For we both alike know that into the discussion of human affairs the question of justice enters only where the pressure of necessity is equal, and that the powerful exact what they can, and the weak grant what they must.
ThucydidesIn practice we always base our preparations against an enemy on the assumption that his plans are good; indeed, it is right to rest our hopes not on a belief in his blunders, but on the soundness of our provisions. Nor ought we to believe that there is much difference between man and man, but to think that the superiority lies with him who is reared in the severest school.
ThucydidesFor if many ill-conceived plans have succeeded through the still greater lack of judgment of an opponent, many more, apparently well laid, have on the contrary ended in disgrace. The confidence with which we form our schemes is never completely justified in their execution; speculation is carried on in safety, but, when it comes to action, fear causes failure.
Thucydides