When you're average, you're just as close to the bottom as you are the top.

Every organism requires an environment of friends, partly to shield it from violent changes, and partly to supply it with its wants.

The vitality of thought is in adventure. Ideas won't keep. Something must be done about them. When the idea is new, its custodians have fervor, live for it, and if need be, die for it.

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

What the learned world tends to offer is one second-hand scrap of information illustrating ideas derived from another second-hand scrap of information. The second-handedness of the learned world is the secret of its mediocrity.

Everyone is a philosopher. Not everyone is good at it.

It is impossible to meditate on time and the mystery of nature without an overwhelming emotion at the limitations of human intelligence.