ON SENSATION.
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CHAPTER I.
SENSATION IN ITSELF.
1. Sensation considered in itself is simply an internal affection; but it is almost always accompanied by a judgment. This judgment may be more or less explicit and more or less noticed by the subject of the sensation.
Suppose I see two architectural ornaments at a proper distance, and I discover no difference between them. In this sensation there are two things to be considered.
I. The internal affection which we call seeing. On this point all doubt is impossible. Whether I am asleep or awake, raving or in my sober senses, whether the ornaments are alike or unlike, whether, in fine, they exist or not, there still exists in my soul the representation which I call seeing the ornaments.
II. I also at the same time form a judgment that, besides the internal affection which I experience, the ornaments exist, that they are in relief, and that they are before my eyes. In this judgment I may be deceived; for I may be asleep or in a delirium; it may be that the ornaments are behind me, and that I only see their reflection in a mirror; it may be that what I see is only a paper placed in such a manner behind a glass, as to make upon the retina of my eyes the same impression as the ornaments would if they were really present; or, finally, it may all be the work of a skilful painter who has given this illusory appearance to his canvas.
From this we see that, admitting the existence of the internal fact of sensation, it is possible:
I. That there is no external object.
II. That the objects exists, but not in the position supposed.
III. That the object is not the architectural ornaments.
IV. That both are plane surfaces; or, that one is in relief, and the other a plane.
This brings us to the evident conclusion that mere sensation has no necessary relation to an external object; for it not only can, but it not unfrequently does, exist without any such object.
This correspondence of the internal to the external belongs to the judgment which accompanies sensation, not to sensation itself.
If brutes refer their sensations to objects, as they probably do, instinct must supply in them the want of judgment, as in the child who has not acquired the use of the intellectual faculties.
Sensation, therefore, in itself considered, affirms nothing. It is a mere affection of our being, an effect produced in our soul, and does not determine whether there is any action of an external object upon our senses, nor whether the object is what it seems to be.
2. Let us imagine an animal reduced to the one sense of touch, and that not developed as in us, but confined to a few rude impressions like those of heat and cold, warmth and dryness; and let us compare it with human sensibility. What an immense distance between the two! Sensibility in such an animal borders on insensibility, whilst in man it approaches intelligence, the representations of his senses are so varied and so extended as to produce within him a whole world, and they might produce infinite others. Man is at the highest round of the ladder, so far as our observation goes, but who can tell how much higher it may be possible to go?
3. However developed and perfected we suppose sensibility, it falls far short of intelligence, from which it must ever remain separated, as from a faculty of a different order. Though we suppose the sensitive faculties capable of indefinite perfectibility, they can never reach the sphere of intelligence, properly so called. This perfectibility would lie in a different order, eternally distinct from that of intellectual beings. If we suppose a color infinitely perfected, it will never become a sound, a sound a taste, a taste a sound, nor a sound a color; because perfectibility is confined to its own order. Therefore, however it may be perfected, sensibility can never become intelligence.
This observation will serve to guard against one of the most fatal errors of our age, which consists in regarding the universe as the result of a mysterious force, which, developing itself by a continual movement, at once spontaneous and necessary, goes on giving birth to beings and elevating species by a perpetual transformation. Thus the greater perfection of the vegetable organization would produce the animal faculties; these being perfected would become sensitive, and in measure as they progressed in the order of sensation they would approach the realm of intelligence, and would finally attain it. There is not a little analogy between this system and that which makes thought a transformed sensation; it effaces the dividing line between intelligent and non-intelligent beings; the sensations of an oyster may, according to it, be so perfected as to be converted into an intelligence superior to that of Bossuet or of Leibnitz; and the development of the faculties of the man-statue would be an emblem of the development of the universe.
4. It may have been already remarked that we are now speaking of the sensitive faculty in itself considered, abstracting from its relations to external objects; and that we therefore comprehend in the word sensation, all affections of the senses, whether actually produced, recollected, or imagined; that is, all affections in all degrees from the first direct consciousness of them, or when they are presented to the being which experiences them, until they reach the limit where intelligence, strictly so called, commences.
It is impossible here to draw the dividing line between the sensible and the intelligible; this requires profound and extensive studies upon sensations compared with ideas, which does not belong to this place: but it will be well to have pointed out the existence of this line, in order to avoid confusion in a most subtle matter, in which every error is attended with the most serious consequences.
5. In what does sensation consist? What is its internal nature? We only know that it is a modification of our being, and that we cannot explain it. No words suffice to convey an idea of a sensation to one who has never experienced it. The man born blind may listen to all that philosophers have said and written on light and colors, but can never imagine what light and colors are.
Experience is the only teacher here; and thus, if we suppose a man's senses to be changed so that green appears to him purple, and purple green, notwithstanding his constant communication with other men, he will never be freed from his error, and he will never suspect that during his whole life he has made use of the words green and purple in a different sense from other men.
6. Analogy and nature incline us to believe that brutes are not mere machines, but that they also have sensations. The vast scale over which irrational beings are distributed, shows that the faculty of feeling is spread over the universe in different degrees, and with a wonderful profusion.
Our experience is confined to the globe in which we live; but are the limits of sensitive life the same as those of our experience? Even on this globe our observation is confined to what the imperfection of our senses, and the instruments which we use, permit; but how far is the chain of life prolonged? Where is its term? Is there not some participation of this mysterious faculty in those beings which we hold to be inanimate? Is the universe, as Leibnitz pretends, composed of a collection of monads endowed with a certain perception? This is indeed an unfounded hypothesis; but since our means of observation are so limited, we should be cautious how we assign boundaries to the realm of life.
7. We ordinarily speak of the faculty of sensation as of something belonging to a very inferior order; so it is, in fact, if compared with intellectual faculties; but this does not prevent it, in itself considered, from being a wonderful phenomenon, of a nature to astonish and confound all who meditate upon it.
Sensation! With this word alone we pass an immense gap in the scale of beings. What is the non-sensible compared with the sensible? The insensible is, but experiences not that it is; there is nothing in it but itself: the sensible experiences that it is; and there is in it something besides itself, all that it feels, all that is represented in it. The insensible, although surrounded with beings, is in complete isolation,—in solitude; the sensible, although alone, may be in a world of infinitely varied representations.
8. The idea of the me is in some sense applicable to every sensitive being; for sensation is inconceivable without a permanent being, which experiences what is transitory; that is, without a being which is one in the midst of multiplicity. Every sensible being, were it capable of reflection, might, in its own way, say I; for it is true of all of them that it is one same being that experiences the variety of sensations. Without this bond, this unity, there is no one sensible being, but a succession of sensations as unconnected phenomena of the whole.
9. There is no sensation without direct consciousness; for, as this is nothing but the very presence of the phenomenon to the being experiencing it, it would be contradictory to say that it feels without consciousness. A sensation experienced, is a sensation present; a sensation not present, that is, not experienced, is inconceivable, is an absurdity.[35]
10. Every sensation involves presence, or direct consciousness, but not representation. I think this distinction important. The sensations of smell, taste, and hearing, are not representative; they remain in themselves, and in their object. The being experiencing them might believe himself enclosed in himself, in an absolute solitude, with no relation to other beings; but touch, and, above all, sight, are by their nature representative; they involve relation to objects; and they imply relation to other beings, not as to mere causes of the internal affection, but as the originals represented in the sensation.
The class of sensible beings endowed with the faculty of representation seems to be of an order very superior to the others; these beings not only have consciousness, but also a mysterious power whereby they see within themselves an entire world.
11. What is the most perfect degree of sensitive life? What the most imperfect? These questions we cannot answer, for we cannot judge of these things otherwise than by experience and analogy. But viewing the immensity of the scale, experience shows us we may infer that nature is far richer than we imagine. Let us not disturb its profound secrets, but be content to suspect that they exist.
MATTER IS INCAPABLE OF SENSATION.
12. The phenomenon of sensibility reveals to us the existence of an order of beings distinct from matter. However perfect we may suppose material organization, it cannot rise to sensation; matter is wholly incapable of sensation; and the absurd system of materialism can neither explain the phenomena of intelligence, nor even of sensation.
It is of little consequence to us that we do not know the intrinsical nature of sensitive being, or of matter; it is enough to know their essential properties, in order to infer with certainty that they belong to distinct orders. It is not true that the principal idea of the essence of things is necessary, in order to demonstrate their absolute contradiction; thousands of times we consider two geometrical figures whose essential property we do not know; yet not, therefore, do we fail to see that they are different, and that one cannot possibly be the other.
Matter, whatever opinion may be entertained of its essential property, is necessarily a composite being; matter without parts, is not matter. A composite being, although called one, inasmuch as its parts are united together, and conspire to the same end, is always a collection of many beings; for the parts though united are still distinct If sensation could be predicated of a composite being, the sensitive would not be a single being, but a collection of beings; but sensation essentially belongs to a being which is one, and if divided is destroyed; therefore, no composite being, however well organized, is capable of sensation.
If we observe what takes place in us, and reason from analogy, to other sensitive beings, we shall discover amid the variety of sensations a single being which perceives them; it is one and the same being that hears, sees, touches, smells, and tastes; that remembers sensations after they have disappeared; that seeks them when agreeable, and avoids them when unpleasant, enjoys the former and suffers in the latter. All this enters into the idea of sensitive being; if brutes had not this common subject of all sensations; were they not one in the midst of multiplicity, identical in diversity, and permanent under succession, they would not be sensitive beings, such as we conceive them to be; they would have no sensation, properly so called; for there is no sensation, in the sense in which we here understand it, without a being affected by it, a being which perceives it.
If we imagine a flow and ebb of sensations without any connection, without a constant being to experience them, the result will not be a sensitive being, but a collection of phenomena, each one of which by itself alone offers the same difficulty as all united, the necessity of a being to experience it.
13. Let us take a being composed of two parts, A and B, and see if it can acquire, for instance, the sensation of sound. If both parts perceive, either both perceive the whole sound, or each a portion of it. If both perceive it entire, one of them is superfluous, for we are only seeking to explain the realization of the phenomenon, which would thus be verified in one alone. If each part hear the sound, not entire, but only a portion of it, we shall have a divided sound; and what is the division of a sound?
But even such an imaginary division does not serve to explain the phenomenon; for the part of the sound perceived by A will not be perceived by B; never, therefore, will there result a complete sensation.
Shall we suppose A and B to be in relation, and to mutually communicate their corresponding parts? But then A perceives all its own part and also what B communicates to it: of what use, then, is B, if A perceives the whole? Why not place the whole primitive sensation in A? We here see that such a communication is an absurd hypothesis, since it would make a successive and mutual communication of the parts, and a perception by each of its own part, and also of that transmitted to it by the others, indispensable to the formation of an entire sensation. Thus we should have not one sensation only, but as many as there are parts; not one sensitive being only, but as many such beings as there are parts.
This hypothesis of communication of the parts paves the way for our system, since it recognizes the necessity of unity to constitute sensation. Why do the parts mutually communicate what they have respectively perceived? Because an entire sensation could not otherwise be formed, and so each part must receive what it has not of itself. The object of this is, that each one may perceive the whole; the sensation, therefore, must be wholly in only one subject; therefore, at the very time that unity is denied, it is acknowledged to be necessary.
14. These parts, A and B, either are simple or they are not; if they are simple, why persist in advocating materialism, when we must finally return to simple beings? It is a manifest contradiction to say that sensation is an effect of organization, and yet place it in a simple being, for the simple cannot be organized; there is no organization where there are no parts organized. If we admit the simple being, and place the sensation in it, the organization will then be, if you choose, a medium, a conduit, an indispensable condition to the realization of the phenomenon; then not it, but the simple being will be the subject. If these parts are not simple, they are composed of others; and of these we may argue the same as of the former; for we must come to simple beings, or else proceed to infinity. If we admit such a process, the sensible being will not be one, but infinite; the difficulties encountered with only two parts, A and B, will be multiplied even to infinity, and so the sensible being will be not one but infinite, and every sensation infinite.
15. Here we find a very serious difficulty. If matter be incapable of perceiving, the soul of brutes is not material; if immaterial, it is a spirit, which cannot be admitted.
Let us determine well the meaning of the words, and this difficulty will vanish. An immaterial being is not the same as a spirit; every spirit is immaterial, but not every thing immaterial is a spirit. Immaterial denotes negation of matter; spirit implies more than this; for we understand by it a simple being endowed with understanding and free-will. The soul of brutes is then immaterial, but not a spirit.
Some one may say, that what is not body is spirit, that between these two classes of beings there is no medium. But why? Whence such certainty? If it be said that there is no medium between the material and the immaterial, this is true; for there is, in truth, no medium between yes and no; every thing either is or is not; but there enters into the idea of spirit much more than the simple negation of matter; there is the idea of an active, intelligent, and free principle.
16. It may then be asked: wherein consists the nature of the soul of brutes? And we ask, wherein consists the nature of the greater part of the things which we perceive? Do we know this nature in itself or in its acts? Do we see our own soul intuitively? Or do we, perchance, know it by the acts of which we are conscious? If so, we know in like manner the sensitive soul by its acts, that is, by perception of the senses; we know that it is not matter, for matter is incapable of sensation; and the reasons which show us that our soul is a simple being, an active principle endowed with understanding and free-will enable us to say that the soul of brutes is a simple being endowed with the faculty of feeling, and with instincts and appetites of the sensible order.
We know not what this active principle in itself considered is, but its acts show it to be a force superior to bodies, one of the many activities which are the life of nature. We encounter this living force in a portion of matter admirably organized; the end of this organization is the harmonious exercise of the faculties of that living being which we call animal. Not to know what this force in itself is, does not prevent us from affirming its existence, for phenomena reveal it to us in an indisputable manner.
17. What, then, will be the fate of these souls, or living forces, if the organization which gives them life be destroyed? Will they be reduced to non-existence, since, not being composed of parts, they cannot be decomposed? Will they continue to exist until their turn shall come to preside over a new organization? It will be well to separate these various questions, and examine them apart.
If the soul of brutes be not composed of parts, it cannot perish by disorganization; what has no organizable parts is not organized, and what is not organized cannot be disorganized. Hence we infer that the soul of brutes cannot perish by corruption, properly so called; for no being not composed of matter can. We see not what difficulty can arise from this view; but the question is only resolved in its negative part, for thus far we know only that the soul of brutes cannot die, or be corrupted by decomposition; we must know what is done with it. Is it annihilated? Does it continue to exist? And if so, in what way? These are different questions.
First of all we must observe, that we have here only conjectures, and these rather as to the possibility than as to the reality. Philosophy may indeed enable us to see what may be, but not what is, for we can know the reality only by experience, which in the present case we cannot have. When sound philosophy, examining this point, is asked what is, its best reply is, that it knows not; if it is asked what may be, it enters into an argumentation founded on general principles, and more especially upon analogy.
18. It is usually said that nothing is annihilated; but this needs some explanation. What is the meaning of annihilation? To cease to be, so that nothing, which before was, remains. If a body be disorganized, it ceases to be as an organized body; but the matter remains, and there is no annihilation. Is it true that nothing is annihilated? Some say we must distinguish between substances and accidents; for, as these latter are a kind of incomplete beings, there is no reason why they should not cease to exist, and nothing of them remain; but in this disappearance there is no annihilation, strictly so called; thus we see things continually transformed, and undergoing a succession of accidents which cease to exist whenever the thing ceases to be modified by them. As to substances, there would indeed be true annihilation should they cease to exist, but this they do not, because no substance is annihilated. Thus some think; we know not how true this system may be, for we know not upon what solid foundation it rests. If a substance be destined to an end, why may it not be annihilated when this end no longer exists? A created being incessantly needs the conservatory action of the Creator, for which reason conservation is said to be a continued creation; when, then, the end to which the created substance was destined ceases, why may it not be annihilated? We see nothing in its being annihilated repugnant to the wisdom or goodness of God. The artificer abandons a tool no longer serviceable; this, in God, would be equivalent to the withdrawal of his conservatory act, and in the creature, to the reduction to non-existence. If it be not repugnant to the wisdom and goodness of God for an organized being to be disorganized, or cease to exist as an organized being, why may he not allow a substance which has accomplished the object for which it was created to cease to exist? From this we infer that it would not be against sound philosophy to maintain that the souls of brutes are reduced to non-existence.
19. But supposing there is no question of annihilation, is there any reason against their continuing to exist? If there be, we know not what it is.
We know not of what use they would be; but we may conjecture that absorbed anew into the bosom of nature they would not be useless. Neither do we know the use of many other beings, and yet we cannot therefore deny their existence, or doubt their utility. Who says that the vital principle residing in brutes can have no object if the organization which it animates be destroyed? Does the destruction of a plant involve, perchance, the extinction of all the vital principles residing in it? Do these principles, by not operating upon the organized being just destroyed, therefore cease to be of any use in the wonderful laboratory of nature? Who will say that a vital principle cannot be useful if it does not act upon an object within our observation? Who will assert that vital principles do not in the recesses of nature act in many and different ways, and that the effects of their activity are not presented very differently according to circumstances, yet always in conformity to laws established by infinite wisdom? Do not the magnificent profusion of radical materials, the gems without number which we everywhere discover, the immense amount of matter susceptible of transformation and assimilation by the living being, the mysteries of generation in the animal and vegetable kingdoms, all indicate to us that there are scattered over the universe an infinite number of vital principles, which exercise their activity in very different ways, and over a scale of astonishing extent? Who shall assure us that the same vital principle may not present very diverse phenomena, according to the conditions which determine its action? Does not the same principle reside in the acorn, as in the gnarled old oak that for ages has defied the fury of the tempest? Did experience not show it to be so, who would ever have suspected the vital principle of a shapeless and filthy caterpillar to be the same as that of a beautiful butterfly? It is not then contrary either to reason or to experience to suppose the soul of brutes, the vital principle residing in them, to continue after the organization of the body is destroyed, and, absorbed anew in the treasures of nature, to be there preserved, not as a useless thing, but in the exercise of its faculties in different ways, according to the conditions to which it is subjected.(29)
CHAPTER III.
SLEEP AND WAKING.
20. The fact of sensation is connected with many others, and from this connection results a great part of our knowledge. It has been said in a tone of great confidence, that it was not possible to demonstrate by sensations the existence of bodies; for as sensations are something purely internal, they cannot enable us to infer the existence of any thing external, and there is no reason for not regarding all our sensations as a collection of individual phenomena, inclosed in our soul. At first view it seems impossible to solve the difficulty; nevertheless, if we examine it thoroughly, we shall see that too great importance has been attached to it.
21. The first objection ordinarily made to the testimony of the senses, is the difficulty of distinguishing with certainty between the state of sleep and that of waking. We receive when asleep impressions similar to those we receive when awake: how shall we know that the illusion is not perpetual? Lamennais, with characteristic exaggeration, says: "He who shall show that all life is not a sleep, an indefinable chimera, will do more than all philosophers have thus far been able to do."
There are here, no doubt, grave difficulties; but we cannot persuade ourselves that they are insolvable. First of all we shall examine if sleep and waking be different, not only in the eyes of common sense, but also in those of reason. Lamennais pretends that only at the tribunal of common consent can a satisfactory and definitive sentence be obtained: we are convinced that very close reasoning can arrive at the same result to which consciousness, common sense, common consent, or, in other words, the testimony of our own being and that of our fellow mortals, conjointly conduce.
22. Man finds in himself a perfectly satisfactory certainty of the difference between sleep and waking: we need no testimony of others to know that we are awake.
The difference between these states must not be solely sought in the clearness and vividness of sensations, and the certainty which they generate. Undoubtedly images are sometimes presented to us in sleep with as much clearness as if we were awake, and our certainty for the instant is complete. Who has not in sleep experienced great joy, or terrible anguish? Sometimes, but very rarely, we have, when we awake, the reminiscence of having in the very act of sleep doubted if we were asleep; but this seldom happens, and it is in general true, that even our dreams are not accompanied by this twilight of reflex reason which warns us of our state and of the illusion that we are under. Ordinarily, while we dream, we have no thought that we are asleep, and we embrace a friend with the same effusion of tenderness, or weep disconsolately over his tomb, with the same affections as we should were all real.
23. The difference is not in momentary uncertainty, for we usually have, on the contrary, complete certainty. Whence, then, is this? How does reason explain it? How does philosophy come to the support of consciousness and common sense? This is the matter we now purpose to examine.
If we abstract sensations having or not having relation to external objects, and also the sufficiency of their testimony in any particular case, and consider them solely as phenomena of our soul, we shall find two orders of facts completely distinguished by marked characters, sleep and waking. In our soul these two orders are totally distinct; even in the system of the idealist this distinction must be recognized.
If we reflect upon what we have experienced since first we had consciousness of what passes within us, we shall observe in our being, two classes of phenomena. Periodically and constantly we experience two series of sensations; some more or less clear, more or less vivid, are confined simply to their object, without the concurrence of many of our faculties, and above all, without reflection upon them; others are always clear, always vivid, accompanied by acts of all our faculties, our reflection upon them, and their difference from those that went before, is entirely subject to our free will in all that is relative; we vary and modify them in a thousand different ways, or suppress and reproduce them.
I see the paper upon which I write; I reflect upon this sight; I abandon and resume it at pleasure; and if I choose, I connect this sensation with others, with a thousand thoughts or different caprices. What takes place in this act, always has happened to me, and always will, whenever that same series of phenomena is produced in me while awake. But if I dream that I write, although it happen not, as it ordinarily does, that I cannot hold my pen exactly right, nor see clearly, but only confusedly, I neither feel the simultaneous exercise of all my faculties, nor reflect upon my present state; I do not have that full consciousness of what I am doing, that clear and strong light which is scattered over all my waking actions and their objects. When awake I think upon what I have done, what I am doing, what I shall do; I recollect my dreams and call them illusions, pronounce them unconnected and extravagant appearances, and compare them with the order and connection of phenomena offered to me while awake. Nothing of this kind takes place in dreams; I may, perhaps, have a clear, lively sensation but it is independent of my will, it is an isolated impression, the use of only one faculty without the aid of the others, without fixed and constant comparisons, such as I make when awake; and above all, this phenomenon quickly vanishes, and I either fall into a state of unconsciousness of my being, or enter another state in which the same series of phenomena as before is reproduced; they are clear, lucid, connected; they stand the test of reason, which compares them with each other, and with anterior phenomena. Apart, then, from all idea of the external world, and even of all being outside of ourselves, we are certain of the distinction between the two orders of phenomena, those of sleep and those of waking.
Therefore, they who attack the certainty of our cognitions because of the difficulty of distinguishing between these states, make use of a very weak argument, and rely upon a fact entirely false. So far am I from believing it impossible to distinguish philosophically between sleep and waking, that I deem the difference between these two states one of the clearest and most certain facts of our nature.
Having established this truth, and supposing no one to doubt that the sensations experienced in sleep are not produced by external objects, and that, consequently, they cannot be a means of acquiring truth, I pass to another more difficult and important question.
CHAPTER IV.
RELATION OF SENSATIONS TO AN EXTERNAL WORLD.
24. Have our sensations any relation to external objects, or are they merely phenomena of our nature? Can we infer the existence of an external world from the existence of that internal world resulting from the union of the scenes presented by sensations?
This question is theoretical, not practical, and depends solely on the force of reasoning, not on the voice of nature,—a voice stronger than all argument, and irresistible. To whatever result the philosophical examination of the relations of the ideal and the real worlds may lead, we must submit to that necessity of our nature which makes us believe in the existence of such relations. The great majority of mankind never have thought, and probably never will think of making such an examination; and yet they have no shadow of doubt that there exists a real world, distinct from us, but in incessant communication with us. Nature precedes philosophy.
We have no wish to show reason to be unable to vindicate the legitimacy of the inference whereby the real is deduced from the ideal, the existence of the external world from that of the internal; we would only point out a landmark to philosophy, which, if it does not illustrate it, may at least inspire it with sobriety in investigating, and with mistrust in its results. Indeed we cannot but see that that science must be erroneous which is opposed to a necessity, and contradicts an evident fact: it merits not to be called philosophy, if it struggles with a law to which all humanity, not even excepting the philosopher who presumes to protest against it, is inevitably subject. All that can be said against this law, may be as specious as you please, but it will only be a vain cavil, a cavil which, if unanswerable by our weak understanding, nature herself will resist until we shall in another life see the depths of these secrets, and how those links are joined whose points of contact reason cannot detect, although nature feels their irresistible union at every moment of her existence.
25. That sensations are something more than mere phenomena of our soul, that they are effects of a cause distinct from ourselves, is seen by comparing them with each other. We refer some to an external object; others we do not: these two orders of phenomena present very different characters.
I now have within me the representation of the country where I was born and spent my earliest years. I see clearly a vast plain with its fields and prairies, its little hills, now forming only isolated hillocks, now stretching in various directions, sinking to the level of the plain, or gradually rising until incorporated with the mountains, the lofty chain of which surrounds all the plain, and makes it a great amphitheatre, with no outlet except on the south, and here and there a chasm, seemingly torn in the mighty wall reared by nature. All this is very perfectly represented within me, although more than a hundred leagues distant, and this whenever, and as long as I choose. The same spectacle may, perhaps, be offered to me without the concurrence of my will, but I am always free to distract myself from it; I may drop the curtain upon this scene, or raise it anew at my pleasure.
What happens in this case is confirmed by many others; and thus I internally experience a series of phenomena representative of external objects, but am under no necessity to submit to them, for I can abandon or resume them by simple acts of my free will.
But, at the same time, I feel within myself another class of phenomena which are not dependent upon my will, and which I cannot abandon and resume at pleasure; they are subject to certain conditions which I cannot dispense with under pain of not attaining my purpose.
I now experience that a painting is represented to me; or, in ordinary language, I see a painting before me. Let us suppose this to be a purely internal phenomenon, and observe the conditions of its existence, abstracting, however, all external reality, that of my own body included, and that, also, of the organs whereby the sensation is, or seems to be, transmitted to me.
Now I experience the sensation; now I do not. What has intervened? The sensation of a motion that has produced another sensation of sight, and has destroyed the first; or, passing from ideal to real language, I have placed my hand between my eyes and the object. But why can I not during the last, reproduce the first sensation? We see clearly that if external objects do exist, and my sensations are produced by them, my sensations must be subject to the conditions which they impose upon them; but if they are only internal phenomena, there is no way of explaining them. This is only the more incomprehensible as we do not find in the sensations, which we consider as mere phenomena with no immediate relation to an external object, a close dependence of some upon others, but rather, on the contrary, great discordance.
26. Purely internal phenomena, those which we regard as truly such, are, so far as their existence and their modifications are concerned, greatly dependent upon the will. I produce in my imagination, whenever I please, a scene representing the Column of the Place VendÔme at Paris, and I suppress it at my pleasure. The same occurs with respect to all other objects which I recollect to have seen; their presence within me depends upon my will. It is true that sometimes objects which we do not wish are represented to us, and that some effort is necessary to make them disappear. If we see a dying person, his countenance pale and damp with sweat, his wandering eyes, his clenched hands, his distorted mouth and painful breathing, interrupted with piteous groans, remain long after stamped upon our imagination: this sad spectacle will often recur to us in spite of ourselves; but it is very certain that if we go into some complicated calculation, or engage in the solution of some difficult problem, we shall succeed in making it disappear. We see by this, that even in exceptional cases, so long as we are of sane mind, our will always exerts a great influence over purely internal phenomena.
It is otherwise with those which have immediate relation to external objects. We cannot, when in presence of the dying person, avoid seeing and hearing him. If these sensations be only a purely internal phenomenon, this phenomenon is of a very different order from that of the other. The one is wholly independent of our will, not so the other.
Purely internal phenomena have a very different mutual relation from that of external phenomena. The will exerts a great influence upon the former, but not upon the latter. The former also are offered either by a mere act of the will, or by themselves, in isolation, and need no connection with other preceding phenomena. I write at Madrid, and all at once I find myself on the banks of the Thames, with its countless fleet of ships and steamers. But this did not require me to pass through the series of phenomena which represent what are called France and Spain. I can represent the Thames to myself immediately, after a thousand sensations, neither connected among themselves, nor with it; but if I would produce in myself the phenomenon called seeing, I must pass through the whole series of phenomena consequent upon a voyage; and this not in any way I may fancy, but so as to feel really and truly all the accompanying pleasures and inconveniences; I must make a true resolution to depart, and arrive punctually at such an hour, at the risk of missing the sensation called, seeing the stage, and another, which I call, seeing myself started; in fine, all the disagreeable sensations arising from such a mischance.
When I would represent this series of internal phenomena, or, in common language, adventures of travel, only internally, I dispose all at my pleasure; I stop, or travel faster; I take steps of a hundred leagues, and pass immediately from one point to another, and I experience none of those inconveniences which render the reality fatiguing. I am in a world where I am master. I command, and the coach is ready, the driver on his box, the postilion in his saddle; and I fly as borne on the wings of the wind. Beautiful landscapes, barren lands, gigantic mountains, and plains whose boundaries join the heavens, all pass before my eyes with wonderful rapidity. Tired of the land, I embark upon the lofty deep; I see the angry waves, and hear, amid their roaring and dashing against the ship, the voice of the captain giving his orders. I see the sailors work the ship; I speak with the passengers, and roam through the cabins; and yet perceive no offensive smell, and neither feel the qualms of sea-sickness, nor observe them in others.
27. If purely internal sensations, especially when they proceed from external sensations, be indeed mutually connected, their connection is not such that it may not be modified in a thousand ways. When we think of the Obelisk of the Place de la Concorde, its fountains and statues, are very naturally presented to us; so, also, are the Palace of the Tuileries, and that of the Chamber of Deputies, the Madeleine, and the Champs-ElysÉes; but we can, by an act of the will, change the scene; and if we choose we may transfer the Obelisk to the Place du Carrousel, and admire the effect it produces there, until, satisfied with the operation, we restore it to its granite base, or think no more of it.
But with sight, or the external phenomenon, we should in vain strive to perform such manoeuvres; everything keeps its place, or, at least, seems to; and the sensations are bound together with bands of iron. One comes after the other, and we cannot pass by any. The mere observation, then, of what passes within us reveals the existence of two wholly distinct orders of phenomena: in the one, everything, or almost everything, depends upon our will; in the other, nothing. In the one, the phenomena have certain mutual relations, very variable, however, and to a great extent subject to our fancy; in the other, they are dependent upon each other, and are produced only under certain conditions. We cannot see, if we do not open the blinds so as to allow the light to enter. Here the phenomena of blinds and sight are necessarily connected; but they are not always so; for we may open them at night, and yet not see; and then we require another auxiliary phenomenon, which is, artificial light. We cannot, if we would, change this law of dependence.
28. What does all this show? Does it not show that the phenomena not dependent upon our will, but subject both as to their existence and accidents to laws which we cannot change, are produced by beings distinct from ourselves? They are not ourselves, for we often exist without them; they are not caused by our will, for they often occur without its concurrence, often also against it; they are not produced one by the other in the purely internal order, for it very frequently happens that a phenomenon which has a thousand times followed another suddenly ceases, however often the former be reproduced. This leads us to examine an hypothesis which will greatly confirm the doctrine we have laid down.
AN IDEALIST HYPOTHESIS.
29. The system of the Idealists cannot stand without supposing the connection and dependence which we refer to external objects, to exist only within us, and the causality which we attribute to external objects, to belong solely to our own acts.
I pull a rope in my chamber, and a bell never fails to ring; or in idealist language, the sensation formed from that union of sensations into which enters what we call the rope and pulling it, produces or involves that other, which we call ringing a bell. Either from habit or some hidden law, that relation of two phenomena will exist, the never interrupted succession of which causes the illusion in us, whereby we transfer to the real order, what is purely imaginary. This is the most irrational explanation possible, and a few observations will show it to be futile.
Today, we pull the rope, and strangely enough, no bell rings: but why not? The causing phenomenon exists; for undoubtedly there passes within us the act called pulling the rope, and yet we pull and pull again, and the bell does not ring. Who has changed the succession of phenomena? Why does not the phenomenon which a little while ago produced another, not produce it now? Nothing new has happened within us, we experience the first phenomenon just as clearly and vividly as before; why, then, is not the second presented? Why is it that formerly we experienced the second whenever we wished, by only exciting the first, and now we cannot? We make the act of our will just as efficaciously as before; who, then, has rendered our will impotent?
Hence we infer: first, that the second phenomenon does not depend upon the first, considered only as a purely internal fact, for this now exists precisely as it did before, and yet produces not the same phenomenon; secondly, that it does not depend upon the act of our will; for this is now as firm and strong as before, and yet produces nothing. We cannot, however, doubt that there is some connection between the two phenomena, for we have innumerable times seen one follow the other, and this cannot be explained by mere chance. Since then, one does not cause the other in the internal order, they must have some dependence in the external order; in other words, still keeping in view the case under examination, although the cause which produced the first phenomenon continues to exist, its connection with that which produced the other phenomenon must be interrupted; and so it was, in fact; for when we pulled the rope no sound followed, for the simple reason that the bell had been removed. This is comprehensible, if there be causes external to what we call sensations; but if there be only simple internal phenomena, no rational explanation can be given.
30. And here it is to be observed, that when we would explain the failure of succession of those phenomena which always have been united, we may recur to many very different ones, such as are internal phenomena, which, as such, have neither relation nor resemblance, and can only have some connection as corresponding to external objects. We may, when seeking the reason why the bell did not ring, in order to explain the cause of the change in the regular order of appearances, think of various causes, which we now consider as mere appearances or internal phenomena; we may have the following sensations: the rope broken, or caught, the bell broken, or removed, or without a tongue. We may attribute the failure of sound to any one of these sensations: but nothing can possibly be more irrational than to attribute it to them, if we regard them as mere internal facts; for as sensations, they nowhere appear. We cannot discourse rationally if we do not make an external object correspond to each of these sensations, of itself alone sufficing to interrupt the connection between pulling the rope and the vibration of the air which produces the sound.
31. Hence we conclude: First, that our sensations considered as purely internal phenomena, are divided into two very different classes; some depend upon our will, others do not; some have no mutual connection, or are variable in their relations, at the pleasure of him who experiences them; others have a certain connection which we can neither change nor destroy. Secondly, we conclude that the existence as well as the modifications of this last class, proceeds from causes not ourselves, independent of our will, and outside of us. That instinct, therefore, which impels us to refer these sensations to external objects, is confirmed by reason: therefore the testimony of the senses, in so far as it assures us of the reality of objects, is admissible at the tribunal of philosophy.
This demonstrates, in a certain manner, the existence of bodies; for we find, in philosophically examining the conception of body, something in it distinct from our own being, the presence of which causes us such and such sensations. We know not the intimate essence of bodies; but even if we did know it, it would not aid our present purpose, for we are not treating of the idea which a philosopher would in such a case form, but of that formed by the generality of men.
IS THE EXTERNAL AND IMMEDIATE CAUSE OF SENSATIONS A FREE CAUSE?
32. A difficulty, at first sight serious, but in reality futile, may be brought against the existence of bodies. Who knows, it may be asked, but what some cause, not at all resembling the idea which we form of bodies, produces in us all the phenomena that we experience? God may, if he pleases, cause one or many sensations in us; and who shall assure us that he does not? Who shall assure us that other beings may not do the same, and so all our imaginations of a corporeal world be a pure illusion?
33. The first and simplest solution that can be given is, that God, being infinitely true, can neither deceive us himself, nor allow other creatures to deceive us constantly and in a way that we cannot resist. But this solution although well founded, just, and reasonable, labors under the inconvenience of establishing the physical by recurring to the moral order; and so it would never satisfy those who desire to see the truth of the testimony of the senses demonstrated by arguments drawn from the nature of things. Such arguments we think we can supply.
34. Our sensations do not proceed immediately from a free cause; the being that produces them, as well as that which experiences them, is subject to fixed and necessary laws. To be convinced of this, we have only to reflect that we cannot, if placed in certain conditions, fail to experience a determinate sensation, and that if these conditions be wanting, we cannot experience it. And this proves that we, as well as the being which causes the impression in us, are subject to a necessary order. Were it not thus, we could not produce the sensation even by the means of certain conditions; for as its cause would be subject to no law, but only to its own free will, it might a thousand times happen, that our will would not agree with its will, and so the desired impression would not be produced.
After experiencing a sensation of touch in which it seems that an opaque body covers our eyes, we do not see, and we cannot with all our efforts produce, the sensation called seeing; on the other hand, if at a corresponding hour and place this sensation of contact ceases to exist, we cannot possibly fail to experience the sensation of seeing different objects. Here, therefore, we are subject to a necessity; the being, also, that causes the sensations in us, is subject to a like necessity; for if we perform the condition once or a thousand times of closing our eyes, once or a thousand times the sensation will disappear; or if we open them once or a thousand times in a light place, so many times also the sensation will be produced; the same, if we retain everything in the same state, and varied at our pleasure, if we change our situation or the objects around us. There does, therefore, exist without us, subject to necessary laws, a collection of beings which produce our sensations.
35. It is remarkable not only that the influence they exert upon us does not flow from election or spontaneity in them, but that they are not even presented as endowed with an activity of their own. A painting hung upon the wall produces in us the same sensation as often as we look at it; and, saving the deterioration of time, it will continue for ever to produce the same sensation.
It is, moreover, evident that these beings are subject to our action, for we can, by acting upon them differently, make them produce different impressions. We touch a ball, and the continuation of the sensation of a hard, polished, spherical body, assures us that it is one and the same being that produces it for a certain length of time; and yet, in this interval, we may receive many and various sensations from the same object, by presenting it to the light in different ways.
36. The subjection of these beings to necessary laws is not necessarily with respect to sensations, but is rather a mutual connection of their own. The connection of impressions which we receive from them is an effect of the dependence of some of them upon others; so that, in order to produce a determinate impression, we often employ an object which is, in itself considered, of no direct use, but which brings another into action, and so leads to what we desire. To raise a curtain has no connection with a magnificent landscape; and yet, oftentimes, we do nothing else when we wish to obtain a pleasant prospect. The relation in question is not then of sensations, but of their objects; the connection of these is what induces us to make use of one of them in order to obtain another. There is, therefore, outside of us a collection of beings subject to fixed laws, as well with respect to our sensations as to themselves mutually; therefore the external world exists, and the internal world, which represents it to us, is not a pure illusion.
CHAPTER VII.
ANALYSIS OF THE OBJECTIVENESS OF SENSATIONS.
37. Is the external world such as we believe it to be? Are the beings, called bodies, which cause our sensations in reality what we believe them? May we not, even after having demonstrated the existence of these beings, and their necessary subjection to constant laws, still doubt whether we have demonstrated the existence of bodies? Does it suffice for this to have proved the existence of external beings in relation among themselves and with us by means of laws fixed and independent of them as of ourselves?
38. Thoroughly to understand this question, it will be well to simplify it, and confine it to a single object.
I hold in my hand and see an orange. I am certain, from what has just been demonstrated, that an external object exists in relation with other beings, and with myself, by necessary laws; I am also certain that I may receive different impressions from it; I see its color, size, and shape, perceive its odor, try its taste; feel in my hand its size, weight, and form, its concavities and convexities, and also hear a little noise when I press it with my hand.
The idea of body is composite, and such is that of the orange; for it is that of something external, extended, colored, odorous, and savory. Whenever all these circumstances exist together, whenever I receive from an object these same impressions, I say that I see an orange.
39. Let us now examine how far the object corresponds to the sensations it causes in us.
What do we mean when we say a thing is savory? Simply, that it produces an agreeable impression upon our palate; and the same is true of smell. Therefore, the two words, odorous and savory, express only the causality of these sensations resident in the external object. We may say the same of color, for, although we commonly transfer the sensation to the object, and openly contradict the philosophical theory of light and color, this contradiction is less real than apparent; for the judgment well examined is found to consist only in referring the impression to determinate objects; so that when we for the first time hear professors of physics tell us that colors are not in the object, we easily accustom ourselves to reconcile the philosophical theory with the impression of the sense; especially since this theory does not render it less true that this or that impression comes to us from this or that object, or its different parts.
40. Here, it is not difficult to explain the phenomena of sensation or their correspondence with external objects; for the correspondence is saved if these objects be really the cause (or occasion) of the sensations. The question of extension is more difficult; for this is as the basis of all other sensible properties; and abstracting its constituting or not constituting the essence of bodies, it is certain that we know no body without extension.
41. The following observation will render palpable the difference between extension and other sensible qualities. He who has never thought of the relation of external objects to his sensations is indescribably confused; he in some sense transfers color, odor, taste, and even sound, to objects themselves, and considers confusedly these things to be qualities inherent in them. Thus the child and the uneducated man believe the color green to be really in the foliage, odor in the rose, sound in the bell, taste in the fruit. But this is readily seen to be a confused judgment, of which they render no perfectly clear account to themselves; a judgment which may be changed or even destroyed without changing or destroying the relations of our sensations with their objects. Even at a very tender age we easily accustom ourselves to refer color to light, and even not to fix it definitively, but to regard it as an impression produced upon our sense by the action of that mysterious agent. It costs us no more to consider smell as a sensation produced by the action of the effluvia of bodies upon the organ of smell; we also cease to consider sound as something inherent in the sonorous body, and come to see in it only the impression caused upon the sense by the vibration of the air, excited in its turn by the vibration of the sonorous body.
These philosophical considerations may, at first sight, seem to be in contradiction to our judgment, but they do not change to us the external world; they cause no inversion of our ideas of it; they only make us fix our attention upon some relations which we had imperfectly defined, and do not allow us to attribute to objects what in reality does not belong to them. They make us limit the testimony of the senses to their appropriate sphere, and in some manner rectify our judgments; but the world continues the same that it was before, excepting that we have discovered in the marvels of nature a closer relation with our own being, and have perceived that our organization and our soul play a more important part in them than we had imagined.
42. If we destroy extension, take this quality from external objects, and regard it as only a mere sensation, of which we only know that there is an external object which causes it, the corporeal world at once disappears. The whole system of the universe will be reduced to a collection of beings which cause us different impressions; without the idea of extension we can neither form any idea of body, nor know if all that we have thought of the world be aught else than a pure illusion. I can easily resign my infantile belief that the color I see in my hand is in it, or the noise made when I clap my hands is in them; but I cannot, do what I will, lay aside the idea of extension; I cannot imagine the distance from my wrist to the extremity of my fingers to be only a pure illusion, that there only exists a being which causes it without my knowing whether in reality this distance exists. I can easily separate from the fruit which I find savory the quality of savor; and I may, if I examine it philosophically, admit, without any inconvenience, that it has nothing resembling taste, but that it is only composed so to affect my palate as to produce an agreeable sensation. But I cannot take from the fruit its extension; in no wise can I regard it as something indivisible; I cannot possibly regard the distance from one of its points to another as a mere sensation. My efforts to consider the savory object as in itself indivisible are all in vain; and if, for a single instant, I seem to have overcome the instinct of nature, every thing is overturned. By the same right that I make the fruit something indivisible, I may make the whole universe so; but an indivisible universe is to me no universe; my intellect is confounded, and all around me is annihilated. I am in worse than chaos; for chaos is at least something, although the elements are in horrible confusion and frightful darkness; but now I am worse off, for the corporeal world, such as I have conceived it to be, returns to nothing.
CHAPTER VIII.
SENSATION OF EXTENSION.
43. Two of our senses perceive extension; sight and touch. Sound, taste, and smell accompany extension, but are something different from it. The sight perceives nothing not extended; extension is every way inseparable from this sensation. We may be so enchanted by the sweet harmony of many instruments as to forget the extension of the instruments, the air, and our organs; but we cannot, in contemplating a painting even in the midst of our most ardent enthusiasm, make its extension vanish. If we withdraw from the Transfiguration of Raphael its extension, the marvel disappears; for even considered as a simple phenomenon of our soul, continuity and distance enter of necessity into its very essence.
The same is true of touch, although less generally so. Hardness and softness, roughness and smoothness, squareness and roundness, all involve extension; but it cannot be denied that there are some impressions of touch, in which it is less clearly involved. The acute pain of a puncture, and others felt without any known external cause, are not so clearly referred to extension, but seem to have something of that simplicity which distinguishes the impressions of the other senses. However this may be, it is certain that the perception of extension belongs in a special manner to sight and touch.
44. In order to form a clear idea of extension in its relations to sensation, we will analyze it at some length.
And first of all, it is to be remarked, that extension involves multiplicity. An extended being is of necessity a collection of beings, more or less closely united by a bond which makes them all constitute one whole, but does not prevent them from continuing many. A splendid painting, wherein the unity of the artist's thought dominates, does not cease to be composed of many parts; the moral chain which unites, does not identify them; it only connects, co-ordinates them, and makes them conspire to one end. The firm adhesion of the molecules forming the diamond does not prevent these molecules from being distinct: the material chain unites, but does not identify them.
There is then no extension without multiplicity: where there is extension, there is, rigorously speaking, not one only being, but many beings.
45. Multiplicity does not constitute extension, for it may exist without extension. Neither the multiplicity of sounds, of tastes, nor of odors, constitutes extension. We conceive in the material, as in the moral and intellectual orders, multiplicity of beings of different orders, and yet this multiplicity involves no idea of extension. Even if we confine ourselves to the purely mathematical order, we find multiplicity without extension, in arithmetical and algebraic quantities. Therefore multiplicity, although necessary, does not alone suffice to constitute extension.
If we reflect upon the species of multiplicity required to constitute extension, we shall observe that it must be accompanied by continuity. Sensations of touch as well as of sight involve continuity; for it is impossible for us to see or to touch, without receiving the impression of objects continuous, immediately adjoining each other, co-existing in their duration, and at the same time presented as continuous one with another in space. Without this continuity, multiplicity does not constitute extension. If, for example, we take four or more points on the paper on which we now write, and by an abstraction consider them as indivisible, this multiplicity will not constitute extension: we must unite them by lines at least imaginary; and if continuity be wanting to the body in which we suppose them situated, we shall find it necessary to recur to the continuity of space; that is, to regard this space as a collection of points whose continuation connects the first points. No possible efforts can enable us to consider a collection of indivisible points, neither continuous nor united by lines, as extension; this collection will be to us as that of beings having no connection with extension. It is worthy of observation, that if we assign them a determinate position in space, this we do only by connecting them with other points, by means of imaginary lines: for we cannot otherwise conceive either distances or position in space. If we attempt to abstract all this, we either fall into intellectual nothingness, we annihilate all idea of the object, or we pass to another order of beings having no relation either to extension or space. We quit matter and sensations, and mount to the realm of spirits.
46. Multiplicity and continuity are therefore necessary to constitute extension; and we believe that these two conditions suffice; for where they exist, extension exists, and with them alone, we form the idea of extension. The object of geometry is extension; and only multiplicity and continuity constitute it. Lines, surfaces, solids, such as are the object of geometry, are only this continuity considered in its greatest abstraction. Empty space suffices, or rather is requisite for geometry; since, it does not, in making its applications to bodies, find all the exactness of continuity in the abstract.
47. If multiplicity and continuity constitute extension in space, it really exists in the objects which cause our sensations. Basing ourselves upon the relation of phenomena among themselves and to their causes, we have shown that external objects correspond to sensations: thus it is that this relation also exists with respect to multiplicity and continuity; these two properties are therefore found in nature. The impressions that we receive by sight and touch, are, although we confine ourselves to a single object, multiple, and consequently correspond to many objects: they are continuous, and consequently correspond to continuous objects.
We will explain this reasoning. Looking at a painting, I receive an impression coming from many different points; and this impression, it must be observed, comes uninterruptedly from the whole surface presented. If, as we have shown, the sight of one external point sufficed to convince me of its existence, that of many will make me sure of the existence of many; and the continuity of the impression will also make me certain of the continuity of the impressing points.
If I touch the object seen, my touch will confirm that testimony of sight, in what corresponds to it, that is, the multiplicity and continuity, I experience the same continued succession of sensations; and this shows me the existence and continuity of the objects causing them.
48. In a few words, extension supposes the co-existence of many objects, in such a way, however, that they are one by continuation of others: of both, sensation makes us certain: therefore the testimony of the senses suffices to make us certain that there are external objects, and that they may produce various impressions. These ideas contain every thing included in the idea of body: therefore the testimony of the senses makes us certain of the existence of bodies.
CHAPTER IX.
OBJECTIVENESS OF THE SENSATION OF EXTENSION.
49. Having proved the testimony of the senses sufficient to assure us of the existence of bodies, we now come to examine how far the ideas it makes us form are correct. It is not enough to know that we may be sure of the existence of extension; we must inquire if it in reality be such as the senses represent it; and what we say of extension is applicable to the other properties of bodies.
In our opinion, the only sensation that we transfer, and cannot help transferring, to the external, is that of extension; all others relate to objects only as effects to causes, not as copies to originals. Sound, taste, and smell represent nothing resembling the objects causing them, but extension does; we attribute extension to objects, and without it we cannot conceive them. Sound outside of me is not sound, but only a simple vibration of the air, produced by the vibration of a body. Taste outside of me is not taste, but only a body applied to an organ of which it causes a mechanical or chemical modification. The same is true of smell. Even in light and colors, outside of me, there is only a fluid which falls upon a surface, and either directly or reflexly comes, or may come, to my eyes. But extension outside of me, independently of all relation with the senses, is true extension, is something whose existence and nature stand in no need of my senses. When I perceive, or imagine that I perceive it, there is in it, and in my impressions, something besides the relation of an effect to its cause; there is the representation, the internal image of what exists externally.
50. In order that the truth of what we have just advanced may be perfectly understood, and strongly felt, we would offer the reader a picture whence determinate sensations may be successively eliminated, and made to mark the degree of elimination which it is possible to reach, but not pass.
Let us suppose all animals at once to lose the sense of taste, or all bodies to be by nature destitute of the property of causing by their contact with an organ the sensation called taste. The external world, nevertheless, continues to exist as before; the same bodies that caused in us the sensations now lost, continue to exist, and may be applied to the very organ they before affected, and cause in it sensations of touch, as of soft or hard, warm or cold. Either savory bodies, or the organs of animals, have undergone some change, which has interrupted their previous relations; a cause which before produced an effect is now seen to be impotent to produce it. This may be owing to a modification of the bodies without changing their nature, so far as we know it; and it is also possible that they have not been changed, but that this difference arises solely from an alteration of the organs. But in any case, the disappearance of this sensation has not made anything resembling it disappear from the universe; if the change has been only in the organs, external bodies remain untouched; and if it has taken place in bodies, it has made them lose a causing property of the sensation, but not a property represented by the sensation.
We have taken all taste from food, and the universe exists as before; let us now take away all odors, by changing odoriferous bodies, or the organ of smell. The same follows as in the case of taste. Odoriferous bodies will continue to exist, and even transmit to our organ the effluvia that before produced the sensation of smell; and the only novelty will be the non-existence of that sensation. Either the disposition to receive the necessary impression will be wanting in our organs, or a causality will have disappeared from the universe, but not a thing represented by the sensation. Gardens will not be despoiled of their beauty, nor the fields of their luxuriant verdure; the tree will still display its leafy bower, and the fair fruit hang from its boughs, and be shaken by the wind.
Let us proceed in our destructive march, and now suddenly make all animals deaf. The musician becomes the actor of a silent pantomime; the bell-rope is pulled, and only the mute metal is struck; conversation is reduced to oral gestures, and the howlings of brutes are only the opening and closing of their mouths. But the air vibrates as before; its columns strike as before the drum of the ear; nothing has been changed; nothing has failed in the universe but one sensation. The lightning ploughs the skies, rivers follow their majestic course, torrents dash onwards with the same rapidity, and the proud cascade still leaps from its lofty rocks, and displays its changing hues and foaming waves.
But let us now commit the greatest cruelty; let us make all living creatures blind. The sun still pours out his immense torrents of the fluid we call light; it is reflected from surfaces, and is refracted from the bodies it meets, and passes to the retinas of eyes that formerly saw, but are now converted into insensible membranes, placed behind a crystal; but every thing called color and sensation of light has disappeared. Yet the universe exists as before, and the celestial bodies still follow their immense orbits.
As it is most difficult for us to abstract the sensation of light and colors from objects; or, in other words, as we have a certain propensity to imagine that there really exist without us impressions which are only in us, and to consider the sensation as a representation of the exterior; so it costs us most to conceive all living creatures to be blind, and nothing to remain of what sensations of this kind represented to us, not even a fluid which reflects from certain surfaces, and passes through some bodies, not otherwise than as an invisible fluid. Wherefore, in condescension to the difficulty which some experience in ceasing to externally realize what exists only within them, we will frame our supposition differently; for it will then be all that the demonstration requires, and we may eliminate from objects whatever relates to any sensation excepting that of extension.
We will not then make all animals blind, nor practise the cruelty of Ulysses in the cave of Polyphemus, but spare in our inversion of the world that destructive instinct. It matters little that men and animals are not blind, provided they cannot see. We will then leave those organs untouched, but we will in return, take all light from the universe; quench like faint torches the sun and stars and all the celestial bodies, extinguish their feeblest scintillations upon the earth, the tall tapers which illumine the rich man's dwelling, and the fire kindled in the peasant's cot, the spark struck from the flint, and the pale phosphorescences emitted from the graves of the dead. Every thing is involved in obscurity, and it is as if that darkness which rested upon the face of the abyss before the Creator said: let there be light, were restored.
We must bear in mind that we have not, by plunging the world into such frightful obscurity, changed any one of its laws. The gigantic orbs describe as before with astonishing rapidity and admirable precision their immense orbits. Hence we infer that although we destroy smell, taste, sound, light, and colors, the world still exists, and we may without difficulty so conceive it to be. We may even destroy the sensation of touch, for it is easy to suppose that we perceive no impression by this sense. We may substitute some sensations, whose causes lie in bodies like those of heat and cold, hardness and softness, for others, without therefore believing the universe no longer to exist.
51. Let us now make another abstraction, and see what will happen. Let us destroy extension. The world resists not this trial; the stars vanish, and the earth disappears beneath our feet, distances no longer exist, and motion is an absurdity: our own body fades away and the whole universe is tumbled into nothingness, or if it continues somehow to exist, it is totally different from what we now imagine it to be.
And so indeed it is. If we abstract extension, if we do not externally realize that sensation, or idea, or whatever else it may be, which we have of it, if we do not consider it as the representation of what exists without us, every thing is overthrown: we know not what to think either of our sensations, or their relation to the objects causing them; things all go roundabout, and one basis of our cognitions fails: in vain we stretch out our arms to lay hold of some fixed point; and we ask in our trouble, if all that we perceive be only a pure illusion, if Berkeley's extravagances be true.
52. It is worthy of remark that, even if we make extension objective by transferring it to the external, it is not altogether correct to say that it is represented by the sensation. It is better to say that it is a receptacle of certain sensations, a condition necessary to the functions of some of the senses, but not their object. Extension abstracted from the sensations of sight and touch, is, as we have already said, reduced to multiplicity and continuity. The knowledge of it comes to us from the senses, but it is different from what the senses represent it to us. When we take color and light from the sensations, received through the sense of sight, we certainly still retain the idea of a thing extended, but not of a visible thing, nor of an object represented by the sensation. In like manner, if we despoil the sensations received through the sense of touch, of those qualities which affect this sense, the object that caused them is not annihilated, neither is it represented by the impressions it transmits to us.
53. These remarks show that we do not transfer our sensations to the exterior, that they are a medium whereby our soul is informed, but not images wherein it contemplates its objects. All sensations indicate an external cause; but some, like those of sight and touch, in an especial manner denote multiplicity and continuity, or extension.
Hence we also infer that the external world is not a pure illusion, but that it really exists with its great masses, its various motions, its unlimited geometry: but much of its beauty lies rather within ourselves than in it. The Creator of it has in an especial manner, shown his infinite wisdom and omnipotent hand in sensible beings, and above all in intelligences. What would the universe be were there no one to feel and to understand? The beauty, the harmony, the marvels of nature consist in the close relation, the continuous communication of objects and sensible beings. The rarest painting, were there no one to perceive and admire its beauty, would be only a collection of lineaments, a hieroglyphic of unintelligible characters; but so soon as it is seen by a feeling and knowing being, it is animated, is what it ought to be; and in this wonderful communication the object gains in beauty all that it imparts of pleasure.
Suppose a collection of instruments disposed by the proper mechanism to execute with admirable precision the highest conceptions of Bellini or Mozart: to what is it all reduced if there be no sensitive being? To vibrations in the air governed by some law, to mere movements of a fluid, subject to geometrical necessity. Introduce a man, and the geometry is changed into celestial harmony, then there is music, enchantment.
The symmetry of the walks of a garden, the elegance of its shrubbery, the color and beauty of its flowers, the fragrance of its odors, are, without a sensitive being, only geometrical figures, surfaces disposed according to some law, volumes of such or such a kind, columns of fluids springing from them and disappearing in space. Introduce man, and the geometrical figures are adorned with a thousand beauties, the flowers covered with gay colors, and the columns of fluids changed into exquisite perfumes.
FORCE OF TOUCH TO MAKE SENSATIONS OBJECTIVE.
54. It has been said that touch is the surest, and perhaps the only witness of the existence of bodies; for without it, all sensations would be nothing more than simple modifications of our being, to which we could attribute no external object. But this I do not believe to be true. We receive by touch an impression, just as we do by the other senses; this impression is in all cases an affection of our being, and not something external. When, from the continuance of these impressions, their order, and their independence of our will, we judge them to proceed from objects without us, our judgment is true not only of impressions of the sense of touch, but also of those of the other senses.
55. One of the reasons whereon it has been attempted to base the superiority of touch to attest the existence of bodies, is that it gives us the idea or sensation of extension; for if we suppose a man to be deprived of all his senses but that of touch, and to pass his hand over the surface of a body, he will experience that continuity of the sensation which involves extension. This observation of those who maintain the supremacy of touch does not prove what they propose. If we pass our sight over various objects, or the different parts of one object, we shall experience the sensation of continuity just as clearly as by touch. We cannot conceive why the sensation of extension must be any clearer when the hand is passed along a balustrade than when it is seen by the eyes.
56. The advocates of this opinion assert that we acquire by the touch of our body a double sensation, which we do not by the other senses. If we pass our hand over our forehead, we feel with both our hand and our forehead, and so verify a continuity of sensations, all originating and terminating in ourselves. Thus we are conscious that both the sensations of our hand and our forehead belong to us.
But this reason, by some deemed conclusive, is nevertheless exceedingly futile; it labors under the sophism called by dialecticians begging of the question, for it supposes what was to be proved. The man destitute of all senses but that of touch will, indeed, experience the two sensations and their continuity; but what can he infer from them? Does he even know that he has either hand or forehead? Suppose him not to know, how is he to acquire this knowledge? Both sensations belong to him, and of this he is internally conscious; but whence they came, he knows not. Does the coincidence of the two sensations, perchance, prove something in favor of the existence of his forehead and hand, objects of which we suppose him to have no idea? If this coincidence proved what is pretended, with still greater reason would it prove the combination of some senses with others to elevate us to the knowledge of the existence of bodies, and consequently that this knowledge is not produced exclusively by touch. Whenever I have the sensation of the motion of placing my hand before my eyes, I find that I lose sight of the objects before me, and in their room is presented another always the same, my hand. If, from this coincidence, I infer the existence of external objects, the supremacy of touch is destroyed, for sight, also, acts a part in the formation of such a judgment. I also observe that when I have the sensation of clapping my hands together, I experience the sensation of hearing the noise of their contact; if, therefore, coincidence is of any account, hearing as well as touch comes in. What I say concerning the clapping of my hands, is applicable to what I experience when I pass a hand over any part of my body, for instance my arm, so as to produce some noise. In this case there are two sensations coincident and continuous.
It will, perhaps, be replied, that these examples refer to different senses, and produce sensations of different kinds. This, however, is of no consequence; for, if the being that perceives, infers the existence of objects from the coincidence of various sensations, the supremacy of touch is destroyed, which is what we undertook to demonstrate.
57. The sensation of the hand is not that of the forehead, for the one is warmer or colder, harder or softer than the other, and so the sensation caused by the hand upon the forehead will not be the same as that produced upon the hand by the forehead. It is to be observed, that the less difference we suppose between the two sensations, the less lively will be the perception of their duality, and consequently the less marked the coincidence on which the judgment is founded. Thus by rigorously analyzing this matter we discover that the diversity of sensations contributes in an especial manner to form judgments of the existence of objects, and therefore the combination of two senses will more conduce to this end than two sensations of one sense. Far, then, from its being necessary to consider touch as alone or superior upon this point, it is only to be held as auxiliary to the other senses.
In truth, it is almost beyond doubt that the sense of touch also requires the aid of the other senses, and that the judgments resulting from it are similar to those coming from the other senses. It is probable that only after repeated trials do we refer the sensation of touch to the object that causes it, or even to the part affected. The man who has had his arm amputated, feels pain as if he still preserved it; and this is because a repetition of acts has formed the habit of referring the cerebral impression to the point where the nerves transmitting it terminate. There is, therefore, no necessary relation between the sense of touch and the object; and this sense is, like the others, liable to illusions. Therefore, it is not exact to say that the idea of body springs up under our hand, if this be understood as excluding touch; for the same is true of the other senses, particularly of sight.
INFERIORITY OF TOUCH COMPARED WITH OTHER SENSES.
58. That superiority, or rather that exclusive privilege, conceded by Condillac and other philosophers to touch, not only has no foundation, as we have just seen, but seems to be in contradiction to the very nature of this sense. In short, it assigns the first place to the coarsest, the most material of all the senses.
It cannot be known what ideas a man reduced to the one sense of touch would form of things; but it seems to me that far from entering into clear and vivid communication with the external world, and finding a sufficient foundation whereon to base his cognitions, he would grope in the profoundest ignorance, and labor under the most transcendental errors.
59. If we compare touch with sight, or even with hearing and smell, we shall at once perceive a very important difference to its disadvantage. Touch transmits to us only impressions of objects immediately joining our body; whereas, the other three, and especially sight, place us in communication with far distant objects. The fixed stars are separated from us by a distance such as almost to pass our imagination, and yet we see them. Neither smell nor hearing, it is true, go so far; but the former fails not to warn us of the existence of a garden at many paces from us; and the latter gives us notice of a battle fought at many leagues distance, of the electric spark which has cloven the clouds on the confines of the horizon, or of the tempest roaring over the immensity of ocean.
60. The limitation of touch to what is immediate to it involves a scarcity of the ideas originating in it alone, and of necessity places it in a lower grade than the other three senses, particularly sight. Let us in order to form clear ideas upon this point compare the range of sight with that of touch relatively to some object, for example, a building. By means of sight we in a few instants obtain an idea of its front, and other external parts; and in a short time become acquainted with its internal divisions, with the arrangement even of its ornaments and furniture. Can we accomplish all this by touch? Even if we suppose the most delicate sense of touch, and the most tenacious memory of the impressions communicated, long hours would be necessary to pass the hand over the front of the building, and form some idea of it. How will it be when we come to the whole exterior of the building? the whole interior? We see that it would be necessary to renounce such a task, that the elaborate workmanship of a cornice, a pedestal, a peristyle, the magnificence of a tower, a cupola, the boldness of an arch, a vault, which the eye seizes in an instant, would require the poor being possessed of touch alone to go often on all fours, climb over dangerous scaffoldings, and expose himself to the danger of falling from fearful heights; and yet he would never be able to acquire the millionth part of what the eyes so easily and so quickly perceive.
Apply these observations to a city, to vast countries, to the universe, and see what immense superiority sight has over touch.
61. We do not indeed find so vast a superiority when we compare touch with the other senses; nevertheless, it does exist in a very high degree.
The first difference is the ability to act from a distance. Certainly, touch also may in some manner perceive the presence or absence of the sun, by means of the impressions of heat and cold; and in like manner the presence or absence, and the more or less close proximity of some bodies, etc.; but not only are these impressions far from having the same variety and rapidity as those of hearing, but they would not even give us any idea of distance, if we had not already perceived it otherwise than by touch.
Heat and cold, dryness and moistness, are what the impressions which some bodies, though distant, may make upon touch are reduced to; and these impressions are clearly of a nature to be exposed to many serious errors.
62. If we suppose a man, having only the sense of touch, to know the presence or absence of the sun above the horizon, his only rule being the temperature of the atmosphere, which depends upon a thousand causes having no connection with the orb of day, it will happen that the natural or artificial change of it will lead him into error. The dampness which we perceive around a lake is a sign of the nearness of the water; but do we not a thousand times experience the feeling of dampness from causes operating on the atmosphere, altogether independent of the waters of a lake?
It is certain that the concentration of all sensitive forces upon one sense, the absence of all distraction, and continual attention to only one kind of sensations, might raise the delicacy of touch to a degree of perfection which we probably do not know; just as the habit of connecting ideas with respect to only one order of sensations, and of forming judgments concerning them, produces a precision, exactness, and variety, far superior to all that we can imagine. But however far we might extend our conjectures upon this head, it is certain that there is a limit in the nature of the organ and of its relations to bodies. This organ must be limited to contiguous objects, in order to receive well determined impressions; and with respect to those that are distant, and can act upon it, they can do this by causing on it an impression such as the nature of both permits, heat or cold, dryness or dampness, and if you will, a certain pressure either greater or less. So far as a great many other objects are concerned, we cannot imagine any action. However much the circle of this class of sensations be enlarged, it must ever be very limited. Moreover, we must observe, that the perfectibility of touch by means of its isolation does not belong to it exclusively, but extends likewise to the other senses; for it is founded on the laws of organization, and the generation of our ideas.
63. To comprehend the superiority of hearing to touch in this matter, we have only to consider the relation of distances, the variety of objects, the rapidity of the succession of sensations, the simultaneousness so much greater in hearing than in touch, and their relations to speech.
I. Relation of distances. On this point, hearing is clearly superior to touch, for the latter generally requires contact, the former does not, but for the due appreciation of its object even requires a distance suited to the class of the sound. Of how many distant objects does hearing inform us of which touch can tell us nothing? The gallop of the horse threatening to trample us under foot, the roaring of the torrent which may carry us away in its course, the thunder rumbling from afar, and announcing the tempest, the roar of cannon, telling that a battle has begun, the rattle of carriages in the streets, drums and bells, and clamor of voices which indicate the explosion of popular fury, the noisy music that proclaims the joy caused by happy news, the concert dedicated to the pleasures of the saloon, the song that brings back melancholy recollections, sentiments also of hope and love, the groan that warns us of suffering, the plaint that afflicts us with the idea of misery; all this hearing tells us, but touch can tell us nothing of any of these.
II. Variety of objects. Those distant objects which we know by touch, are of necessity little varied; and for the same reason the ideas resulting from it will be liable to a deplorable confusion and to great uncertainty. Hearing, on the contrary, informs us of infinite and exceedingly different objects, and that, too, with perfect precision and exactness.
III. Rapidity of the succession of impressions. It is evident that hearing has here an incalculable superiority over touch. When touch perceives by juxtaposition, it is under the necessity of successively going over the objects and even their different parts if it would receive varied impressions; and this, however small their number, requires much time. If the objects do not act by juxtaposition, but by some medium, the succession will require much more time, and there will be much less variety. Compare this slowness to the rapidity with which hearing perceives a whole series of sounds in musical combinations, the infinite inflexions of the voice, the countless number of distinct articulations, the infinity of noises of all kinds which we uninterruptedly perceive and classify, and refer to their corresponding objects.
IV. The simultaneousness of sensations so vast in hearing, is extremely limited in touch; for in the latter it can only be in relation to a few objects; but in the other it extends to many very different objects.
V. But what most triumphantly indicates the superiority of hearing to touch, is the facility it affords us of placing ourselves in communication, by means of speech, with the mind of our fellow-mortals,—a facility, resulting from the rapidity of succession already remarked. Undoubtedly, this communication of mind with mind, may be established by touch, if we express our words by characters sufficiently raised to be distinguished: but what an immense difference between these impressions and those of hearing? Even if we suppose habit and a concentration of all the sensitive forces to have produced such a facility in passing the fingers over lines, as far to surpass all that we see in the most dexterous players of musical instruments, what comparison can there be instituted between this velocity and that of hearing? How much time would be requisite only to go over tablets whereon is written a discourse which we hear in a few minutes? Moreover, all men have means of hearing, they need only make use of their organs. But in order to converse by touch, it is necessary to prepare tablets, which can only serve for one object, and cannot be at the same time used by two persons; whereas by means of hearing, one man alone may in brief time communicate an infinity of ideas to thousands of listeners.
CAN SIGHT ALONE GIVE US THE IDEA OF A SURFACE?
64. I have, I believe, made the inferiority of touch to sight and hearing palpable, and have, consequently, shown the extravagance of endeavoring to make it the basis of all cognitions, to found upon it the certainty of the judgments to which our other senses lead us, and to make it a supreme judge to decide in the last appeal upon the doubts that may arise.
I hold it to be manifestly untrue that we cannot make the transition from the internal to the external world, or from the existence of sensations to that of the objects causing them, otherwise than by means of touch; for not only have I combated the principal, or rather the solitary reason upon which it is pretended to found this privilege, but I have also demonstrated the mode of making this transition with respect to all the senses, reasoning from the very nature and connection of internal phenomena.
I have likewise said and proved that the sensation of extension is the only one that is representative, and that in all others there was only a relation of causality, that is, a connection of some sensation or an internal phenomenon with an external object, without our transferring to this any thing resembling what we experienced in that.
65. There are two senses which inform us with certainty of extension, sight and touch. We shall not now inquire if that be a true sensation which we have of extension, or if it be an idea of a very different order, resulting from the sensation. I propose hereafter to examine this point, but shall now confine myself to comparing sight with touch only as tending to give us the sensation of extension, or, if you will, to furnish us with what is necessary to form an idea of it.
We cannot but see that extension lies within the domain of touch, and that, too, whether it be considered only as a surface, or also as a solid. The same faculty cannot be denied to sight, so far as surfaces are concerned; for it is impossible to see if at least a plane be not presented to the eye. A point without extension cannot be painted upon the retina, but the instant an object is painted, it has painted parts. We can by no effort of our imagination, conceive colors without extension; for what is color without a surface over which it may extend?
66. So hostile was Condillac to the sense of sight that he was unwilling to allow it even the faculty of perceiving extension in surfaces; but as he is of all philosophers the one who has most contributed to the propagation and establishment of this opinion, we will examine his doctrine and its fundamental reasons. We have only to read the chapters in which he explains it, to see that he was not himself very confident of its truth, but that he felt himself contradicted by both experience and reason.
In his TraitÉ des Sensations,[36] where he examines the ideas of a man limited to the sense of sight, he says that colors are distinguished by the sight because they seem to form a surface of which the eyes occupy a part, and then asks: "Will our statue, judging itself to be at one time many colors, perceive itself as a sort of colored surface?" We must bear in mind that, according to Condillac, the statue confined to one sense will believe itself the sensation, that is, it will think that it is the odor, the sound, or the taste, according as the sense of smell, hearing, or taste, is the sense in exercise; for which reason, if a surface enter into the sensation of sight, the statue ought to believe itself a colored surface. I shall not examine the correctness of these observations, but shall confine myself to the main point, which is the relation of sight to a surface.
67. According to Condillac, the statue will never believe itself a colored surface, that is, although it may perceive the color, it will not perceive the surface. Let the philosopher himself speak, for his own words will suffice to condemn his opinion, and to show the uncertainty with which he advanced it, or else the obscurity under which it labors: "The idea of extension supposes the perception of many things, some distinct from others. This perception we cannot deny to the statue, for it feels that it is repeated outside of itself as many times as there are colors modifying it. When it is the red, it feels itself outside of the green; when the green, it feels itself outside of the red, and so with other colors." Some may imagine that, conformably to these principles, Condillac goes on to establish that sight gives us the idea of extension, since it makes us perceive things, some outside of others, in which, according to him, the idea of extension exactly consists. But he does not; far from following the true road, he miserably loses his way; he not only violates the principle he has just laid down, but notably changes the state of the question. He continues: "But in order to have a distinct and precise idea of magnitude, it is necessary to see how the things perceived, some outside of others, are connected, how they mutually terminate, and how they are all enclosed in the limits which bound them." This, I repeat, is to change the state of the question; we are not now treating of a distinct and precise idea, but simply of an idea. How far the idea of extension given by sight is perfect, is another question; although it is manifest that if sight can give us an idea of extension, it will come by continual exercise to render this idea more perfect.
68. The statue, in Condillac's opinion, could not perceive itself to be circumscribed by any limit, because it could know nothing beyond itself; but did he not just now tell us that the statue would believe itself different colors; that some of these were outside of others; and that when it would be one, it would perceive itself outside of the others? Does this not imply not only one but many limits?
This difficulty did not altogether escape Condillac; for after having asked if the me of the statue, when modified by a blue surface, bordered with white, would not believe itself a limited blue color, he says: "At first sight we were inclined to believe that it would; but the contrary opinion is much more probable." But why? "The statue cannot perceive itself extended by this surface, save inasmuch as each part modifies it in the same way; each part should produce the sensation of blue color; but if it is alike modified by a foot of this surface and by an inch, it cannot perceive itself, in this modification, to be one magnitude rather than another. Therefore it does not perceive itself as magnitude; therefore the sensation of color does not involve the idea of extension." It is easy to see that Condillac either supposes what is in debate, or else says nothing to the point. According to him, the statue is alike modified by a foot of colored surface and by an inch. If by this he means that the two modifications are identical under all aspects, he supposes the very thing he ought to have proved; for this is precisely the point in dispute, whether surfaces differing in magnitude do, or do not, produce different sensations. If he means, as his words seem to indicate, that the sensation as color, and solely as color, is the same in a foot of colored surface as in an inch, he utters, indeed, an incontestable truth, but one not at all to his purpose. Undoubtedly, the sensation of blue, as blue, is the same in different magnitudes, and no one ever thought of denying it. But this is not the question: it is whether, the color remaining one and the same, the sensation of sight is modified differently, according to the variety of magnitude of the colored surface. Condillac denies it, but in an uncertain and hesitating way. We believe his negation to be so groundless that the direct contrary may be proved.
69. I would ask Condillac if he can have color without surface; if an object without extension can be painted upon the retina; if we can even conceive a color without extension. No one of these is possible, sight is therefore necessarily accompanied by extension.
70. Condillac places the idea of extension in some things being presented to us outside of others. This, as he him self confesses, is verified in the sensation of color; therefore the sight of what is colored must produce the idea of extension. Condillac's subterfuge here is an exceedingly weak one. He pretends that it is necessary, in order to have the idea of extension, to have that of its limits. But first of all, we have shown from his own doctrine that these limits are perceived by the senses; besides it is a very strange pretension to attribute to sight the faculty of giving us the idea of unlimited extension, and to deny to it that of producing the idea of limitation; as if there did not by the very fact of our seeing what is extended, rise within us the idea of limitation, if from no other cause, from the very limitation of our organ; or as if an unlimited were not more inconceivable than a limited sensation.
But suppose the limits not be perceived by the senses, does unlimited extension therefore cease to be extension? Is it not rather extension of the highest order? Does the idea of space without end, because unlimited, cease to be an idea of extension?
71. Two colored circles, one an inch, and the other a yard in diameter, are placed before our eyes; will the effect produced upon the retina be the same in both, abstraction made from all sensation of touch? Evidently not; experience shows the contrary, and the reason is founded on the laws of the reflection of light, and on mathematical principles. If the impressions are different, the difference will be perceived; therefore the difference of magnitude can be appreciated.
We will now suppose some one in spite of reason and experience to persist in maintaining that the sensation of the two circles will be the same in order to make the extravagance, even the ridiculousness of this opinion palpable. Let us imagine the two circles to be of a red color, and terminated by a blue line; and now placing the less upon the greater circle so as to bring their centres together, we ask, will not the eye cast upon the figure see the less within the greater circle? Will not the blue line that terminates the circle of an inch in diameter be sure to be contained within the blue line that terminates the other circle of a yard in diameter? But what else is the perception of extension than the perception of some parts beyond others? Is it not to perceive the difference of magnitude, to perceive some greater than others, and containing them? Evidently it is. The sight therefore perceives magnitude; therefore it perceives extension.
72. We may still further confirm this truth. Experience teaches, and did it not exist, reason would still teach that there must be a limit to the field of sight, according to our distance from the object. Thus, when we fix our sight upon a wall of great extent we do not see it all, but only a part. Now suppose an object of given magnitude to be within the range of sight, but not so great as to cover the surface embraced by the eye. According to Condillac's system, there can be no difference in the perception, provided the color be the same; whence, it will follow, that the sensation will be just the same, whether the object occupy the whole, or only an exceedingly minute part, of the visual field. It will likewise follow, that, if this visual field be, for example, a great white curtain a hundred yards square, and the object a piece of blue cloth a yard square, the sensation will be just the same whether the blue cloth be one inch or ninety yards square.
73. These arguments, which must have occurred at least confusedly to Condillac, made him hesitate in his expressions, and even use contradictory language. We may have already observed this in the passages cited, but we shall see it yet more clearly in the following:—"We have no term to express with exactness the sentiment that the statue modified by many colors at one time has of itself; but in fine, it knows that it exists in many ways, and perceives itself in a certain mode as a colored point beyond which are others, in which it turns to find itself; and under this point of view, it may be said, that it perceives itself extended." He had before said, that color did not seem extended to the statue, until, sight being instructed by touch, the eye became accustomed to refer the one simple sensation to all the points of the surface: and in the very next line, as we have just seen, he asserts the contrary; the statue now perceives itself to be extended, and the ideologist discovers no way of avoiding the contradiction, but to warn us that the sentiment of extension will be vague because it wants limits. This is a contradiction which we have already made evident. But whence this want of limits? If various figures of different colors, green, red, etc., be supposed to be upon a visual field of a hundred yards square of white surface, the sight will, as is evident, perceive the limits of these figures; where, then, did Condillac discover that illimitation of which he talks?
74. Although it is very true that even if the sensation of color were to involve that of extension, it would not therefore follow that it would produce it in us, because we do not take from sensations all the ideas they contain, but those only which we know. This does not at all affect the present question. We do not treat of what we can take from the sensation, but of what is in it. If Condillac maintains that we may take the idea of extension from the sensation of touch, by what right does he deny the same faculty with respect to sight, supposing the idea of extension to be contained in both sensations?
If I mistake not, this is a tacit confession of the falseness of his opinion. The idea of extension is in the sensation of sight, but we cannot take it thence. Why not? Because it is vague. But then what is to prevent exercise, involving comparison and reflection, from rendering it distinct? The difficulty consists in acquiring it in one way or another; to perfect it is the work of time.
Undoubtedly the first sensations of sight will not have that exactness which they have after much exercise; but the same is true of the sense of touch. This sense is perfected like the others; it like them needs to be educated, so to speak; and those born blind, who, by force of concentration and labor, come to possess it to an astonishing degree of delicacy, offer us a manifest proof of this truth.
CHAPTER XIII.
CHESELDEN'S BLIND MAN.
75. Cheselden's blind man, of whom Condillac spoke, in confirmation of his opinions, presents no phenomenon upon which they can rest. This blind person was a youth of thirteen or fourteen years of age, upon whom Cheselden, a distinguished London surgeon, performed the operation of removing cataracts, first from one eye, then from the other. He could before the operation tell day and night, and in a very strong light distinguish, white, black, and red. This is an important circumstance, and merits attention. The phenomena the most remarkable, and having the most relation to the question now before us, were the following:
I. When he began to see, he believed that objects touched the external surface of his eye. This would seem to show that sight alone cannot enable us to judge of distances; but, after close examination, we shall clearly see that the argument is not conclusive. No one will pretend that sight, in the first moment of its exercise, can communicate equally clear and distinct ideas to us, as when experience has accustomed us to compare its different impressions. This is the same with touch as with sight. A blind person, from his frequent custom of guiding himself, in many of his movements by sensations of touch alone, comes to know the position and distances of objects with wonderful precision. If we suppose a man deprived of the sense of touch suddenly to acquire it, neither will he at first judge with the same certainty the objects of this sense as after having exercised it. Experience teaches that the sense of touch is capable of a high degree of perfection. We see it in blind persons at its highest point; and probably the lowest point of its perfection, in the first moments of its exercise, would greatly resemble that of sight at the instant of being freed from the cataracts; objects would be presented to it likewise in confusion; and the subject experiencing them could not well appreciate their differences until practice had taught him how to distinguish and classify.
With respect to distance, it is to be observed, that this blind person of Cheselden, so far from having the habit of appreciating it, had false ideas upon it. As he was not totally blind, the light, which he perceived through the cataracts, was sufficient to even enable him to distinguish between white, black, and red, which seemed to him to touch his eye. We may form some idea of this by observing what happens to us if we close our eyes in a very strong light. Hence he ought, when he gained his sight, to have imagined that the new sight was the same as the old, and, consequently, that nothing had happened but a simple change of object. A person totally blind would have better shown the power of sight to appreciate distances; for he would have had no habit either favorable or unfavorable to their knowledge.
II. It cost him much trouble to conceive that there were other objects beyond those he saw; he could not distinguish limits; every thing seemed to him immense. Although he knew by experience that his chamber was smaller than the whole house, he could not conceive how he could see this.
From these facts Condillac draws a confirmation of his system. We are astonished that he should pretend to found an entire philosophy upon such data. We submit the following considerations to the reader:
76. The subject is here a youth of thirteen or fourteen years, and consequently without any habit of observation. He would naturally express very confusedly the impressions he received in so new and strange a situation.
The organ of sight must, when exercised for the first time, be exceedingly weak, and consequently perform its sensitive functions only in a very imperfect way. We ourselves repeatedly experience that we cannot, if we suddenly pass from darkness to light, especially if it be a very strong light, distinguish objects, but we see every thing in great confusion; what then would happen to a poor child, when at the age of thirteen years, he for the first time opens his eyes to the light?
According to Cheselden's own account, objects were presented to him in such confusion that he could not distinguish them, no matter what their size or shape. This confirms what we have just said, that the partial, if not the sole cause of the confusion, was that the organ did not produce impressions well, because if these had been properly produced, he would have been able to distinguish the limits of the different colors; for, in simple sensation, to see is to distinguish.
We are also told that he could not recognize by sight the objects which he knew by touch. But this only proves that not having been able to compare the two orders of sensations, he could not know what corresponded in one to the impressions of the other. By touch he would have known a spherical body; but as he was still ignorant of the impression which a globe makes on the eye, it is clear that if any one should show him a ball which he had handled a thousand times, he would not even have suspected that the object seen was the same which he had touched. This leads me to another observation which I consider very important.
77. The child on whom these experiments were made was obliged to express his sensations in the visual order, in a language which he did not understand. For any one who is deprived of one of the senses must be absolutely ignorant of all the ideas which have their origin in that sensation. Hence it follows that he knows nothing of the language relating to that sense, and the ideas which he joins to the words are entirely different from what those who possess that sense mean to express. The blind man will speak of colors and the impressions produced by sight, because he hears others speak of these things; but for him the word to see does not mean to see, light is not light, nor color color, as we understand them, but they express different ideas which he has formed according to the circumstances, in conformity with the explanations he has heard. What importance then should we attach to what a child may say who, besides the thoughtlessness natural to his age, is placed in a situation new to him, and required to express his ideas in a language which he does not know? He is asked, for example, if he can distinguish a greater object from another which is smaller, without considering that the words greater and smaller as he understood them, inasmuch as they expressed abstract ideas, or were referred to the sensations of touch, were altogether new to him when applied to objects seen, since he had no means of knowing what was meant when referred to a sensation which he experienced for the first time. If within a circle, a number of smaller circles of a different color were described, he would see the smaller circles within the circumference of the greater; but if asked if one appeared greater than the rest, or if he could distinguish the limits which, separated the smaller circles from each other, he could not but give very absurd answers, which the observers might perhaps take as the expression of curious phenomena. They speak to him of figures, lines, extremities, size, position, and distances in relation to sight, and as he is ignorant of this language, yet knows not that he is ignorant of it, he must necessarily talk in a very strange manner. A more attentive and profound observer would have perceived the same misunderstanding as when a deaf man disputes without hearing what was said.
These remarks are further confirmed by the contradiction in the account of Cheselden. The oculist tells us that the child could not distinguish the objects, even those which differed most in form and size: but that he found those most agreeable which were the most regular. He must then have distinguished them; for otherwise, the sensation could not have been more or less pleasing. And here in choosing an alternative in this contradiction, we must hold that he distinguished the objects, since there is a strong argument in its favor. When two objects, the one regular, the other irregular, were presented to him, and he was questioned as to their resemblance and difference, he must have answered so absurdly as to create the suspicion that he could not distinguish them. The reason of this is, that besides the confusion of sensations, to which he was always more or less subject, he was also ignorant of the language, and although he distinguished the objects plainly, still he could not understand what he was asked, nor express what he felt. But when examined as to the nature of the impression and whether it was pleasing or otherwise, he found himself on a field common to all sensations, the ideas of pleasure and displeasure were not new to him, and he could say without confusion, this pleases me; that is displeasing to me.
To sum up what I have said, I believe that the phenomena of Cheselden's blind man, only prove that sight, like all the other senses, needs a certain education, that its first impressions are necessarily confused, that the organ acquires the proper strength and precision only after long practice, and finally, that the judgments formed in consequence, must be very incorrect until comparison, joined with reflection, has taught how to rectify inaccuracies.[37]
CHAPTER XIV.
CAN SIGHT GIVE US THE IDEA OF A SOLID?
78. It has been asserted that sight can not give us the idea of size or of a solid, but that this can be obtained only by the help of touch. I believe the contrary may be proved with convincing certainty.
What is a solid? It is the union of three dimensions. If sight can give us the idea of surfaces which consist of two, why not also of solids which consist of three dimensions? This one reflection is enough to show that it has been denied without reason; but I shall not stop with this, but shall prove, by the most rigorous observation, and the analysis of its phenomena, that sight can give us the idea of a solid.
79. I willingly agree, that if we suppose a man deprived of all the other senses, to have his eyes immovably fixed on an immovable object, he would never be able to distinguish between what is solid and what is merely perspective in the object; or, in other words, that all the objects permanently painted on the retina will appear to be projected on a plane. The reason of this is founded on the very laws of the organ of this sense, and of the transmission of its impressions to the brain.
The soul refers the sensation to the extremity of the visual ray; and since in the present instance it has been unable to make any comparisons, it can have no motive for placing these extremities at unequal distances, which constitutes the third dimension.
In order to understand this better, let us suppose the object to be a cube placed so that three of its sides are seen. It is evident that although the three surfaces are equal, they will not appear so to the eye, because their respective positions do not permit them to send their rays equally to it. But as the soul has not had occasion to compare this sensation with any other, it can not calculate the difference produced by the different positions and distances, but must refer all the points to the same plane, regarding the sides of the cube as unequal; though, in reality, they are not so.
Sight, in this case, presents the whole object on a perspective plane; and as it could have no means of calculating the distance of the object from the eye, it would probably believe it joined to the eye, or, more strictly speaking, the sensation would represent only a simple phenomenon, the relations and cause of which we could not explain.
80. It is likewise probable, that if, while the eye remained fixed, we could open and shut the lids, we might form the idea that the object seen was outside of us; so that by this motion alone, we should obtain a point of comparison, by the succession of the alternate disappearance and reproduction of the sensation of the object by the interposition or non-interposition of an obstacle. Then the idea of a greater or less distance would arise, and as this would be in the direction perpendicular to the plane of the object, we should already have the idea of a solid.
Fortunately, nature has been more beneficent to us, and we are not obliged to limit ourselves to a supposition which thus curtails our means of acquiring ideas. Still it will not be useless to have examined the phenomenon on this supposition; for, from this examination, we shall gain light to understand what I propose to demonstrate.
81. In order that sight may originate the idea of a solid, it requires motion. This motion is an indispensable condition, though it may be either in the object or in the eye itself.
Let us suppose an immovable eye, and see how by the motion of the objects, the sensation of sight may present or produce the idea of a solid. The only difficulty is to show how it can add to the two dimensions which constitute the plane, the third which forms the solid.
Let a fixed eye be directed to a point where there is a right rectangular parallelopipedon B, so placed that its two bases are wholly concealed, and let the right line drawn from the centre of the eye to the edge of the parallelopipedon divide the plane angle into two equal parts. Let us also suppose the sides of the parallelopipedon to be of different colors,—white, green, red, and black. In this case, the eye sees the two planes as one, and the edge appears as a right line separating the two parts of the same plane which differ only in color. It is impossible for it to conceive the inclination of the two planes, because as it refers the object to the extremity of the visual ray, and has not been able to compare the varieties which result from difference of position and distance, and from the manner in which the object receives the light, it can only distinguish the different parts of the same plane.
It is well known that perspective can perfectly imitate a solid. For, if instead of the solid B, we suppose two planes exactly representing the two sides seen, the sensation will be the same, the illusion complete. Therefore, there are two distinct ways of producing the same sensation; and consequently, unless there has been a previous comparison, there is no means of distinguishing them apart; but the idea which would naturally result would be the most simple; that is, the idea of a plane.
82. If we suppose the parallelopipedon B to revolve on a vertical axis, it will present the four planes successively to the eye, and they will appear greater or less according to their inclination to the visual ray, the surface of the plane reaching its maximum when perpendicular to the ray, and its minimum when parallel to it.
The succession and variety of the sensations will immediately produce the idea of motion; for the same planes of the parallelopipedon are seen in different positions. The uniform manner in which these planes succeed one another, will also suggest the idea that the green which appears a few moments after the black, is the same which was seen a few moments before; and so of the other colors. Also, as one is constantly hiding behind the other, this naturally gives rise to the idea of extension in the direction, or continuation of the visual ray; and this is sufficient to produce the idea of size or of a solid. When we see a plane we have the two dimensions which constitute a surface; to form the idea of a solid, we need only the idea of one dimension more; this can not be found in the same plane, but is produced by the motion of the parallelopipedon.
83. This motion which we have supposed to be around a vertical axis, we may equally suppose to take place around a horizontal axis. We shall then see in succession the two opposite sides, and the bases of the parallelopipedon with different appearances, according to their various positions; or, in other words, according to the angle formed by the planes and the visual ray. These appearances will help more and more to form the idea of the third dimension, which is not to be found in the primitive plane, and consequently to supply what was wanted to constitute the idea of a solid.
84. Just as we have supposed the eye fixed and the object movable, we may suppose the eye in motion and the object immovable. The result is the same; for, it is evident that if the eye should move around the parallelopipedon, now vertically, and now horizontally, it would experience the same sensations as when it was quiet, and the parallelopipedon moved. Thus, although we suppose the subject wholly deprived of the sense of touch, so as to be unable to perceive its own motion, it can still form the idea of solid by the impressions of sight alone. True, it could distinguish which moved, the eye or the object, but this does not interfere with the formation of the idea composed of the three dimensions.
SIGHT AND MOTION.
85. I said that the observer could not distinguish between his own motion and that of the object; sight alone can not give us a true idea of motion. Thus in a boat, although we are certain that we are moving, the motion seems to us to be in the objects along the shore. Also if the motion of the object and that of the observer are simultaneous, in the same direction, and with the same velocity, all appearance of motion is lost. But if there are two objects, one of which moves in the same direction as ourselves, and the other in the opposite direction, we perceive only the latter. Thus in a canal boat, the horse which walks on the bank in the same direction which the boat follows, seems to move without advancing. Of the two motions of the horse, we perceive only the vertical, the horizontal escapes us.
The reason of this is clear, we can judge the object only by our impressions. When the impression varies, we have the idea of motion; but not otherwise. When the object or the eye is in motion, there is a succession of impressions on the retina, from which the idea of motion arises. But if the motion of the eye accompanies the motion of the object, one cancels the other, the impression on the retina is constant, and the object does not seem to move.
86. In the same manner if the motion of the object and that of the eye are simultaneous, but of unequal velocity, we perceive only the difference; that is to say, if the motion of the eye be represented by 3 and that of the object by 5, the motion of the object will appear as 2, or the difference between 5 and 3. If our motion is more rapid than the motion of the object, although in the same direction, the object will appear to move in the opposite direction, as when we sail down a river faster than the current, the water seems to flow backwards. An immovable object at the same time seems to move in a direction opposite to our own with greater velocity than the current; for, here also, of the two motions we perceive only the difference. The motion of the boat, which is equal to 5, seems transferred to the fixed object, which appears to move in the opposite direction with the velocity represented by 5; and if we suppose the velocity of the current to be equal to 3, it will have the appearance of moving backwards with a velocity of 5-3, or 2.
87. From these considerations it would seem to follow that although sight is sufficient to give us the idea of motion, it is not sufficient to enable us to distinguish our own motion from that of the object, but for this we have need of touch. But this is not so; for by sight alone, we can distinguish the motion of the eye from that of the object, and if in some cases this is impossible, the same is true of touch.
We must observe that in the above examples touch is of much less use than sight in order to preserve us from illusions. How by the aid of touch alone could we perceive the motion of a boat gliding smoothly down a river? Sometimes by the help of sight we observe this motion, especially if we regard the objects along the bank which we pass; but touch is essentially limited to what affects the body immediately, and therefore cannot discover motion when the body is not affected by it.
It is also well to observe that we do not refer the motion perceived by touch to the objects around us until after we have acquired this habit by means of repeated comparisons. When for the first time the hand is passed over an object, we are unable to tell whether the hand moves over the body, or the body under the hand.
The reason of this is that the sensation of motion is essentially a successive sensation, and this succession exists equally whether the hand moves or the object. Let us suppose the hand to pass along an object of a varied surface, we shall experience the variety of sensations corresponding to the surface; suppose now that the hand remains motionless, and the object passes under it with the same velocity, pressure, and friction, the sensations will be the same as before. Every one must have observed that when leaning on a slippery object, it is often difficult to tell whether it is the object which moves, or ourselves. Therefore touch also confirms what we have advanced, that the distinction between the motion of the member and that of the object does not arise from simple sensation.
88. In this respect, therefore, touch does not help sight; let us see if sight alone can enable us to distinguish between the motion of the eye and that of the object. We have already observed that a single sensation with respect to one object only is insufficient, but there is no difficulty in proving that this result may be obtained by the comparison of different sensations.
Let us suppose the eye at a point A, looking at an object B; the object will appear at the extremity of the range of the sight as if projected on a plane. To be more definite we will imagine the object B to be a column in the middle of a large hall, and the point A a corner of the same hall. The column will appear to the eye to be a part of the opposite wall. If the eye changes its position, the column will appear in another part of the wall; so that if the eye should pass around the column, it would appear successively on every part of the wall. The same succession of phenomena would be observed if the eye should remain fixed and the column should move around it; for it is evident that if the observer is placed in the centre of the room, and the column moves around him, the column will appear on all the parts of the opposite wall. From this we infer that only one sensation of sight, with only one object, is not enough to determine whether the eye moves or the object.
But if instead of one object we suppose several moving simultaneously, it is easy to see how the distinction of motions arises. Let us suppose that at the same time that the eye sees the column, it also sees other objects, such as chandeliers, statues, or other columns, placed between the eye and the opposite wall. If the eye moves every time the column changes its position on the opposite wall, the other columns, the chandeliers, statues, everything in the room seems to change its position; whereas, if the column moves and the eye remains fixed, the column alone changes its position, while everything else remains motionless. Therefore sight alone gives us two distinct orders of phenomena of motion:
I. The first, in which all the objects change their position.
II. The second, in which one object only changes its position.
These two orders of phenomena cannot remain unperceived; for by the help of reflection excited and enlightened by the repetition of the phenomena, we must come to the conclusion that when there is an entire and constant change of all the objects, it is not they that move, but the eye; and that when only one or a part of the objects change their position, the rest remaining fixed, it is not the eye that moves, but the objects which change their position. When everything around us changes we infer that it is the eye that moves; when one or two change their position we conclude that they move and not the eye. This is not merely a supposition, it is the reality. The ideas derived from touch are essentially limited, and it is therefore impossible that they should proceed from distant objects which cannot be touched.
89. I believe I have demonstrated that the pretended superiority of touch is without foundation, and that the opinion which makes this the basis of our knowledge of external objects, the touch-stone of the certainty of the sensations transmitted by the other senses, is an error. Without it we can acquire the certainty of the existence of bodies; without it we can form the idea of surfaces and solids; without it we discover motion, and distinguish the motion of the object from that of the organ which receives the impression. The theory of sensation here explained, and the results which are deduced from the relations of the dependence or independence of the phenomena among themselves, and with our will, may all be applied to the sight as well as to the touch.
90. Summing up all we have said, we have the following results:
I. We distinguish sleep from waking, even abstracting the objectiveness of the sensations.
II. We distinguish two orders of phenomena of sensation;—the one internal, the other external, here also abstracting their objectiveness.
III. The senses give us certainty of the existence of bodies.
IV. Sensations have no type in the external object of what they represent, except extension and motion.
V. Touch is not the basis or touch-stone of certainty.
VI. All that we know by means of the senses may be reduced to this; that there are external beings, that is to say, beings placed outside of ourselves, which are extended, subject to necessary laws, and which produce in us the effects which we call sensations.
POSSIBILITY OF OTHER SENSES.
91. Lamennais writes: "Who can say that a sixth sense would not disturb the harmony of the others by a contrary impression? On what foundation could he deny it? If we suppose other senses different from those which nature gave us, might not our sensations and our ideas be different? Perhaps a slight modification in our organs would be sufficient to ruin our whole science. Perhaps there are beings so organized that their sensations are wholly opposed to ours, and what is true for us is false for them, and reciprocally. For, if we examine the matter closely, what necessary connection is there between our sensations and the reality? And if there were such a connection, how could the senses make it known to us?"[38]
The questions which these words raise are of the highest importance and merit a serious examination.
92. Is there any intrinsical impossibility of an organization different from ours, and an order of sensations different from those which we experience? It seems not; and if this impossibility exists, it is unknown to man.
Whatever opinion we adopt as to the manner in which external objects act upon the soul by means of the organs of the body, there is no necessary relation, nor even analogy, between the object and the effect which it produces in us.
A body receives upon its surface rays of the fluid which we call light, these rays are reflected upon the retina, which is another surface in communication with the brain. So far all is well, and easily understood. There is a fluid which moves, goes from one surface to another, and may cause this or that purely physical effect on the cerebral matter; but what connection is there between this and the impression of a distinct order which we call seeing, an impression which is neither the fluid nor the motion, but an affection of which the living and thinking being, the me is intimately conscious?
If, instead of the luminous fluid and its mechanism, we suppose another, as, for example, the air which vibrates upon the tympanum, what essential reason is there why this should not produce a sensation similar to that of sight? It must be confessed that it is impossible to assign an essential reason. To one who has no idea of our present organization, both phenomena are equally incomprehensible.
93. What has been said of sight and hearing may be applied to the other senses. In all there is a bodily organ affected by a body; we see the surfaces placed one before or under the other, we see motions of one kind or another; but how can we pass over the immense distance which separates these physical phenomena from the phenomenon of sensation? For my part, I see no way to do it; this point is a barrier to the human intellect; all appearances indicate that there is no connection between these two orders of phenomena except what the will of the Creator has freely established; if there is any necessary connection, this necessity is a secret to man. Examine the textures which receive the impression of the objects, the material substance which composes the nervous system which is the organ of sensations, and say what relation you can find between the physical phenomena of this matter and the wonderful harmony of sensible phenomena.
94. Still greater will be the difficulty if you consider that, although protected from any injury, the organs cease to produce sensations from the moment they are deprived of communication with the substance of the brain. The phenomena of light are produced in the cavity of the skull amid the most profound darkness; and all the wonderful magic of sensations by which the magnificent spectacle of the universe is presented to our mind, which plunges the soul into raptures at the sound of music, and which produces such varied and delightful sensations of taste and odors, all arises in the brain, a whitish, rude, and unformed substance, from the appearance of which no one could imagine it destined to such noble functions.
95. Why is it that when the nerve A, in communication with the brain is affected, we experience the sensation which we call seeing, or if the nerve B is affected, the sensation which we call hearing, and so of the other senses? There may be a reason, but, at least, we do not know it; and it is probably no other than the free will of the Creator.
Here, it is true, philosophy confesses its weakness, but, at the same time, it shows its power; for it sees the immense distance which separates these phenomena, between which there can be no point of communication but what is established by the Almighty. When there are second causes, it is the merit of philosophy to discover them; but when there are none, its merit is in rising to the first cause. A confession of its ignorance is sometimes a more sublime act of reason than the impotent effort of an unbounded pride. If the perception of profound truths exalts the intellect, is not the intellect exalted in perceiving its own ignorance, which is sometimes a profound truth?
96. The existence of another sense is, then, possible; at least, we see no impossibility of it. If the deaf man who has no idea of sound, and the blind man who knows not what color is, would be foolish to deny the possibility of those sensations of which they are deprived, can we, with any more show of reason, assert the impossibility of an order of sensations different from what we possess? If we examine the system of sensations by the light of reason, we can discover no essential dependence between the sensations and their respective organs, nor between the organs and the objects and circumstances by which they are affected. Why does the impression of the light upon my eyes cause in me a particular sensation, which cannot result from the same impression on a different part of my body? Why may not the brain receive the same impression in various forms? Why must this fluid which we call light, and no other, produce the impression? Why may not this same sensation of seeing proceed equally from other affections of the brain? A violent blow on the head produces the sensation of many luminous points, whence the common expression of "seeing stars by daylight." We must confess that philosophy knows nothing of these secrets, that as yet it has not been able to penetrate them, and it can give no answer to these questions. It sees an order of facts, but no necessary connection between them, or rather, judging from its ideas of mind and body, every thing induces it to believe that these phenomena in our life depend solely on the will of our Creator.
97. If an entirely new order of sensations is possible, there may be beings with six or seven senses. The imagination cannot conceive their nature; but reason sees in them no impossibility.
EXISTENCE OF NEW SENSES.
98. Is it certain that we have only five ways of sensation? I have some doubts on this point. In order to present them with the greatest clearness, and solve the questions which they raise, it is well to settle the meaning of the terms.
What is sensation? In the ordinary acceptation of the word, it is the perception of the impression transmitted to us by one of the organs of the five senses. Thus understood it is clearly limited to the action of the organs, but if considered as expressing a certain class of animal phenomena, it is the experiencing of any affection produced by an impression of the organism. Even in common use the word sensation in its broadest signification is not restricted to the impressions of the five senses, and although we make a great difference between sentiment and sensation; still we are often forced to confound them, and to use the word sensation to express things which have nothing whatever to do with the five senses. Thus we say: "The news made a great sensation;" "I cannot resist the force of such strong sensations," etc., in which cases it is evident that there is no reference to seeing, hearing, smelling, tasting, or touching, but to a different order of affections of the soul.
99. I said we were forced to use the word in the broader meaning; it is the truth which forces us. For, to the eyes of philosophy, the phenomenon of sensation consists in the production in the soul of a particular affection determined by an impression on an organ; and of whatever order this affection may be, and whatever organ may be affected, the animal phenomenon is substantially the same. The difference is in the class of affections and of the organ which is their medium, the essence of the phenomenon does not change. And if by sensations we understand such distinct orders of affections as those of sight and of touch, why may we not include other impressions caused by any other organ, whatever that organ may be?
100. Whatever use we may make of the word sensation, it is certain that we experience many affections caused by organic impressions, besides those of the five senses. What are passions but affections of the soul, springing from organic impressions? Does not the mere presence of an object often excite love, anger, pity, joy, grief, and many other sentiments of the soul?
You may say there is an essential difference between the impressions of the senses and those of the passions, that the former are independent of all previous idea and reflection, which the latter more or less presuppose. Thus, when an object is present to our open eyes, we cannot but see it and always in the same manner; and yet this object will excite in us at one time one passion, at another time another, and sometimes none; and almost always with great difference in the degree of its intensity. Moreover it is not only the mere presence of the object which causes an affection, but certain conditions are necessary, for example; the remembrance of a benefit or of an injury, etc., from which it is easy to see that there is an essential difference between the two classes of impressions.
101. If we reflect well upon this objection we shall find that though it is specious and under many aspects true, it contradicts nothing which I have asserted. I did not deny that the new impressions were subject to very different conditions from those that govern the five senses; but on the contrary I have all along supposed a difference not only in the class of impressions and the diversity of the organ, but also in the manner in which the organ is affected, and the circumstances in which the sensation is produced in the soul. I only contended that the animal phenomenon was substantially the same, that we find in it the three things which constitute its nature; a corporeal object; an organ affected by this object; and an impression produced in the soul. Because this impression cannot exist without the aid of this or that idea, this or that recollection, it does not follow that the phenomenon does not exist, or that it is not the same; it is merely to impose a new condition, and nothing more.
102. But there is no necessity of admitting that some previous idea or reflection is requisite in order that the sight of the object may produce certain impressions in the soul;—daily experience proves the contrary. How is it that the presence of an object charms in an instant a tender and perhaps innocent heart? Whence then arises that sudden fascination which is preceded by no idea, accompanied by no affection, and is scarce voluntary? Not from the thought of gross enjoyments; for perhaps he of whom I speak knows not their existence until he experiences this emotion; he feels for the first time in his breast a trouble unknown before. We must therefore recur to an organic affection similar to that which we find in the other senses. Certain conditions of age and temperament may be requisite, one object may have been necessary, among a thousand, in particular circumstances, of which the soul can give no account to itself though affected by them; yet it is still true that there is an external object, an affection of the organism, and an impression in the soul, all connected together by a mysterious, but undeniable bond.
It is easy to discover a series of strong impressions in the phenomena relating to reproduction; but although they presuppose the action of some one of the five senses, they nevertheless belong to a different order. No physiological studies are necessary to prove that these affections depend on the organization, and that they are greatly influenced by age, health, temperament, food, climate, and the seasons.
103. There is a difference between sentiments and sensations which, though it does not change the fact physiologically and psychologically considered, still greatly modifies it in its intellectual and moral relations. The passions are commonly excited by an animate and sensible object, whence it would seem that there is more communication between mind and mind, between soul and soul, than there is between one body and another. The sad and mournful appearance not only of a man, but even of an animal, immediately excites in our breast the sentiment of compassion, because it expresses the suffering of a living being. This only proves that nature has mysterious ways by which it transmits to us the knowledge of hidden things; but this transmission is made by the medium of a body which affects in some way our organic constitution. There is here, if you please, a more admirable, more penetrating, and more spiritual a magic than that of the senses alone; but the difference is in the degree, not in the nature of the phenomena.
It is certain that living beings, and those of the same species in particular, are in a constant communication which mutually excites their affections, and that these affections frequently suppose a mysterious correspondence with unknown agencies. Physical nature is full of fluids whose qualities are daily becoming known through scientific observation. The phenomena of electricity and galvanism have revealed secrets of which we had no suspicion before. Who can tell by what means the functions of this vast and complicated system of animal life, spread over the universe, are performed? It is probable that there are profound secrets in the correspondence and relation of organisms and in the way in which they influence one another yet to be discovered; perhaps they will remain forever veiled to the eyes of mortality.
104. Is it true that sensible beings can alone excite the passions? or have not inanimate causes repeatedly affected our organs? Why are we sometimes joyful and sometimes sad, at some times peaceful and at others irritable, when we have had no communication with any living being? It is clear that this depends on the affections of our organism, and has no relation to the state of other sensible beings.
105. Therefore, besides the impressions caused by the five senses, there are others which proceed from purely corporeal and inanimate objects. Besides the phenomena of ordinary sensations, there are others which differ from them only in the kind of impression and the organ affected; and there is no more difference between these sensations and the former than there is between the impressions of one and those of another of the five senses. Therefore it is not correct to say that there are only five kinds of sensation.
SOLUTION OF LAMENNAIS' OBJECTION.
106. From the preceding observations we shall now deduce an important consequence,—the solution of the difficulty presented by Lamennais. The existence of new senses would involve new sensations, it is true; but they would not disturb the harmony of those we already have. We have shown that bodies affect our organs in a different manner, and produce impressions different from those of the five senses; but this does not disturb the agreement of our sensations, nor change our ideas. Consequently, the supposition of Lamennais would not involve the disorder which he suspects.
107. Sensations in themselves are mere affections of the soul, and have no external object which corresponds to them except the existence and extension of bodies. Therefore a new order of sensations would only be a new order of affections, which would in nowise alter our ideas.
From what we have hitherto said, it is easy to see that the supposition of Lamennais is already realized; for there are sensations different from those of the five senses; therefore this supposition does not contradict the nature and order of our ideas, nor the certainty of our knowledge.
A musical instrument beautifully fashioned has charms for the ear, the eye, and the touch, none of these impressions destroys the other; if we suppose it placed in new relations with our organs, so as to produce in the soul new impressions, why is it impossible that they should accord? Does the melody of its sound cease because our soul experiences new affections whose nature has no connection with it? Certainly not. Why then fear the overthrow of our knowledge by the introduction of a new order of sensations? Why give such importance to a supposition, the effects of which we can very well calculate, and which, if we examine the phenomena of our present sensations, we find already realized?
108. It is true that we know of no other means of placing ourselves in contact with external objects than the five senses; but it is equally true, that this contact existing, the impressions in the soul correspond mysteriously to the external objects; so that, while we observe the sensations by which the communication is established, it is still impossible for us to explain them.
Let us examine the magical effects of music. They are of two orders; the purely auditive, and the intellectual or moral. The first stop at the ear, the second pass to the brain and to the heart; and one may be admirably organized for the former, yet unable to appreciate the latter. Two persons listen to a sonata, both hear the material music, but the intellectual and moral effects are not the same on both. Both perceive the least defect in the time or in the instrument, both admire the art of the composer, both are charmed; but while the heart of one is unmoved, the brain and the heart of the other are bounding with delight, the power of his fancy is multiplied, thoughts and images crowd upon his mind, as though he had caught inspiration from the magic notes of the music. His heart is transported with tenderness, melancholy, hatred, love, anger, generosity, and courage. He is under a magical influence which, moves him in spite of himself; the vibrations of a chord have raised in his heart a mysterious tempest which the might of reason can hardly quiet.
109. From this we must conclude, that besides the ordinary relations between objects and the organs of the senses, there are other relations still more intimate and more delicate between these objects and our organic system, and that these latter are as certain as the former. In them there is greater variety of individuals, and the conditions necessary to produce determinate results are less known, but there can be no doubt of their existence, and this in the eyes of sound philosophy is sufficient to dissipate those absurd suppositions which would pretend to undermine the edifice of our knowledge.
110. Thus, then, the objection is answered, which says: "If we had another sense, what would it tell us?" Nothing which would destroy the certainty of our knowledge, or the nature and order of our ideas. The only new result would be one more added to the many ways in which objects now affect us. The same thing would happen to us as to a man who after being deprived of the sense of smell, should suddenly regain it: he would have one sensation more; the same thing would happen to us as to a man who experiences a new sentiment which he had not known before: he has one affection more. New impressions have their own rank, neither interfering with, nor changing those which previously existed.
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