“We must operate with partial knowledge, and be provisionally content with probabilities.”

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

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

“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.”

“If you have character, endeavor, personality, courage and the capacity for concentrated labor, you will do what is your destiny – and, perhaps, even do it well.”

“History is an excellent teacher with few pupils.”

“A book is like a quarrel. One word leads to another, and may erupt in blood or print, irrevocably.”