On the other hand, we must now return to a closer consideration of
the conception of a psychical mechanism. {100} And here we find that
this mechanism, in spite of its explaining so much, is itself so
obscure that we can hardly form any idea concerning it. The motive
enters the mind by way of a conscious sensual impression; this is the
first link of the process; the last link {101} appears as the
conscious motive of an action. Both, however, are entirely unlike,
and neither has anything to do with ordinary motivation, which
consists exclusively in the desire that springs from a conception
either of pleasure or dislike--the former prompting to the attainment
of any object, the latter to its avoidance. In the case of instinct,
pleasure is for the most part a concomitant phenomenon; but it is not
so always, as we have already seen, inasmuch as the consummation and
highest moral development of instinct displays itself in self-
sacrifice.

The true problem, however, lies far deeper than this. For every
conception of a pleasure proves that we have experienced this
pleasure already. But it follows from this, that when the pleasure
was first felt there must have been will present, in the
gratification of which will the pleasure consisted; the question,
therefore, arises, whence did the will come before the pleasure that
would follow on its gratification was known, and before bodily pain,
as, for example, of hunger, rendered relief imperative? Yet we may
see that even though an animal has grown up apart from any others of
its kind, it will yet none the less manifest the instinctive impulses
of its race, though experience can have taught it nothing whatever
concerning the pleasure that will ensue upon their gratification. As
regards instinct, therefore, there must be a causal connection