In short, absolute, so-called mathematical, factors never find a firm basis in military calculations. From the very start, there is an interplay of possibilities, probabilities, good luck and bad, that weaves its way throughout the length and breadth of the tapestry. In the whole range of human activities, war most closely resembles a game of cards.
Carl von ClausewitzThe difficulty of accurate recognition constitutes one of the most serious sources of friction in war, by making things appear entirely different from what one had expected.
Carl von ClausewitzKind-hearted people might of course think there was some ingenious way to disarm or defeat an enemy without too much bloodshed, and might imagine this is the true goal of the art of war. Pleasant as it sounds; it is a fallacy that must be exposed: War is such a dangerous business that the mistakes which come from kindness are the very worst.
Carl von Clausewitz