Therefore, to estimate the enemy situation and to calculate distances and the degree of difficulty of the terrain so as to control victory are virtues of the superior general.
So the principles of warfare are: Do not depend on the enemy not coming, but depend on our readiness against him. Do not depend on the enemy not attacking, but depend on our position that cannot be attacked.
Steam was till the other day the devil which we dreaded. Every pot made by any human potter or brazier had a hole in its cover, to let off the enemy, lest he should lift pot and roof and carry the house away.
A commander in chief ought to say to himself several times a day: If the enemy should appear on my front, on my right, on my left, what would I do? And if the question finds him uncertain, he is not well placed, he is not as he should be, and he should remedy it.
Now we will no longer concede so easily that anyone has the truth; the rigorous methods of inquiry have spread sufficient distrust and caution, so that we experience every man who represents opinions violently in word and deed as any enemy of our present culture, or at least as a backward person. And in fact, the fervor about having the truth counts very little today in relation to that other fervor, more gentle and silent, to be sure, for seeking the truth, a search that does not tire of learning afresh and testing anew.
When it comes time to protecting the homeland, the United States of America must be right 100 percent of the time. And the enemy, which desires to strike us again, only has to be right once.