Civilized people have exchanged some part of their chances of happiness for a measure of security.

The wish to be able to fly is to be understood as nothing else than a longing to be capable of sexual performance.

The moment a man questions the meaning and value of life, he is sick, since objectively neither has any existence; by asking this question one is merely admitting to a store of unsatisfied libido to which something else must have happened, a kind of fermentation leading to sadness and depression.

We know less about the sexual life of little girls than of boys. But we need not feel ashamed of this distinction; after all, the sexual life of adult women is a 'dark continent' for psychology.

The view is often defended that sciences should be built up on clear and sharply defined basal concepts. In actual fact no science, not even the most exact, begins with such definitions. The true beginning of scientific activity consists rather in describing phenomena and then in proceeding to group, classify and correlate them.

The adoption of the required attitude of mind towards ideas that seem to emerge "of their own free will" and the abandonment of the critical function that is normally in operation against them seem to be hard of achievement for some people. The "involuntary thoughts" are liable to release a most violent resistance, which seeks to prevent their emergence. If we may trust that great poet and philosopher Friedrich Schiller, however, poetic creation must demand an exactly similar attitude.

Where does a thought go when it's forgotten?