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 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.