Humor and knowledge are the two great hopes of our culture.

I am convinced that of all the people on the two sides of the great curtain, the space pilots are the least likely to hate each other. Like the late Erich von Holst, I believe that the tremendous and otherwise not quite explicable public interest in space flight arises from the subconscious realization that it helps to preserve peace. May it continue to do so!

In nature we find not only that which is expedient, but also everything which is not so inexpedient as to endanger the existence of the species.

We do not take humor seriously enough.

All living beings have received their weapons through the same process of evolution that moulded their impulses and inhibitions; for the structural plan of the body and the system of behaviour of a species are parts of the same whole.... Wordsworth is right: there is only one being in possession of weapons which do not grow on his body and of whose working plan, therefore, the instincts of his species know nothing and in the usage of which he has no correspondingly adequate inhibition.

Every man gets a narrower and narrower field of knowledge in which he must be an expert in order to compete with other people. The specialist knows more and more about less and less and finally knows everything about nothing.

Philosophers are people who know less and less about more and more, until they know nothing about everything. Scientists are people who know more and more about less and less, until they know everything about nothing.