For this reason I think that no observations of my own perceptions, feelings or thoughts can give me the slightest reason for supposing a connection between any of them and any feeling, perception, or thought in another person. The argument is perfectly general, since _all_ my perceptions, feelings and thoughts do have to one another those relations in virtue of which I call them mine; and which, when I talk of a perception, feeling or thought as being _another persons_, I mean to say that it has _not_ got to any of mine. I can, therefore, merely from observation of _this_ class of data never obtain the slightest reason for belief in the existence of a feeling, perception, or thought which does _not_ stand in these relations to one of mine--which _is,_ that is to say, the feeling, perception or thought, of another person. But how different is the case, if we adopt the hypothesis, which I wish to recommend--if we assume the existence of that other class of data which I have called "sense-contents!" On this hypothesis, that which I perceive, when I perceive a movement of my own body, is _real_; that which I perceive when I perceive a movement of another's body is _real_ also. I can now observe not merely the relation between my _perception_ of a movement of my body and my own feelings, but also a relation between a _real_ movement of my body and my own feelings. And there is no reason why I should not be justified in inferring that another person's feelings stand _in the same relation_ to the real movements of his body, in which I observe my own feelings to stand to similar real movements of mine. But there is another argument which may still be urged by those who hold that my own perceptions, thoughts, and feelings, by themselves, may be sufficient to justify a belief in the existence of other persons. It may be said: "Our observation of our own perceptions may be sufficient to _verify_ or _confirm_ the hypothesis that other persons exist. This hypothesis is one which "works." The assumption that other persons have particular thoughts, feelings and perceptions enables us to predict that they will have others and that our own perceptions will be modified accordingly: it enables us to predict future perceptions of our own; and we find that these predictions are constantly verified. We observe that we do have the perceptions, which the hypothesis leads us to expect we should have. In short, our perceptions occur just as they would do, _if_ the hypothesis were true; our perceptions behave _as if_ other persons had the perceptions, thoughts and feelings which we suppose them to have. Surely, then, they confirm the truth of the hypothesis--they give some reason to think it probably true?"