“He [Freud] would remain a firm dualist for clinical, theoretical, and aesthetic reasons. The cases of his patients amply confirmed his contention that psychological activity is essentially pervaded by conflict. What is more, the very concept of repression, that cornerstone of psychoanalytic theory, presupposes a fundamental division in mental operations: Freud separated the repressing energies from the repressed material. Finally, his dualism had an elusive aesthetic dimension. It is not that Freud was helplessly obsessed with the image of two infuriated swordsmen slashing at one another to the death; his analysis of the oedipal triangle, for one, shows him able to discard polarities when the evidence demands it. But the phenomenon of dramatic opposites seems to have given Freud a sense of satisfaction and closure: his writings abound in confrontations of active and passive, masculine and feminine, love and hunger, and now, after the war, life and death.”
–Peter Gay, Freud: A Life for our Time
“The walls of Chauvet Cave thus seem to reveal an Aurignacian art that is profoundly marked by the theme of duality.”
–Jean Clottes, Chauvet Cave: The Art of Earliest Times