Part 7

But now, besides these kinds of "things," "objects," or "contents," which we perceive, as we say, "by the senses," there is also another kind which we can be said to observe. Not only can I observe a red and blue book side by side; I can also observe myself observing them. I can perceive a red patch moving towards a white, and I can also perceive my perception of this movement. And what I wish to make as plain as I can is that my perception of the movement of a coloured patch can at least be distinguished from that movement itself. I wish to make it plain that to observe a coloured patch moving is to observe one thing; and to observe myself observing a coloured patch moving is another. When I observe my own perception of a movement, I observe something _more_ than when I merely observe the movement, and something very different from the movement. I may perceive a red and a blue book side by side on a shelf; and at another time I may perceive a red ball moving towards a white. The red and blue patch, of one shape, at rest side by side, are different from the red, of another shape, moving towards the white; and yet, when I say that both are "perceived," I mean by "perceived" one and the same thing. And since, thus, two different things may both be perceived, there must also be some difference between each of them and what is meant by saying that it is perceived. Indeed, in precisely the same way In which I may observe a spatial relation between a red patch and a blue (when I observe them "side by side") I do, when I observe my own perception of them, observe a spatial relation between it and them. I observe a distance between my perception and the red and blue books which I perceive, comparable in magnitude with the breadth or height of the blue book, just as these are comparable in magnitude with one another. And when I say I observe a distance between my perception of a red book and that red book itself, I do not mean that I observe a distance between my eyes, or any other part of what I call my body, and the red patch in question. I am talking not of my eyes, but of my actual perception. I observe my perception of a book to be near the book and further from the table, in exactly the same sense in which I observe the book to be near the shelf on which it stands, and further from the table. And just as, if the distance between a red patch and a white is to be perceived, the red patch must be different from the white, so, if I perceive a certain distance between my perception and the red patch, my perception must be different from the red patch which I perceive.

I assume, then, that we observe, on the one hand, coloured patches of certain shapes and sizes, and their spatial relations to one another, together with all the other kinds of "contents," which we should usually be said to perceive "through the senses." And, on the other hand, we also sometimes observe our own perceptions of such "contents" and our thoughts. And these two kinds of "content" are different from one another: my perception of a red patch with gold letters on it, is not itself a red patch with gold letters on it; and hence, when I observe my perception of this patch, I observe something different from that which I observe when I merely perceive the patch. Either of these two kinds of "content"--either colours, moving or at rest, sounds, smells, and all the rest--or, on the other hand, my perceptions of these--either of these two kinds, or both, might conceivably, since both are observed, give grounds for a generalisation concerning what exists. But, as I have said, if observations are to give any ground for such a generalisation, it must be assumed that what Is observed _exists_ or is _real._ And since, as I have insisted, when I observe my _perception_ of a red patch with gold letters on it, I observe something different from what I observed when I merely observed a red patch with gold letters on it, it follows that to assume the existence of my perception of this red and gold is _not_ the same thing as to assume the existence of the red and gold itself.

But what, it may be asked, do I mean by this property of "existence" or "reality," which may, it would seem, belong to every content, which I observe, or may again belong to none, or which may belong to some and not to others? What is this property which may belong to my perception of a movement, and yet not belong to the movement perceived, or which may again belong to the movement perceived and not to my perception of it, or which may again belong to both or to neither?

It is necessary, I think, to ask this question at this point, because there are some philosophers who hold that, in the case of some kinds of "content," at all events, to say that they "exist" is to say that they are "perceived." Some hold that to say "A exists" is to say neither more nor less than "A is perceived"--that the two expressions are perfect synonyms; and others again would say that by "A exists or is real" we may mean _more_ than that "A is perceived," but that we must at least mean this. Now, I have hitherto used the word "existence" pretty freely, and I think that, when I used it, I used it in its ordinary sense. I think it will generally have suggested to you precisely what I meant to convey, and I think that, in some cases at all events, it will not even have occurred to you to doubt whether you did understand what I meant by it. But, if these philosophers are right, then, if you _have_ understood what I meant by it, I have all along been using it in a sense, which renders the end of my last paragraph perfect nonsense. If these philosophers are right, then, when I assert that what _is_ perceived may yet _not_ exist, I am really asserting that what _is_ perceived may yet _not_ be perceived--I am contradicting myself. I am, of course, quite unaware that I am doing so. But these philosophers would say _either_ you are contradicting yourself, _or_ you are not using the word "exists" in its ordinary sense. And either of these alternatives would be fatal to my purpose. If I am not using the word in its ordinary sense, then I shall not be understood by anyone; and, if I am contradicting myself, then what I say will not be worth understanding.

Now, with one class of these philosophers--the class to which, I think, Berkeley belongs--I think I can put myself right comparatively easily. The philosophers I mean are those who say that it is only in the case of one particular class of "contents" (the kind of "content" which Berkeley calls "ideas") that to say "the 'content' A exists" is to say "A is perceived," and who admit that in the case of other contents--myself and my perceptions and thoughts, for example--to say that _these_ exist or are real, is to say of them something different from this. These philosophers admit, that is to say, that the word "exists" has two different senses: and that in only one of these senses is it synonymous with the words "is perceived." When (they hold) I say of such a content as a red patch with gold letters on it that it "exists" I _do_ mean that it is perceived; but when I say of my _perception_ of such a patch that _it_ exists, I do _not_ mean that my perception is perceived but something different from this. Now, it would be nothing strange that one and the same word should be used in two different senses; many words are used in many different senses. But it would, I think, be something very strange indeed, if in the case of a word which we constantly apply to all sorts of different objects, we should uniformly apply it to one large class of object in the one sense and the one sense only and the other large class in the other sense and the other sense only. Usually, in the case of such ambiguous words, it happens that, in different contexts, we apply it to one and the same object in _both_ senses. We sometimes wish to say of a given object that it has the one property, and sometimes we wish to say of the same object that it has the other property; and hence we apply the same word to the same object, at one time in one sense, and at another in the other. I think, therefore, that, even if there were these two different senses of the word "existence," it would be very unlikely that we should not commonly, in some contexts, apply it in the sense, in which (as is alleged) it does apply to perceptions, to "contents" which are not perceptions. Indeed, I think, it is quite plain that we constantly do ask, with regard to what is not a perception, whether _it_ exists, in precisely the same sense, in which we ask, with regard to a perception, whether _it_ exists. We ask in precisely the same sense: Was the Roc a real bird, or merely an imaginary one? and, did Sindbad's perception of the Roc really exist, or is it a fiction that he perceived a Roc? I think, therefore, that the sense in which these philosophers admit that we do apply the word "existence" to perceptions, is one in which we also commonly apply it to "contents" other than perceptions. But, even if this is not the case, I can set myself right with them by a simple explanation. I need merely explain that the sense in which I am proposing to enquire whether a red patch exists, is precisely the sense in which they admit that my perception of a red patch does exist. And in this sense, it is plain that to suppose that a thing may exist, which is not perceived, or that it may _not_ exist, although it is perceived, is at least not self-contradictory.

But there may be other philosophers who will say that, in the case of a perception also, to say that it exists or is real is to say that it is perceived--either that alone or something more as well. And to these philosophers I would first point out that they are admitting that the proposition "This perception is real" is significant. There is some sense or other in which we may say: "Alexander's perception of an elephant was real or did exist, but Sindbad's perception of a Roc was _not_ real--never did exist": the latter proposition is, in some sense or other, not self-contradictory. And then I would ask of them: When they say, that to call a perception "real" is to assert that it is perceived, do they mean by this that to call it real is to assert that it is _really_ perceived, or not? If they say "No," then they are asserting that to call a perception "real" is merely to say that it was perceived in the sense in which Sindbad _did_ perceive a Roc: they are asserting that to call it "real" is not to say, in any sense, that it was _really_ perceived: they are asserting that to call a perception "real" is to say that it was perceived, in some sense quite other than that in which we ordinarily use the word: for we certainly commonly mean, when we say "A was perceived," that a perception of A was "real": we should commonly say that Sindbad did _not_ perceive a Roc--meaning that no such perception ever did exist. I do not think they do mean this; and, in any case, if they do, I think it is plain that they are wrong. When we say that a perception is "real," we certainly do not mean merely that it is the object of another perception, which may itself be quite unreal--purely Imaginary. I assume, therefore, that when they say: To call a perception "real" is to say that it is perceived; they mean, what we should naturally understand, namely, that: To call it "real" is to say that it is _really_ perceived--to say that it is the object of another perception, which is also _real_ in the same sense. And, if they mean this, then what they say is certainly untrue. Their definition of reality is circular. It cannot be the case that the _only_ sense in which a perception may be said to be real, is one in which to call it so is to assert that not it alone, but another perception is real also. It cannot be the case that the assertion "A is real" is _identical_ with the assertion "A and B are both real," where A and B are different, and "real" is used in the same sense as applied to both. If it is to be true that the assertion "A is real" _ever_, in any sense, includes the assertion "A is _really_ perceived," there must be another sense of the word "real," in which to assert "A is real" is to assert _less_ than "A is _really_ perceived"--the sense, namely, in which we here assert that the _perception_ of A is real.

We find, therefore, that the other class of philosophers were at least right in this: they were right in allowing that the sense in which we commonly say that our perceptions exist is one in which "exist" does not include, even as a part of its meaning, "is perceived." We find that there is a common sense of the word "existence," in which to say "A exists" must mean _less_ than "A is _really_ perceived": since, otherwise, the only possible definition of the word "existence" would be a circular definition. And I may point out that two other definitions, which have been sometimes suggested by philosophers as giving what we commonly mean by "reality" or "existence" are vitiated by the same fault--they also are circular. Some philosophers have sometimes suggested that when we call a thing "real," we mean that it is "systematically connected" in some way with other things. But, when we look into their meaning, we find that what they mean is (what, indeed, is alone plausible)--systematically connected with other _real_ things. And it may possibly be the case that we sometimes use the word "real" in this sense: but, at least, it must be certainly the case, that, if we do, we _also_ use it in another and simpler sense--the sense in which it is employed in the proposed definition. And other philosophers have suggested that what we mean by "real" is--"connected in some way with a purpose--helping or hindering, or the object of a purpose." But if we look into their meaning, we find they mean--connected with a _real_ purpose. And hence, even if we do sometimes mean by "real," "connected with a _real_ purpose," it is plain we also sometimes mean by "real" something simpler than this--that namely, which is meant by "real" in the proposed definition.

It is certain, therefore, that we do commonly use the word "existence" in a sense, in which to say "A exists" is _not_ to say "A is perceived," or "A is systematically connected with other real things," or "A is purposive." There is a simpler sense than any of these--the sense in which we say that our own perceptions do exist, and that Sindbad's perceptions did not exist. But when I say this, I am by no means denying that what exists, in this simple sense, may not always _also_ exist in all the others; and that what exists in any of them may not _also_ always exist in this. It is quite possible that what exists is always _also_ perceived, and that what is perceived always _also_ exists. All that I am saying is that, even if this is so, this proposition is significant--is not merely a proposition about the meaning of a word. It is not self-contradictory to suppose that some things which exist are not perceived, and that some things which are perceived do not exist.

But, it may be asked: What is this common simple sense of the word "exists"? For my own part, it seems to me to be so simple that it cannot be expressed in other words, except those which are recognised as its synonyms. I think we are all perfectly familiar with its meaning: it is the meaning which you understood me to have throughout this paper, until I began this discussion. I think we can perceive at once what is meant by asserting that my perception of black marks on a white ground is "real," and that no such perception as Sindbad's of a Roc was ever "real": we are perfectly familiar with the property which the one perception is affirmed to possess, and the other to be without. And I think, as I have said, that this property is a simple one. But, whatever it is, this, which we ordinarily mean, is what I mean by "existence" or "reality." And this property, we have seen, is certainly neither identical with nor inclusive of that complex one which we mean by the words "is perceived."

I may now, then, at last approach the main question of my paper. Which among the "contents" which I observe will give me reason to suppose that my observation of some of them is generally preceded or accompanied or followed by the existence of certain particular perceptions, thoughts or feelings in another person? I have explained that the "contents" which I actually observe may be divided into two classes: on the one hand, those which, as we commonly say, we perceive "through the senses"; and, on the other hand, my perceptions of these last, my thoughts, and my feelings. I have explained that if any of these observed contents are to give reason for a generalisation about what exists, _they_ must exist. And I have explained that with regard to both classes of "contents" I am using the word "exist" in precisely the same sense--a sense, in which it is certainly not self-contradictory to suppose that what _is_ perceived, does not exist, and that what is _not_ perceived, does exist; and, in which, therefore, the assumption that a red patch with gold letters on it exists, is a _different_ assumption from the assumption that my _perception_ of a red patch with gold letters on it exists; and the assumption that my _perception_ of a red patch with gold letters on it exists, is a _different_ assumption from the assumption that a red patch with gold letters on it exists.

What, then, that we observe, can give us any reason for believing that anyone else has certain particular perceptions, thoughts or feelings? It has, I think, been very commonly assumed that the observation of my own perceptions, thoughts, and feelings, can, by itself, give me such a reason. And I propose, therefore, to examine this assumption. If, as I hope to show, it is false; it will then follow, that if our own observation gives us any reason whatever, for believing in the existence of other persons, we must assume the existence, not only of our own perceptions, thoughts and feelings, but also of some, at least, among that other class of data, which I may now, for the sake of brevity, call "sense-contents"; we must assume that some of them exist, in precisely the same sense in which we assume that our perceptions, thoughts, and feelings exist.

The theory which I propose to examine is, then, the following. My observation of my own thoughts, feelings, and perceptions may, it asserts, give me some reason to suppose that another person has thoughts, feelings, and perceptions similar to some of mine. Let us assume, accordingly, that my own thoughts, feelings, and perceptions do exist; but that none of the "sense-contents," which I also observe, do so. Where among my perceptions am I to look for any which might conceivably give me a reason for supposing the existence of other perceptions similar to my own? It is obvious where I must look. I have perceptions which I call perceptions of other people's bodies; and these are certainly similar in many respects to other perceptions of my own body. But I also observe that certain kinds of perceptions of my own body are preceded by certain other perceptions, thoughts, or feelings of mine. I may, for instance, observe that when I perceive my hand suddenly catch hold of my foot in a particular way, this perception was preceded by a particular kind of feeling of pain. I may, perhaps, observe this often enough to justify the generalisation that the perception of that particular motion of my body is generally preceded by that particular feeling of pain. And in this way I may perhaps have reason for quite a number of generalisations which assert that particular kinds of perceptions of my own body are generally preceded by other particular kinds of perceptions, thoughts, or feelings of my own.