Education with inert ideas is not only useless; it is above all things harmful.
Art flourishes where there is a sense of adventure.
Error is the price we pay for progress.
No science can be more secure than the unconscious metaphysics which tacitly it presupposes.
Everyone is a philosopher. Not everyone is good at it.
Mathematics, in its widest significance, is the development of all types of formal, necessary, deductive reasoning.