between the motivating sensual conception and the will to perform the
instinctive action, and the pleasure of the subsequent gratification
has nothing to do with the matter. We know by the experience of our
own instincts that this causal connection does not lie within our
consciousness; {102a} therefore, if it is to be a mechanism of any
kind, it can only be either an unconscious mechanical induction and
metamorphosis of the vibrations of the conceived motive into the
vibrations of the conscious action in the brain, or an unconscious
spiritual mechanism.

In the first case, it is surely strange that this process should go
on unconsciously, though it is so powerful in its effects that the
will resulting from it overpowers every other consideration, every
other kind of will, and that vibrations of this kind, when set up in
the brain, become always consciously perceived; nor is it easy to
conceive in what way this metamorphosis can take place so that the
constant purpose can be attained under varying circumstances by the
resulting will in modes that vary with variation of the special
features of each individual case.

But if we take the other alternative, and suppose an unconscious
mental mechanism, we cannot legitimately conceive of the process
going on in this as other than what prevails in all mental mechanism,
namely, than as by way of idea and will. We are, therefore,
compelled to imagine a causal connection between the consciously
recognised motive and the will to do the instinctive action, through
unconscious idea and will; nor do I know how this connection can be
conceived as being brought about more simply than through a conceived
and willed purpose. {102b} Arrived at this point, however, we have
attained the logical mechanism peculiar to and inseparable from all