Now, the plain man accepts the argument from analogy, here insisted upon, every day of his life. He is continually forming an opinion as to the contents of other minds on a basis of the bodily manifestations presented to his view. The process of inference is so natural and instinctive that we are tempted to say that it hardly deserves to be called an inference. Certainly the man is not conscious of distinct steps in the process; he perceives certain phenomena, and they are at once illuminated by their interpretation. He reads other men as we read a book--the signs on the paper are scarcely attended to, our whole thought is absorbed in that for which they stand. As I have said above, the psychologist accepts the argument, and founds his conclusions upon it. Upon what ground can one urge that this inference to other minds is a doubtful one? It is made universally. We have seen that even those who have theoretic objections against it, do not hesitate to draw it, as a matter of fact. It appears unnatural in the extreme to reject it. What can induce men to regard it with suspicion? I think the answer to this question is rather clearly suggested in the sentence already quoted from Professor Huxley: "It is wholly impossible absolutely to prove the presence or absence of consciousness in anything but one's own brain, though, by analogy, we are justified in assuming its existence in other men." Here Professor Huxley admits that we have something like a proof, for he regards the inference as _justified_. But he does not think that we have _absolute proof_--the best that we can attain to appears to be a degree of probability falling short of the certainty which we should like to have. Now, it should be remarked that the discredit cast upon the argument for other minds has its source in the fact that it does not satisfy a certain assumed standard. What is that standard? It is the standard of proof which we may look for and do look for where we are concerned to establish the existence of material things with the highest degree of certainty. There are all sorts of indirect ways of proving the existence of material things. We may read about them in a newspaper, and regard them as highly doubtful; we may have the word of a man whom, on the whole, we regard as veracious; we may infer their existence, because we perceive that certain other things exist, and are to be accounted for. Under certain circumstances, however, we may have proof of a different kind: we may see and touch the things themselves. Material things are open to direct inspection. Such a direct inspection constitutes _absolute proof_, so far as material things are concerned.