CONCLUSION
Although I have emphasised the part that dissociation plays in the production of beliefs and actions, yet dissociation is only a particular manifestation of the unconscious and it is the latter which is becoming the field of research as to the causes of human action.
From the evolutionary standpoint consciousness is a late development. Man sacrificed many advantages when he rose above the beast; in every mere bodily endowment he has superiors in the animal world, and as the influence of consciousness has become more and more important so the sphere of his unconscious actions has diminished.
The bird needs no foresight for the building of her nest: the impulse to build comes and must be obeyed. When migration time arrives there is no reasoned plan of going to a distant land, no scheming of routes or destinations: she just goes.
So it is with the intricate instincts of other creatures, of the wasp that builds her brood-cell, fills it with living victims, and places there an egg of whose future she can know nothing.
Seeing these things we marvel at the intelligence of the agent, but the child who ties a rag round a stick and gives it a name uses more initiative than any other animal possesses.
Here, rather late, I will introduce McDougall's definition of an instinct:—
'Instinct is an innate psycho-physical tendency to pay attention to objects of a certain class, to experience emotional excitement of peculiar quality on such perceptions, and to act or have an impulse to act in a particular way with regard to that object.'
We can see that instinct suffices for the bird or insect, living almost entirely in the unconscious, to carry on the important affairs of life. Even in regard to what looks like the exercise of reason or memory we can find a parallel in the human unconscious.