How else could it have occurred to man to divide the cosmos, on the analogy of day and night, summer and winter, into a bright day-world and a dark night-world peopled with fabulous monsters, unless he had the prototype of such a division in himself, in the polarity between the conscious and the invisible and unknowable unconscious?
Primitive man's perception of objects is conditioned only partly by the objective behavior of the things themselves, whereas a much greater part is often played by intra-psychic facts which are not related to the external objects except by way of projection.
This is due to the simple fact that the primitive has not yet experienced that ascetic discipline of mind known to us as the critique of knowledge.
To him the world is a more or less fluid phenomenon within the stream of his own fantasy, where subject and object are undifferentiated and in a state of mutual interpenetration. ~Carl Jung; Psychological Aspects of the Mother Archetype; CW 9, Part 1: The Archetypes and the Collective Unconscious. P. 187.