Activity in War is movement in a resistant medium. Just as a man immersed in water is unable to perform with ease and regularity the most natural and simplest movement, that of walking, so in War, with ordinary powers, one cannot keep even the line of mediocrity. This is the reason that the correct theorist is like a swimming master, who teaches on dry land movements which are required in the water, which must appear grotesque and ludicrous to those who forget about the water. This is also why theorists, who have never plunged in themselves, or who cannot deduce any generalities from their experience, are unpractical and even absurd, because they only teach what every one knows—how to walk.
Further, every War is rich in particular facts, while at the same time each is an unexplored sea, full of rocks which the General may have a suspicion of, but which he has never seen with his eye, and round which, moreover, he must steer in the night. If a contrary wind also springs up, that is, if any great accidental event declares itself adverse to him, then the most consummate skill, presence of mind, and energy are required, whilst to those who only look on from a distance all seems to proceed with the utmost ease. The knowledge of this friction is a chief part of that so often talked of, experience in War, which is required in a good General. Certainly he is not the best General in whose mind it assumes the greatest dimensions, who is the most over-awed by it (this includes that class of over-anxious Generals, of whom there are so many amongst the experienced); but a General must be aware of it that he may overcome it, where that is possible, and that he may not expect a degree of precision in results which is impossible on account of this very friction. Besides, it can never be learnt theoretically; and if it could, there would still be wanting that experience of judgment which is called tact, and which is always more necessary in a field full of innumerable small and diversified objects than in great and decisive cases, when one’s own judgment may be aided by consultation with others. Just as the man of the world, through tact of judgment which has become habit, speaks,