Knowledge in war is very simple, being concerned with so few subjects, and only with their final results at that. But this does not make its application easy.

After we have thought out everything carefully in advance and have sought and found without prejudice the most plausible plan, we must not be ready to abandon it at the slightest provocation. should this certainty be lacking, we must tell ourselves that nothing is accomplished in warfare without daring; that the nature of war certainly does not let us see at all times where we are going; that what is probable will always be probable though at the moment it may not seem so; and finally, that we cannot be readily ruined by a single error, if we have made reasonable preparations.

Talent and genius operate outside the rules, and theory conflicts with practice.

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.

In war, while everything is simple, even the simplest thing is difficult. Difficulties accumulate and produce frictions which no one can comprehend who has not seen war.

However 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.

It is even better to act quickly and err than to hesitate until the time of action is past.