No science can be more secure than the unconscious metaphysics which tacitly it presupposes.

Learning is often spoken of as if we are watching the open pages of all the books which we have ever read, and then, when occasion arises, we select the right page to read aloud to the universe.

A philosopher of imposing stature doesn't think in a vacuum. Even his most abstract ideas are, to some extent, conditioned by what is or is not known in the time when he lives.

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

The motive of success is not enough.

On the ostensible exactitude of certain branches of human knowledge, including mathematics. The exactness is a fake.

Error itself may be happy chance.