From a certain temperature on, the molecules 'condense' without attractive forces; that is, they accumulate at zero velocity. The theory is pretty, but is there some truth in it.

I must seem like an ostrich who forever burries its head in the relativistic sands in order not to face the evil quanta.

You have to learn the rules of the game. And then you have to play better than anyone else.

A man's ethical behaviour should be based effectually on sympathy, education, and social ties and needs; no religious basis is necessary. Man would indeed be in a poor way if he had to be restrained by fear of punishment and hope of reward after death.

We shall require a substantially new manner of thinking if mankind is to survive.

It is every man's obligation to put back into the world at least the equivalent of what he takes out of it.

The family that prays together...is brainwashing their children.