Among human beings, a cat is merely a cat; among cats, a cat is a prowling shadow in a jungle.

Dumb dog. I bought a dog whistle. He won't use it.

My dear Miss Glory, Robots are not people. They are mechanically more perfect than we are, they have an astounding intellectual capacity, but they have no soul.

You still stand watch, O human star, burning without a flicker, perfect flame, bright and resourceful spirit. Each of your rays a great idea - O torch which passes from hand to hand, from age to age, world without end.

Cognition is not fighting, but once someone knows a lot, he will have much to fight for, so much that he will be called a relativist because of it.

All the year round there is spring, all through life is youth; there is always something which may flower.

A short life is better for mankind, for a long life would deprive man of his optimism.