essions.
By a process of trial and error, perhaps, the elements necessary to
effect the adaptive response may be assembled and the problem solved.

"It is evident here that the physiological factors in the dilemma or
problem as this is presented to the cortex are by no means simple
sensory impressions, but definitely organized systems of neural
discharge, each of which is a physiological resultant of the reflexes,
automatisms, impulses, and inhibitions characteristic of its appropriate
subcortical centers. The precise form which these subcortical
combinations will assume in response to any particular excitation is in
large measure determined by the structural connections _inter se_....

"From the standpoint of the cerebral cortex considered as an essential
part of the mechanism of higher conscious acts, every afferent stimulus,
as we have seen, is to some extent affected by its passage through
various subcortical association centers (i.e., it carries a quale of
central origin). But this same afferent impulse in its passage through
the spinal cord and brain stem may, before reaching the cortex,
discharge collateral impulses into the lower centers of reflex
cooerdination, from which incipient (or even actually consummated) motor
responses are discharged previous to the cortical reaction. These motor
discharges may, through the 'back stroke' action, in turn exert an
influence upon the slower cortical reaction. Thus the lower reflex
response may in a literal physiological sense act _into_ the cortical
stimulus complex and become an integral part of it."[37]

It seems clear, then, that conscious behavior involves a certain
_process_ of organization which constitutes a differential. The units
entering into this process are "definitely organized systems of neural
discharge," the antecedent organization of these several systems being
due either to the inherited or to the acquired structure of the nervous
system. Given a certain amount of plasticity, the nervous system builds
up specific forms of response for certain objects or situations, and
these forms of response subsequently become the material from which new
organizations or new modes of response are constructed. The achievements
of the past, accordingly, become stepping-stones to new achievement. The
new organization, moreover, is not determined by a mechanism
antecedently provided, but has a peculiar flexibility, so as to meet the
demands of a new situation. That is, a