the species. For instance, supposing this and that to have a like claim to be a species of the genus in question, then if the one [10] is a species, so also is the other; and if that which is less generally thought to be so is a species, so also is that which is more generally thought to be so.
Moreover, to establish a view, you should look and see if the genus is predicated in what it is of those things to which it has been ascribed as genus, supposing there to have been given not one single species but several different ones; [15] for then clearly it will be the genus. If, on the other hand, a single species has been given, look and see whether the genus is predicated of the other species as well; for then, again, the result will be that it is predicated of several different species.
Since some people think that the differentia, too, is a predicate of the various [20] species in what it is, you should distinguish the genus from the differentia by employing the aforesaid elementary principles—first, that the genus has a wider denotation than the differentia; then, that in giving what a thing is it is more fitting to state the genus than the differentia, for anyone who says that man is an animal [25] shows what man is better than he who describes him as terrestrial; also that the differentia always signifies a quality of the genus, whereas the genus does not do this of the differentia; for he who says terrestrial describes an animal of a certain quality, whereas he who says animal does not describe a terrestrial thing of a certain quality.
The differentia, then, should be distinguished from the genus in this manner. [30] Now since it seems that if what is musical, in being musical, possesses knowledge in some respect, then also music is a particular kind of knowledge; and also that if what walks is moved in walking, then walking is a particular kind of movement; you should therefore examine in the aforesaid manner any genus in which you want to establish the presence of something: e.g., if you wish to prove that knowledge is [35] essentially conviction, see whether the knower in knowing is convinced; for then clearly knowledge will be a particular kind of conviction. You should proceed in the same way also in regard to the other cases of this kind.
Moreover, seeing that it is difficult to distinguish whatever always follows along with a thing, and is not convertible with it, from its genus, if this follows that universally, whereas that does not follow this universally—as e.g. calm always [128b1] follows windlessness and divisible follows number, but not conversely (for the divisible is not always a number, nor windlessness calm)—you may yourself argue as though the one which always follows is the genus, whenever the other is not convertible with it; if, on the other hand, some one else puts forward the proposition, [5] do not accept it universally. An objection to it is that not-being always follows what is coming to be (for what is coming to be is not) and is not convertible with it (for what is not is not always coming to be), but nevertheless not-being is not the genus [10] of coming to be; for not-being has not any species at all.
Questions, then, in regard to genus should be investigated in the ways described.
1 · The question whether the attribute stated is or is not a property, should [15] be examined by the following methods. A property is given either in its own right and for always or relative to something else and for a time: e.g. it is property in its own right of man to be by nature a civilized animal; a relative property is one like that of the soul in relation to the body, viz. that the one is fitted to command, and the other to obey; a property that always holds is one like the property which belongs to God, of being an immortal living being; a property that holds for a time is [20] one like the property which belongs to any particular man of walking in the gymnasium.
When a property is given relatively to something else, there are either two problems or four. For if you ascribe this same property to one thing and deny it of another, only two problems arise, as in the case of a statement that it is a property of [25] a man, in relation to a horse, to be a biped. For one might try both to show that a man is not a biped, and also that a horse is a biped: in both ways the property would be upset. If on the other hand you ascribe one of two attributes to each of two things, and deny it in each case of the other, there will then be four problems; as in the case of a statement that it is a property of a man in relation to a horse for the former to be [30] a biped and the latter a quadruped. For then it is possible to try to show both that a man is not naturally a biped, and that he is a quadruped, and also that the horse is a biped, and that it is not a quadruped. If you prove any of these at all, the intended attribute is demolished.20
A property in its own right is one which is ascribed to a thing in comparison with everything else and distinguishes it from everything else, as does being a [35] mortal living being capable of receiving knowledge in the case of man. A property relative to something else is one which separates its subject off not from everything else but only from a particular definite thing, as does the property which virtue possesses, relative to knowledge, viz. that the former is naturally produced in more than one faculty, whereas the latter is produced in that of reason alone, and in those who have a reasoning faculty. A property for always is one which is true at every [129a1] time, and never fails, like being compounded of soul and body, in the case of a living creature. A property for a time is one which is true at some particular time, and does not of necessity always follow; as, of some particular man, that he walks in the [5] market-place.
To ascribe a property relatively to something else means to state the difference between them as it is found either universally and always, or for the most part and in most cases: thus a difference that is found universally and always, is one such as man possesses relatively to a horse, viz. being a biped; for a man is always and in every case a biped, whereas no horse is ever a biped. On the other hand, a difference [10] that is found for the most part and in most cases, is one such as the faculty of reason possesses relative to that of desire and spirit, in that the former commands, while the latter obeys; for the reasoning faculty does not always command, but sometimes also is under command, nor is that of desire and spirit always under command, but [15] also on occasion assumes the command, whenever the man’s soul is vicious.
Of properties the most general are those which hold in their own right and always and the relative. For a relative property gives rise, as we said before, to several problems; for of necessity the problems arising are either two or four, so that [20] arguments in regard to these are several. A property in its own right and one for always you can discuss in relation to many things, or can observe in relation to many periods of time: if in its own right, discuss it in relation to many things; for the property ought to belong to its subject relatively to every single thing that there is, so that if the subject is not distinguished relatively to everything else, the property will not have been given correctly. A permanent property you should observe in [25] relation to many periods of time; for if it does not or did not, or is not going to, belong, it will not be a property. On the other hand, about a temporary property we do not inquire further than in regard to the present; and so arguments in regard to it are not many; whereas a general problem is one in regard to which it is possible for [30] arguments both numerous and good to arise.
The so-called relative property, then, should be examined by means of the commonplace arguments relating to accident, to see whether it belongs to the one thing and not to the other; on the other hand, permanent and essential properties should be considered by the following methods.
2 · First, see whether the property has or has not been rendered correctly. Of [129b1] a rendering being incorrect or correct, one test is to see whether the terms in which the property is stated are not or are more familiar—for destructive purposes, whether they are not so, and for constructive purposes, whether they are so. Of the terms not being more familiar, one test is to see whether the property which he [5] renders is altogether more unintelligible than the subject whose property he has stated; for, if so, the property will not have been stated correctly. For we form a property for the sake of knowledge; the terms, therefore, in which it is rendered should be more familiar; for in that case it will be possible to conceive it more adequately. E.g. anyone who has stated that it is a property of fire to bear a very [10] close resemblance to the soul, uses the term soul, which is less intelligible than fire—for we know better what fire is than what soul is—, and therefore bearing a very close resemblance to the soul can not be a correctly stated property of fire. Another test is to see whether the attribution of the one to the other fails to be more familiar. For not only should the property be more familiar than its object, but also it should be something whose attribution to it is more familiar. For he who does not [15] know whether it belongs to the object, will not know either whether it belongs to it alone. Hence whichever of these results happens, the property becomes unclear. Thus (e.g.) a man who has stated that it is a property of fire to be the primary element wherein the soul is naturally found, has introduced something more [20] unintelligible than fire, viz. whether the soul is found in it, and whether it is found there primarily; and therefore to be the primary element in which the soul is naturally found will not be a correctly stated property of fire. On the other hand, for constructive purposes, see whether the terms in which the property is stated are more familiar, and whether they are more familiar in each of the aforesaid ways. For then the property will have been correctly stated in this respect; for of [25] constructive rules for correctness, some will prove correctness in a certain respect only, while others will prove it without qualification. Thus (e.g.) a man who has said that the possession of perception is a property of animal has both used more familiar terms and has rendered the property more familiar in each of the aforesaid senses; so that to possess perception will in this respect have been correctly rendered as a property of animal.
[30] Next, for destructive purposes, see whether any of the words given in the property is used in more than one way, or whether the whole expression too signifies more than one thing. For then the property will not have been correctly stated. Thus (e.g.) seeing that to perceive signifies more than one thing, viz. to possess perception, and to use perception, having perception will not be a correctly stated [130a1] property of animal. The reason why neither the word, nor the whole expression signifying the property should have more than one use is this, that an expression having more than one use makes what is said unclear, because the man who is about to attempt an argument is in doubt which of the various uses the expression has; and [5] this will not do, for the object of giving the property is to gain knowledge. Moreover, in addition to this, it is inevitable that those who render a property after this fashion should be somehow refuted whenever any one addresses his deduction to that one of the several uses which does not agree. For constructive purposes, on the other hand, see whether neither any of the terms nor the expression as a whole has more than [10] one use; for then the property will have been correctly stated in this respect. Thus (e.g.) seeing that ‘body’ does not bear several meanings, nor ‘quickest to move upwards in space’, nor yet the whole expression made by putting them together, it would be in this respect a correctly stated property of fire to be the body quickest to move upwards in space.
[15] Next, for destructive purposes, see if the term of which he renders the property is used in more than one way, and it has not been determined which of them it is whose property he is stating; for then the property will not have been correctly rendered. The reasons why this is so are quite clear from what has been said above; for the same results are bound to follow. Thus (e.g.) seeing that ‘the knowledge of [20] this’ signifies many things—for it means the possession of knowledge by it, and the use of knowledge by it, and the possession of knowledge about it, and the use of knowledge about it—no property of the knowledge of this could be rendered correctly unless it were determined which of these it is whose property is being rendered. For constructive purposes, a man should see if the term of which he is stating the property does not have many uses but is one and simple; for then the property will have been correctly stated in this respect. Thus (e.g.) seeing that man [25] is used in a single way, being a naturally civilized animal will be in this respect correctly stated as a property of man.
Next, for destructive purposes, see whether the same term has been repeated in the property. For people often do this unawares in rendering properties, just as they [30] do in their definitions as well; but a property to which this has happened will not have been correctly stated; for the repetition of it confuses the hearer. Thus inevitably it becomes unclear, and further, such people are thought to babble. Repetition of the same term is likely to happen in two ways: one is, when a man [35] repeatedly uses the same word, as would happen if any one were to render, as a property of fire, the body which is the most rarefied of bodies (for he has repeated the word ‘body’); the second is, if a man replaces words by their definitions, as would happen if any one were to render, as a property of earth, the substance which is by its nature most easily of all bodies borne downwards in space, and were then to [130b1] substitute ‘substances of such and such a kind’ for ‘bodies’ (for a body and a substance of such and such a kind are one and the same thing). For he will have repeated the word ‘substance’. Hence neither of the properties will be correctly [5] stated. For constructive purposes, on the other hand, see whether he avoids ever repeating the same word; for then the property will in this respect have been correctly rendered. Thus (e.g.) seeing that he who has stated animal capable of acquiring knowledge as a property of man has not used the same term several times, the property will in this respect have been correctly rendered of man. [10]
Next, for destructive purposes, see whether he has rendered in the property any term that belongs to everything. For one which does not distinguish its subject from other things is useless, and it is the business of what is stated in properties, as also of what is stated in definitions, to distinguish. Hence the property will not have been correctly rendered. Thus (e.g.) a man who has stated that it is a property of [15] knowledge to be belief incontrovertible by argument, because it is one, has used in the property a term of that kind, viz. one, which belongs to everything; and therefore the property of knowledge could not have been correctly stated. For constructive purposes, on the other hand, see whether he has avoided all terms that are common to everything and used a term that distinguishes the subject from something; for then the property will in this respect have been correctly stated. Thus (e.g.) inasmuch as he who has said that it is a property of a living creature to have a [20] soul has used no term that is common to everything, it will in this respect have been correctly stated to be a property of a living creature to have a soul.
Next, for destructive purposes see whether he renders more than one property of the same thing, without a definite proviso that he is stating more than one; for then the property will not have been correctly stated. For just as in the case of [25] definitions too there should be no further addition beside the account which shows the substance of the thing, so too in the case of properties nothing further should be rendered beside the account that makes what is stated a property; for such an addition is made to no purpose. Thus (e.g.) a man who has said that it is a property of fire to be the most rarefied and lightest body has rendered more than one [30] property (for each term is true of fire alone); and so it could not be a correctly stated property of fire to be the most rarefied and lightest body. On the other hand, for constructive purposes, see whether he has avoided giving more than one property of the same thing, and has given one only; for then the property will in this respect [35] have been correctly stated. Thus (e.g.) a man who has said that it is a property of a liquid to be a body adaptable to every shape has given a single property and not several, and so the property of liquid will in this respect have been correctly stated.
3 · Next, for destructive purposes, see whether he has used in addition either the actual subject whose property he is rendering, or any of its species; for then the [131a1] property will not have been correctly stated. For the object of giving the property is to gain knowledge: now the subject itself is just as unintelligible as itself, while any one of its species is posterior to it, and so is no more familiar. Accordingly it is impossible to gain any knowledge by the use of these terms. Thus (e.g.) any one who [5] has said that it is a property of animal to be the substance to which man belongs as a species has employed one of its species, and therefore the property will not have been correctly stated. For constructive purposes, on the other hand, see whether he avoids introducing either the subject itself or any of its species; for then the property will in this respect have been correctly stated. Thus (e.g.) a man who has stated that it is a property of a living creature to be compounded of soul and body has used in [10] addition neither the subject itself nor any of its species, and therefore in this respect the property of a living creature will have been correctly rendered.
You should inquire in the same way also in the case of other terms that do or do not make the subject more familiar: thus, for destructive purposes, see whether he has used in addition anything either opposite to the subject or, in general, anything [15] simultaneous by nature with it or posterior to it; for then the property will not have been correctly stated. For an opposite is simultaneous by nature with its opposite, and what is simultaneous by nature or is posterior to it does not make its subject more familiar. Thus (e.g.) any one who has said that it is a property of good to be the most direct opposite of evil, has used in addition the opposite of good, and so the [20] property of good could not have been correctly rendered. For constructive purposes, on the other hand, see whether he has used in addition neither anything opposite to, nor, in general, simultaneous by nature with the subject, nor posterior to it; for then the property will in this respect have been correctly rendered. Thus (e.g.) a man who has stated that it is a property of knowledge to be the most convincing belief has not used in addition anything either opposite to, or simultaneous by nature with, or [25] posterior to, the subject; and so the property of knowledge will in this respect have been correctly stated.
Next, for destructive purposes, see whether he has rendered as property something that does not always21 follow the subject but sometimes ceases to be its property; for then the property will not have been correctly described. For there is no necessity either that the name of the subject must also be true of anything to [30] which we find it belonging; or that the name of the subject will be untrue of anything to which it is found not to belong. Hence the property will not have been correctly stated. Moreover, in addition to this, even after he has rendered the property it will not be clear whether it belongs, seeing that it is the kind of attribute that may fail; and so the property will not be clear. Thus (e.g.) a man who has stated [35] that it is a property of animal sometimes to move and sometimes to stand still has given as a property the kind of thing which sometimes is not a property, and so the property will not have been correctly stated. For constructive purposes, on the other hand, see whether he has rendered something that of necessity must always be a property; for then the property will have been in this respect correctly stated. Thus [131b1] (e.g.) a man who has stated that it is a property of virtue to be what makes its possessor good has rendered as property something that always follows, and so the property of virtue will in this respect have been correctly rendered.
Next, for destructive purposes, see whether in rendering a present property he [5] has omitted to make a definite proviso that it is a present property which he is rendering; for else the property will not have been correctly stated. For in the first place, any unusual procedure always needs a definite proviso; and for the most part everybody is accustomed to render as property some attribute that always follows. In the second place, a man who omits to provide definitely whether it was the [10] present property which he intended to state, is obscure; and one should not give any occasion for adverse criticism. Thus (e.g.) a man who has stated it as the property of a particular man to be sitting with a particular man, states the present property, and so he cannot have rendered the property correctly, seeing that he has described it without any definite proviso. For constructive purposes, on the other hand, see whether, in giving a present property, he has, in stating it, made a definite proviso [15] that it is the present property that he is stating; for then the property will in this respect have been correctly stated. Thus (e.g.) a man who has said that it is the property of a particular man to be walking now, has made this distinction in his statement, and so the property will have been correctly stated.
Next, for destructive purposes, see whether he has rendered a property of the kind whose presence is not obvious except by perception; for then the property will [20] not have been correctly stated. For every perceptible attribute, once it passes beyond the range of perception, becomes obscure. For it is not clear whether it still belongs, because it is known only by perception. This will be true in the case of any attributes that do not always and necessarily follow. Thus (e.g.) any one who has stated that it is a property of the sun to be the brightest star that moves over the [25] earth, has used in the property something, viz. moving over the earth, of a kind which is known by perception; and so the sun’s property will not have been correctly rendered; for it will be obscure, whenever the sun sets, whether it continues to move over the earth, because perception then fails us. For constructive purposes, on the [30] other hand, see whether he has rendered the property of a kind that is not obvious by perception, or, if it is perceptible, must clearly belong of necessity; for then the property will in this respect have been correctly stated. Thus (e.g.) a man who has stated that it is a property of a surface to be the primary thing that is coloured, has used in addition something perceptible, being coloured, but something which [35] evidently always belongs, and so the property of surface will in this respect have been correctly rendered.
Next, for destructive purposes, see whether he has rendered the definition as a property; for then the property will not have been correctly stated; for the property [132a1] of a thing ought not to show its essence. Thus (e.g.) a man who has said that it is a property of man to be a terrestrial two-footed animal has rendered as a property of man something that signifies his essence, and so the property of man will not have been correctly rendered. For constructive purposes, on the other hand, see whether [5] the property which he has rendered is predicated convertibly without, however, signifying its essence; for then the property will in this respect have been correctly rendered. Thus (e.g.) he who has stated that it is a property of man to be a naturally civilized animal has rendered the property so as to be predicated convertibly without, however, showing its essence, and so the property of man will in this respect have been correctly rendered.
[10] Next, for destructive purposes, see whether he has rendered the property without having placed it in what it is. For of properties, as also of definitions, the first term to be rendered should be the genus, and then the rest of it should be appended immediately afterwards, and should distinguish its subject from other things. Hence a property which is not stated in this way will not have been correctly [15] rendered. Thus (e.g.) a man who has said that it is a property of a living creature to have a soul has not placed living creature within what it is and so the property of a living creature will not have been correctly stated. For constructive purposes, on the other hand, see whether a man first places within what it is the subject whose property he is rendering, and then appends the rest; for then the property will in this respect have been correctly rendered. Thus (e.g.) he who has stated that it is a [20] property of man to be an animal capable of receiving knowledge, has rendered the property after placing the subject within what it is, and so the property of man will in this respect have been correctly rendered.
4 · The inquiry, then, whether the property has been correctly rendered or no, should be made by these means. The question, on the other hand, whether what is stated is or is not a property at all, you should examine from the following points [25] of view. For the commonplace rules which establish absolutely that the property is correctly stated will be the same as those that constitute it a property at all; accordingly they will be described in the course of them.
Firstly, then, for destructive purposes, take a look at each subject of which he has rendered the property, and see (e.g.) if it fails to belong to any of them at all, or [30] to be true of them in respect of that character of which he has rendered the property; for then what is stated to be a property will not be a property. Thus, for example, inasmuch as it is not true of the geometrician that he cannot be deceived by an argument (for a geometrician is deceived when his figure is misdrawn), it will not be a property of the man of science that he is not deceived by an argument. For constructive purposes, on the other hand, see whether the property rendered be true [35] of every instance, and true in that particular respect; for then what is stated not to be a property will be a property. Thus, for example, inasmuch as being an animal capable of receiving knowledge is true of every man, and true of him qua man, it [132b1] will be a property of man to be an animal capable of receiving knowledge. [This commonplace rule means—for destructive purposes, see if the account fails to be true of that of which the name is true; and if the name fails to be true of that of which the account is true; for constructive purposes, on the other hand, see if the [5] account too is predicated of that of which the name is predicated, and if the name too is predicated of that of which the account is predicated.]22
Next, for destructive purposes, see if the account fails to apply to that to which the name applies, and if the name fails to apply to that to which the account applies; for then what is stated to be a property will not be a property. Thus (e.g.) inasmuch [10] as being a living being that partakes of knowledge is true of God, while man is not predicated of God, to be a living being that partakes of knowledge will not be a property of man. For constructive purposes, on the other hand, see if the name as well is predicated of that of which the account is predicated, and if the account as well is predicated of that of which the name is predicated. For then what is stated [15] not to be a property will be a property. Thus (e.g.) living creature is true of that of which having a soul is true, and having a soul is true of that of which living creature is true; and so having a soul will be a property of living creature.
Next, for destructive purposes, see if he has rendered a subject as a property of that which is said to be in the subject; for then what has been stated to be a property [20] will not be a property. Thus (e.g.) inasmuch as he who has rendered fire as the property of the body with the most rarefied particles, has rendered the subject as the property of its predicate, fire will not be a property of the body with the most rarefied particles. The reason why the subject will not be the property of that which is found in the subject is this, that then the same thing will be the property of a [25] number of things that are specifically different. For the same thing has quite a number of specifically different predicates that belong to it alone, and the subject will be a property of all of these, if anyone states the property in this way. For constructive purposes, on the other hand, see if he has rendered what is found in the subject as a property of the subject; for then what has been stated not to be a [30] property will be a property, if it is predicated only of the things of which it has been stated to be a property. Thus (e.g.) he who has said that it is a property of earth to be specifically the heaviest body has rendered of the subject as its property something that is said of the object alone, and is said of it as a property, and so the property of earth will have been rightly stated.
Next, for destructive purposes, see if the property has been given by way of [35] participation; for then what is stated to be a property will not be a property. For an attribute which belongs by way of participation is a constituent part of the essence; [133a1] and an attribute of that kind will be a differentia applying to some one species. E.g., inasmuch as he who has said that being terrestrial and two-footed is a property of man has rendered the property by way of participation, being terrestrial and [5] two-footed will not be a property of man. For constructive purposes, on the other hand, see if he has avoided rendering the property by way of participation, or as showing the essence, though the subject is predicated convertibly with it; for then what is stated not to be a property will be a property. Thus (e.g.) he who has stated that to be naturally percipient is a property of animal has rendered the property neither by way of participation nor as showing the essence, though the subject is [10] predicated convertibly with it; and so to be naturally percipient will be a property of animal.
Next, for destructive purposes, see if the property may belong not simultaneously, but either as posterior or as prior to the name; for then what is stated to be a property will not be a property—either never, or not always. Thus (e.g.) inasmuch [15] as it is possible for walking through the market-place to belong to an object as prior and as posterior to ‘man,’23 walking through the market-place will not be a property of man—either never, or not always. For constructive purposes, on the other hand, see if it always and of necessity belongs simultaneously, without being either a definition or a differentia; for then what is stated not to be a property will be a [20] property. Thus (e.g.) being an animal capable of receiving knowledge always and of necessity belongs simultaneously with ‘man’, and is neither differentia nor definition, and so being an animal capable of receiving knowledge will be a property of man.
Next, for destructive purposes, see if the same thing fails to be a property of [25] things that are the same so far as they are the same; for then what is stated to be a property will not be a property. Thus, for example, inasmuch as it is no property of an object of pursuit to appear good to certain persons, it will not be a property of the desirable either to appear good to certain persons; for an object of pursuit and the desirable are the same. For constructive purposes, on the other hand, see if the same thing is a property of something that is the same in so far as it is the same. For then [30] what is stated not to be a property will be a property. Thus (e.g.) inasmuch as it is said to be a property of a man, in so far as he is a man, to have a tripartite soul, it will also be a property of a mortal, in so far as he is a mortal, to have a tripartite soul. This commonplace rule is useful also in dealing with accident; for the same attributes ought either to belong or not belong to the same things, in so far as they are the same.
[35] Next, for destructive purposes, see if the property of things that are the same in kind fails to be always the same in kind; for then neither will what is stated to be a [133b1] property be a property of the subject in question. Thus (e.g.) inasmuch as a man and a horse are the same in kind, and it is not always a property of a horse to stand still by his own initiative, it will not be a property of a man to move by his own initiative; [5] for to stand still and to move by one’s own initiative are the same in kind, because they belong to each of them in so far as each is an animal. For constructive purposes, on the other hand, see if of things that are the same in kind the property is always the same in kind; for then what is stated not to be a property will be a property. Thus (e.g.) since it is a property of man to be two-footed and terrestrial, it will also be a property of a bird to be two-footed and winged; for each of these is the same in kind, in so far as the one pair are species that fall under the same genus, being under the [10] genus animal, while the other pair are differentiae of the genus, viz. of animal. This commonplace rule is false whenever one of the properties mentioned belongs to some one species only while the other belongs to many, as does terrestrial quadruped.
Inasmuch as ‘same’ and ‘different’ are used in several ways, it is a job to render [15] to a sophistical questioner a property that belongs to one thing and that only. For an attribute that belongs to something qualified by an accident will also belong to the accident taken along with the subject which it qualifies; e.g. an attribute that belongs to man will belong also to white man, if there is a white man, and one that [20] belongs to white man will belong also to man. One might, then, discredit the majority of properties, by representing the subject as being one thing in itself, and another thing when combined with its accident, saying, for example, that man is one thing, and white man another. Again, one might do so by representing as different a [25] certain state and what is called after that state; for an attribute that belongs to the state will belong also to what is called after that state, and one that belongs to what is called after a state will belong also to the state: e.g. inasmuch as the condition of the scientist is called after his science, it will not be a property of science that it is incontrovertible by argument; for then the scientist also will be incontrovertible by [30] argument. For constructive purposes, however, you should say that the subject of an accident is not different without qualification from the accident taken along with its subject; though it is called another thing because what it is to be them is different; for it is not the same thing for a man to be a man and for a white man to be a white [35] man. Moreover, you should take a look along the inflections, and say that the man of science is not that which is incontrovertible by argument, but he who is incontrovertible by argument, and that science is not that which is incontrovertible [134a1] by argument, but she who is incontrovertible by argument.24 For against an objector who sticks at nothing the defence should stick at nothing.
5 · Next, for destructive purposes, see if, while intending to render an [5] attribute that naturally belongs, he states it in his language in such a way as to indicate one that invariably belongs; for then it would seem that what has been stated to be a property is upset. Thus (e.g.) the man who has said that being two-footed is a property of man intends to render the attribute that naturally belongs, but his expression indicates one that invariably belongs; accordingly, being [10] two-footed will not be a property of man; for not every man is possessed of two feet. For constructive purposes, on the other hand, see if he intends to render the property that naturally belongs, and indicates it in that way in his language; for then the property will not be upset in this respect. Thus (e.g.) he who renders as a property of man, being an animal capable of receiving knowledge, both intends, and by his [15] language indicates, the property that belongs by nature, and so being an animal capable of receiving knowledge will not be upset or shown in that respect not to be a property of man.
Moreover, as regards all the things that are called as they are primarily after something else, or primarily in themselves, it is a job to render the property of such [20] things. For if you render a property of what is so called after something else, then it will be true of its primary subject as well; and if you state it of its primary subject, then it will be predicated also of the thing that is so called after this other. Thus (e.g.) if any one renders being coloured as a property of surface, being coloured will be true of body as well; whereas if he ascribes it to body, it will be predicated also of [25] surface. Hence the name as well will not be true of that of which the account is true.
In the case of some properties it happens for the most part that some error is incurred because of a failure to define how and to what things the property is stated to belong. For every one tries to render as the property of a thing something that [30] belongs to it either naturally, as being two-footed belongs to man, or actually, as having four fingers belongs to a particular man, or specifically, as consisting of most rarefied particles belongs to fire, or without qualification, as living to living being, or in virtue of something else, as being prudent to the soul, or as the primary subject, as being prudent to the rational faculty, or because the thing is in a certain state, as [35] being incontrovertible by argument belongs to a scientist (for simply and solely by reason of his being in a certain state will he be incontrovertible by argument), or because it is the state possessed by something, as being incontrovertible by [134b1] argument belongs to science, or because it is partaken of, as perceiving belongs to animal (for other things as well perceive, e.g. man, but they perceive because they partake of animal), or because it partakes of something else, as living belongs to a particular kind of living being. Accordingly he makes a mistake if he has failed to [5] add the word ‘naturally’ (because what belongs naturally may fail to belong to the thing to which it naturally belongs, as (e.g.) it belongs to man to have two feet); or if he does not make a definite proviso that he is rendering what actually belongs (because it will not be such as to belong to it, e.g. the man’s possession of four [10] fingers); or if he has not shown that he states it as the primary subject, or in virtue of something else (because then its name will not also be true of that of which the account is true, as is the case with being coloured, whether rendered as a property of surface or of body); or if he has not said beforehand that he has rendered a property to a thing either because that thing possesses a state, or because it is a state possessed by something (because then it will not be a property—for, supposing he [15] renders the property to something as being a state possessed, it will belong to what possesses that state; while supposing he renders it to what possesses the state, it will belong to the state possessed, as did being incontrovertible by argument when stated as a property of science or of the scientist); or if he has not indicated beforehand that the property belongs because the thing partakes of, or is partaken of by, something (because then the property will belong to certain other things as [20] well—for if he renders it because its subject is partaken of, it will belong to the things which partake of it; whereas if he renders it because its subject partakes of something else, it will belong to the things partaken of, as (e.g.) if he were to state living to be a property of a particular kind of living being, or just of living being); or if he has not expressly distinguished the property that belongs specifically (because then it will belong only to one of the things that fall under the term of which he states the property—for the superlative belongs only to one of them, e.g. being lightest as applied to fire). Sometimes, too, a man may even add the word [25] ‘specifically’, and still make a mistake. For the things in question should all be of one species, whenever the word ‘specifically’ is added; and in some cases this does not occur, as it does not, in fact, in the case of fire. For fire is not all of one species; for live coals and flame and light are each of them fire, but are of different species. The reason why, whenever ‘specifically’ is added, there should not be any species [30] other than the one mentioned, is this, that if there is, then the property in question will belong to some of them in a greater and to others in a less degree, as happens with consisting of most rarefied particles in the case of fire; for light consists of more rarefied particles than live coals and flame. And this should not happen unless the name too is predicated in a greater degree of that of which the account is true to a [35] greater degree; otherwise it will not be the case that where the account is true to a greater degree the name too is true to a greater degree. Moreover, in addition to [135a1] this, the same attribute will be the property both of the term which has it without qualification and of that element therein which has it25 in the highest degree, as is the condition of consisting of most rarefied particles in the case of fire; for this same attribute will be a property of light as well; for it is light that consists of the most [5] rarefied particles. If, then, any one else renders a property in this way one should attack it; for oneself, one should not give occasion for this objection, but should define in what manner one states the property at the actual time of making the statement.
Next, for destructive purposes, see if he has stated a thing as a property of itself; for then what has been stated to be a property will not be a property. For a [10] thing itself always shows its own essence, and what shows the essence is not a property but a definition. Thus (e.g.) he who has said that becoming is a property of beautiful has rendered the term as a property of itself (for beautiful and becoming are the same); and so becoming will not be a property of beautiful. For constructive purposes, on the other hand, see if he has avoided rendering a thing as a property of [15] itself, but has yet stated a convertible predicate; for then what is stated not to be a property will be a property. Thus he who has stated animate substance as a property of living creature has not stated living creature as a property of itself, but has rendered a convertible predicate, so that animate substance will be a property of living creature.
Next, in the case of things consisting of like parts, you should look and see, for [20] destructive purposes, if the property of the whole is not true of the part, or if that of the part is not predicated of the whole; for then what has been stated to be a property will not be a property. In some cases it happens that this is so; for sometimes in rendering a property in the case of things that consist of like parts a [25] man may have his eye on the whole, while sometimes he may address himself to what is predicated of the part; and then in neither case will it have been rightly rendered. Take an instance referring to the whole: the man who has said that it is a property of the sea to be the largest volume of salt water, has stated the property of something that consists of like parts, but has rendered an attribute of such a kind as [30] is not true of the part (for a particular sea is not the largest volume of salt water); and so the largest volume of salt water will not be a property of the sea. Now take one referring to the part: the man who has stated that it is a property of air to be breathable has stated the property of something that consists of like parts, but he has stated an attribute such as, though true of some air, is still not predicable of the whole (for the whole of the air is not breathable); and so breathable will not be a [135b1] property of air. For constructive purposes, on the other hand, see whether, while it is true of each of the things with similar parts, it is also a property of them taken as a collective whole; for then what has been stated not to be a property will be a property. Thus (e.g.) while it is true of earth everywhere that it naturally falls [5] downwards, it is a property of the various particular pieces of earth taken as the Earth,26 so that it will be a property of earth naturally to fall downwards.
6 · Next, look from the point of view of the opposites, and first from that of the contraries, and see, for destructive purposes, if the contrary of the term rendered fails to be a property of the contrary subject. For then neither will the contrary of the first be a property of the contrary of the second. Thus (e.g.) inasmuch as [10] injustice is contrary to justice, and the lowest evil to the highest good, but to be the highest good is not a property of justice, therefore to be the lowest evil will not be a property of injustice. For constructive purposes, on the other hand, see if the contrary is the property of the contrary; for then also the contrary of the first will be a property of the contrary of the second. Thus (e.g.) inasmuch as evil is contrary to [15] good, and objectionable to desirable, and desirable is a property of good, objectionable will be a property of evil.
Secondly look from the point of view of relative terms and see, for destructive purposes, if the correlative of the term rendered fails to be a property of the correlative of the subject; for then neither will the correlative of the first be a property of the correlative of the second. Thus (e.g.) inasmuch as double is relative [20] to half, and in excess to exceeded, while in excess is not a property of double, exceeded will not be a property of half. For constructive purposes, on the other hand, see if the correlative is a property of the correlative; for then also the correlative of the first will be a property of the correlative of the second: e.g. inasmuch as double is relative to half, and the proportion 1 : 2 is relative to the [25] proportion 2 : 1, while it is a property of double to be in the proportion of 1 : 2: it will be a property of half to be in the proportion of 2 : 1.