The course of human history is determined, not by what happens in the skies, but what takes place in our hearts.

Civilization never stands still; if in one country it is falling back, in another it is changing, evolving, becoming more complicated, bringing fresh experience to body and mind, breeding new desires, and exploiting Nature's cupboard for their satisfaction.

The German Fuhrer, as I have consistently maintained, is an evolutionist; he has consistently sought to make the practices of Germany conform to the theory of evolution.

Tribal life comes automatically to an end when a primitive people begins to live in a town or a city, for sooner or later a tribal organization is found to be incompatible with life in a city.

My personal conviction is that science is concerned wholly with truth, not with ethics.

Human nature, as manifested in tribalism and nationalism, provides the momentum of the machinery of human evolution.

The discovery of agriculture was the first big step toward a civilized life.