We have penetrated far less deeply into the regularities obtaining within the realm of living things, but deeply enough nevertheless to sense at least the rule of fixed necessity... what is still lacking here is a grasp of the connections of profound generality, but not a knowledge of order itself.

One should guard against preaching to young people success in the customary form as the main aim in life. The most important motive for work in school and in life is pleasure in work, pleasure in its result, and the knowledge of the value of the result to the community.

Man like every other animal is by nature indolent. If nothing spurs him on, then he will hardly think, and will behave from habit like an automaton.

Those instrumental goods which should serve to maintain the life and health of all human beings should be produced by the least possible labour of all.

Genius simply cannot be reduced to a set of rules for anyone to follow.

If a theory can not be explained to a child, then the theory is probably worthless.

If I had it [life] to do all over again, I'd have been a plumber.