The paranoid is never entirely mistaken.

In almost every place where we find totems we also find a law against persons of the same totem having sexual relations with one another and consequently against their marrying. This, then, is 'exogamy', an institution related to totemism.

In the last analysis the entire field of psychology may reduce to biological electrochemistry.

The dream acts as a safety-valve for the over-burdened brain.

A layman will no doubt find it hard to understand how pathological disorders of the body and mind can be eliminated by 'mere' words. He will feel that he is being asked to believe in magic. And he will not be so very wrong, for the words which we use in our everyday speech are nothing other than watered-down magic. But we shall have to follow a roundabout path in order to explain how science sets about restoring to words a part at least of their former magical power.

The idea of life having a purpose stands and falls with the religious system.

The pleasure principle long persists, however, as the method of working employed by the sexual instincts, which are so hard to 'educate', and, starting from those instincts, or in the ego itself, it often succeeds in overcoming the reality principle, to the detriment of the organism as a whole.