Learning preserves the errors of the past as well as its wisdom.

The defense of morals is the battle-cry which best rallies stupidity against change.

The aims of scientific thought are to see the general in the particular and the eternal in the transitory.

The deepest definition of youth is life as yet untouched by tragedy.

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

From the very beginning of his education, the child should experience the joy of discovery.

The paradox is now fully established that the utmost abstractions are the true weapons with which to control our thought of concrete fact.