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.

Hatred of humanity and love of animals make a very bad combination.

All the advantages that man has gained from his ever-deepening understanding of the natural world that surrounds him, his technological, chemical and medical progress, all of which should seem to alleviate human suffering... tends instead to favor humanity's destruction.

The human mind, in taking us down the path of technocracy, has become the adversary of life itself and collaterally the adversary of the human soul.

We had better dispense with the personification of evil, because it leads, all too easily, to the most dangerous kind of war: religious war.

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

It is a good morning exercise for a research scientist to discard a pet hypothesis every day before breakfast. It keeps him young.