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 manœuvres; 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.