Taboo restrictions are distinct from religious or moral prohibitions. They are not based upon any divine ordinance, but may be said to impose themselves on their own account. They differ from moral prohibitions in that they fall into no system that declares quite generally that certain abstinences must be observed and gives reasons for that necessity.
Sigmund FreudThe analytic psychotherapist thus has a threefold battle to wage -- in his own mind against the forces which seek to drag him down from the analytic level; outside the analysis, against opponents who dispute the importance he attaches to the sexual instinctual forces and hinder him from making use of them in his scientific technique; and inside the analysis, against his patients, who at first behave like opponents but later on reveal the overvaluation of sexual life which dominates them, and who try to make him captive to their socially untamed passion.
Sigmund Freud