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 ClausewitzIntelligence alone is not courage, we often see that the most intelligent people are irresolute. Since in the rush of events a man is governed by feelings rather than by thought, the intellect needs to arouse the quality of courage, which then supports and sustains it in action.
Carl von ClausewitzTwo qualities are indispensable: first, an intellect that, even in the darkest hour, retains some glimmerings of the inner light which leads to truth; and second, the courage to follow this faint light wherever it may lead.
Carl von ClausewitzHowever much pains may be taken to combine the soldier and the citizen in one and the same individual, whatever may be done to nationalize wars, never will it be possible to do away with the professionalism of the business; and if that cannot be done, then those who belong to it will always look upon themselves as a kind of guild, in the regulations, laws, and customs in which the "Spirit of War" finds its expression. It would be very wrong to look down upon this corporate spirit, or esprit de corps, which may and should exist more or less in every Army.
Carl von Clausewitz