ntitious, or that in the absence of mind changes
of brain could be what they are; for it belongs to the very causation of
these changes that they should have a mental side. The use of mind to
animals is thus rendered apparent; for intelligent volition is thus
shown to be a true cause of adjustive movement, in that the cerebration
which it involves could not otherwise be possible: the causation would
not otherwise be complete.

A simple illustration may serve at once to render this doctrine more
easily intelligible, and to show that, if accepted, the doctrine, as it
appears to me, terminates the otherwise interminable controversy on the
freedom of the will.

In an Edison lamp the light which is emitted from the burner may be said
indifferently to be caused by the number of vibrations per second going
on in the carbon, or by the temperature of the carbon; for this rate of
vibration could not take place in the carbon without constituting that
degree of temperature which affects our eyes as luminous. Similarly, a
train of thought may be said indifferently to be caused by brain-action
or by mind-action; for, _ex hypothesi_, the one could not take place
without the other. Now, when we contemplate the phenomena of volition by
themselves, it is as though we were contemplating the phenomena of light
by themselves: volition is produced by mind in brain, just as light is
produced by temperature in carbon. And just as we may correctly speak of
light as the cause, say, of a photograph, so we may correctly speak of
volition as the cause of bodily movement. That particular kind of
physical activity which takes place in the carbon could not take place
without the light which causes a photograph; and, similarly, that
particular kind of physical activity which takes place in the brain
could not take place without the volition which causes a bodily
movement. So that volition is as truly a cause of bodily movement as is
the physical activity of the brain; seeing that, in an absolute sense,
the cause is one and the same. But if we once clearly perceive that what
in a relative sense we know as volition is, in a similar sense, the
cause of bodily movement, we terminate the question touching the freedom
of the will. For this question in its last resort--and apart from the
ambiguity which has been thrown around it by some of our
metaphysicians--is merely the question whether the will is to be
regarded as a cause of Nature. And the theory which