The author considers knowledge as a complex process, in which the conscious and unconscious moments are intertwined. The article convincingly shows a special role of the unconscious in the initial period of the formation of knowledge (when it has probable nature).The first conjectures about something new (unknown) often arise at the level of the unconscious, and in the nomination of hypotheses and their further justification, both conscious, and unconscious moments are always intertwined. The article pays attention to the fact that the relationship of human existence (the subject of cognition) with the existence of the world plays an important role in the formation and representation of knowledge. And this is a multi-faceted relationship which passes through the consciousness and unconsciousness.

Key words: cognition, consciousness, unconsciousness, probable knowledge, existence.