The world's greatest thinkers have often been amateurs; for high thinking is the outcome of fine and independent living, and for that a professional chair offers no special opportunities.

It is here [in mathematics] that the artist has the fullest scope of his imagination.

Sex lies at the root of life, and we can never learn to reverence life until we know how to understand sex.

The romantic embrace can only be compared with music and with prayer.

All arguments are meaningless until we gain personal experience. One must win one's own place in the spiritual world painfully and alone. There is no other way of salvation. The Promised Land always lies on the other side of a wilderness.

On the threshold of the moral world we meet the idea of Freedom, 'one of the weightiest concepts man has ever formed,' once a dogma, in the course of time a hypothesis, now in the eyes of many a fiction, yet we cannot do without it, even although we may be firmly convinced that our acts are determined by laws that cannot be broken.

Jealousy, that dragon which slays love under the pretence of keeping it alive.