Chapter II: Part 2

The true analysis of a sensation or idea is as follows. The element that is common to them all, and which I have called "consciousness," really _is_ consciousness. A sensation is, in reality, a case of 'knowing' or 'being aware of' or 'experiencing' something. When we know that the sensation of blue exists, the fact we know is that there exists an awareness of blue. And this awareness is not merely, as we have hitherto seen it must be, itself something distinct and unique, utterly different from blue: it also has a perfectly distinct and unique relation to blue, a relation which is _not_ that of thing or substance to content, nor of one part of content to another part of content. This relation is just that which we mean in every case by 'knowing.' To have in your mind 'knowledge' of blue, is _not_ to have in your mind a 'thing' or 'image' of which blue is the content. To be aware of the sensation of blue is _not_ to be aware of a mental image--of a "thing," of which 'blue' and some other element are constituent parts in the same sense in which blue and glass are constituents of a blue bead. It is to be aware of an awareness of blue; awareness being used, in both cases, in exactly the same sense. This element, we have seen, is certainly neglected by the 'content' theory: that theory entirely fails to express the fact that there is, in the sensation of blue, this unique relation between blue and the other constituent. And what I contend is that this omission is _not_ mere negligence of expression, but is due to the fact that though philosophers have recognised that _something_ distinct is meant by consciousness, they have never yet had a clear conception of _what_ that something is. They have not been able to hold _it_ and _blue_ before their minds and to compare them, in the same way in which they can compare _blue_ and _green._ And this for the reason I gave above: namely that the moment we try to fix our attention upon consciousness and to see _what_, distinctly, it is, it seems to vanish: it seems as if we had before us a mere emptiness. When we try to introspect the sensation of blue, all we can see is the blue: the other element is as if it were diaphanous. Yet it _can_ be distinguished if we look attentively enough, and if we know that there is something to look for. My main object in this paragraph has been to try to make the reader _see_ it; but I fear I shall have succeeded very ill.

It being the case, then, that the sensation of blue includes in its analysis, beside blue, _both_ a unique element 'awareness' _and_ a unique relation of this element to blue, I can make plain what I meant by asserting, as two distinct propositions, (1) that blue is probably not part of the content of the sensation at all, and (2) that, even it were, the sensation would nevertheless not be the sensation _of_ blue, if blue had only this relation to it. The first hypothesis may now be expressed by saying that, if it were true, then, when the sensation of blue exists, there exists a _blue awareness_: offence may be taken at the expression, but yet it expresses just what should be and is meant by saying that blue is, in this case, a _content_ of consciousness or experience. Whether or not, when I have the sensation of blue, my consciousness or awareness is thus blue, my introspection does not enable me to decide with certainty: I only see no reason for thinking that it is. But whether it is or not, the point is unimportant, for introspection _does_ enable me to decide that something else is also true: namely that I am aware _of_ blue, and by this I mean, that my awareness has to blue a quite different and distinct relation. It is possible, I admit, that my awareness is blue _as well_ as being _of_ blue: but what I am quite sure of is that it is _of_ blue; that it has to blue the simple and unique relation the existence of which alone justifies us in distinguishing knowledge of a thing from the thing known, indeed in distinguishing mind from matter. And this result I may express by saying that what is called the _content_ of a sensation is in very truth what I originally called it--the sensation's _object._

But, if all this be true, what follows?

Idealists admit that some things really exist of which they are not aware: there are some things, they hold, which are not inseparable aspects of _their_ experience, even if they be inseparable aspects of some experience. They further hold that some of the things of which they are sometimes aware do really exist, even when they are not aware of them: they hold for instance that they are sometimes aware of other minds, which continue to exist even when they are not aware of them. They are, therefore, sometimes aware of something which is _not_ an inseparable aspect of their own experience. They do _know some_ things which are _not_ a mere part or content of their experience. And what my analysis of sensation has been designed to show is, that whenever I have a mere sensation or idea, the fact is that I am then aware of something which is equally and in the same sense _not_ an inseparable aspect of my experience. The awareness which I have maintained to be included in sensation is the very same unique fact which constitutes every kind of knowledge: "blue" is as much an object, and as little a mere content, of my experience, when I experience it, as the most exalted and independent real thing of which I am ever aware. There is, therefore, no question of how we are to "get outside the circle of our own ideas and sensations." Merely to have a sensation is already to _be_ outside that circle. It is to know something which is as truly and really _not_ a part of _my_ experience, as anything which I can ever know.

Now I think I am not mistaken in asserting that the reason why Idealists suppose that everything which _is_ must be an inseparable aspect of some experience, is that they suppose some things, at least, to be inseparable aspects of _their_ experience. And there is certainly nothing which they are so firmly convinced to be an inseparable aspect of their experience as what they call the _content_ of their ideas and sensations. If, therefore, _this_ turns out in every case, whether it be also the content or not, to be at least _not_ an inseparable aspect of the experience of it, it will be readily admitted that nothing else which _we_ experience ever is such an inseparable aspect. But if we never experience anything but what is _not_ an inseparable aspect of _that_ experience, how can we infer that anything whatever, let alone _everything,_ is an inseparable aspect of _any_ experience? How utterly unfounded is the assumption that "_esse_ is _percipi"_ appears in the clearest light.

But further I think it may be seen that if the object of an Idealist's sensation were, as he supposes, _not_ the object but merely the content of that sensation, if, that is to say, it really were an inseparable aspect of his experience, each Idealist could never be aware either of himself or of any other real thing. For the relation of a sensation to its object is certainly the same as that of any other instance of experience to its object; and this, I think, is generally admitted even by Idealists: they state as readily that _what_ is judged or thought or perceived is the _content_ of that judgment or thought or perception, as that blue Is the content of the sensation of blue. But, if so, then when any Idealist thinks he is _aware_ of himself or of any one else, this cannot really be the case. The fact Is, on his own theory, that himself and that other person are in reality mere _contents_ of an awareness, which is aware _of_ nothing whatever. All that can be said is that there is an awareness in him, _with_ a certain content: it can never be true that there is in him a consciousness _of_ anything. And similarly he is never aware either of the fact that he exists or that reality is spiritual. The real fact, which he describes in those terms, is that his existence and the spirituality of reality are _contents_ of an awareness, which is aware of nothing--certainly not, then, of it own content.

And further if everything, of which he thinks he is aware, is in reality merely a content of his own experience he has certainly no _reason_ for holding that anything does exist except himself: it will, of course, be possible that other persons do exist; solipsism will not be necessarily true; but he cannot possibly infer from anything he holds that it is not true. That he himself exists will of course follow from his premiss that many things are contents of _his_ experience. But since everything, of which he thinks himself aware, is in reality merely an inseparable aspect of that awareness; this premiss allows no inference that any of these contents, far less any other consciousness, exists at all except as an inseparable aspect of his awareness, that is, as part of himself.

Such, and not those which he takes to follow from it, are the consequences which _do_ follow from the Idealist's supposition that the object of an experience is in reality merely a content or inseparable aspect of that experience. If, on the other hand, we clearly recognise the nature of that peculiar relation which I have called "awareness of anything"; if we see that _this_ is involved equally in the analysis of _every_ experience--from the merest sensation to the most developed perception or reflexion, and that _this_ is in fact the only essential element in an experience--the only thing that is both common and peculiar to all experiences--the only thing which gives us reason to call any fact mental; if, further, we recognise that this awareness is and must be in all cases of such a nature that its object, when we are aware of it, is precisely what it would be, if we were not aware: then it becomes plain that the existence of a table in space is related to my experience of _it_ in precisely the same way as the existence of my own experience is related to my experience of _that._ Of both we are merely aware: if we are aware that the one exists, we are aware in precisely the same sense that the other exists; and if it is true that my experience can exist, even when I do not happen to be aware of its existence, we have exactly the same reason for supposing that the table can do so also. When, therefore, Berkeley, supposed that the only thing of which I am directly aware is my own sensations and ideas, he supposed what was false; and when Kant supposed that the objectivity of things in space _consisted_ in the fact that they were "Vorstellungen" having to one another different relations from those which the same "Vorstellungen" have to one another in subjective experience, he supposed what was equally false. I am as directly aware of the existence of material things in space as of my own sensations; and _what_ I am aware of with regard to each is exactly the same--namely that in one case the material thing, and in the other case my sensation does really exist. The question requiring to be asked about material things is thus not: What reason have we for supposing that anything exists _corresponding_ to our sensations? but: What reason have we for supposing that material things do _not_ exist, since _their_ existence has precisely the same evidence as that of our sensations? That either exist _may_ be false; but if it is a reason for doubting the existence of matter, that it is an inseparable aspect of our experience, the same reasoning will prove conclusively that our experience does not exist either, since that must also be an inseparable aspect of our experience of _it._ The only _reasonable_ alternative to the admission that matter exists _as well as_ spirit, is absolute Scepticism--that, as likely as not _nothing_ exists at all. All other suppositions--the Agnostic's, that something, at all events, does exist, as much as the Idealist's, that spirit does--are, if we have no reason for believing in matter, as baseless as the grossest superstitions.

[1] _International Journal of Ethics,_ October, 1902.

THE NATURE AND REALITY OF OBJECTS OF PERCEPTION

There are two beliefs in which almost all philosophers, and almost all ordinary people are agreed. Almost everyone believes that he himself and what he directly perceives do not constitute the whole of reality: he believes that _something_ other than himself and what he directly perceives _exists_ or is _real._ I do not mean to say that almost everyone believes that what he directly perceives is real: I only mean that he does believe that, whether what he directly perceives is real or not, something other than it and other than himself certainly is so. And not only does each of us thus agree in believing that _something_ other than himself and what he directly perceives is real: almost everyone also believes that _among_ the real things, other than himself and what he directly perceives, are other persons who have thoughts and perceptions in some respects similar to his own. That most people believe this I think I need scarcely try to show. But since a good many philosophers may appear to have held views contradictory of this one, I will briefly point out my reason for asserting that most philosophers, even among those (if any) who have believed the contradictory of this, have yet held this as well. Almost all philosophers tell us something about the nature of _human_ knowledge and _human_ perception. They tell us that _we_ perceive so and so; that the nature or origin of _our_ perceptions is such and such; or (as I have just been telling you) that men in general have such and such beliefs. It might, indeed, be said that we are not to interpret such language too strictly: that, though a philosopher talks about _human_ knowledge and _our_ perceptions, he only means to talk about his own. But in many cases a philosopher will leave no doubt upon this point, by expressly assuming that there are other perceptions, which differ in some respects from his own: such, for instance, is the case when (as is so common nowadays) a philosopher introduces psycho-genetic considerations into his arguments --considerations concerning the nature of the perceptions of men who existed before and at a much lower stage of culture than himself. Any philosopher, who uses such arguments, obviously assumes that perceptions other than his own have existed or been real. And even those philosophers who think themselves justified in the conclusion that neither their own perceptions nor any perceptions like theirs are _ultimately_ real, would, I think admit, that _phenomenally_, at least, they _are_ real, and are certainly _more_ real than some other things.

Almost everyone, then, does believe that some perceptions other than his own, and which he himself does not directly perceive, are real; and believing this, he believes that something other than himself and what he directly perceives is real. But how do we know that anything exists except our own perceptions, and what we directly perceive? How do we know that there are any other people, who have perceptions in some respects similar to our own?

I believe that these two questions express very exactly the nature of the problem which it is my chief object, in this paper, to discuss. When I say these words to you, they will at once suggest to your minds the very question, to which I desire to find an answer; they will convey to you the very same meaning which I have before my mind, when I use the words. You will understand at once what question it is that I mean to ask. But, for all that, the words which I have used are highly ambiguous. If you begin to ask yourselves what I do mean by them, you will find that there are several quite different things which I might mean. And there is, I think, great danger of confusing these different meanings with one another. I think that philosophers, when they have asked this question in one sense, have often answered it in quite a different sense; and yet have supposed that the answer which they have given is an answer to the very same question which they originally asked. It is precisely because there is this ambiguity--this danger of confusion, in the words which I have used, that I have chosen to use them. I wish to point out as clearly as I can, not only what I do mean by them, but also some things which I do _not_ mean; and I wish to make it clear that the questions which I do _not_ mean to ask, are different questions from that which I do mean to ask.

I will take the second of my two questions, since there is in the other an additional ambiguity to which I do not now wish to call attention. My second question was: How do we know that there exist any other people who have perceptions in some respects similar to our own? What does this question mean?

Now I think you may have noticed that when you make a statement to another person, and he answers "How do you know that that is so?" he very often means to suggest that you do _not_ know it. And yet, though he means to suggest that you do not _know_ it, he may not for a moment wish to suggest that you do not _believe_ it, nor even that you have not that degree or kind of conviction, which goes beyond mere belief, and which may be taken to be essential to anything which can properly be called knowledge. He does not mean to suggest for a moment that you are saying something which you do not believe to be true, or even that you are not thoroughly convinced of its truth. What he does mean to suggest is that what you asserted was not _true_, even though you may not only have believed it but felt sure that it was true. He suggests that you don't _know_ it, in the sense that what you believe or feel sure of is not true.

Now I point this out, not because I myself mean to suggest that we don't know the existence of other persons, but merely in order to show that the word "know" is sometimes used in a sense in which it is not merely equivalent to "believe" or "feel sure of." When the question "How do you _know_ that?" is asked, the questioner does not merely mean to ask "how do you come to believe that, or to be convinced of it?" He sometimes, and I think generally, means to ask a question with regard to the _truth_, and not with regard to the _existence_ of your belief. And similarly when I ask the question "How do we know that other people exist?" I do _not_ mean to ask "How do we come to believe in or be convinced of their existence?" I do not intend to discuss this question _at all._ I shall not ask what _suggests_ to us our belief in the existence of other persons or of an external world; I shall not ask whether we arrive at it by inference or by "instinct" or in any other manner, which ever has been or may be suggested: I shall discuss no question of any kind whatever with regard to its origin, or cause, or the way in which it arises. These psychological questions are _not_ what I propose to discuss. When I ask the question "How do we know that other people exist?" I do _not_ mean:

"How does our belief in their existence arise?"

But if I do not mean this what do I mean P I have said that I mean to ask a question with regard to the _truth_ of that belief; and the particular question which I mean to ask might be expressed in the words: _What reason have_ we for our belief in the existence of other persons? But these are words which themselves need some explanation, and I will try to give it.

In the first place, then, when I talk of "a reason," I mean _only_ a good reason and _not_ a bad one. A bad reason is, no doubt, a reason, in one sense of the word; but I mean to use the word "reason" exclusively in the sense in which it is equivalent to "good reason." But what, then, is meant by a good reason for a belief? I think I can express sufficiently accurately what I mean by it in this connection, as follows:--A good reason for a belief is a proposition which is true, and which would not be true unless the belief were also true. We should, I think, commonly say that when a man knows such a proposition, he has a good reason for his belief; and, when he knows no such proposition, we should say that he has no reason for it. When he knows such a proposition, we should say he knows something which is a reason for thinking his belief to be true--something from which it _could_ be validly inferred. And if, in answer to the question "How do you know so and so?" he were to state such a proposition, we should, I think, feel that he had answered the question which we meant to ask. Suppose, for instance, in answer to the question "How do you know that?" he were to say "I saw it in the _Times."_ Then, if we believed that he had seen it in the _Times_, and also believed that it would not have been in the _Times_, unless it had been true, we should admit that he had answered our question. We should no longer doubt that he did _know_ what he asserted, we should no longer doubt that his belief was true. But if, on the other hand, we believed that he had not seen it in the _Times_--if, for instance, we had reason to believe that what he saw was not the statement which he made, but some other statement which he mistook for it; or if we believed that the kind of statement in question was one with regard to which there was no presumption that, being in the _Times_, it would be true: in _either_ of these cases we should, I think, feel that he had _not_ answered our question. We should still doubt whether what he had said was true. We should still doubt whether he _knew_ what he asserted; and since a man cannot tell you how he _knows_ a thing unless he does know that thing, we should think that, though he might have told us truly how he _came to believe it,_ he had certainly not told us how he _knew_ it. But though we should thus hold that he had _not_ told us _how he knew_ what he had asserted, and that he had given us no reason for believing it to be true; we must yet admit that he had given us a reason in a sense--a _bad_ reason, a reason which was no reason because it had no tendency to show that what he believed was true; and we might also be perfectly convinced that he had given us _the reason_ why he believed it--the proposition by believing which he was induced also to believe his original assertion.

I mean, then, by my question, "How do we know that other people exist?" what, I believe, is ordinarily meant, namely, "What reason have we for believing that they exist?" and by this again I mean, what I also believe is ordinarily meant, namely, "What proposition do we believe, which is both true itself and is also such that it would not be true, unless other people existed?" And I hope it is plain that this question, thus explained, is quite a different question from the psychological question, which I said I did _not_ mean to ask--from the question, "How does our belief in the existence of other people arise?" My illustration, I hope, has made this plain. For I have pointed out that we may quite well hold that a man has told us how a belief of his arises, and even what was the reason which made him adopt that belief, and yet may have failed to give us any _good reason_ for his belief--any proposition which is both true itself, and also such that the truth of his belief follows from it. And, indeed, it is plain that if any one ever believes what is false, he is believing something for which there _is_ no good reason, in the sense which I have explained, and for which, therefore, he cannot possibly have a good reason; and yet it plainly does not follow that his belief did not arise in anyway whatever, nor even that he had no reason for it--no bad reason. It is plain that false beliefs do arise in some way or other--they have origins and causes: and many people who hold them _have_ bad reasons for holding them--their belief does arise (by inference or otherwise) from their belief in some other proposition, which is not itself true, or else is not a _good_ reason for holding that, which they infer from it, or which, in some other way, it induces them to believe. I submit, therefore, that the question, "What good reason have we for believing in the existence of other people?" is different from the question, "How does that belief arise?" But when I say this, I must not be misunderstood; I must not be understood to affirm that the answer to both questions _may_ not, in a sense, be the same. I fully admit that the very same fact, which suggests to us the belief in the existence of other people, _may_ also be a good reason for believing that they do exist. All that I maintain is that the question whether it is a good reason for that belief is a different question from the question whether it suggests that belief: if we assert that a certain fact _both_ suggests our belief in the existence of other persons and is _also_ a good reason for holding that belief, we are asserting two different things and not one only. And hence, when I assert, as I shall assert, that we _have_ a good reason for our belief in the existence of other persons, I must not be understood also to assert either that we infer the existence of other persons from this good reason, or that our belief in that good reason suggests our belief in the existence of other persons in any other way. It is plain, I think, that a man may believe two true propositions, of which the one would not be true, unless the other were true too, without, in any sense whatever, having arrived at his belief in the one _from_ his belief in the other; and it is plain, at all events, that the question whether his belief in the one _did_ arise from his belief in the other, is a different question from the question whether the truth of the one belief follows from the truth of the other.

I hope, then, that I have made it a little clearer what I mean by the question: "What reason have we for believing in the existence of other people?" and that what I mean by it is at all events different from what is meant by the question: "How does our belief in the existence of other people arise?"

But I am sorry to say that I have not yet reached the end of my explanations as to what my meaning is. I am afraid that the subject may seem very tedious. I can assure you that I have found it excessively tedious to try to make my meaning clear to myself. I have constantly found that I was confusing one question with another, and that, where I had thought I had a good reason for some assertion, I had in reality no good reason. But I may perhaps remind you that this question, "How do we know so and so?" "What reason have we for believing it?" is one of which philosophy is full; and one to which the most various answers have been given. Philosophy largely consists in giving reasons; and the question what are good reasons for a particular conclusion and what are bad, is one upon which philosophers have disagreed as much as on any other question. For one and the same conclusion different philosophers have given not only different, but incompatible, reasons; and conversely different philosophers have maintained that one and the same fact is a reason for incompatible conclusions. We are apt, I think, sometimes to pay too little attention to this fact. When we have taken, perhaps, no little pains to assure ourselves that our own reasoning is correct, and especially when we know that a great many other philosophers agree with us, we are apt to assume that the arguments of those philosophers, who have come to a contradictory conclusion, are scarcely worthy of serious consideration. And yet, I think, there is scarcely a single reasoned conclusion in philosophy, as to which we shall not find that some other philosopher, who has, so far as we know, bestowed equal pains on his reasoning, and with equal ability, has reached a conclusion incompatible with ours. We may be satisfied that we are right, and we may, in fact, be so; but it is certain that _both_ cannot be right: either our opponent or we must have mistaken bad reasons for good. And this being so, however satisfied we may be that it is not we who have done so, I think we should at least draw the conclusion that it is by no means easy to avoid mistaking bad reasons for good; and that no process, however laborious, which is in the least likely to help us in avoiding this should be evaded. But it is at least possible that one source of error lies in mistaking one kind of reason for another--in supposing that, because there is, in one sense, a reason for a given conclusion, there is also a reason in another, or that because there is, in one sense, no reason for a given conclusion, there is, therefore, no reason at all. I believe myself that this _is_ a very frequent source of error: but it is at least a possible one. And where, as disagreements show, there certainly is error on one side or the other, and reason, too, to suppose that the error is not easy to detect, I think we should spare no pains in investigating any source, from which it is even possible that the error may arise. For these reasons I think I am perhaps doing right in trying to explain as clearly as possible not only what reasons we have for believing in an external world, but also in what sense I take them to be reasons.

I proceed, then with my explanation. And there is one thing, which, I think my illustration has shown that I do _not_ mean. I have defined a reason for a belief as a true proposition, which would not be true unless the belief itself--what is believed--were also true; and I have used, as synonymous with this form of words, the expressions: A reason for a belief is a true proposition from which the truth of the belief _follows_ from which it _could_ be _validly inferred._ Now these expressions might suggest the idea that I mean to restrict the word "reason," to what, in the strictest sense, might be called a _logical_ reason--to propositions from which the belief in question _follows,_ according to the rules of inference accepted by Formal Logic. But I am _not_ using the words "follow," "validly inferred," in this narrow sense; I do _not_ mean to restrict the words "reason for a belief" to propositions from which the laws of Formal Logic state that the belief could be deduced. The illustration which I gave is inconsistent with this restricted meaning. I said that the fact that a statement appeared in the _Times_ might be a good reason for believing that that statement was true. And I am using the word "reason" in the wide and popular sense, in which it really might be. If, for instance, the _Times_ stated that the King was dead, we should think that was a good reason for believing that the King was dead; we should think that the _Times_ would not have made such a statement as that unless the King really were dead. We should, indeed, not think that the statement in the _Times_ rendered it absolutely _certain_ that the King was dead. But it _is_ extremely unlikely that the _Times_ would make a statement of this kind unless it were true; and, in that sense, the fact of the statement appearing in the _Times_ would render it _highly probable_--much more likely than not--that the King was dead. And I wish it to be understood that I am using the words "reason for a belief" in this extremely wide sense. When I look for a good reason for our belief in the existence of other people, I shall not reject any proposition merely on the ground that it only renders their existence probable--only shows it to be more likely than not that they exist. Provided that the proposition in question does render it _positively probable_ that they exist, then, if it also conforms to the conditions which I am about to mention, I shall call it a "good reason."

But it is not every proposition which renders it probable that other people exist, which I shall consider to be a good answer to my question. I have just explained that my meaning is wide in one direction--in admitting _some_ propositions which render a belief merely probable; but I have now to explain that it is restricted in two other directions. I do mean to exclude certain propositions which do render that belief probable. When I ask: What reason have _we_ for believing in the existence of other people? a certain ambiguity is introduced by the use of the plural "we." If each of several different persons has a reason for believing that he himself exists, then it is not merely probable, but certain, according to the rules of Formal Logic, that, in a sense, _they_ "have a reason for believing" that several people exist; each has a reason for believing that he himself exists; and, therefore, all of them, taken together, have reasons for supposing that several persons exist. If, therefore, I were asking the question: What reason have _we_ for believing in the existence of other persons? in this sense, it would follow that if each of us has a reason for believing in his own existence, these reasons, taken together, would be a reason for believing in the existence of all of us. But I am not asking the question in this sense: it is plain that this is not its natural sense. What I do mean to ask is: Does _each single one_ of us know any proposition, which is a reason for believing that _others_ exist? I am using "we," that is to say, in the sense of "each of us." But again I do mean _each_ of us: I am not merely asking whether some _one_ man knows a proposition which is a reason for believing that other men exist. It would be possible that some one man, or some few men, should know such a proposition, and yet the rest know no such proposition. But I am not asking whether this is the case. I am asking whether among propositions of the kind which (as we commonly suppose) all or almost all men know, there is any which is a reason for supposing that other men exist. And in asking this question I am not begging the question by supposing that all men do exist. My question might, I think, be put quite accurately as follows. There are certain kinds of belief which, as we commonly suppose, all or almost all men share. I describe this kind of belief as "our" beliefs, simply as an easy way of pointing out which kind of belief I mean, but without assuming that all men do share them. And I then ask: Supposing a single man to have beliefs of this kind, which among them would be a good reason for supposing that other men existed having like beliefs?

This, then, is the first restriction which I put upon the meaning of my question. And it is, I think, a restriction which, in their natural meaning, the words suggest. When we ask: What reason have we for believing that other people exist? we naturally understand that question to be equivalent to: What reason has _each_ of us for that belief? And this question again is naturally equivalent to the question: Which among the propositions that a single man believes, but which are of the kind which (rightly or wrongly) we assume all men to believe, are such that they would not be true unless some other person than that man existed? But there is another restriction which, I think, the words of my question also naturally suggest. If we were to ask anyone the question: How do you know that you did see that statement in the _Times_? and he were to answer "Because I did see it in the _Times_ and in the _Standard_ too," we should not think that he had given us a _reason_ for the belief that he saw it in the _Times._ We should not think his answer a _reason_, because it asserts the very thing for which we require a reason. And similarly when I ask: How do we know that any thing or person exists, other than ourselves and what we directly perceive? What reason have we for believing this? I must naturally be understood to mean: What proposition, _other_ than one which itself asserts or presupposes the existence of something beyond ourselves and our own perceptions, is a reason for supposing that such a thing exists? And this restriction obviously excludes an immense number of propositions of a kind which all of us do believe. We all of us believe an immense number of different propositions about the existence of things which we do not directly perceive, and many of these propositions are, in my sense, good reasons for believing in the existence of still other things. The belief in the existence of a statement in the _Times,_ when we have not seen that statement, may, as I implied, be a good reason for believing that someone is dead. But no such proposition can be a good answer to my question, because it asserts the very kind of thing for which I require a reason: it asserts the existence of something other than myself and what I directly perceive. When I am asking: What reason have I for believing in the existence of anything but myself, my own perceptions, and what I do directly perceive? you would naturally understand me to mean: What reason, _other than_ the existence of such a thing, have I for this belief?

Each of us, then, we commonly assume, believes some true propositions, which do not themselves assert the existence of anything other than himself, his own perceptions, or what he directly perceives. Each of us, for instance, believes that he himself has and has had certain particular perceptions: and these propositions are propositions of the kind I mean--propositions which do not themselves assert the existence of anything _other than_ himself, his own perceptions, and what he directly perceives: they are, I think, by no means the only propositions of this kind, which most of us believe: but they _are_ propositions of this kind. But, as I say, I am not assuming that each of us--each of several different people--does believe propositions of this kind. All that I assume is that at least one man does believe some such propositions. And then I ask: Which among those true propositions, which one man believes, are such that they would probably not be true, unless some other man existed and had certain particular perceptions? Which among them are such that it _follows_ (in the wide sense, which I have explained) from their truth, that it is more likely than not that some other man has perceptions? This is the meaning of my question, so far as I have hitherto explained it: and I hope this meaning is quite clear. It is in this sense that I am asking: What reason have we for believing that other people exist? How do we know that they exist? This, indeed, is not _all_ that I mean by that question: there is one other point--the most important one--which remains to be explained. But this is _part_ of what I mean to ask; and before I go on to explain what else I mean, I wish first to stop and enquire what is the answer to this part of my question. What is the answer to the question: Which among the true propositions, of a kind which (as we commonly assume) each of us believes, and which do not themselves assert the existence of anything other than that person himself, his own perceptions, or what he directly perceives, are such that they would probably not be true unless some other person existed, who had perceptions in some respects similar to his own?

Now to this question the answer is very obvious. It is very obvious that in this sense we have reasons for believing in the existence of other persons, and also what some of those reasons are. But I wish to make it quite plain that this is so: that in this sense one man _has_ a reason for believing that another has certain perceptions. All that I am asking you to grant, is, you see, that some of you would not be having just those perceptions which you now have, unless I, as I read this paper, were perceiving more or less black marks on a more or less white ground; or that I on the other hand, should not be having just those perceptions which I now have, unless some other persons than myself were hearing the sounds of my voice. And I am not asking you even to grant that this is certain--only that it is positively probable--more likely than not. Surely it is very obvious that this proposition is true. But I wish to make it quite clear what would be the consequences of denying that any such propositions are true--propositions which assert that the existence of certain perceptions in one man are a reason for believing in the existence of certain perceptions in another man--which assert that one man would probably not have had just those perceptions which he did have, unless some other man had had certain particular perceptions. It is plain, I think, that, unless some such propositions are true, we have no more reason for supposing that Alexander the Great ever saw an elephant, than for supposing that Sindbad the Sailor saw a Roc; we have no more reason for supposing that anybody saw Julius Caesar murdered in the Senate House at Rome, than for supposing that somebody saw him carried up to Heaven in a fiery chariot. It is plain, I think, that if we have any reason at all for supposing that in all probability Alexander the Great did see an elephant, and that in all probability no such person as Sindbad the Sailor ever saw a Roc, part of that reason consists in the assumption that some other person would probably not have had just those perceptions which he did have, unless Alexander the Great had seen an elephant, and unless Sindbad the Sailor had not seen a Roc. And most philosophers, I think, are willing to admit that we have some reason, in some sense or other, for such propositions as these. They are willing to admit not only that some persons probably did see Julius Caesar murdered in the Senate House; but also that some persons, other than those who saw it, had and have _some reason_ for supposing that some one else probably saw it. Some sceptical philosophers might, indeed, deny both propositions; and to refute their views, I admit, other arguments are needed than any which I shall bring forward in this paper. But most philosophers will, I think, admit not only that facts, for which there is, as we say, good historical evidence, are probably true; but also that what we call good historical evidence really is in some sense a good reason for thinking them true. Accordingly I am going to assume that many propositions of the following kind are true. Propositions, namely, which assert that one man would probably not have certain perceptions which he does have, unless some other man had certain particular perceptions. That some of you, for instance, would probably not be having precisely the perceptions which you are having, unless I were having the perception of more or less black marks on a more or less white ground. And, in this sense, I say, we certainly have reasons for supposing that other people have perceptions similar, in some respects, to those which we sometimes have.

But when I said I was going to ask the question: What reason have we for supposing that other people exist? you will certainly not have thought that I merely meant to ask the question which I have just answered. My words will have suggested to you something much more important than merely this. When, for instance, I said that to the question "How do you know that?" the answer "I saw it in the _Times"_ would be a satisfactory answer, you may have felt, as I felt, that it would not in all circumstances be regarded as such. The person who asked the question might, in some cases, fairly reply: "That is no answer: how do you know that, because you saw a thing in the _Times_, it is therefore true?" In other words he might ask fora _reason_ for supposing that the occurrence of a particular statement in the _Times_ was a reason for supposing that statement true. And this is a question to which we all believe that there may be an answer. We believe that, with some kinds of statements which the _Times_ makes--some kinds of statements with regard to Fiscal Policy for example--the fact that the _Times_ makes them is no reason for supposing them to be true: whereas with regard to other kinds of statements, which it makes, such a statement, for instance, as that the King was dead, the fact that it makes them _is_ a reason for supposing them true. We believe that there are some kinds of statements, which it is very unlikely the _Times_ would make, unless they were true; and others which it is not at all unlikely that the _Times_ might make, although they were not true. And we believe that a reason might be given for distinguishing, in this way, between the two different kinds of statement: for thinking that, in some cases (on points, for instance, which, as we should say, are not simple questions of fact) the _Times_ is fallible, whereas in other cases, it is, though not absolutely infallible, very unlikely to state what is not true.

Now it is precisely in this further sense that I wish to consider: what reason have we for believing that certain particular things, other than ourselves, our own perceptions, and what we directly perceive, are real? I have asserted that I do have certain perceptions, which it is very unlikely I should have, unless some other person had certain particular perceptions; that, for instance, it is very unlikely I should be having precisely those perceptions which I am now having unless someone else were hearing the sound of my voice. And I now wish to ask: What reason have I for supposing that this is unlikely? What reason has any of us for supposing that any such proposition is true? And I mean by "having a reason" precisely what I formerly meant. I mean: What other proposition do I know, which would not be true, unless my perception were connected with someone else's perception, in the manner in which I asserted them to be connected? Here again I am asking for _a good reason_; and am not asking a psychological question with regard to origin. Here again I am not asking for a reason, in the strict sense of Formal Logic; I am merely asking for a proposition which would probably not be true, unless what I asserted were true. Here again I am asking for some proposition of a kind which _each_ of us believes; I am asking: What reason has _each_ of us for believing that some of his perceptions are connected with particular perceptions of other people in the manner I asserted?--for believing that he would not have certain perceptions that he does have, unless some other person had certain particular perceptions? And here again I am asking for a _reason_--I am asking for some proposition _other_ than one which itself asserts: When one man has a perception of such and such a particular kind, it _is_ probable that another man has a perception or thought of this or that other kind.