he facts appertaining to both sides
of the matter, ends in the only alternative guess which remains open.
And if that most troublesome individual, the 'plain man' of Locke,
should say it seems at least opposed to common sense to suppose that
there is anything in a burning candle or a rolling billiard-ball
substantially the same as mind, the answer is that if he could look into
my brain at this moment he would see nothing there but motion of
molecules, or motion of masses; and apart from the accident of my being
able to tell him so, his 'common sense' could never have divined that
these motions in my brain are concerned in the genesis of my spoken
thoughts.

* * * * *

It is obvious that from this hypothesis as to the substantial identity
of mind and motion, two important questions arise; and I feel that some
reference to these questions is in present circumstances forced upon me,
because they have both been considered in precisely the same connexion
by one of the most powerful intellects that was ever sent out into the
world by this University. I mean the late Professor Clifford. As my
intimate and valued friend, I desire to mention his name in this place
with all the affection, as well as with all the admiration, to which I
well know it is so fully entitled; and if I appear to mention him only
in order to disagree with him, this is only because I know equally well
that in his large and magnanimous thought differences of philosophical
opinion were never felt to weaken the bonds of friendship.

In his well-known lecture on Body and Mind, Professor Clifford adopted
the hypothesis of identity which we are now considering, and from it was
led to the conclusion that if in the case of cerebral processes motion
is one with mind, the same must be true of motion wherever it occurs;
or, as he expressed it subsequently, the whole universe must be made of
mind-stuff. But in his view, although matter in motion presents what may
be termed the raw material of mind, it is only in the highly elaborated
constitution of the human brain that this raw material is sufficiently
wrought up to yield a self-conscious personality. Hence the dissolution
of a human brain implies the dissolution of a human mind; and hence also
the universe, although entirely composed of mind-stuff, is itself
mindless. Now, all I have to say about these two deductions is
this--they do not necessarily follow from the theory which is be