Education with inert ideas is not only useless; it is above all things harmful.

One main factor in the upward trend of animal life has been the power of wandering.

It is natural to think that an abstract science cannot be of much importance in affairs of human life, because it has omitted from its consideration everything of real interest.

The whole of mathematics consists in the organization of a series of aids to the imagination in the process of reasoning.

From the moment of birth we are immersed in action, and can only fitfully guide it by taking thought.

No religion can be considered in abstraction from its followers, or even from its various types of followers.

...the self-satisfied dogmatism with which mankind at each period of its history cherishes the delusion of the finality of existing modes of knowledge.