Philosophical Studies. G. E. Moore
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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.
But what kind of reason can be given for believing a proposition of this sort? For believing a proposition which asserts that, since one particular thing exists, it is probable that another particular thing also exists? One thing I think is plain, namely that we can have no good reason for believing such a proposition, unless we have good reason for believing some generalisation. It is commonly believed, for instance, that certain so-called flint arrow-heads, which have been discovered, were probably made by prehistoric men; and I think it is plain that we have no reason for believing this unless we have reason to suppose that objects which resemble these in certain particular respects are generally made by men—are more often made by men than by any other agency. Unless certain particular characteristics which those arrow-heads have were characteristics which belonged at least more frequently to articles of human manufacture than to any articles not made by men, it would surely be just as likely as not that these arrowheads were not made by men—that they were, in fact not arrow-heads. That is to say, unless we have reason to assert a generalisation—the generalisation that objects of a certain kind are generally made by men, we have no reason to suppose that these particular objects, which are of the kind in question, were made by men. And the same, so far as I can see, is true universally. If we ever have any reason for asserting that, since one particular thing exists, another probably exists or existed or will exist also part of our reason, at least, must consist in reasons for asserting some generalisation—for asserting that the existence of things of a particular kind is, more often than not, accompanied or preceded or followed by the existence of things of another particular kind. It is, I think, sometimes assumed that an alternative to this theory may be found in the theory that the existence of one kind of thing "intrinsically points to," or is "intrinsically a sign or symbol of" the existence of another thing. It is suggested that when a thing which thus points to the existence of another thing exists, then it is at least probable that the thing "pointed to" exists also. But this theory, I think, offers no real alternative. For, in the first place, when we say that the existence of one thing A is a "sign of" or "points to" the existence of another thing B, we very commonly actually mean to say that when a thing like A exists, a thing like B generally exists too. We may, no doubt, mean something else too; but this we do mean. We say, for instance, that certain particular words, which we hear or read, are a "sign" that somebody has thought of the particular things which we call the meaning of those words. But we should certainly hesitate to admit that the hearing or reading of certain words could be called a "sign" of the existence of certain thoughts, unless it were true that when those words are heard or read, the thoughts in question generally have existed. If when those words were heard or read, the thoughts had generally not existed, we should say that, in one sense of the word at all events, the hearing of the words was not a sign of the existence of the thoughts. In this sense, therefore, to say that the existence of A "points to" or "is a sign of" the existence of B is actually to say that when A exists, B generally exists also. But, no doubt, the words "points to" "is a sign of" may be used in some other sense: they may, for instance, mean only that the existence of A suggests in some way the belief that B exists. And in such a case we certainly might know that the existence of A pointed to the existence of B, without knowing that when A existed B generally existed also. Let us suppose, then, that in some such sense A does "point to" the existence of B; can this fact give us a reason for supposing it even probable that B existed. Certainly it can, provided it is true that when A does point to the existence of B, B generally exists. But surely it can do so, only on this condition. If when A points to the existence of B, B, nevertheless, does not generally exist, then surely the fact that A points to the existence of B can constitute no probability that B does not exist: on the contrary it will then be probable that, even though A "points to" the existence of B, B does not exist. We have, in fact, only substituted the generalisation that A's pointing to B is generally accompanied by the existence of B, for the generalisation that A's existence is generally accompanied by the existence of B. If we are to have any reason for asserting that, when A points to or is a sign of the existence of B, B probably exists, we must still have a reason for some generalisation—for a generalisation which asserts that when one thing points to the existence of another, that other generally exists.
It is plain, then, I think, that if we are to find a reason for the assertion that some particular perception of mine would probably not exist, unless someone else were having or had had a perception of a kind which I can name, we must find a reason for some generalisation. And it is also plain, I think, that in many cases of this kind the generalisation must consist in an assertion that when one man has a certain kind of perception, some other man generally has had