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