Speak out in acts; the time for words has passed, and only deeds will suffice.

Art flourishes where there is a sense of adventure.

Civilizations can only be understood by those who are civilized.

Every philosophy is tinged with the coloring of some secret imaginative background, which never emerges explicitly into its train of reasoning.

Fools act on imagination without knowledge, pedants act on knowledge without imagination.

Fundamental progress has to do with the reinterpretation of basic ideas.

Human life is driven forward by its dim apprehension of notions too general for its existing language.

I have always noticed that deeply and truly religious persons are fond of a joke, and I am suspicious of those who aren't.

Ideas won't keep; something must be done about them.

Intelligence is quickness to apprehend as distinct form ability, which is capacity to act wisely on the thing apprehended.

It is the business of the future to be dangerous; and it is among the merits of science that it equips the future for its duties.

It requires a very unusual mind to undertake the analysis of the obvious.

It takes an extraordinary intelligence to contemplate the obvious.

Life is an offensive, directed against the repetitious mechanism of the Universe.

Man can acquire accomplishments or he can become an animal, whichever he wants. God makes the animals, man makes himself.

Periods of tranquility are seldom prolific of creative achievement. Mankind has to be stirred up.

Philosophy is the product of wonder.

Simple solutions seldom are. It takes a very unusual mind to undertake analysis of the obvious.

Speech is human nature itself, with none of the artificiality of written language.

The absolute pacifist is a bad citizen; times come when force must be used to uphold right, justice and ideals.