Life is short, the art is long, the problems pressing.

In man, at least, satisfaction is commonly followed by boredom.

... men as a rule are more preoccupied with the dangers that threaten their life than interested in the biological forces on which they depend for a constructive existence.

Human diversity makes tolerance more than a virtue; it makes it a requirement for survival.

There is a demon in technology. It was put there by man and man will have to exorcise it before technological civilization can achieve the eighteenth-century ideal of humane civilized life.

It is often by a trivial, even an anecdotal decision, that we direct our activities into a certain channel, and thus determine which of the potential expressions of our individuality become manifest. Usually we know nothing of the ultimate orientation or of the outlet toward which we travel, and the stream sweeps us to a formula of life from which there is no returning. Every decision is like a murder, and our march forward is over the stillborn bodies of all our possible selves that will never be.

Biologically, man is still the great amateur of the animal kingdom; he is unique in his lack of anatomical and physiological specialization.