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

Just as no one can be forced into belief, so no one can be forced into unbelief.

Neither in my private life nor in my writings, have I ever made a secret of being an out-and-out unbeliever.

Immorality, no less than morality, has at all times found support in religion.

The motive forces of phantasies are unsatisfied wishes, and every single phantasy is the fulfillment of a wish, a correction of unsatisfying reality.

We may insist as often as we like that man's intellect is powerless in comparison to his instinctual life, and we may be right in this. Nevertheless, there is something peculiar about this weakness. The voice of the intellect is a soft one, but it will not rest until it has gained a hearing. Finally, after a countless succession of rebuffs, it succeeds.

As regards intellectual work it remains a fact, indeed, that great decisions in the realm of thought and momentous discoveries and solutions of problems are only possible to an individual, working in solitude.