Teaching is not a lost art, but the regard for it is a lost tradition.

Above all, the ability to feel the force of an argument apart from the substance it deals with is the strongest weapon against prejudice.

Life is given us as a passion.

If civilization has risen from the Stone Age, it can rise again from the Wastepaper Age.

Out of man's mind in free play comes the creation Science. It renews itself, like the generations, thanks to an activity which is the best game of homo ludens: science is in the strictest and best sense a glorious entertainment.

Simple English is no one’s mother tongue. It has to be worked for.

Schools are not intended to moralize a wicked world, but to impart knowledge and develop intelligence, with only two social aims in mind: prepare to take on one's share in the world's work, and perhaps in addition, lend a hand in improving society, after schooling is done.