Plato's psychology, like his politics, has an authoritarian cast. He believes that, for the proper inner harmony to be achieved, reason, in alliance with spirit, must exercise a strict control over the desires, inhibiting some, and eliminating others. (...)
Like Plato, Freud sees such repression as inescapable, both within society and within the individual, if civilized human life is to be viable. However Freud also recognizes that, beyond a certain point, excessive repression becomes harmful and self-defeating. Desires which are repressed do not simply disappear, they continue to exist, but remain unconscious. If the repression is too severe, the thwarted desires find expression in substitute satisfactions.