" Notwithstanding our rationalistic attempts to argue it out of existence, psychic reality is and remains a genuine source of anxiety whose danger increases the more it is denied. The biological instincts then meet not only with outer obstacles but with an internal resistance. The same psychic system which, on one side, is based on the concupiscence of the instincts, rests on the other side on an opposing will which is at least as strong as the biological urge. "

― C.G. Jung , Symbols of Transformation (Collected Works 5)