CH. i] ON HUMAN UNDERSTANDING 115 that each soul preserves all its preceding impressions, and cannot divide itself equally in the manner just mentioned; the future in each substance is perfectly united to the past; this is what constitutes the identity of the individual. Memory, furthermore, is not necessary, nor even always possible, because of the multitude of present and past impressions which co-op erate in our present thoughts, for I do not believe that there are in man thoughts of which there is not some effect at least confused or some remnant mixed with subsequent thoughts. We can forget many things, but we could also remember them long after if we would recall them as we ought.
§ 13. Ph. Those who chance to sleep without dreaming can never be convinced that their thoughts are active.
Tli. [One is feebly conscious in sleep, even when it is dream less. The process of waking up itself shows this, and the easier you are awakened the more you are conscious of what goes on without, although this consciousness is not always strong enough to cause you to awake.]
§ 14. Ph. It appears very difficult to conceive that the soul is thinking at this moment in a sleeping man and the next in one awake, without remembering its thoughts.
Th. [Not only is that easy to conceive, but also something like it is observed every day that we are awake; for we always have objects which strike our eyes and ears, and, as a result, the soul is touched also, without our taking notice of it, because our attention is bent upon other objects, until this object becomes strong enough to draw it to itself, by redoubling its action or by some other means; it is like a particular sleep with reference to that object, and this sleep becomes general when our atten tion ceases to regard all objects together. Division of attention, in order to weaken it, is also a means of putting yourself to sleep.]
Ph. I learned from a man, who in his youth had applied him self to study and had a tolerably felicitous memory, that he never had a dream until he had had the fever, from which he had just recovered at the time he spoke with me, at the age of twenty -five or twenty-six years.
Tli. [I have also been told of a student, more advanced in years, who never had a dream. But it is not upon dreams alone that you must base the perpetuity of the soul's perception, since I have shown how, even while asleep, it has some perception of what goes on without.]
110 LEIBNITZ'S CRITIQUE OF LOCKE [BK. n § 15. Ph. To think frequently and not to preserve a single moment the memory of your thought, is to think in a useless manner.
Tli. [All impressions have their effect, but all the effects are not always perceptible; when I turn to one side rather than to the other, it is very often through a series of minute impressions of which I am not conscious, and which render one movement a little more uncomfortable than the other. All our unpre meditated actions are the results of a concurrence of minute perceptions, and even our customs and passions, which influ ence so much our deliberations, come therefrom; for these habits grow little by little, and, consequently, without the minute perceptions, we should not arrive at these noticeable dis positions. I have already remarked that he who would deny these effects in the sphere of morals, would imitate the poorly taught class who deny insensible corpuscles in physics; and yet I see that among those who speak of liberty are some who, taking no notice of these unperceived impressions, capable of inclining the balance, imagine an entire indifference in moral actions, like that of the ass of Buridan l equally divided between two meadows. Concerning this we shall speak more fully later. I admit, however, that these impressions incline with out necessitating.
Ph. Perhaps we might say that in the case of a man awake who thinks, his body counts for something and that memory is preserved by means of marks in the brain/out when he is asleep the soul thinks apart by itself.
1 John Buridan, a celebrated Nominalist of the 14th century, the date of whose birth and death is unknown. He studied at Paris under William of Occam (died 1347) and was for many years Professor of Philosophy in the University of Paris, and in 1327 its rector. In philosophy his only authority was reason. In the third book, first question, of his Qusestiones in decem libros ethicorum Aristolelis, 1489, he discussed in an "independent and interesting manner " the question of the freedom of the will, reaching conclusions similar to those of Locke. In his view the liberty possessed by the soul consists in " a certain power of suspending the deliberative process, and determining the direction of the intellect; otherwise the will is entirely dependent on the view of the mind, the last result of examination." The story of the ass as an illus tration of the indeterminism of the will " is not," as Sir William Hamilton says (Reid, 8th ed., Vol. 1, p. 238, note) he has ascertained, " to be found in his writings." On Buridan, cf. Ueberweg, Hint, of Philos., English transla tion, Vol. 1, pp. 465-4(5(3; Prautl, Gesch. d. Logik, Vol. 4, 14-38; Stockl, Gesch. d. Philos. d. Mittelalters, Vol. 2, 1023-1028. — TK.
CH. i] ON HUMAN UNDERSTANDING 117 Th. I am very far from saying that, since I believe there is always an exact correspondence between the body and the soul, and since I employ the impressions of the body of which we are not conscious, whether awake or asleep, in order to prove that the soul has in itself similar ones. I maintain even that something goes on in the soul which cor responds to the circulation of the blood and to all the internal movements of the viscera, of which we are never conscious however, just as those who live near a water-mill do not per ceive the noise it makes. In fact, if there were impressions in the body during sleep or waking hours, by which the soul was not touctied or in any wise affected, limits would be given to the union of the soul and of the body, as if corporeal impressions required a certain form and size in order for the soul to perceive them; which is not at all tenable if the soul is incorporeal, for there is no relation between an incorporeal substance and this or that modification of matter. In a word, it is a great source of error to believe that there is no perception in the soul besides those of which it is con scious.
§ 16. Ph. The greater part of the dreams which we remem ber are extravagant and incoherent. We should then say that the soul owes the power of rational thought to the body, or that it retains none of its rational soliloquies.
Th. [The body responds to all the soul's thoughts, rational or not, and dreams have also their marks in the brain as well as the thoughts of those who are awake.
§ 17. Ph. Since you are so sure that the soul is always actually thinking, I wish you would tell me what the ideas are which are in the child's soul before it is united to the body, or just at the time of its union, before it has received any idea by means of sensation.
Th. It is easy to satisfy you by our principles. The soul's perceptions correspond always naturally to the constitution of the body, and when there are a multitude of movements con fused and little distinguished in the brain, as happens in the case of those who have little experience, the soul's thoughts (following the order of the things) cannot be more distinct. Yet the soul is never deprived of the help of sensation, because it always expresses its body, and this body is always impressed 118 LEIBNITZ'S CRITIQUE OF LOCKE [BK. n by its surroundings J in an infinite number of ways, but which often give only a confused impression.
§ 18. Ph. But here is still another question which the author of this Essay asks. I very much wish (says he) that those who maintain so confidently that the soul of man or (what is the same thing) man thinks always, would tell me how they know it?
Th. [I do not know but that more confidence is necessary to deny that anything goes on in the soul of which we are not conscious; for that which is perceivable must be composed of parts which are not so, nothing can spring into being at once, thought no more than motion. In short, it is as if some one asked to-day how we know the insensible corpuscles.
§ 19. Ph. I do not ^remember that those who tell us that the soul always thinks ever say that man always thinks.
Th. [I think that is because they understand their state ment of the separated soul, and yet they voluntarily admit that man always thinks during the union. For myself, who have reasons for holding that the soul is never separated from the entire body, I believe that we can state absolutely that man always does and will think.]
Ph. To say that the body is extended without having parts, and that a thing thinks without being conscious that it thinks, are two assertions which appear equally unintelligible.
Th. [Pardon me, sir; I am obliged to tell you that when you advance the statement that there is nothing in the soul of which it is not conscious, you beg the question which has al ready prevailed in all our former discussion, or you have been desirous to use it to destroy innate ideas and truths. If we agree to this principle, in addition to the fact that we believe it contrary to experience and reason, we should surrender with out reason to our feeling, which, I believe, I have rendered sufficiently intelligible. But besides the fact that our oppo nents, skilful as they are, have brought no proof of that which they urge so often and so positively, it is easy to show them the contrary; i.e. that it is impossible for us always to think 1 Gerhardt reads: " frappe paries ambians d'une infinite de manieres, mais qni souvent lie donnent qu'une impression confuse." Erdmann and Jacques read: "frappe par les autres, qui 1'environnent, d'nne infinite de manieres, mais qui souvent ne font qu'une impression confuse." — TR.
CH. i] ON HUMAN UNDERSTANDING 119 expressly upon all our thoughts; otherwise, the spirit would reflect upon each reflection to infinity without ever being able to pass to a new thought. For example, in my consciousness of some present feeling, I should always think that I think, and still think that I think of my thought, and thus to infinity. But it is very necessary that I cease reflecting upon all these reflections, and that there be at length some thought which is allowed to pass without thinking of it; otherwise, we should dwell always upon the same thing.]
Ph. But would there not be as good ground for maintaining that a man is always hungry, by saying that he can be hungry without feeling it?
Th. There is just the difference; hunger has particular rea sons which do not always exist. Nevertheless, it is true also that even when you are hungry you do not think of it every moment; but when you do think of it you feel it, for it is a very marked disposition; there is always irritation in the stomach, but it is necessary for it to become very strong to cause hunger. The same distinction ought always to be made between thoughts in general and remarkable thoughts. Thus, what appears to put a ridiculous construction upon our opinion, serves to confirm it.]
§ 23. Ph. One can now ask, when man begins to have ideas in his thought? And it seems to me that the reply must be, when he has some sensation.
Th. [I am of the same opinion; but it is by a principle a little peculiar, for I believe that we are never without thoughts, and also never without sensation. I distinguish only between ideas l ^tid thoughts; for we always have all pure or distinct ideas Independently of the senses; but thoughts always corre spond to some sensation.]
§ 25. But the mind is passive only in the perception of simple ideas, which are the rudiments or materials of knowl edge, while it is active when it forms complex ideas.
Th. [How can it be that the mind is passive merely with regard to the perception of all simple ideas, since, accord ing to your own admission, there are simple ideas whose per- 1 Gerhardt reads: "Je distingue settlement entre les idoes et les pensces "; Erdtnann and Jacques read: "Je distingue settlement entre sensations et pense'es." — TR.
120 LEIBNITZ'S CRITIQUE OF LOCKE [BK. n ception comes from reflection, and since the mind l gives itself thoughts from reflection, for it is itself which reflects? Whether it can refuse them is another question, and doubtless it cannot (refuse them) without some reason, which turns it aside from them, when there is some occasion for it.]
Ph. [It seems that hitherto we have discussed ex professo. Now that we are going to come to the detail of ideas, I hope that we shall be more agreed, and that we shall differ only in some particulars.]
Th. [I shall be delighted to see able men adopting the views which I hold to be true, for they are adapted to improve them and to show them in a good light.]
CHAPTER II SIMPLE IDEAS § 1. Ph. I hope then that you will admit that there are simple and complex ideas; thus heat and softness in wax, and cold in ice, furnish simple ideas, for the soul has a uniform conception of them, which is not distinguishable into different ideas.
Th. [I believe that we can affirm that these sense-ideas are simple in appearance, because, being confused, they do not give the mind the means of distinguishing their contents. In like manner distant things appear round, because their angles can not be discerned, although some confused impression of them is received. It is manifest, for example, that green arises from a mixture of blue and yellow; thus it is possible to believe that the idea of green is also composed of these two ideas. And yet the idea of green appears to us as simple as that of blue or that of warmth. So we are to believe that the ideas of blue and warmth are not as simple as they appear. I readily consent, however, to treat these ideas as simple ideas, because at least our apperception does not divide them, but it 1 Gerhardt reads: " et que 1'esprit se donnc "; Erdmann and Jacques read: "et qu'au moins 1'esprit se doime," and since the miiid at least gives itself.
en. in] ON HUMAN UNDERSTANDING 121 is necessary to proceed to their analysis by means of other experiences and by reason, in proportion as they can be ren dered more intelligible.1 And it is also seen thereby that there are perceptions of which we are not conscious. For the perceptions of ideas simple in appearance are composed of per ceptions of the parts of which these ideas are composed, with out the mind's being conscious of them, for these confused ideas appear simple to it.]
CHAPTER III OF IDEAS WHICH COME TO US BY ONE SENSE ONLY Ph. ISTow we can arrange simple ideas according to the means by which we pergeive them, for that is done, 1, by means of one sense only; 2, by means of more than one sense; 3, by reflection, or 4, by all the ways 2 of sensation as well as by reflection. Thus of those which enter by a single sense which is particularly adapted to receive them, light and colors enter only by the eyes; all kinds of noises, sounds, and tones enter by the ears; the different tastes by the palate; and odors by the nose. These organs or nerves carry them to the brain, and if any one of these organs chance to be disordered, these sensations cannot be admitted by any artificial gate. The most considerable qualities belonging to the touch are cold, heat, and solidity. The others consist either in the configura tion of the sensible parts, as smooth and rough, or in their union, as compact, hard, soft, brittle.3 Tli. [I quite agree, sir, with what you say, although I may remark that, according to the experiment of the late M. Mariotte 4 upon the defect of vision with regard to the optic 1 Erdmann's and Jacques's texts of chap. 2 end here; Gerhardt's text adds the following: "Et 1'on voit encor par la qu'il y a des perceptions dont on ne s'appercoit point. Car les perceptions des idees simples en apparence sont composees des perceptions des parties dont ces idees sont composees, sans que 1'esprit s'en appereoive, car ces idees confuses luy paroissent simples." — TR.
8 Locke uses these forms, instead of the more common abstract forms end ing in -ness. Hence I have used them in the translation. — TR.
4 Edme Mariotte, a celebrated French physicist, born about 1(520, died 1684. He was in some sense the initiator of experimental physics in France. The experiment here referred to, and the resulting discovery of the blind spot at 122 LEIBNITZ'S CRITIQUE OF LOCKE [BK. 11 nerve, it seems to me that the membranes receive the sensa tion rather than the nerves, and there is an irregular en trance for the hearing and the taste, since the teeth and the vertex assist in causing any sound to be heard, and that tastes make themselves known to some extent through the nose, by reason of the connection of these organs. But all that makes no change in the foundation of things as regards the explica tion of ideas. As for the qualities belonging to touch, you can say that smoothness or roughness, hardness or softness, are only modifications of resistance or solidity.]
CHAPTER IV OF SOLIDITY § 1. Ph. You will doubtless agree that the idea of solidity is caused by the resistance we find in a body to the en trance of another body into the place it occupies until it has left it. That which thus hinders the approach of two bodies when they are moved one toward another I call solidity. If any one finds it more to the purpose to call it impenetrability, I give my consent. But I believe that the term solidity bears a more positive character. This idea seems most intimately connected with and essential to body, and can be found only in matter.
Th. It is true that we find resistance in touch, when another body reluctantly gives place to our own, and it is also true that bodies dislike to occupy the same place. Many, how ever, doubt whether this repugnance is invincible, and it is well also to consider that the resistance which is found in matter is derived in more than one way and by means of reasons quite different. A body resists another either when it must leave the place which it has already occupied, or when it fails to enter the place into which it was ready to enter, because the other tries to enter also, in which case it may happen that, the one not yielding to the other, they stop or mutually repel each the entrance of the optic nerve, was made in 1668. An account of it is given in a short paper in the second volume of his collected works. CEuvres de Mariottc, 2 vols., Leyden: 1717, 4to. — TR.
CH. iv] ON HUMAN UNDERSTANDING 123 other. The resistance is seen in the change of that (body) to which resistance is offered, whether it loses its force, changes its direction, or both happen at once. Now you can say in general that this resistance arises from the repugnance which two bodies have to occupy the same place, which may be called impenetrability. Thus when one body makes an effort to enter, it at the same time forces the other to attempt to leave or to prevent its entrance. But that kind of incompati bility which makes one or the other, or both together, yield, being once assumed, there are several reasons besides the one named which make one body resist another which endeavors to compel its departure. They are either in it or in the neigh boring bodies. There are two which are in itself; one is pas sive and constant, the other active and variable. The first is what I call inertia,1 after Kepler 2 and Descartes, which impels matter to resist motion, and which it is necessary to destroy by force in order to move a body, supposing that there were neither gravity nor adhesion. Thus a body which undertakes to drive forward another, experiences for that reason this re sistance. The other cause, which is active and variable, con sists in the impetuosity of the body itself, which does not yield without resistance at the moment its own impetuosity carries it into a place. The same reasons reappear in the neighboring bodies when the body which resists is unable to yield without causing the others to yield also. But then a new consideration comes in — viz.: compactness (fermete) or the adhesion of one body to another. This adhesion3 makes it impossible to move one body without at the same time mov ing the other to which it adheres, and this causes a kind of traction in reference to this other. This adhesion so acts that, even should we put aside inertia and manifest impetuosity, there would be resistance; for if space is conceived as filled with matter perfectly fluid, and if a single hard body were placed within it, this hard body (supposing there were in the fluid neither inertia nor impetuosity) will be moved therein without finding any resistance; but if space were full of little 1 Gerhardt reads " incertie "; evidently an error. — TR.
2 John Kepler, laTl-KJ.SO, one of the creators of modern astronomy. His complete works were edited by Dr. Ch. Frisch, Jounnis Kepleri opera omnia, 8 vols., Frankfort: 1858-1871. — TR.
8 Erdmann and Jacques add " souvent," often. — TR.
124 LEIBNITZ'S CRITIQUE OF LOCKE [me. n cubes, the resistance which the hard body would find, should it be moved among the cubes, would come from the fact that the little hard cubes, on account of their hardness or because of the adhesion of their parts one to another, would with diffi culty be separated as much as would be necessary to make a circle of movement, and to fill up the place of the body moved at the moment it departs. But if two bodies should enter at the same time by the two ends into a tube open on both sides, and should fill it to its capacity, the matter in this tube, how ever fluid it be, would resist by its impenetrability alone. Thus, in the resistance of which we are here treating, we have to consider the impenetrability of bodies, inertia, impetuosity, and adhesion. It is true that, in my opinion, this adhesion of bodies arises from a more subtile motion of one body toward another; but, as this is a point which may be disputed, it must not be assumed at first. And for the same reason we must only assume at first an original, essential solidity, which makes the place always equal to the body, that is to say that the in compatibility, or, to speak more accurately, the non-consistence1 of bodies in the same place is a perfect impenetrability which receives neither more nor less, since many maintain that sensi ble solidity can arise from a repugnance on the part of bodies to be found in the same place, but which will not prove to be an invincible repugnance. For all the ordinary Peripatetics and many others believe that the same matter can fill more or less space, which phenomenon they call rarefaction or conden sation, not in appearance only (as when water is squeezed from a sponge), but rigorously, like the scholastic conception of the air. I am not of this opinion; but I do not think that I ought at first to assume the opposite opinion, the senses, apart from the reasoning faculty, not sufficing to establish this perfect im penetrability, which I hold to be true in the order of nature, but which is not learned by sensation alone. And some one may claim that the resistance of bodies to compression arises from an effort of the parts to spread themselves when they have not their entire liberty. For the rest the eyes aid greatly in proving these qualities, coming to the assistance of 1 Leibnitz's word is " 1'inconsistence," and, as it is apparently technical, I have decided to transfer it, merely changing the form of the negative in- to non- to avoid ambiguity. — Tit.
en. iv] ON HUMAN UNDERSTANDING 125 touch. And at bottom solidity, so long as it presents a dis tinct idea, is conceived by pure reason, although the senses furnish the reasoning faculty with the proof that it is in nature.
§ 4. Ph. We are at least agreed that the solidity of a body carries with it the filling of the space it occupies in such a way as absolutely to exclude every other body [if a space can be found in which there was none before], while hardness [or the consistence rather which some call compactness (fer- me£e)], is a strong union of certain parts of matter, which make up masses of a sensible size, so that the whole mass does not easily change its form.
Th. [This consistence, as I have already remarked, is pre cisely what makes it difficult to move one part of a body with out the other, so that when one part is pushed, the other, which is not pushed, and which does not fall within the line of tendency, is nevertheless induced to go from that side by a kind of traction; and, further, if this last part finds any obsta cle which holds or pushes it back, it draws it along, or holds back, also, the first part; and this action is always reciprocal. The same thing sometimes happens in the case of two bodies which do not touch and which do not form a continuous body whose parts are contiguous; and yet, the one pushed compels the other to go without pushing it, so far as the senses can give us knowledge. Of this the animant,1 electrical attraction, 1 See Krauth-Flemlng, Vocal). Philos. Sciences, pp. 28, 29, and 571, edition of 1877, New York: Sheldon & Co., 1883. The animant is that which pos sesses and imparts life. Together with its cognates animality, animalish, animalist, used frequently hy Cudworth. See Intell. Kyst., 514, " Ut sit Animans, that it be Animant, or endued with Life, Sense, and Understand ing." Ibid., 198. "But no Atheist ever acknowledged conscious animality to be a first principle in the universe; nor that the whole was governed by any animalist, sentient, and understanding nature, presiding over it as the head of it." The term being technical, and, with its cognates, more or less current in the seventeenth ceiitnry, it seemed best to retain it, de-lining and illustrating as above. Its meaning is, I think, sufficiently evident. It is to be noticed, however, that Erdmann, in his Errores Typogr aphid, prefixed to his edition, reads aimnnt instead of animant. Jacques's text also has aimant. The translation would then be: The loadstone or magnet; and Schaarschmidt, following this reading, renders it " der Magnet," in his German translation of the Noureaux Essais, in J. H. v. Kirclimann's Philos. liibliothck, Berlin, 1873. As I translate on the basis of Gerhardt's text I retain his read ing and its translation, with the note explaining the term, although at the present writing the reading of Erdmann and Jacques seems more congruous with the context, and so more likely to be the true one. — TB.
126 LEIBNITZ'S CRITIQUE OF LOCKE [BK. n and that which was formerly ascribed to the fear of a vacuum, furnish examples.]
Ph. It seems that, in general, hard and soft are names which we give to things solely as related to the particular constitu tion of our bodies.