The rushed existence into which industrialized, commercialized man has precipitated himself is actually a good example of an inexpedient development caused entirely by competition between members of the same species. Human beings of today are attacked by so-called manager diseases, high blood pressure, renal atrophy, gastric ulcers, and torturing neuroses: they succumb to barbarism because they have no more time for cultural interests.

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.

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

More than any other product of human scientific culture scientific knowledge is the collective property of all mankind.

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.

The neuro-physiological organization which we call instinct functions in a blindly mechanical way, particularly apparent when its function goes wrong.

I believe that present day civilized man suffers from insufficient discharge of his aggressive drive