An Introduction to Philosophy, George Stuart Fullerton [books to read in your 20s .TXT] 📗

world is known as directly as it is possible for the external world to be known, and that one can get no more of it than is presented in sensation. If a sense is lacking, an aspect of the world as given is also lacking; if a sense is defective, as in the color-blind, the defect is reflected in the world upon which one gazes.

Such considerations, especially when taken together with what has been said at the close of the last section about the futility of looking for a reality behind our sensations, may easily suggest rather a startling possibility. May it not be, if we really are shut up to the circle of our experiences, that the physical things, which we have been accustomed to look upon as non-mental, are nothing more than complexes of sensations? Granted that there seems to be presented in our experience a material world as well as a mind, may it not be that this material world is a mental thing of a certain kind—a mental thing contrasted with other mental things, such as imaginary things?

This question has always been answered in the affirmative by the idealists, who claim that all existence must be regarded as psychical existence. Their doctrine we shall consider later (sections 49 and 53). It will be noticed that we seem to be back again with Professor Pearson in the last chapter.

To this question I make the following answer: In the first place, I remark that even the plain man distinguishes somehow between his sensations and external things. He thinks that he has reason to believe that things do not cease to exist when he no longer has sensations. Moreover, he believes that things do not always appear to his senses as they really are. If we tell him that his sensations are the things, it shocks his common sense. He answers: Do you mean to tell me that complexes of sensation can be on a shelf or in a drawer? can be cut with a knife or broken with the hands? He feels that there must be some real distinction between sensations and the things without him.

Now, the notions of the plain man on such matters as these are not very clear, and what he says about sensations and things is not always edifying. But it is clear that he feels strongly that the man who would identify them is obliterating a distinction to which his experience testifies unequivocally. We must not hastily disregard his protest. He is sometimes right in his feeling that things are not identical, even when he cannot prove it.

In the second place, I remark that, in this instance, the plain man is in the right, and can be shown to be in the right. "Things" are not groups of sensations. The distinction between them will be explained in the next section.

17. THE DISTINCTION BETWEEN SENSATIONS AND "THINGS"—Suppose that I stand in my study and look at the fire in the grate. I am experiencing sensations, and am not busied merely with an imaginary fire. But may my whole experience of the fire be summed up as an experience of sensations and their changes? Let us see.

If I shut my eyes, the fire disappears. Does any one suppose that the fire has been annihilated? No. We say, I no longer see it, but nothing has happened to the fire.

Again, I may keep my eyes open, and simply turn my head. The fire disappears once more. Does any one suppose that my turning my head has done anything to the fire? We say unhesitatingly, my sensations have changed, but the fire has remained as it was.

Still, again, I may withdraw from the fire. Its heat seems to be diminished. Has the fire really grown less hot? And if I could withdraw to a sufficient distance, I know that the fire would appear to me smaller and less bright. Could I get far enough away to make it seem the faintest speck in the field of vision, would I be tempted to claim that the fire shrunk and grew faint merely because I walked away from it? Surely not.

Now, suppose that I stand on the same spot and look at the fire without turning my head. The stick at which I am gazing catches the flame, blazes up, turns red, and finally falls together, a little mass of gray ashes. Shall I describe this by saying that my sensations have changed, or may I say that the fire itself has changed? The plain man and the philosopher alike use the latter expression in such a case as this.

Let us take another illustration. I walk towards the distant house on the plain before me. What I see as my goal seems to grow larger and brighter. It does not occur to me to maintain that the house changes as I advance. But, at a given instant, changes of a different sort make their appearance. Smoke arises, and flames burst from the roof. Now I have no hesitation in saying that changes are taking place in the house. It would seem foolish to describe the occurrence as a mere change in my sensations. Before it was my sensations that changed; now it is the house itself.

We are drawing this distinction between changes in our sensations and changes in things at every hour in the day. I cannot move without making things appear and disappear. If I wag my head, the furniture seems to dance, and I regard it as a mere seeming. I count on the clock's going when I no longer look upon its face. It would be absurd to hold that the distinction is a mere blunder, and has no foundation in our experience. The rôle it plays is too important for that. If we obliterate it, the real world of material things which seems to be revealed in our experience melts into a chaos of fantastic experiences whose appearances and disappearances seem to be subject to no law.

And it is worthy of remark that it is not merely in common life that the distinction is drawn. Every man of science must give heed to it. The psychologist does, it is true, pay much attention to sensations; but even he distinguishes between the sensations which he is studying and the material things to which he relates them, such as brains and sense-organs. And those who cultivate the physical sciences strive, when they give an account of things and their behavior, to lay before us a history of changes analogous to the burning of the stick and of the house, excluding mere changes in sensations.

There is no physicist or botanist or zoölogist who has not our common experience that things as perceived by us—our experiences of things—appear or disappear or change their character when we open or shut our eyes or move about. But nothing of all this appears in their books. What they are concerned with is things and their changes, and they do not consider such matters as these as falling within their province. If a botanist could not distinguish between the changes which take place in a plant, and the changes which take place in his sensations as he is occupied in studying the plant, but should tell us that the plant grows smaller as one recedes from it, we should set him down as weak-minded.

That the distinction is everywhere drawn, and that we must not obliterate it, is very evident. But we are in the presence of what has seemed to many men a grave difficulty. Are not things presented in our experience only as we have sensations? what is it to perceive a thing? is it not to have sensations? how, then, can we distinguish between sensations and things? We certainly do so all the time, in spite of the protest of the philosopher; but many of us do so with a haunting sense that our behavior can scarcely be justified by the reason.

Our difficulty, however, springs out of an error of our own. Grasping imperfectly the full significance of the word "sensation," we extend its use beyond what is legitimate, and we call by that name experiences which are not sensations at all. Thus the external world comes to seem to us to be not really a something contrasted with the mental, but a part of the mental world. We accord to it the attributes of the latter, and rob it of those distinguishing attributes which belong to it by right. When we have done this, we may feel impelled to say, as did Professor Pearson, that things are not really "outside" of us, as they seem to be, but are merely "projected" outside—thought of as if they were "outside." All this I must explain at length.

Let us come back to the first of the illustrations given above, the case of the fire in my study. As I stand and look at it, what shall I call the red glow which I observe? Shall I call it a quality of a thing, or shall I call it a sensation?

To this I answer: I may call it either the one or the other, according to its setting among other experiences.

We have seen (section 15) that sensations and things merely imaginary are distinguished from one another by their setting. With open eyes we see things; with our eyes closed we can imagine them: we see what is before us; we imagine what lies behind our backs. If we confine our attention to the bit of experience itself, we have no means of determining whether it is sensory or imaginary. Only its setting can decide that point. Here, we have come to another distinction of much the same sort. That red glow, that bit of experience, taken by itself and abstracted from all other experiences, cannot be called either a sensation or the quality of a thing. Only its context can give us the right to call it the one or the other.

This ought to become clear when we reflect upon the illustration of the fire. We have seen that one whole series of changes has been unhesitatingly described as a series of changes in my sensations. Why was this? Because it was observed to depend upon changes in the relations of my body, my senses (a certain group of experiences), to the bit of experience I call the fire. Another series was described as a series of changes in the fire. Why? Because, the relation to my senses remaining unchanged, changes still took place, and had to be accounted for in other ways.

It is a matter of common knowledge that they can be accounted for in other ways. This is not a discovery of the philosopher. He can only invite us to think over the matter and see what the unlearned and the learned are doing at every moment. Sometimes they are noticing that experiences change as they turn their heads or walk toward or away from objects; sometimes they abstract from this, and consider the series of changes that take place independently of this.

That bit of experience, that red glow, is not related only to my body. Such experiences are related also to each other; they stand in a vast independent system of relations, which, as we have seen, the man of science can study without troubling himself to consider sensations at all. This system is the external world—the external world as known or as knowable, the only external world that it means anything for us to talk about. As having its place in this system, a bit of experience is not a sensation, but is a quality or aspect of a thing.

Sensations, then, to be sensations, must be bits of experience considered in their relation to some organ of sense. They should never be confused with qualities of things, which are experiences in a different setting. It is as unpardonable to confound the two as it is to confound sensations with things imaginary.

We may not, therefore, say that "things" are groups of sensations. We may, if we please, describe them as complexes of qualities. And we may not say that the "things" we perceive are really "inside" of us and are merely "projected outside."

What can "inside" and