ermine, then, the connections of the mental facts. Indeed
this has become the method of modern psychology. It has brought about
the intimate relation between psychology and the physiology of the
brain, and has given us, as foundation, the theory of psychophysical
parallelism; the theory that there is no psychical process without a
parallel brain process. But the real center of the theory lies indeed in
the fact which we discussed; it lies in the fact that we cannot have any
explanation of mental states as such at all, if we do not link them with
physical processes.

Is it necessary to express again the assurance that such statements of a
parallelism between mind and brain in no way interfere with an
idealistic view of inner life? Have we not seen clearly enough that
these mental facts which are conceived parallel to physiological brain
processes do not represent the immediate reality of our inner life, that
our life reality is purposive and as such outside of all causal
explanation, and that we have to take a special, almost artificial,
point of view to consider inner life at all as objects, as contents of
consciousness, and thus as psychological material? But since we have
seen that for certain purposes such a point of view is necessary, as
soon as we have taken it we must be consistent. Our inner life in its
purposive reality has therefore nothing to do with brain processes, but
if we are on the psychological track and consider man as a system of
psychological phenomena, then to be sure, we must see that our only
possible interest lies in the finding of necessary causal connections.
But these cannot be found otherwise than by linking the mental facts
with the physical ones, the psychological material with the processes of
the brain.

Of course, that mental experience stands in intimate relations to the
body is a knowledge which does not wait for such philosophical
arguments. That mind and body come in contact is a conviction which goes
with every single sense perception. I see and hear because light and
sound stimulate my sense organs, and the sense organs stimulate my
brain. The explanation of perception through causes in the physical
system seems the more natural as it is evident that in such cases there
are no psychical causes which might have brought forward the perception.
If I suddenly hear bells ringing, there was on the mental side nothing
preceding which could be responsible for my sound perception. And the