3 is prime, 5 is prime, 7 is prime, 9 is a paradox; as is a paradox why the number 1 is not prime if it has no other divisors besides himself.

Perhaps the best hope for the future of mankind is that ways will be found of increasing the scope and intensity of sympathy.

Inferences of Science and Common Sense differ from those of deductive logic and mathematics in a very important respect, namely, when the premises are true and the reasoning correct, the conclusion is only probable.

A smile happens in a flash, but its memory can last a lifetime.

Calculus required continuity, and continuity was supposed to require the infinitely little; but nobody could discover what the infinitely little might be.

This, however, is a passing nightmare; in time the earth will become again incapable of supporting life, and peace will return.

For love of domination we must substitute equality; for love of victory we must substitute justice; for brutality we must substitute intelligence; for competition we must substitute cooperation. We must learn to think of the human race as one family.