The Mind or Pure Understanding

The subject of this third treatise is a little dry and sterile. It examines the mind considered in itself and without any relation to the body, in order to recognize the weaknesses that are proper to it and the errors it holds only from itself. The senses and imagination are fruitful and inexhaustible sources of wanderings and illusions; but the mind, acting by itself, is not so subject to error. One had difficulty finishing the two preceding treatises; one has difficulty beginning this one. It is not that one cannot say enough things about the properties of the mind, but it is that one does not seek here so much its properties as its weaknesses. One should not therefore be surprised if this treatise is not so ample, and if it does not discover as many errors as those that preceded it. One should not complain either if it is a little dry, abstract and demanding. One cannot always, in speaking, stir the senses and imagination of others, and even one should not always do so. When a subject is abstract, one can hardly render it sensible without obscuring it; it suffices to render it intelligible. There is nothing so unjust as the ordinary complaints of those who wish to know everything and who wish to apply themselves to nothing. They become angry when one begs them to render themselves attentive; they wish always to be touched, and that one incessantly flatters their senses and passions. But what then? We recognize our powerlessness to satisfy them. Those who write novels and comedies are obliged to please and to render attentive; for us, it is enough if we can instruct even those who make an effort to render themselves attentive.

The errors of the senses and imagination come from the nature and constitution of the body, and are discovered by considering the dependence of the soul on it; but the errors of pure understanding can only be discovered by considering the nature of the mind itself and of the ideas that are necessary to it for knowing objects. Thus, to penetrate the causes of the errors of a pure understanding, it will be necessary to dwell in this book on the consideration of the nature of the mind and intellectual ideas.

We shall speak first of the mind, according to what it is in itself and without any relation to the body to which it is united; so that what we shall say of it could be said of pure intelligences, and a fortiori of what we call here pure understanding: for, by this word, pure understanding, we pretend to designate only the faculty that the mind has of knowing external objects, without forming corporeal images of them in the brain to represent them to itself. We shall treat afterward of intellectual ideas by means of which pure understanding perceives external objects.

Thought alone is essential to the mind. Sensing and imagining are only modifications.

I do not believe that, after having thought seriously about it, one can doubt that the essence of the mind consists only in thought, just as the essence of matter consists only in extension, and that, according to the different modifications of thought, the mind sometimes wills and sometimes imagines, or finally that it has several other particular forms; just as, according to the different modifications of extension, matter is sometimes water, sometimes wood, sometimes fire, or that it has an infinity of other particular forms.

I warn only that by this word, thought, I do not mean here the particular modifications of the soul, that is to say such or such thought, but thought capable of all sorts of modifications or thoughts; just as by extension one does not mean such or such extension, as round or square, but extension capable of all sorts of modifications or figures. And this comparison can cause difficulty only because one does not have a clear idea of thought, as one has of extension; for one knows thought only by inner feeling or by conscience, as I shall explain below.

I do not believe either that it is possible to conceive a mind that does not think, although it is very easy to conceive one that does not feel, that does not imagine, and even that does not will; just as it is not possible to conceive a matter that is not extended, although it is quite easy to conceive one that is neither earth nor metal, nor square nor round, and which is not even in motion. One must conclude from this that as it can happen that there is matter which is neither earth nor metal, nor square nor round, nor even in motion, it can happen also that a mind feels neither heat nor cold, neither joy nor sadness, imagines nothing, and even wills nothing; so that all these modifications are not essential to it. Thought alone is therefore the essence of the mind, just as extension alone is the essence of matter.

But just as if matter or extension were without movement, it would be entirely useless and incapable of that variety of forms for which it is made, and it is not possible to conceive that an intelligent being would have wished to produce it in that way; thus, if a mind or thought were without will, it is clear that it would be entirely useless, since this mind would never carry itself toward the objects of its perceptions, and it would not love the good for which it is made: so that it is not possible to conceive that an intelligent being would have wished to produce it in that state. Nevertheless, as movement is not of the essence of matter, since it supposes extension; so to will is not of the essence of the mind, since to will supposes perception.

Thought alone is therefore properly what constitutes the essence of the mind, and the different ways of thinking; such as sensing and imagining are only the modifications of which it is capable, and by which it is not always modified: but to will is a property that always accompanies it, whether it is united to a body or separated from it; which however is not essential to it, since it supposes thought, and one can conceive a mind without will as a body without movement.

However the power of willing is inseparable from the mind, although it is not essential to it; just as the capacity of being moved is inseparable from matter, although it is not essential to it. For, just as it is not possible to conceive a matter that one cannot move, so it is not possible to conceive a mind that cannot will, or that is not capable of some natural inclination. But also, just as one conceives that matter can exist without any movement, one conceives likewise that the mind can be without any impression of the author of nature toward the good, and consequently without will; for the will is nothing other than the impression of the author of nature that carries us toward good in general, as we have explained at greater length in the first chapter of the Treatise on the Senses.

We do not know all the modifications of which our soul is capable

What we have said in that Treatise on the Senses, and what we have just said of the nature of the mind, does not suppose that we know all the modifications of which it is capable; we make no such suppositions. We believe, on the contrary, that there is in the mind a capacity to receive successively an infinity of diverse modifications that the same mind does not know.

The smallest part of matter is capable of receiving a figure of three, six, ten, a thousand sides, finally the circular and elliptical figure, which one can consider as figures of an infinite number of angles and sides. There is an infinite number of different species of each of these figures, an infinite number of triangles of different species, still more figures of four, six, ten, ten thousand sides, and of infinite polygons; for the circle, the ellipse, and generally every regular or irregular curvilinear figure, can be considered as an infinite polygon; the ellipse, for example, as an infinite polygon, but whose angles made by the sides are unequal, being greater toward the small diameter than toward the large, and so of other infinite polygons more composite and more irregular.

A simple piece of wax is therefore capable of an infinite number, or rather an infinitely infinite number of different modifications, that no mind can comprehend. What reason then to imagine that the soul, which is much nobler than the body, is capable only of the sole modifications it has already received?

If we had never felt either pleasure or pain, if we had never seen either color or light, finally if we were, with respect to all things, like blind and deaf persons with respect to colors and sounds, would we have reason to conclude that we would not be capable of all the sensations we have of objects? However these sensations are only modifications of our soul, as we have proved in the Treatise on the Senses.

One must therefore agree that the capacity the soul has to receive different modifications is as great as the capacity it has to conceive; I mean that as the mind cannot exhaust or comprehend all the figures of which matter is capable, it cannot comprehend all the different modifications that the powerful hand of God can produce in the soul, even if it knew as distinctly the capacity of the soul as it knows that of matter: which is not true, for the reasons I shall give in chapter VII of the second part of this book.

If our soul here below receives only very few modifications, it is because it is united to a body and depends on it. All its sensations relate to its body; and as it does not enjoy God, it has none of the modifications that this enjoyment must produce. The matter of which our body is composed is capable of only very few modifications during our lifetime. This matter can be resolved into earth and vapor only after our death. Now it cannot become air, fire, diamond, metal; it cannot become round, square, triangular: it must be flesh, and have the figure of a man so that the soul may be united to it. It is the same with our soul; it is necessary that it have the sensations of heat, cold, color, light, sounds, odors, tastes, and several other modifications, so that it remains united to its body. All these sensations apply it to the preservation of its machine. They agitate it and frighten it as soon as the least spring unbends and breaks, and thus the soul must be subject to them as long as its body is subject to corruption; but when it will be clothed in immortality and we will no longer fear the dissolution of its parts, it is reasonable to believe that it will no longer be touched by these inconvenient sensations that we feel despite ourselves, but by an infinity of others entirely different of which we now have no idea, which will surpass all feeling and will be worthy of the greatness and goodness of the God whom we shall possess.

It is therefore without reason that one imagines penetrating the nature of the soul in such a way that one has the right to assert that it is capable only of knowledge and love; this could be maintained by those who attribute their sensations to external objects or to their own body, and who claim that their passions are in their body: for, in effect, if one removes from the soul all its passions and sensations, all that remains recognized in it is nothing more than a consequence of knowledge and love. But I do not conceive how those who have returned from these illusions of our senses can persuade themselves that all our sensations and all our passions are only knowledge and love, I mean species of confused judgments that the soul makes of objects in relation to the body it animates. I do not understand how one can say that light, colors, odors, etc., are judgments of the soul, for it seems to me on the contrary that I perceive distinctly that light, colors, odors and other sensations are modifications entirely different from judgments.

They are different from our knowledge and our love, and even they are not always consequences of them

But let us choose more vivid sensations that apply the mind more. Let us examine what these persons say of pain or pleasure. They wish, following several very considerable authors [3], that these feelings are only consequences of the faculty we have of knowing and willing, and that pain, for example, is only the chagrin, opposition and aversion that the will has for things it knows to be harmful to the body it animates. But it seems evident to me that this is to confuse pain with sadness, and that so far from pain being a consequence of the knowledge of the mind and the action of the will, on the contrary it precedes both.

For example, if one put a burning coal in the hand of a man who sleeps or who warms his hands behind his back, I do not believe that one can say with any verisimilitude that this man would first know that some movements contrary to the good constitution of his body would take place in his hand; that then his will would oppose them, and that his pain would be a consequence of this knowledge of his mind and this opposition of his will. It seems to me on the contrary that it is indubitable that the first thing this man would perceive when the coal touched his hand would be the pain, and that this knowledge of the mind and this opposition of the will are only consequences of the pain, although they are truly the cause of the sadness that would follow from the pain. But there is much difference between this pain and the sadness it produces. Pain is the first thing the soul feels; it is preceded by no knowledge, and it can never be agreeable in itself. On the contrary, sadness is the last thing the soul feels; it is always preceded by some knowledge, and it is always very agreeable in itself. This appears sufficiently from the pleasure that accompanies the sadness one feels at the tragic representations of theaters, for this pleasure increases with the sadness; but pleasure never increases with pain. Comedians, who study the art of pleasing, know well that one must not bloody the theater, because the sight of a murder, although feigned, would be too terrible to be agreeable. But they never fear to touch the spectators with too great a sadness, because in effect sadness is always agreeable when there is reason to be touched by it. There is therefore an essential difference between sadness and pain, and one cannot say that pain is nothing other than a knowledge of the mind joined to an opposition of the will.

For all other sensations, such as odors, tastes, sounds, colors, most men do not think that they are modifications of their soul. They judge on the contrary that they are spread upon objects, or at least that they are in the soul only as the idea of a square and a round; that is to say that they are united to the soul, but that they are not its modifications; and they judge thus because they do not touch them much, as I have shown in explaining the errors of the senses.

One believes therefore that one must agree that one does not know all the modifications of which the soul is capable, and that besides those it has through the organs of the senses, it can happen that it has still an infinity of others that it has not experienced and that it will not experience until after it is delivered from the captivity of its body.

However one must avow that just as matter is capable of an infinity of different configurations only because of its extension, the soul also is capable of different modifications only because of thought; for it is visible that the soul would not be capable of the modifications of pleasure, pain, nor even of all those that are indifferent to it, if it were not capable of perception or thought.

It suffices us therefore to know that the principle of all these modifications is thought. If one wishes even that there be in the soul something that precedes thought, I do not wish to dispute it: but as I am sure that no one has knowledge of his soul except through thought or through the inner feeling of everything that passes in his mind, I am assured also that if anyone wishes to reason on the nature of the soul, he should consult only this inner feeling which incessantly represents him to himself as he is, and not imagine, against his own conscience, that the soul is an invisible fire, a subtle air, a harmony, or some other similar thing.