simply is that two distinct facts stand to
be explained by the theory of conscious automatism--first, why psychosis
should ever have been developed as a mysterious appendage to neurosis;
and, secondly, why the association between these things should be so
intimate and precise. Assuredly, on the principles of evolution, which
materialists at least cannot afford to disregard, it would be a wholly
anomalous fact that so wide and general a class of phenomena as those of
mind should have become developed in constantly ascending degrees
throughout the animal kingdom, if they are entirely without use to
animals. If psychosis is, as supposed, a function of neurosis, the
doctrine of natural selection alone would forbid us to imagine that this
function differs from all other functions in being itself functionless.
If it would be detrimental to the theory of natural selection that any
one isolated structure--such as the tail of a rattlesnake--should be
adapted to perform a function useless to the animal possessing it, how
utterly destructive of that theory would be the fact that all the
phenomena of mind have been elaborated as functions of nerve-tissue
without any one of them ever having been of any use either to the
individual or to the species. And the difficulty that thus arises is
magnified without limit when we remember that the phenomena of mind are
invariable in their association with cerebral structure, grade for
grade, and process for process.

It is of no argumentative use to point to the fact that many adaptive
movements in animals are performed by nerve-centres apart from any
association with consciousness or volition, because all the facts on
this head go to prove that consciousness and volition come in most
suggestively just where adaptive movements begin to grow varied and
complex, and then continue to develop with a proportional reference to
the growing variety and complexity of these movements. The facts,
therefore, irresistibly lead to the conclusion (if we argue here as we
should in the case of any other function) that consciousness and
volition are functions of nerve-tissue super-added to its previous
functions, in order to meet new and more complex demands on its powers
of adaptation.

Neither is it of any argumentative use to point to the fact that
adaptive actions which originally are performed with conscious volition
may by practice come to be performed without conscious volition. For it
is certain that