nds all others. The progress of modern discovery
has in no respect weakened the force of Descartes's remark, that between
that of which the differential attribute is Thought and that of which
the differential attribute is Extension, there can be no similarity, no
community of nature whatever. By no scientific cunning of experiment or
deduction can Thought be weighed or measured or in any way assimilated
to such things as may be made the actual or possible objects of
sense-perception. Modern discovery, so far from bridging over the chasm
between Mind and Matter, tends rather to exhibit the distinction between
them as absolute. It has, indeed, been rendered highly probable that
every act of consciousness is accompanied by a molecular motion in the
cells and fibres of the brain; and materialists have found great comfort
in this fact, while theologians and persons of little faith have been
very much frightened by it. But since no one ever pretended that thought
can go on, under the conditions of the present life, without a
brain, one finds it rather hard to sympathize either with the
self-congratulations of Dr. Buchner's disciples [8] or with the terrors
of their opponents. But what has been less commonly remarked is the
fact that when the thought and the molecular movement thus occur
simultaneously, in no scientific sense is the thought the product of the
molecular movement. The sun-derived energy of motion latent in the food
we eat is variously transformed within the organism, until some of
it appears as the motion of the molecules of a little globule of
nerve-matter in the brain. In a rough way we might thus say that the
chemical energy of the food indirectly produces the motion of these
little nerve-molecules. But does this motion of nerve-molecules now
produce a thought or state of consciousness? By no means. It simply
produces some other motion of nerve-molecules, and this in turn
produces motion of contraction or expansion in some muscle, or becomes
transformed into the chemical energy of some secreting gland. At no
point in the whole circuit does a unit of motion disappear as motion to
reappear as a unit of consciousness. The physical process is complete in
itself, and the thought does not enter into it. All that we can say is,
that the occurrence of the thought is simultaneous with that part of the
physical process which consists of a molecular movement in the brain.
[9] To be sure, the thought is always there when s