IDEAS
The common sense functions like a seal, which imprints the figures or ideas, which come to it in a pure and incorporeal form from the external senses, in the phantasy or imagination, which is like wax.
Rules, XII. X, 414.
Although everyone commonly believes that the ideas which we have in our thought are entirely similar to the objects from which they proceed, I do not see any reason to believe this; but I notice, on the contrary, many experiments which ought to make us doubt it.
The World, I. XI, 3-4.
Those [figures] which are traced by the [animal] spirits upon the surface of the [pineal] gland, which is the seat of the imagination, and of the common sense, ought to be taken to be the ideas, that is for the forms or images which the rational soul considers immediately, when, after it has been united to this machine [the body], it imagines or senses some object.
Treatise on Man. XI, 176-177.
Note that I say: imagine or sense; since I want to understand generally, under the name Idea all the impressions that the [animal] spirits can receive when they emerge from the [pineal] gland, all of which are attributed to the common sense, when they depend upon the presence of their objects; but they can also proceed from many other causes, as I will explain to you later, and then they are to be attributed to the imagination.
Treatise on Man. XI, 177.
There need not be, in all this, any resemblance between the ideas that it [the soul] conceives and the movements [of the nerves] which cause these ideas.
Dioptrics, VI. VI, 131.
Since our ideas can receive their forms and their existence only from certain external objects or from ourselves, they can represent only the reality or perfection which is in these objects or in ourselves.
Letter to Vatier, Feb. 22, 1638. I, 560-561.
Among the ideas, some seem to me to be born with me [innate], others to be foreign and to come from outside me [adventitious], and others to be made and invented by me [factitious or fictitious].
Meditations, III. IX, 29.
I find in my mind two completely different ideas of the sun: one takes its origin in the senses, and ought to be placed in the category of those which I said come from outside myself, according to which the sun appears to me to be extremely small; the other idea is derived from the reasons of astronomy, i.e., from certain innate notions, or perhaps is formed by myself in some way or another, according to which it appears to me to be several times larger than all the earth.
Meditations, III. IX, 31.
Every idea being a work of the mind, its nature is such that it requires no other formal reality than that which it receives and borrows from the thought or the mind, of which it is only a mode, i.e., a manner or fashion of thinking.
Meditations, III. IX, 32.
The natural light makes me know with certainty that ideas are within me like pictures or images which can, truly, easily fall short of the perfection of the things from which they have been derived but which can never contain anything greater or more perfect.
Meditations, III. IX, 33.
By the word idea, I understand everything that can be in our thought, and I have distinguished three sorts of them: namely, some are adventitious, like the ordinary idea of the sun; some are constructed [factae] or factitious, to which rank one can assign those that the astronomers have of the sun, through their reasoning; and others are innate, like the idea of God, of the soul, of body, of the triangle, and in general all those which represent true, immutable and eternal essences.
Letter to Mersenne, June 16, 1641. III, 383.
I do not call only the images which are painted in the imagination by the name “idea”; on the contrary, I do not call them by that name at all, so long as they are in the corporeal imagination; but I generally call everything that is in our mind by the name “idea,” whenever we conceive a thing, in whatever manner we conceive it.
Letter to Mersenne, July, 1641. III, 392-393.
If he [an uknown author] wishes to take the word idea in the way that I have said quite expressly that I take it, without stopping at the equivocation of those who restrict the word to the images of material things which are formed in the imagination, it will be easy for him to recognize that, by the idea of God, I understand nothing other than what every man usually means when he speaks of God.
Letter to Mersenne, July, 1641. III, 393.
Everything that we conceive without an image is a purely mental idea, and everything that we conceive with an image is an idea of the imagination.
Letter to Mersenne, July, 1641. III, 395.
In the word idea there is an equivocation: either it can be taken materially as an operation of my understanding, and in this sense one cannot say that it is more perfect than I am; or it can be taken objectively [i.e., in terms of its object] for the thing which is represented by that operation, which, even though it is not supposed to exist outside of my understanding, can nevertheless be more perfect than I am, by reason of its essence.
Meditations, Preface. VII, 8.
The idea is the thing itself, as it is conceived or thought, insofar as it is objectively in the understanding.
Replies, I. IX, 81.
By the word idea I understand that form of each of our thoughts, by the immediate perception of which we have knowledge of these thoughts. In such a way that I cannot express anything by words when I understand what I am saying except from the fact that there is in me the idea of the thing which is signified by my words. And thus I do not only give the name idea to the images which are depicted in my imagination; on the contrary, I do not call them by that name at all, insofar as they are in the corporeal imagination, i.e., insofar as they are depicted in some parts of the brain, but solely insofar as they inform the mind itself, when it applies itself to that part of the brain.
Replies, II. IX, 124.
I take the name idea to mean all that is immediately conceived by the mind. So that, when I will and when I fear, because I simultaneously conceive that I will and that I fear, this act of will and this fear are included by me among the ideas; and I make use of this word, because it was commonly taken by philosophers to signify the forms of the conceptions of the divine understanding, even though we do not recognize in God any phantasia or corporeal imagination; and I did not know any word that would be more proper.
Replies, III. IX, 141.
If one has no idea [of God], that is, no perception which corresponds to the signification of the word God, then one says in vain that he believes that God exists.
Letter to Clerselier. IX, 210.
[Concerning] the idea of God, it should be noted that it is not a case of the essence of the idea according to which it is only a mode existing in the soul (this mode being no more perfect than the man), but it is a case of objective perfection, which the principles of metaphysics teach as being contained formally or eminently in its cause.
Letter to Regius, June, 1642. III, 566.
I do not introduce any difference between the soul and its ideas, other than as between a piece of wax and the various shapes which it can receive.
Letter to Mesland, May 2, 1644(?). IV, 113.
As it is not properly an action, but a passion of the wax, to receive various shapes, it seems to me that it is also a passion in the soul to receive such or such an idea, and that there are only its volitions which are actions; and its ideas are placed in it, partly by the objects which touch the senses, partly by the impressions which are in the brain, and partly also by the dispositions which have preceded these in the soul itself, and by the movements of its will; as the wax receives its shapes, partly from other bodies which press into it, partly from the shapes or other qualities which are already in it, as from the fact that it is more or less heavy or soft, etc., and partly also from its motion, when it has been moved and has in itself the force to continue to move itself.
Letter to Mesland, May 2, 1644(?). IV, 113-114.
In addition [to ideas which represent things] there are the ideas of common notions, which are not ideas of things properly speaking; but then idea is taken in a larger sense.
Burman. V, 153.
See impressions; materially; formally; will.
IDEAS, ADVENTITIOUS
[I do not] say that all ideas are innate, but that there are also adventitious ideas, as for example the ideas of the city of Leiden, the city of Alkmaar, etc.
Burman. V, 165.
IDEAS, INNATE
I hold that all those [ideas] which include neither affirmation nor negation are innate for us; for the sense organs bring nothing to us which is like the idea which is aroused in us at their occasion, and thus this idea must have been in us previously.
Letter to Mersenne, July 23, 1641. III, 418.
When I consider which figures can be inscribed in a circle, it is not at all necessary that I think that every figure which has four sides is among them; on the contrary, I cannot even pretend that this is so, as long as I refuse to consider any thoughts which I cannot conceive clearly and distinctly. And as a consequence there is a great difference between false suppositions, like this one, and the truly innate ideas, of which the first and principal idea is that of God.
Meditations, V. IX, 54.
When I say that some idea is innate, or that it is naturally imprinted in our souls, I do not understand that it is always present to our thought, because then there would be no innate ideas; but simply that we have in us the faculty of producing it.
Replies, III. IX, 147.
I never wrote or concluded that the mind required innate ideas which were in some way different from its faculty of thinking; but when I observed the existence in me of certain thoughts which proceeded, not from extraneous objects nor from the determination of my will, but solely from the faculty of thinking which is within me, then, that I might distinguish the ideas or notions (which are the forms of these thoughts) from other thoughts adventitious or factitious, I termed the former innate. In the same sense we say that in some families generosity is innate, in others certain diseases like gout or gravel, not that on this account the babes of these families suffer from these diseases in their mother’s womb, but because they are born with a certain disposition or propensity for contracting them.
Notes against a Program, XII.
See seeds of truth, seeds of thought; perfection.
IDENTITY
The surface [of the Host at the Sacrament] remains numerically the same as that which existed previously between the air and the bread, because it does not take its numerical identity from the identity of bodies in which it exists, but solely from the identity or resemblance of the dimensions: as we can say that the Loire is the same river which existed ten years ago, even though it is not the same water and though perhaps also there is no particle of the same earth which surrounded that water.
Letter to Mesland, Feb. 9, 1644. IV, 164-165.
IMAGES
One must not suppose that, in order to sense, the soul must contemplate some images which are sent by the objects to the brain, as our philosophers commonly say; or, at least, one must conceive the nature of these images quite differently from them.
Dioptrics, IV. VI, 112.
There are no images which completely resemble the objects which they represent: for otherwise there would be no distinction between the object and its image: but it suffices for them to resemble their object in a few things.
Dioptrics, IV. VI, 113.
The images of objects are not formed only at the back of the eye, but they also pass from there to the brain.
Dioptrics, V. VI; 128.
IMAGINATION
In order to make use of the assistance of the imagination, we must note that every time that one deduces something which is unknown from some other thing which is already known, one never discovers a new type of being; the process of knowledge only permits us to see that the thing for which we are searching participates, in some way or another, in the nature of those things which are given in the problem.
Rules, XIV. X, 438.
The imagination itself, with the ideas which exist in it, is nothing other than a real, veritable body, with extension and figure.
Rules, XIV. X, 441.
I am currently dissecting the heads of various animals, in order to explain what imagination, memory, etc., consist of.
Letter to Mersenne, Nov.-Dec., 1632. I, 263.
It seems to me that those who want to use their imagination in order to comprehend [the ideas of God and the soul] do the same as those who want to use their eyes in order to hear sounds or smell odors.
Discourse, IV. VI, 37.
The imagination [is] that which can variously change the ideas and compose new ideas out of them, and, by the same means, distribute the animal spirits in the muscles so as to make the limbs and the body move in so many various ways.
Discourse, V. VI, 55.
The part of the mind which helps most in mathematics, namely the imagination, hinders more than it helps in metaphysical speculations.
Letter to Mersenne, Nov. 13, 1639. II, 622.
When I consider attentively what the imagination is, I find that it is nothing other than a certain application of the faculty of knowing, to the body which is intimately present to it, and which therefore exists.
Meditations, VI. IX, 57.
I have need of a particular intense application of mind, in order to imagine, which I do not use in order to conceive; and that particular application of the mind shows clearly the difference there is between imagination, and intellection or pure conception.
Meditations, VI. IX, 58.
In order to imagine, for example, a pentagon, there is need of a particular contention of the mind which gives us that figure (that is, its five sides and the space that they enclose) as present, which we do not use for conceiving.
Replies, III. IX, 139.
See intellection; tablet, blank.
IMAGINE
To imagine is nothing other than to contemplate the shape or the image of a corporeal thing.
Meditations, II. IX, 22.
See consider.
Imagining is a way of thinking which is appropriate for material things.
Discourse, IV. VI, 37.
The faculties of imagining and of sensing belong to the soul, because they are species of thoughts; and nevertheless they only belong to the soul insofar as it is joined to the body, because they are the sort of thoughts without which one can conceive the soul completely pure.
Letter to Gibieuf, Jan. 19, 1642. III, 479.
IMMORTALITY
I have not written a word [in the Meditations] about the immortality of the soul, but you should not be astonished about that; for I would not know how to demonstrate that God could not annihilate it, but only to show that it is of a nature entirely distinct from that of the body, and as a consequence that it is not naturally subject to death with the body, which is all that is required to establish religion; and it is also all that I proposed to prove.
Letter to Mersenne, Dec. 24, 1640(?). III, 265-266.
The human body can easily perish, but the mind or the soul of man (which I do not distinguish) is immortal by its very nature.
Meditations, Summary. IX, 10.
I confess that I have nothing to say in reply [to the objection that immortality is not proved in the Meditations]; for I do not have so much presumption as to attempt to determine, by the force of human reasoning, a thing which depends only on the pure will of God.
Replies, II. IX, 120.
IMMUTABILITY
What foundation could one find which is more firm and solid, upon which to establish a truth, what could one wish for, than to take the firmness and the immutability which is in God?
The World, VII. XI, 43.
IMPENETRABILITY
Impenetrability belongs to the essence of the extended, and not to the essence of anything else.
Letter to More, Apr. 15, 1649. V, 342.
IMPOSSIBILITY
All impossibility, or, if I may make use here of the word of the School, all implicantia, consists solely in our concept or thought, which cannot conjoin ideas which are contrary to one another; and impossibility cannot consist in anything which is beyond the understanding, because, simply from the fact that it is beyond the understanding, it is manifest that it does not imply anything, but that it is possible.
Replies, II. IX, 119.
IMPRESSIONS
I conceive that various impressions are formed in the brain [of animals], some by external objects which move the senses, others by the internal dispositions of the body, or by the vestiges of preceding impressions which have remained in the memory, or by the agitation of spirits which come from the heart, or also in man by the action of the soul, which has some power to change the impressions which are in the brain, as, reciprocally, these impressions have the power to excite thoughts in the soul which do not depend upon the will.
Letter to Elisabeth, Oct. 6, 1645. IV, 310.
IMPUDENCE
Impudence or effrontery, which is a scorn of shame, and often also of pride, is not a passion, because there is in us no particular movement of the [animal] spirits which excites it; but it is a vice opposed to shame, and also to pride, insofar as one or the other of these is good, just as ingratitude is opposed to gratitude, and cruelty to pity.
Passions, III, 207. XI, 483.
A person may be said to believe on impulse if he judges things by some spontaneous belief, without having been convinced by any reasoning.
Rules, XII. X, 424.
INCLINATIONS
I cannot conceive of natural inclinations except in something which has understanding, and I do not even attribute it to animals which do not have reason; but I explain everything that we call natural appetites or inclinations in them solely by the rules of mechanics.
Letter to Mersenne, Oct. 28, 1640. III, 213.
When I say that these little balls [i.e., the particles of light] make some effort, or rather that they have the inclination, to move away from the centers about which they revolve, I do not understand that one attributes to them any thought from which that inclination proceeds, but only that they are so situated and disposed to move that they would actually move away, if they were not held back by any other cause.
Principles, III, 56. IX2, 131.
INDECISION
Indecision is another species of fear, which keeps the soul as though it were in balance, among many actions that it could perform, and thus keeps it from doing any of them, giving it time to choose before it decides.
Passions, III, 170. XI, 459.
INDEFINITE
I here make a distinction between indefinite and infinite. And there is nothing which I call properly infinite, except that in which I do not find limits in any parts, in which sense God alone is infinite. But the things which I simply see no end to, under some consideration, like the extension of imaginary spaces, the multitude of numbers, the divisibility of the part of a quantity, and other similar things, I call simply indefinite, and not infinite, because they are not without end or limits in every part.
Replies, I. IX, 89-90
When we see things in which, in a certain sense, we do not notice any limits, we will not be certain for that reason that they are infinite, but we will simply say that they are indefinite.
Principles, I, 26. IX2, 36.
I do not say that the world is infinite, but indefinite only. In which there is a quite notable difference: for, to say that a thing is infinite, one ought to have some reason which makes it known as such, of a sort that one can have of God alone; but to say that a thing is indefinite, it suffices to have no reason by which one can prove that it has limits.
Letter to Chanut, June 6, 1647. V, 51.
INDIFFERENCE
Although I have written that indifference is rather a fault than a perfection in our own freedom, it does not follow from that that it is the same in God.
Letter to Mersenne, Apr. 21, 1641. III, 360.
A total indifference in God is a very great proof of his omnipotence.
Replies, VI. IX, 233.
Indifference seems to me properly to signify the state of the will when it is not impelled in one direction rather than in another by the perception of the true or the good; and it is in this sense that I took it when I wrote that the lowest degree of freedom is that in which we determine ourselves to things about which we are indifferent.
Letter to Mesland, Feb. 9, 1645. IV, 173.
INDIFFERENT
I have not said that man was indifferent only where he lacks knowledge; but rather that he is all the more indifferent as he knows fewer reasons which impel him to choose one side rather than the other.
Letter to Mesland, May 2, 1644(?). IV, 115.
See free.
INDIGNATION
The evil done by others, when it is not related to us, only makes us indignant toward them; and when it is related to us, it also excites anger.
Passions, II, 65. XI, 378.
Indignation is a species of hate or aversion, which one has naturally against those who do some evil, of whatever nature it might be.
Passions, III, 195. XI, 475.
INDUCTION
See enumeration.
INDUCTION, MATHEMATICAL
When a deduction is complex and involved, we give it the name of enumeration or [mathematical] induction, because the understanding cannot then include it all in the same instant, but its certainty depends in some way upon memory, which must retain the judgments concerning each of the parts of the enumeration, so that a single conclusion can be derived from all of them together.
Rules, XI. X, 408.
INERTIA
I do not recognize any inertia or natural resistance to motion in bodies, any more than does M. Mydorge, and believe that, when only one man walks, he makes the whole mass of the earth move ever so little, because he weighs it down, now in one place, and afterward in another.
Letter to Huygens, Dec. 1638. II, 466-467.
INERTIA, NATURAL
The more matter a body contains, the more natural inertia it has.
Letter to Debeaune, Apr. 30, 1639. II, 543.
The mind in infancy is so caught up in the body that it has no thoughts other than those which derive from its attachment to the body.
Burman. V, 150.
INFINITE
I have never discussed the infinite except to submit myself to it, and not to determine what it is or is not.
Letter to Mersenne, Jan. 28, 1641. III, 293.
That by which the infinite differs from the finite is real and positive, and the limitation by which the finite differs from the infinite is a nonentity or a negation of being.
Letter to “Hyperaspistas,” Aug., 1641. III, 427.
The infinite, insofar as it is infinite, is not actually comprehended, but nevertheless it is understood.
Replies, I. IX, 89.
To understand clearly and distinctly that a thing is such that one cannot find limits to it, is clearly to understand that it is infinite.
Replies, I. IX, 89.
We will call these [material] things indefinite rather than infinite, in order to reserve to God alone the word infinite; because we do not notice any limits upon his perfections, and also because we are completely sure that there cannot be any limits.
Principles, I, 27. IX2, 37.
As for ourselves, we can never find any limit whatever in these things [number, quantity, etc.], and thus, from our point of view, they are indefinite, or better, infinite without doubt, for the indefinite, repeatedly multiplied, as is here the case, is the infinite itself. And thus, perhaps we can say that the world is infinite; the same for number, etc. But, from the point of view of God, perhaps he conceives and comprehends determinate limits to the world, to number, to quantity, and perhaps he comprehends something greater than the world, than number, etc., which will thus be finite for him.
Burman. V, 167.
I would not dare to say that [the world] is infinite, because I conceive that God is greater than the world, not because of his extent, which I do not conceive in God, as I have said many times, but because of his perfection.
Letter to More, Apr. 15, 1649. V, 344.
See indefinite.
INGRATITUDE
As for ingratitude, it is not a passion: for nature has not placed in us any motion of the [animal] spirits which excites it; but it is solely a vice directly opposed to gratitude, insofar as the latter is always virtuous and one of the principal links of human society.
Passions, III, 194. XI, 474.
INSTANT
The word instant excludes only temporal priority.
Letter to Mersenne, May 17, 1638. II, 143.
INSTINCTS
I distinguish two sorts of instincts: one is in us insofar as we are men and is purely intellectual; this is the natural light or intuitus mentis [mental intuition], in which alone I hold that men should trust; the other is in us insofar as we are animals, and is a certain natural impulsion for the conservation of our body, for the enjoyment of corporeal pleasures, etc., which ought not always to be followed.
Letter to Mersenne, Oct. 16, 1639. II, 599.
See understanding.
INTELLECTION
[Imagination] differs from pure intellection solely in that the mind, when conceiving [i.e., using pure intellection] turns in some way toward itself, and considers one of the ideas that it has; but in imagining, it turns toward the body, and considers something there which conforms to the idea that it has formed by itself or which it has received through the senses.
Meditations, VI. IX, 58.
INTELLECTUAL NATURE
The idea of intellectual nature in general, when considered as without limitation, is that which represents God to us, and when considered as limited, is that of an Angel or a human soul.
Letter to °°°, May, 1637. I, 353.
INTENTIONAL SPECIES
When I see a stick, it is not necessary to imagine that little images come from it, flying through the air, commonly called intentional species, which pass to my eye, but only that the rays of light reflected from the stick excite some movements in the optic nerve, and, by means of them, in the brain itself.
Replies, VI. IX, 236-237.
INTUITION
Concerning the objects which are proposed for our study, it is necessary to seek out, not what others have thought, or what we ourselves conjecture, but that of which we can have a clear and evident intuition, or what we can deduce with certainty.
Rules, III. X, 366.
By intuition I understand, not the fluctuating testimony of the senses, nor the misleading judgment that proceeds from the blundering constructions of imagination, but the conception which an unclouded and attentive mind gives us so readily and distinctly that we are wholly freed from doubt about what we understand. Or, what comes to the same thing, intuition is the undoubting conception of an unclouded and attentive mind, and springs from the light of reason alone; it is more certain than deduction itself, in that it is simpler, though deduction, as we have noted above, cannot be erroneously conducted by us.
Rules, III. X, 368.
We distinguish intuition of the mind from certain deduction, in that in the latter we may conceive a sort of movement or succession, but not in the former; and because, in addition, for deduction, unlike intuition, there is no need of actual, present experience, since deductions borrow their certitude, in some fashion, from memory.
Rules, III. X, 370.
The manner in which we must use intellectual intuition becomes apparent to us when we compare it with the vision of the eyes.
Rules, IX. X, 401.
In order to speak of intellectual intuition, we require two elements: first, that the proposition be comprehended clearly and distinctly; and second, that it be comprehended completely in a single moment, and not in several successive moments.
Rules, XI. X, 407.
There can be no error in intuition alone, whether the things which are intuited are simple or composite.
Rules, XIII. X, 432.
Intuitive knowledge is an elucidation of the mind, by which it sees those things in the light of God, which it pleases him to show it, by a direct impression of the divine light upon our understanding, which in this case is not considered as an agent, but solely as receiving the rays of divinity.
Letter to Newcastle, Mar. or Apr., 1648. V, 136.
See instinct.
INVENTION
When I was a youth, with a view to ingenious discoveries, I asked myself if I would not be able to invent for myself, without depending upon reading from any author. From that time on, little by little, I perceived that I proceeded according to determinate rules.
Cogitationes Privatae. X, 214.
One cannot conceive a thing so well, and make it his own, when he learns it from someone else, as when he invents it himself.
Discourse, VI. VI, 69.
IRON
We do not have any [metal other than iron or steel] which bows less easily to the hammer, without the aid of the fire, which is made to melt with so much trouble, or which can be made so hard, without the mixture of any other body.
Principles, IV, 136. IX2, 273.