Adolescent stage in the development of the human race from which humanity should free itself.
Sigmund FreudIn the last analysis the entire field of psychology may reduce to biological electrochemistry.
Sigmund FreudIn the theory of psycho-analysis we have no hesitation in assuming that the course taken by mental events is automatically regulated by the pleasure principle. We believe, that is to say, that the course of those events is invariably set in motion by an unpleasurable tension, and that it takes a direction such that its final outcome coincides with a lowering of that tension that is, with an avoidance of unpleasure or a production of pleasure.
Sigmund Freud