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.

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

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.

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.

Man appears to be the missing link between anthropoid apes and human beings.

The scientist knows very well that he is approaching ultimate truth only in an asymptotic curve and is barred from ever reaching it; but at the same time he is proudly aware of being indeed able to determine whether a statement is a nearer or a less near approach to the truth.

Historians will have to face the fact that natural selection determined the evolution of cultures in the same manner as it did that of species.