In 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.

A strong egoism is a protection.

Whatever fosters the growth of civilization works at the same time against war.

An unrestricted satisfaction of every need presents itself as the most enticing method of conducting one's life, but it means putting enjoyment before caution, and soon brings its own punishment.

When one does not have what one wants, one must want what one has.

The defense against childish helplessness is what lends its characteristic features to the adult's reaction to the helplessness which he has to acknowledge - a reaction which is precisely the formation of religion.

It is a great injustice to persecute homosexuality as a crime, and cruelty too