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

“History is an excellent teacher with few pupils.”

“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.”

“Civilizations are the generations of the racial soul. As family-rearing, and then writing, bound the generations together, handing down the lore of the dying to the young, so print and commerce and a thousand ways of communication may bind the civilizations together, and preserve for future cultures all that is of value for them in our own. Let us, before we die, gather up our heritage, and offer it to our children.”

“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.”

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