The inclination to aggression constitutes the greatest impediment to civilization.

It is impossible to overlook the extent to which civilization is built upon a renunciation of instinct.

Dreams are the guardians of sleep and not its disturbers.

The great question that has never been answered, and which I have not yet been able to answer, despite my thirty years of research into the feminine soul, is 'What does a woman want?'

No, our science is no illusion. But an illusion it would be to suppose that what science cannot give us we can get elsewhere.

None believes in his own death. In the unconscious everyone is convinced of his own immortality.

From error to error one discovers the entire truth.