e nothing there. Could we ever find out our error? And in a field
where it is impossible to prove error, must it not be equally
impossible to prove truth?

The doubt has seemed by no means a gratuitous one to certain very
sensible practical men. "It is wholly impossible," writes Professor
Huxley,[1] "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." "The existence
of my conception of you in my consciousness," says Clifford,[2]
"carries with it a belief in the existence of you outside of my
consciousness. . . . How this inference is justified, how
consciousness can testify to the existence of anything outside of
itself, I do not pretend to say: I need not untie a knot which the
world has cut for me long ago. It may very well be that I myself am
the only existence, but it is simply ridiculous to suppose that anybody
else is. The position of absolute idealism may, therefore, be left out
of count, although each individual may be unable to justify his dissent
from it."

These are writers belonging to our own modern age, and they are men of
science. Both of them deny that the existence of other minds is a
thing that can be _proved_; but the one tells us that we are "justified
in assuming" their existence, and the other informs us that, although
"it may very well be" that no other mind exists, we may leave that
possibility out of count.

Neither position seems a sensible one. Are we justified in assuming
what cannot be proved? or is the argument "from analogy" really a proof
of some sort? Is it right to close our eyes to what "may very well
be," just because we choose to do so? The fact is that both of these
writers had the conviction, shared by us all, that there are other
minds, and that we know something about them; and yet neither of them
could see that the conviction rested upon an unshakable foundation.

Now, I have no desire to awake in the mind of any one a doubt of the
existence of other minds. But I think we must all admit that the man
who recognizes that such minds are not directly perceived, and who
harbors doubts as to the nature of the inference which leads to their
assumption, may, perhaps, be able to say that _he feels certain_ that
there are other minds; but must we not at the same time admit that he
is scarcely in a position to say: _it is certain_ that there are other
mind