Homo duplex is a view promulgated by Émile Durkheim, a macro-sociologist of the 19th century, saying that a man on the one hand is a biological organism, driven by instincts, with desire and appetite and on the other hand is being led by morality and other elements generated by society.
What allows a person to go beyond the "animal" nature is the most common religion that imposes specific normative system and is a way to regulate behaviour.
But the young educated adults of the 90s got to watch all this brave new individualism and self-expression and sexual freedom deteriorate into the joyless and anomic self-indulgence of the Me Generation.
Today's sub-40s have different horrors, prominent among which are anomie and solipsism and a peculiarly American loneliness: the prospect of dying without once having loved something more than yourself.
[1] Sigmund Freud used these ideas in his essay Civilization and Its Discontents, he wrote civilisation is created through restraint – is "built up upon a renunciation of instinct"[2]