The conservative who resists change is as valuable as the radical who proposes it.

The laws of biology are the fundamental lessons of history.

The influence of geographic factors diminishes as technology grows. The character and contour of a terrain may offer opportunities for agriculture, mining, or trade, but only the imagination and initiative of leaders, and the hardy industry of followers, can transform the possibilities into fact...Man, not the earth, makes civilization.

The conservative who resists change is as valuable as the radical who proposes it.

Mozart began his works in childhood and a childlike quality lurked in his compositions until it dawned on him that the Requiem he was writing for s a stranger was his own.

The present is the past rolled up for action, and the past is the present unrolled for understanding.

A great civilization is not conquered from without until it has destroyed itself from within.