The Undiscovered Self (Great Minds)

by C.G. Jung

As I explained above, instinct has two main aspects: on the one hand, that of dynamism, drive or drift, and on the other, specific meaning and intention. It is highly probable that all man’s psychic functions have an instinctual foundation, as is obviously the case with animals. It is easy to see that in animals instinct functions as the spiritus rector of all their behavior. This observation lacks certainty only where the learning capacity begins to develop, for instance in the higher apes and in man. In the animals, as a result of their learning capacity, instinct undergoes numerous modifications and differentiations; in civilized man the instincts are so split up that only a few of the basic ones can be recognized with any certainty in their original form. The most important are the two fundamental instincts and their derivatives, and these have been the exclusive concern of medical psychology so far.