An unflinching determination to take the whole evidence into account is the only method of preservation against the fluctuating extremes of fashionable opinion.

It is more important that a proposition be interesting than that it be true.

A clash of doctrine is not a disaster, it is an opportunity.

Value is coextensive with reality.

The pursuit of mathematics is a divine madness of the human spirit.

Through and through the world is infested with quantity: To talk sense is to talk quantities. It is no use saying the nation is large. . . . How large? It is no use saying the radium is scarce. . . . How scarce? You cannot evade quantity. You may fly to poetry and music, and quantity and number will face you in your rhythms and your octaves.

Fertilization of the soul is the reason for the necessity of art.