We must produce a great age, or see the collapse of the upward striving of our race.

Do not teach too many subjects and what you teach, teach thoroughly.

Every epoch has its character determined by the way its population reacts to the material events which they encounter.

Inventive genius requires pleasurable mental activity as a condition for its vigorous exercise

Without adventure civilization is in full decay. ... The great fact [is] that in their day the great achievements of the past were the adventures of the past.

An open mind is all very well in its way, but it ought not to be so open that there is no keeping anything in or out of it.

The ultimate metaphysical ground is the creative advance into novelty.