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 acausingproperty of the sensation, but not a propertyrepresentedby 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; andthe 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 evendestroy 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 wetake 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 allreduced 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.