I should like to raise the question whether the inevitable stunting of the sense of smell as a result of man's turning away from the earth, and the organic repression of the smell-pleasure produced by it, does not largely share in his predisposition to nervous diseases.

What we call happiness in the strictest sense comes from the (preferably sudden) satisfaction of needs which have been dammed up to a high degree.

A state of consciousness is characteristically very transitory; an idea that is conscious now is no longer so a moment later, although it can become so again under certain conditions that are easily brought about.

The whole life of instinct serves the one end of bringing about death.

The only unnatural sexual behavior is none at all.

Cruelty and intolerance to those who do not belong to it are natural to every religion.

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