ficially, piece by piece, out of unextended sensa tions, though we can neither understand how they come to form an extended surface, nor how they are subsequently projected outside our body? Why insist, in spite of appearances, that I should go from my conscious self to my body, then CHAP, i THE IMAGE AND REALITY 45 from my body to other bodies, whereas in fact I place myself at once in the material world in general, and then gradually cut out within it the centre of action which I shall come to call my body and to distinguish from all others? — There are so many illusions gathered round this belief in the originally unex- tended character of our external perception; there are, in the idea that we project outside our selves states which are purely internal, so many misconceptions, so many lame answers to badly stated questions, that we cannot hope to throw light on the whole subject at once. We believe that light will increase, as we show more clearly, behind these illusions, the metaphysical error which confounds the unbroken extensity with homo geneous space, and the psychological error which confounds ' pure perception ' with memory. But these illusions are, nevertheless, connected with real facts, which we may here indicate in order to correct their interpretation.
The first of these facts is that our senses require education. Neither sight nor touch is able at objection the outset to localize impressions. A SKo-cSS series °f comparisons and inductions is ofdtheasenses necessary, whereby we gradually co- i^?o!als™han" ordinate one impression with another, education. Hence philosophers may jump to the belief that sensations are in their essence inexten- sive, and that they constitute extensity by their juxtaposition. But is it not clear that, upon the 46 MATTER AND MEMORY CHAP, i hypothesis just advanced, our senses are equally in need of education, — not of course in order to accom modate themselves to things, but to accommodate themselves to each other? Here, in the midst of all the images, there is a certain image which I term my body, and of which the virtual action reveals itself by an apparent reflexion of the surround ing images upon themselves. Suppose there are so many kinds of possible action for my body: there must be an equal number of systems of reflexion for other bodies; and each of these systems will be just what is perceived by one of my senses. My body, then, acts like an image which reflects others, and which, in so doing, analyses them along lines corresponding to the different actions which it can exercise upon them. And, consequently, each of the qualities perceived in the same object by my different senses symbolizes a particular direction of my activity, a par ticular need. Now, will all these perceptions of a body by my different senses give me, when united, the complete image of that body? Cer tainly not, because they have been gathered from a larger whole. To perceive all the influences from all the points of all bodies would be to de scend to the condition of a material object. Con scious perception signifies choice, and consciousness mainly consists in this practical discernment. The diverse perceptions of the same object, given by my different senses, will not, then, when put to gether, reconstruct the complete image of the CHAP. I THE IMAGE AND REALITY 47 object; they will remain separated from each other by intervals which measure, so to speak, the gaps in my needs. It is to fill these intervals that an education of the senses is necessary. The aim of this education is to harmonize my senses with each other, to restore between their data a continuity which has been broken by the discon tinuity of the needs of my body, in short to re construct, as nearly as may be, the whole of the material object. This, on our hypothesis, ex plains the need for an education of the senses. Now let us compare it with the preceding explana tion. In the first, unextended sensations of sight combine with unextended sensations of touch and of the other senses, to give, by their synthesis, the idea of a material object. But, to begin with, it is not easy to see how these sensations can ac quire extension, nor how, above all, when exten sion in general has been acquired, we can explain in particular the preference of a given one of these sensations for a given point of space. And then we may ask by what happy agreement, in virtue of what pre-established harmony, do these sen sations of different kinds co-ordinate themselves to form a stable object, henceforth solidified, common to my experience and to that of all men, subject, in its relation to other objects, to those inflexible rules which we call the laws of nature? In the second, ' the data of our different senses ' are, on the contrary, the very qualities of things, perceived first in the things rather than in us: 48 MATTER AND MEMORY CHAK I is it surprising that they come together, since abstraction alone has separated them? — On the first hypothesis, the material object is nothing of ah1 that we perceive: you put on one side the con scious principle with the sensible qualities, and on the other a matter of which you can predicate nothing, which you define by negations because you have begun by despoiling it of all that reveals it to us. In the second, an ever-deepening know ledge of matter becomes possible. Far from depriving matter of anything perceived, we must on the contrary bring together all sensible quali ties, restore their relationship, and re-establish among them the continuity broken by our needs. Our perception of matter is, then, no longer either relative or subjective, at least in principle, and apart, as we shall see presently, from affection and especially from memory; it is merely dissevered by the multiplicity of our needs. — On the first hypothesis, spirit is as un knowable as matter, for you attribute to it the undefinable power of evoking sensations we know not whence, and of projecting them, we know not why, into a space where they will form bodies. On the second, the part played by consciousness is clearly defined: consciousness means virtual action; and the forms acquired by mind, those which hide the essence of spirit from us, should, with the help of this second principle, be removed as so many concealing veils. Thus, on our hypo thesis, we begin to see the possibility of a clearer CHAP, i THE IMAGE AND REALITY 49 distinction between spirit and matter, and of a reconciliation between them. But we will leave this first point and come to the second.
The second fact brought forward consists in what was long termed the ' specific energy of the nerves.' We know that stimulation of Objection drawn from the optic nerve by an external shock or the so-called •specific by an electnc current will produce a energy, of the * * nerves.— visual sensation, and that this same electric current applied to the acoustic or to the glosso-pharyngeal nerve will cause a sound to be heard or a taste to be perceived. From these very particular facts have been deduced two very general laws: that different causes acting on the same nerve excite the same sensation; and that the same cause, acting on different nerves, provokes different sensations. And from these laws it has been inferred that our sensations are merely signals, and that the office of each sense is to translate into its own language homogeneous and mechanical movements occurring in space. Hence, as a conclusion, the idea of cutting our perception into two distinct parts, thenceforward incapable of uniting: on the one hand homogeneous move ments in space, and on the other unextended sen sations in consciousness. Now, it is not our part to enter into an examination of the physiological problems raised by the interpretation of the two laws: in whatever way these laws are understood, whether the specific energy is attributed to the nerves or whether it is referred to the centres, insur- B 50 MATTER AND MEMORY CHAP, i mountable difficulties arise. But the very existence of the laws themselves appears more and more problematical. Lotze himself already suspected a fallacy in them. He awaited, before putting faith in them, ' sound waves which should give to the eye the sensation of light, or luminous vibra tions which should give to the ear a sound/ l The truth is that all the facts alleged can be brought back to a single type: the one stimulus capable of producing different sensations, the multiple stimuli capable of inducing the same sensation, are either an electric current or a mechanical cause capable of determining in the organ a modi fication of electrical equilibrium. Now we may well ask whether the electrical stimulus does not include different components, answering objec tively to sensations of different kinds, and whether the office of each sense is not merely to extract from the whole the component that concerns it. We should then have, indeed, the same stimuli giving the same sensations, and different stimuli provoking different sensations. To speak more precisely, it is difficult to admit, for instance, that applying an electrical stimulus to the tongue would not occasion chemical changes; and these changes are what, in all cases, we term tastes.
On the other hand, while the physicist has been able to identify light with an electro-magnetic disturbance, we may say, inversely, that what he 1 Lotze, Metaphysic, Oxford, 1887, vol. ii, p. 206.
CHAP, i THE IMAGE AND AFFECTIVE SENSATION 5 1 calls here an electro-magnetic disturbance is light, so that it is really light that the optic nerve per ceives objectively when subject to electrical stimulus. The doctrine of specific energy appears to be nowhere more firmly based than in the case of the ear: nowhere also has the real existence of the thing perceived become more probable. We will not insist on these facts, because they will be found stated and exhaustively discussed in a recent work.1 We will only remark that the sensations here spoken of are not images per ceived by us outside our body, but rather affec tions localized within the body. Now it results from the nature and use of our body, as we shall see, that each of its so-called sensory elements has its own real action, which must be of the same kind as its virtual action on the external objects which it usually perceives; and thus we can understand how it is that each of the sensory nerves appears to vibrate according to a fixed manner of sensation. But to elucidate this point we must consider the nature of affection. Thus we are led to the third and last argument which we have to examine.
This third argument is drawn from the fact that we pass by insensible degrees from the repre sentative state which occupies space, to the affective state which appears to be unextended.
1 Schwarz, Das Wahrnehmungsproblem, Leipzig, 1892, pp- 313 and seq.
52 MATTER AND MEMORY CHAP. I Hence it is inferred that all sensation is naturally and necessarily unextended, Objections.-, •, drawn from so that extensity is superimposed upon •subjectivity' sensation, and the process of percepstates.— tion consists in an extenonzation of internal states. The psychologist starts, whwett is in f act, from his body, and, as the im pressions received at the periphery of this body seem to him sufficient for the recon- stitution of the entire material universe, to his body he at first reduces the universe. But this first position is not tenable; his body has not, and cannot have, any more or any less reality than all other bodies. So he must go farther, follow to the end the consequences of his principle, and, after having narrowed the universe to the surface of the living body, contract this body itself into a centre which he will end by supposing unextended. Then, from this centre will start unextended sensations, which will swell, so to speak, will grow into extensity, and will end by giving extension first to his body, and afterwards to all other material objects. But this strange supposition would be impos sible if there were not, in point of fact, between images and ideas, the former extended and -the latter unextended, a series of intermediate states, more or less vaguely localized, which are the affective states. Our understanding, yielding to its customary illusion, poses the dilemma, that a thing either is or is not extended; and as the CHAP, i THE IMAGE AND AFFECTIVE SENSATION 53 affective state participates vaguely in extension, is in fact imperfectly localized, we conclude that this state is absolutely unextended. But then the successive degrees of extension, and extensity itself, will have to be explained by I know not what ac quired property of unextended states; the history of perception will become that of internal unex tended states which acquire extension and project themselves without. Shall we put the argument in another form? There is hardly any percep tion which may not, by the increase of the action of its object upon our body, become an affection, and, more particularly, pain. Thus we pass in sensibly from the contact with a pin to its prick. Inversely the decreasing pain coincides with the lessening perception of its cause, and exteriorizes itself, so to speak, into a representation. So it does seem, then, as if there were a difference of degree and not of nature between affection and perception. Now, the first is intimately bound up with my per sonal existence: what, indeed, would be a pain detached from the subject that feels it? It seems therefore that it must be so with the second, and that external perception is formed by projecting into space an affection which has become harm less. Realists and idealists are agreed in this method of reasoning. The latter see in the material universe nothing but a synthesis of sub jective and unextended states; the former add that, behind this synthesis, there is an indepen dent reality corresponding to it; but both con- 54 MATTER AND MEMORY CHAP, i elude, from the gradual passage of affection to representation, that our representation of the material universe is relative and subjective, and that it has, so to speak, emerged from us, rather than that we have emerged from it.
Before criticizing this questionable interpretation of an unquestionable fact, we may show that it does not succeed in explaining, or even in throwing light upon, the nature either of pain or of perception. That affective states, essentially bound up with my personality, and vanishing if I disappear, should acquire extensity by losing intensity, should adopt a definite position in space, and build up a firm, solid experience, always in accord with itself and with the experience of other men — this is very difficult to realize. Whatever we do, we shall be forced to give back to sen sations, in one form or another, first the exten sion and then the independence which we have tried to do without. But, what is more, affection, on this hypothesis, is hardly clearer than repre sentation. For if it is not easy to see how affec tions, by diminishing in intensity, become representations, neither can we understand how the same phenomenon, which was given at first as perception, becomes affection by an increase of intensity. There is in pain something positive and active, which is ill explained by saying, as do some philosophers, that it consists in a con fused representation. But still this is not the principal difficulty. That the gradual augmen- CHAP, i NATURE OF AFFECTIVE SENSATION 55 tation of the stimulus ends by transforming per ception into pain, no one will deny; it is none the less true that this change arises at a definite moment: why at this moment rather than at another? and what special reason brings about that a phenomenon of which I was at first only an indifferent spectator suddenly acquires for me a vital interest? Therefore, on this hypothesis I fail to see either why, at a given moment, a dim inution of intensity in the phenomenon confers on it a right to extension and to an apparent independence; or why an increase of intensity should create, at one moment rather than at another, this new property, the source of positive action, which is called pain.
Let us return now to our hypothesis, and show that affection must, at a given moment, arise out Real of the image. We shall thus undero?pataTttflis stand how it is that we pass from a Unavailing perception which has extensity to an affection which is believed to be unex- tended. But some preliminary remarks on the real significance of pain are indispensable.
When a foreign body touches one of the pro longations of the amoeba, that prolongation is retracted; every part of the protoplasmic mass is equally able to receive a stimulation and to react against it; perception and movement being here blended in a single property, — contrac tility. But, as the organism grows more com plex, there is a division of labour; functions 56 MATTER AND MEMORY CHAP. I become differentiated, and the anatomical ele ments thus determined forego their independence. In such an organism as our own, the nerve fibres termed sensory are exclusively empowered to transmit stimulation to a central region whence the vibration will be passed on to motor elements. It would seem then that they have abandoned individual action to take their share, as outposts, in the manoeuvres of the whole body. But none the less they remain exposed, singly, to the same causes of destruction which threaten the organ ism as a whole; and while this organism is able to move, and thereby to escape a danger or to repair a loss, the sensitive element retains the relative immobility to which the division of labour con demns it. Thence arises pain, which, in our view, is nothing but the effort of the damaged element to set things right, — a kind of motor tendency in a sensory nerve. Every pain, then, must consist in an effort, — an effort which is doomed to be unavailing. Every pain is a local effort, and in its very isolation lies the cause of its impotence; because the organism, by reason of the solidarity of its parts, is able to move only as a whole. It is also because the effort is local that pain is entirely disproportioned to the danger incurred by the living being. The danger may be mortal and the pain slight; the pain may be unbearable (as in toothache) and the danger insignificant. There is then, there must be, a precise moment when pain intervenes: it is when the interested CHAP, i NATURE OF AFFECTIVE SENSATION 57 part of the organism, instead of accepting the stimulation, repels it. And it is not merely a dif ference of degree that separates perception from affection, but a difference in kind.
Now, we have considered the living body as a kind of centre whence is reflected on the surround ing objects the action which these objects exercise upon it: in that reflexion external perception consists. But this centre is not a mathematical point; it is a body, exposed, like all natural bodies, to the action of external causes which threaten to disintegrate it. We have just seen that it resists the influence of these causes. It does not merely reflect action received from without; it struggles, and thus absorbs some part of this action. Here is the source of affection. We might there fore say, metaphorically, that while perception measures the reflecting power of the body, affection measures its power to absorb.
But this is only a metaphor. We must con sider the matter more carefully, in order to under- stand clearly that the necessity of affec- t^on follows from the very existence of perception. Perception, understood as virtual action. we understand it, measures our possible action upon things, and thereby, inversely, the possible action of things upon us. The greater the body's power of action (symbolized by a higher degree of complexity in the nervous system), the wider is the field that perception embraces. The distance which separates our body from an object 58 MATTER AND MEMORY CHAP, i