what comes only from a flat picture is derived from a body, so that in this case there is in our judgments all at once a me tonymy and a metaphor; for even the figures of rhetoric pass into sophisms when they impose on us. This confusion of the effect with the cause, whether true or false, often enters into our judgments, moreover, upon other things. Thus we feel our bodies, or what touches them, and we move our arms by means of an immediate physical influence, which we think 1 Gaspard Desargues, 1593-16(52, a French geometer and engineer, a friend of Descartes, Gassendi, Pascal, and Roberval, who wrote on the application of geometry to the arts as well as on geometry itself. These writings have been lost and their titles are known only through the engraver Bosse. Of his Methods universelle de mettre en perspective des objects donnes rdellement, on en devis, avec leurs proportions, mesures, dloignments, sans employer aucun point qui soil hors du champ de I'ouvrac/e, 1630 or 1636, Descartes thus speaks in a letter to Mersenne ("written toward the end of April, 1637," according to Cousin, (Eunres de Descartes, Vol. 6, pp. 250-256, Paris: 1824- 1826), "Je n'ai recu que depuis pen de jours le petit livre in folio, qui traite de la perspective: il n'est pas a de'sapprouver, outre que la curiosite et la nettete du langage de son auteur sont a estimer," I received only a few days ago the little book in folio treating of perspective: it is not to be con demned: further the exactness and perspicuity of the author's language are to be admired. — TR.
138 LEIBNITZ'S CRITIQUE OF LOCKE [HK. 11 constitutes the connection of the soul with, the body, while in truth we feel and change in that way only what is in us.
Ph. I will at this time propose to you a problem which the learned Mr. Molyneux,1 who employs so profitably his excel lent genius in the promotion of the sciences, communicated to the illustrious Mr. Locke. Here it is nearly in his own terms: Suppose a man blind from birth, now grown up, who has learned to distinguish by touch a cube from a globe of the same metal, and almost of the same size, so that when he touches the one or the other he can tell which is the cube and which the globe. Suppose that the cube and the globe being placed upon the table, this blind man comes to enjoy his sight. The question is, if in seeing them without touching them he could distinguish them, and tell which is the cube and which the globe. I pray you, sir, tell me what is your opinion upon the matter.
Tli. I ought to give some time to thought upon this ques tion, which appears to me quite curious: but since you press me for an immediate reply, I would venture to say between ourselves that I think that supposing the blind man knows that these two figures which he sees are those of the cube and the globe, he could distinguish them and say, without touch ing, This is the globe, this the cube.
Ph. I fear lest it may be necessary to put you in the crowd of those who have failed to answer Mr. Molyneux; for he sent word in the letter which contained this question, that, having proposed it upon the occasion of Mr. Locke's Essay on Under standing to different persons of very penetrating minds, he had found scarcely one among them who at once gave such a reply upon that point as he thinks should be made, although they were convinced of their error after having heard his reasons. The reply of this penetrating and judicious author is negative; for (he adds) while this blind man has learned by experience of some kind the globe and the cube as they affect his touch, he does not, however, yet know that what affects the touch in such or such manner must strike the eyes 1 William Molynenx, 1050-1098, an eminent mathematician. He founded in Dublin, in January, 1084, a Philosophical Society on the model of the Royal Society at London. His principal work, Dioptrica Nova, in two parts, was published at London in 1092-1709, in 4to. — TK.
en. ix] ON HUMAN UNDERSTANDING 139 in such or such manner, nor that the projecting angle of the cube, which presses his hand in an unequal manner, must appear to his eyes as it appears in the cube. The author of the Essay declares himself at once of the same opinion.
Th. Perhaps Mr. Molyneux and the author of the Essay are not so far from my opinion as at first appears, and the reasons for their view, contained apparently in the letter of the for mer, who has employed them with success in order to convince men of their error, have been purposely suppressed by the latter in order to give more exercise to the minds of his readers. If you will weigh my reply, you will find, sir, that I have placed therein a condition which can be considered as comprised in the question — viz.: that the question is that of distinguishing alone, and that the blind man knows that the two figured bodies, which he should distinguish, are there, and that thus each of the appearances which he sees is that of the cube or that of the globe. In this case it appears to me beyond doubt that the blind man who ceases to be such can distinguish them by the principles of reason, united with that sense-knowledge with which touch has before furnished him. For I do not speak of that which he will do perhaps in fact and immediately, dazzled and confused by the novelty, or from some other cause little accustomed to draw inferences. The basis of my view is that in the globe there are no points dis tinguished by the side of the globe itself, all there being level and without angles, while in the cube there are eight points distinguished from all the others. If there were not this means of discerning the figures, a blind man could not learn the rudiments of geometry by touch. But we see that those born blind are capable of learning geometry, and have indeed always certain rudiments of a natural geometry, and that most often geometry is learned by sight alone, without the use of touch, as indeed a paralytic or other person to whom touch has been.almost denied might and even must do. And these two geometries — that of the blind man and that of the paralytic — must meet and agree, and indeed return to the same ideas, although there are no common images. This again shows how necessary it is to distinguish images from exact ideas, which consist in definitions. It would really be very interesting and instructive to make a complete examination of the ideas of a man born blind, to understand the descriptions he makes of figures. For he may come to this, and he may even understand the doctrine of optics, so far as it is depend ent upon distinct and mathematical ideas, although he could not attain to a conception of clair-confiis, that is to say, the image of light and of colors. This is why a certain one born blind, after having attended lessons in optics, which he appeared fully to understand, replied to some one who asked him what he thought light was, that he thought it must be something pleasant like sugar. It would likewise be very important to examine the ideas which a man born deaf and dumb may have of things not figured, whose description we usually have in words, and which he must have in a manner wholly different from, though it may be equivalent to ours, as Chinese writing is in fact equivalent to our alphabet, although it is infinitely different, and might appear to have been in vented by a deaf man. I learn, through the favor of a great prince, of one born deaf and dumb in Paris, whose ears have at last attained to the performance of their function, that he has now learned the French language (for it is from the court of France that he was summoned not long since), and that he could say very curious things about the conceptions he had in his former condition and about the change of his ideas when he commenced to exercise the sense of hearing. These per sons born deaf and dumb can go farther than we think. There was one in Oldenburg in the time of the last Count who became a good painter, and showed himself very rational in other respects. A very learned man, a Breton by nation, told me that at Blainville, about ten leagues from Nantes, belonging to the Duke of Rohan, there was, about 1690, a poor man, who lived in a hut near the castle outside of the town, who was born deaf and dumb, and who carried letters and other things to the town and found the houses, following some signs which the persons accustomed to employ him made him. Finally the poor man became blind also, but did not give up rendering some service and carrying letters into the town to whatever place they indicated to him by touch. He had a board in his hut which, extending from the door to the place where his feet were, informed him by its motion when any one entered his house. Men are very negligent in en. ix] ON HUMAN UNDERSTANDING 141 not obtaining an exact knowledge of the modes of thought of such persons. If he no longer lives, there is probably some one in the vicinity who could still give some information respecting him, and make us understand how they showed him the things he was to do. But to return to what the man born blind, who begins to see, would think of the globe and the cube, seeing them without touching them, I reply that he will distinguish them, as I have just said, if any one informs him that the one or the other of the appearances or perceptions which he has of them belongs to the cube or to the globe; but, without this previous instruction, I admit that he will not at first venture to think that the kinds of pictures which they make of themselves in the depths of his eyes, and which might come from a flat picture upon the table, represent the bodies, until touch convinces him of the fact, or until, by force of reasoning upon the rays of light according to optics, he understands by the lights and shades that there is a some thing which arrests these rays of light, and that it must be exactly what remains for him in touch, which result he will finally reach when he sees this globe and this cube revolve, and change the shadows and the appearances in accordance with the motion, or even when, these two bodies remaining at rest, the light which illumines them changes its place, or his eyes change their position. For these are about the means we have of distinguishing from afar a picture or a perspec tive, which represents a body, from the body itself.
§ 11. Ph. [Let us return to perception in general.] It dis tinguishes animals from inferior beings.
Th. [I am inclined to the belief that there is some percep tion and appetition also in the plants, because of the great analogy which exists between plants and animals; and if, as is commonly supposed, there is a vegetable soul, it of necessity has perception. Yet I do not cease to attribute to mechanism all that takes places in the bodies of plants and animals, except their first formation. Thus I agree that the move ment of the plant called sensitive arises from mechanism, and I do not approve of having recourse to the soul when the question is that of explaining the detail of the phenomena of plants and animals.]
§ 14. Ph. It is true that for myself, indeed, I cannot help 142 LEIBNITZ'S CRITIQUE OF LOCKE [UK. 11 believing that even in those kinds of animals which are like the oysters and mussels there is some feeble perception; for quick sensations would serve only to discommode an animal which is constrained to live always in the place where chance has put it, where it is watered with water, cold or warm, pure or salt, according as it comes to it.
Th. [Very well, I also believe that we can say almost as much of plants; but in man's case, his perceptions are accom panied with the power of reflection, which passes to the act when there is any occasion. But when he is reduced to a state in which he is as it were in a lethargy and almost without feeling, reflection and consciousness cease, and universal truths are not thought of. But the innate and acquired faculties and dispositions, and even the impressions which are received in this state of confusion, do not cease on that account, and are not effaced, though they are forgotten. They will even have their turn one day in contributing to some notable result, for nothing is useless in nature; all confusion must develop itself; the animals even, having attained to a condition of stupidity, ought some day to return to perceptions more ele vated; and, since simple substances always endure, we must not judge of eternity by a few years.]
CHAPTER X OF RETENTION §§ 1, 2. Ph. The other faculty of the mind, by which it advances farther toward the knowledge of things than by sim ple perception, is that which I call retention, which conserves the knowledge received by the senses or by reflection. Reten tion works in two ways: in actually conserving the present idea, which I call contemplation; and in preserving the power to bring them again before the mind, and this is what is called memory.
Th. [One retains also and contemplates innate knowledge, and very often one cannot distinguish the innate from the acquired. There is also a perception of images — either those CH. xi] ON HUMAN UNDERSTANDING 143 which have already existed for some time, or those which are formed anew in us.]
§ 2. Ph. But you believe with us that these images or ideas cease to be anything as soon as they are not actually matters of consciousness; and that to say that there are ideas reserved in the memory means at bottom only that the soul has in some instances the power of reviving the perceptions it has already had with a feeling which at the same time convinces it that it has previously had these kinds of perceptions.
Th. [If ideas were only forms or modes of thoughts, they would cease with them; but you yourself have admitted, sir, that they are internal objects, and in this way can subsist. And I am astonished that you can always be satisfied with these naked powers or faculties, which you would apparently reject in the scholastic philosophers. It would be necessary to explain a little more distinctly in what this faculty consists and how it is exercised; and that would make known that there are dispositions which are the remains of past impres sions in the soul as well as in the body, but of which we are conscious only when the memory finds some occasion for them. And if nothing restored past thoughts, as soon as we no longer think of them, it would be impossible to explain how the memory can preserve them; and to recur for this purpose to this naked faculty is to speak nowise intelligibly.
CHAPTEK XI OF DISCERNMENT OR THE FACULTY OF DISTINGUISHING IDEAS § 1. Ph. Upon the faculty of distinguishing ideas depends the evidence and certainty of several propositions which pass for innate truths.
Th. I admit that to think of these innate truths and to unravel them discernment is necessary; but they do not on that account cease to be innate.]
§ 2. Ph. Now, vivacity of mind consists in recalling promptly ideas; but judgment in representing them clearly and distinguishing them exactly.
144 LEIBNITZ'S CRITIQUE OF LOCKE [BK. n Tli. [Perhaps each is vivacity of imagination, and judg ment consists in the examination of propositions according to reason.]
Ph. [I am not averse to this distinction of mind and judg ment. And sometimes there is judgment in not employing it too much. For example: to examine certain witty thoughts by the severe rules of truth and good reasoning is in a certain sense an insult.
Tli. [This remark is a good one; witty thoughts must have at least some apparent foundation in reason, but it is not necessary to examine them minutely with too much scrupu lousness, as it is not necessary to look at a picture from a position too near it. It is in this, it seems to me, that Father Bouhours fails more than once in his Art de penser dans les ouvrages d? esprit 1 as when he despises this sally of Lucan: 2 Victrix causa diis placuit, sed victa Catoni.
§ 4. Ph. Another operation of the mind in respect to its ideas is the comparison it makes of one idea with another as regards extension, degrees, time, place, or some other circum stance; it is upon this that the great number of ideas com prised under the term relation depends.
Tli. [According to my view, relation is more general than comparison, for relations are either of comparison or of concur rence. The first concern the congruity or incongruity (I take these terms in a less extended sense) which comprises resem blance, equality, inequality, etc. The second comprise some connection, as that of cause and effect, of whole and parts, of position and order, etc.]
§ 6. Ph. The composition of simple ideas, for the purpose of making complex ideas, is also an operation of our mind. We may refer to this the faculty of extending ideas by uniting those of the same kind, as in forming a dozen from several units.
Th. [The one is doubtless as much composition as the 1 Dominique Bouhours, 1628-1702, one of the ablest masters of the French language in the seventeenth century. The title of his work here jjiven follows Gerhardt's text. The correct title is: Maniere de bicn pentter dans les ouvrages d'esprit, Paris, 1G87. There were several editions. — TR.
en. xi] ON HUMAN UNDERSTANDING 145 other; but composition of similar ideas is simpler than that of different ideas.]
§ 7. Ph. A dog will nurse young foxes, will play with them, and will have for them the same fondness as for her own puppies, if they can be made to suck her so long as is needful for the milk to spread through their entire body. Moreover it does not appear that animals, who have a large number of young at once, have any knowledge of their num ber.
Th. [The love of animals arises from a pleasure which is increased by habit. But as for the precise number, men even can know the numbers of things only by some skill, as in using numerical names in order to count, or figural arrangements which make them know at once without counting if anything is wanting.]
§ 10. Ph. Animals do not form abstract thoughts.
Th. [I agree. They apparently recognize whiteness, and notice it in the chalk or the snow; but this is not yet abstrac tion, for that demands a consideration of what is common, separated from what is particular, and consequently there enters into it the knowledge of universal truths, which is not given to the animals. It is well said also that the animals which speak do not use words to express general ideas, and that men deprived of the use of speech and of words do not cease to invent other general signs. I am pleased also to see that you here and elsewhere so well observe the advantages of human nature.]
§ 11. Ph. If animals have some ideas, and are not pure ma chines, as some maintain, we cannot deny that they have reason in a certain degree, and, for myself, it appears as evident that they reason as that they feel. But it is only upon particular ideas that they reason according as their senses represent these ideas to them.
Th. [Animals pass from one imagination to another by the connection which they have felt here before; for example, when his master takes a stick, the dog fears a whipping. And in many instances children with the rest of mankind proceed nowise differently in their passages from thought to thought. This might be called consecution and reasoning in a very broad sense. But I prefer to conform to the received usage in conse- L 146 LEIBNITZ'S CRITIQUE OF LOCKE [UK. n crating these terms to man and in limiting them to the knowl edge of some reason of the connection of perceptions, which sensations alone cannot give; their effect being only to cause us naturally to expect at another time this same connection which we have noticed before, although perhaps the reasons are no longer the same, a fact which often deceives those who are governed only by the senses.]
§ 13. Ph. Idiots lack vivacity, activity, and movement in the intellectual faculties, whereby they are deprived of the use of reason. Madmen seem to be at the opposite extreme, for it does not appear to me that these latter have lost the power to reason, but having wrongly united certain ideas, they take them for truths, and deceive themselves in the same way as those who reason justly upon false principles. Thus you will see a madman who thinks he is king maintaining by a just consequence that he should be served, honored, and obeyed according to his rank.
Th. [Idiots do not exercise reason, and they differ from some stupidpersons who have good judgment, but, not having prompt conception, they are despised and disturbed as he would be who wished to play ombre with persons of distinction and thought too long and too often of the part he must take. I remember a learned man who, having lost his memory by the use of certain drugs, was reduced to this condition, but his judgment always appeared. A man wholly mad lacks judg ment on nearly every occasion; but the vivacity of his imagi nation may make him agreeable. But there are particular madmen who make a false supposition at an important point in their lives, and reason justly thereupon, as you have well said. There is such a man, well known at a certain court, who believes himself destined to redress the affairs of the Protestants and to bring France to reason, for which purpose God caused the greatest personages to pass through his body in order to ennoble it; he desires to marry all the princesses he sees to be marriageable, but after having made them holy, in order to have a holy progeny who are to rule the land; he attributes all the misfortunes of war to the little attention paid to his advice. In speaking with a certain sovereign, he takes every necessary measure not to lower his dignity. When they enter into conversation with him, he maintains CH. xn] ON HUMAN UNDERSTANDING 147 himself so well that I have doubted more than once whether his madness is not feigned, for he is not inconvenienced by it. However, those who know him more intimately assure me that his madness is wholly genuine.]
CHAPTER XII OF COMPLEX IDEAS Ph. The understanding bears not a little resemblance to a room wholly dark, which has only certain small openings to let in from outside exterior and visible images, so that if these images, coining to be painted in this dark room, could remain there and be placed in order, so that they could be found upon occasion, there would be a great resemblance between this room and the human understanding.
Th. [To make the resemblance greater, you should suppose that in this room there was a canvas to receive the images, not even, but diversified by folds, representing the (kinds of) in nate knowledge; further, that this canvas or membrane being stretched would have a kind of elasticity or power of action, and also an action and reaction accommodated as much to the past folds as to the newly arrived kinds of impressions. And this action would consist in certain vibrations or oscillations, such as are seen in a stretched string so touched that it gives forth a kind of musical sound. For not only do we receive images or outlines in the brain; but we form besides new ones, when we look at complex ideas. Thus the canvas that repre sents our brain is necessarily active and elastic. This com parison would explain tolerably well what passes in the brain; but as for the soul, which is a simple substance or monad, it represents without extension these same varieties of extended masses and perceives them.1] § 3. Ph. Now complex ideas are either modes or substances or relations.
1 According to the principle of Pre-established Harmony. Cf. Systems nouveau de la nature, etc., Ki95, §§ 14, 15; Gerhardt, 4, 484, 485; Erdmann, 127, 128; Jacques, 1, 475, 476; translation, Appendix, p.. — TR.
148 LEIBNITZ'S CRITIQUE OF LOCKE [BK. n Th. [This division of the objects of our thought into sub stances, modes,1 and relations is sufficiently to my taste. I be lieve that qualities are only modifications of substances, and that the understanding adds thereto the relations.2 From this follows more than you think.]
Ph. Modes are either simple (as a dozen, a score, which are composed of simple ideas of the same kind, i.e. of units) or mixed (as beauty), into which enter simple ideas of different kinds.
Th. Perhaps dozen or score are only relations, and are con stituted only in connection with the understanding. Units are separate, and the understanding gathers them together how ever dispersed they be. Yet, although relations are from the understanding, they are not groundless or unreal. For in the first place understanding is the origin of things; and indeed the reality even of all things, simple substances excepted, ulti mately consists only of perceptions of the phenomena of sim ple substances. It is often the same with regard to the mixed modes; i.e. it is necessary to refer them rather to the rela tions.]
§ 6. Ph. The ideas of substances are certain combinations of ' simple ideas, which are supposed to represent particular and: distinct things, subsisting by themselves, among which ideas the obscure notion of substance, which is assumed without • knowing what it is in itself, is always considered as the first -• and chief.