ABSOLUTE
I call “absolute” everything which contains in itself, in the pure and simple state, the nature with which we are concerned: such as everything which is considered as independent, cause, simple, universal, one, equal, similar, straight, or orther qualities like this; and I apply the term “absolute” to the simplest and easiest, because of the use that we make of it in the resolution of our questions.
Rules, VI. X, 381-382
See relative.
ABSTRACTION
There is a great difference [between distinction and abstraction], for in distinguishing a substance from its accidents one ought to consider each separately, which greatly helps in knowing it; if, instead, one separates a substance from its accidents solely by abstraction, that is, if one considers it all alone without thinking of them, that prevents one from knowing it as well, because it is by the accidents that the nature of the substance is manifested.
Letter to Clerselier. IX, 217.
To find out whether my idea is rendered incomplete, or inadaequata, by some abstraction of my mind, I simply examine whether I have derived it, not from some external object which is more complete, but from some other idea which I have myself, which is more ample or complete, and this per abstractionem intellectus, i.e., by turning my thought from what is comprised in that more ample idea, in order to apply it better and to make myself more attentive to the other part.
Letter to Gibieuf, Jan. 19, 1642.
III, 474-475.
There is a great difference between abstraction and exclusion. If I said only that the idea which I have of my soul does not represent it to me as dependent upon the body, and identified with it, that would be only an abstraction, from which I could only form a negative argument with a faulty conclusion. But I say that that idea represents it to me as a substance which can exist, even though everything which belongs to the body is excluded from it; from which I form a positive argument and conclude that it can exist without the body.
Letter to Mesland, May 2, 1644(?). IV, 120.
ACCIDENT
I certainly admit, to tell the truth, that one substance can be applied to another substance; but, when that happens, it is not the substance which takes the form of an accident, it is only the mode or the fashion in which it happens: for example, when clothing is applied to a man, it is not the clothing, but the being clothed, which is an accident.
Replies, VI. IX, 235.
What we call an accident is anything that is present or absent whithout the corruption of the subject, although, when considered in itself, it might perhaps be a substance, as clothes are accidents of a man.
Letter to Regius, Dec., 1641. III, 460.
It is not accidental that the human body is united to the soul, for that is its proper nature.
Letter to Regius, Dec., 1641. III, 460.
See substances.
ACTION
Action and passion are one and the same thing, to which two different names have been given, by which it can be referred, at one time to the term from which the action starts, and at another time to that at which it terminates, or in which it is received; so that there cannot be the least moment when there is a passion without an action.
Letter to “Hyperaspistas,” Aug., 1641. III, 428.
In corporeal things every action and passion consists in a single local motion, and it is called action when this motion is considered in the mover, and passion when it is considered in the thing which is moved; from which it also follows that, when these words are applied to immaterial things, it is necessary to consider something in them which is analogous to motion, and that that which is on the part of the mover must be called action, as is volition in the soul, and that which is on the part of the thing moved must be called passion, like intellection and vision in the same soul.
Letter to Regius, Dec., 1641. III, 454-455.
See passion.
ACTION AT A DISTANCE
Often the motion of the smallest bodies extends its action to the greatest distances; and thus the light of the sun and the farthest stars passes in an instant to the earth.
Principles, III, 79. IX2, 147.
AEOLIPILES
What you see coming out of aeolipiles is similar to what you see in the vapors or smokes which come from water when it is placed next to the fire.
Letter to Mersenne, Feb. 25, 1630. I, 118.
AERIAL
Concerning the particles which I have called aerial, I do not include under this name all those which are separated from one another, but only those which, without being very agitated or very solid, move separately from one another; this makes the bodies where they are remain rarefied, and keeps them from being readily condensed. And because the particles which compose the air are, for the most part, of this nature, I have called them aerial.
Description of Human Body, IV. XI, 260.
AFFECTIONS
See emotions.
AFFLICTIONS
All our afflictions, whatever they are, do not depend primarily on the reasons to which we attribute them, but only on the emotion and the internal turmoil that nature excites in us.
Letter to Pollot, Jan. 21, 1641. III, 279-280.
AGREEABLE
Among the objects of a sense, the most agreeable to the mind is not the one that is easiest to perceive with that sense, nor that which is hardest. It is the object of which the perception is not so easy that it overwhelms the natural inclination by which the senses tend toward their objects, nor so difficult that it fatigues the sense.
Compendium Musicae, II. X, 92.
AIR
After fire, there is nothing more liquid than air, and one can see with the naked eye that its particles move about individually.
The World, III. XI, 14.
As for the second element, which can be taken as the element of Air, I conceive it as a very subtle liquid, in comparison with the third element; but, in comparison with the first, it has a certain size, and a certain shape, in each of its particles, and one must imagine that they are almost all round, and joined together, like grains of sand and dust.
The World, V. XI, 24-25.
The air is nothing other than a mass of particles of the third element, which are so fine and so detached from one another that they obey all the movements of the matter of the sky which is among them: which is the cause that the air is rare, liquid and transparent, and that the tiny particles of which it is composed can be of all sorts of shapes.
Principles, IV, 45. IX2, 226.
ALGEBRA
Now we see another type of arithmetic, called “algebra,” which is destined to do for numbers what the ancients did for geometrical figures.
Rules, IV. X, 373.
AMERICA
One ought to place more faith in a single witness who, after making a voyage to America, tells us that he has seen the antipodes, than in a thousand others who have previously denied that there were any, without having any reason for it other than that they didn’t know about them.
Replies, VI. IX, 227.
ANACLASTIC
Consider the case of a man who was a student of mathematics and who sought to find out about that line which in optics is called the “anaclastic”: it is that in which parallel rays refract in such a matter that they all come together, after refraction, in a single point; our man will easily notice that the determination of that line depends on the ratio between the angles of refraction and the angles of incidence; but he will not be able to find out what that ratio is, inasmuch as it pertains not only to mathematics, but also to physics.
Rules, VIII. X, 393-394.
ANAGRAM
If we wanted to make the best anagram, by transposing the letters of some given word, it would not be necessary to go from the easiest to the most difficult, nor to distinguish the absolute from the relative, because this is not the place to do all that; it will suffice to examine the transpositions of the letters by means of an order such that the same combinations will never appear twice, and that their number be divided into a certain number of classes, in such a way that the ones that we are searching for will be apparent when they appear.
Rules, VII. X, 391.
ANALYSIS
Analysis shows the true path by which a thing has been methodically invented, and shows how the effects depend upon their causes; in such a way that, if the reader wishes to follow, and look carefully at all that it contains, he will not understand whatever is demonstrated less perfectly, and make it less his own, than if he himself had invented it.
Replies, II. IX, 121.
See synthesis.
ANALYTIC
The analytic manner of writing which I followed [in the Meditations] permits making suppositions sometimes, when one has not yet carefully examined the subject, as it appeared in my first Meditation, where I supposed many things which I then refuted in the following Meditations.
Replies, II. IX, 121.
ANGELS
We judge that the least of the angels are incomparably more perfect than men.
Letter to Chanut, June 6, 1647. V, 56.
The knowledge of angels escapes us almost entirely, because, as I have said, we cannot derive it from our mind, and we also know nothing, which the subject ordinarily requires, about whether they can be united to a body, since the Old Testament often represents them in bodily form, and similar things. It is preferable for us to follow Scripture on this point and to believe that they were young men, that they appeared as such, and so on.
Burman. V, 157.
Anger can sometimes excite a desire for vengeance so violent that it makes us imagine more pleasure in punishing our enemy than in saving our honor or our life.
Letter to Elisabeth, Sept. 1, 1645. IV, 285.
In anger, a prompt desire for vengeance is often mixed with love, hate, and sadness.
Passions, II, 117. XI, 415.
Anger is a species of hate or aversion, which we have against those who have done some evil, or who have attempted to do harm, not indifferently to anyone at all, but particularly to us.
Passions, III, 199. XI, 477.
One can distinguish two species of anger: one is quite prompt, and has strong external manifestations, but nevertheless has little effect and can easily be appeased; the other does not appear so clearly at first, but eats away further at the heart and has more dangerous effects.
Passions, III, 201. XI, 479.
ANIMALS
All the movements of the lower animals are produced, even though they have absolutely no cognition of things, but only a purely bodily imagination.
Rules, XII. X, 415.
As for animals, we certainly notice movements in them similar to those which follow our imaginations or sensations, but they do not for that reason have imaginations or sensations.
Letter to Gibieuf, Jan. 19, 1642. III, 479.
See beasts.
If someone claims that a living being is an animate body, without having explained beforehand the sense of the words body and animate, and if he does not act otherwise as he goes through all the metaphysical degrees [of the tree of Porphyry], certainly he pronounces words, and even words which are arranged in a certain order, but he says nothing; for that does not signify anything which can be conceived and form a clear and distinct idea in our mind.
Search for Truth. X, 517.
ANTIPODES
In the discovery of the antipodes, the report of a few seamen who have gone around the earth was believed, rather than thousands of philosophers who did not believe that it was round.
Letter to Clerselier. IX, 212.
A POSTERIORI
As for what I supposed at the beginning of the Meteorology, I could not demonstrate it a priori without giving all my physics; but the experiments that I deduced necessarily from it, and which cannot be deduced in the same way from other principles, seemed to me to demonstrate it well enough a posteriori.
Letter to Vatier, Feb. 22, 1638. I, 563.
APPETITES
See sensations.
APPETITES, NATURAL
The first sense that I call internal comprises hunger, thirst, and all the other natural appetites; and it is excited in the soul by the movements of the nerves of the stomach, the throat and all the other parts which serve natural functions, for which there are such appetites.
Principles, IV, 190. IX2, 311.
APPREHENSION
Apprehension [receptio] is an action or rather an animal passion similar to that of automata, by which we receive the motion of things.
Letter to Regius, May, 1641. III, 373.
Those who can sufficiently examine the consequences of the [eternal] truths and of our rules will be able to know the effects by their causes; and, to explain myself in the terms of the School, will be able to have a priori demonstrations of everything that can be produced in the new World.
The World, VII. XI, 47.
ARGUMENTATION
In this life you do not see in God and by his light that he is one; but you conclude it from a proposition that you have made about him, and you derive it by the force of argumentation, which is a machine which is frequently defective.
Letter to Newcastle, Mar. or Apr., 1648. V, 139.
ARITHMETIC AND GEOMETRY
Of all the sciences known as yet, Arithmetic and Geometry alone are free from any taint of falsity or uncertainty.
Rules, II. X, 364.
In the easiest sciences, arithmetic and geometry, we have sufficient evidence that the ancient Geometricians made use of a certain analysis which they extended to the resolution of all problems, though they begrudged the secret to posterity.
Rules, IV. X, 373.
I would hope that the reader had a natural taste for the study of arithmetic and geometry, although I would prefer that he had never paid any attention to them, rather than having been taught in the ordinary way.
Rules, XIV. X, 442.
ARTERIES
The arteries are tubes, through which the blood, warmed and rarefied in the heart, passes from there into all the other parts of the body, to which it carries warmth and material for nourishing them.
Description of Human Body, I. XI, 227.
Men erroneously compare the sciences, which entirely consist in the cognitive exercise of the mind, with the arts, which only the first appearance of the object which was presented, depend upon an exercise and disposition of the body.
Rules, I. X, 359.
ASPECTS
As for the sort of distinction that comes between two different aspects [façons] of the same substance, it is striking that we can know one of these aspects [or modes] without the other, as the shape without the motion, and the motion without the shape; but we cannot think distinctly about one or the other if we do not know that they both depend upon the same substance.
Principles, I, 61. IX2, 52.
ASTONISHMENT
The surprise [which produces wonder] has enough power to make the [animal] spirits, which are in the cavities of the brain, flow toward the spot where there is the impression of the object which is wondered at, so that sometimes all of them are impelled there, in such a way that they are all so occupied in conserving that impression that none of them flow into the muscles, nor even turn in any way from the first traces which they have followed in the brain: this makes the whole body remain immobile like a statue, and such that one can perceive nor, as a consequence, can one acquire any particular knowledge of it. It is that which is commonly called being astonished [or shocked]; and astonishment is an excess of wonder, which can never be anything but harmful.
Passions, II, 73. XI, 382-383.
ASTROLOGERS
All the astrologers, who know nothing about the nature of the heavenly bodies, and without ever having perfectly observed their movements, hope to be able to predict their influences.
Rules, V. X, 380.
I see that those who brag about having secrets, for example in alchemy or in astrology, no matter how ignorant and impertinent they may be, never fail to find curious people who pay very well for their impostures.
Letter to Chanut, Mar. 31, 1649. V, 327.
ASTRONOMERS
With the aid of imaginary circles, astronomers describe their phenomena.
Rules, XII. X, 417.
ATHEISTS
Everything that the atheists say in combating against the existence of God always depends either on pretending that God has human affections, or on attributing to our minds so much force and wisdom that we have the presumption to want to determine and comprehend what God can and ought to do.
Meditations, Preface. VII, 9.
As for the science of an atheist, it is easy to show that he cannot know anything with certainty and assurance; for, as I have already said, the less powerful he recognizes the author of his being to be, the more he will have occasion to suspect that his nature is so imperfect that he is deceived, even in the things that seem very evident to him; and he will never be able to escape from this doubt, if he does not first recognize that he has been created by a true God, principle of all truth, who cannot be a deceiver.
Replies, VI. IX, 230.
ATOMS
It implies a contradiction [to say] that there are atoms, or particles of matter which have extension and which nevertheless are indivisible, because one cannot have the idea of an extended thing, without being able also to have the idea of its half, or its third, or, as a consequence, without being able also to conceive it as divisible into two or three parts.
Letter to Gibieuf, Jan. 19, 1642. III, 477.
There cannot be atoms, or particles of bodies which are indivisible, as some philosophers have imagined.
Principles, II, 20. IX2, 74.
There is a contradiction in saying that there are atoms which are conceived as extended and at the same time indivisible, because, even though God could certainly have made them such that no creature could divide them, we cannot comprehend how he could deprive himself of the power to divide them himself.
Letter to More, Feb. 5, 1649. V, 273.
See particles.
ATTRIBUTE
Whenever we see a quality assigned to anything by nature, whether it is a mode that can suffer change, or the very essence of that thing, manifestly unchangeable, we term that quality its attribute.
Notes against a Program, II. VIII 2, 348.
All the attributes taken together are in truth the same thing as the substance, but not taken one by one, and separately from one another.
Burman. V, 155.
ATTRIBUTE, PRINCIPAL
Each substance has a principal attribute; that of the soul is thought, and extension is that of the body.
Principles, I, 53. IX2, 48.
AUTOMATA
None of this will seem strange to those who, — knowing how many different automata, or moving machines, the industry of men can make, without using more than a very few pieces, in comparison with the great multitude of bones, muscles, nerves, arteries, veins, and all the other parts which are in the body of each animal, — consider the body as a machine, which, having been made by the hands of God, is incomparably better coordinated and has much more admirable movement in it, than any of those which could be invented by men.
Discourse, V. VI, 55-56.
Never, unless it were by accident, would these automata respond, either by words or even by signs, appropriately to those who ask them questions.
Letter to Reneri, Apr. May, 1638. II, 40
If we were accustomed to seeing automata which perfectly imitated all of our actions that they were able to imitate, and anything other than automata, because we would find they in any way that all animals which do not have reason were if we took them to be only automata, we would not suspect differ from us in all the same things as do the automata.
Letter to Mersenne, July 30, 1640. III, 121.
See machine.
AVERSIONS
It is easy to think that the strange aversions of some people, such that they cannot bear the odor of roses, or the presence of a cat, or similar things, come only from the fact that at the beginning of their life they were badly injured by some similar objects, or they had some sensation in sympathy with an injury to their mother when she was pregnant.
Passions, II, 136. XI, 429.
AXIOMS
For all the time that they [axioms] are clearly and distinctly perceived [their truth is manifest], because our soul is of such a nature that it cannot refuse to accept whatever it comprehends distinctly; but because we often remember conclusions which we have derived from such premises, without paying attention to the premises themselves, I say then that without the knowledge of God we could claim that they are uncertain.
To Regius, May 24, 1640. III, 64.
The knowledge of first principles or axioms is not usually called science by the dialecticians.
Replies, II. IX, 110.
See common notions; principles.