There is no "indication of reality" in the unconscious, so that it is impossible to distinguish between truth and emotionally-charged fiction. (This leaves open the possible explanation that sexual phantasy regularly makes use of the theme of the parents.)
Sigmund Freud, 1897
Freud's view that it is impossible in the unconscious to distinguish powerful fantasies from actual experience remained at the core of psychoanalysis. For him memory and fantasy were not easily separated, and his focus on their interconnections has put psychoanalysis at the center of many debates about childhood and our memory of it.
Many scientists of the time asked how the nervous system could recognize the difference between a perception, a memory, and a fantasy. Freud concluded that there were no neurological "indications of reality" in the unconscious.