But it may equally be that he has tried the first plan (and this is what I call human greatness) merely as a feint to pin down the enemy, so as to surprise him later at a point where he has not been expecting an attack. Thus at Ulm, Mack, who expected the enemy to advance from the west, was surrounded from the north where he thought he was perfectly safe. My example is not a very good one, as a matter of fact. And Ulm is a better type of enveloping battle, which the future will see reproduced, because it is not only a classic example from which generals will seek inspiration, but a form that is to some extent necessary (one of several necessities, which leaves room for choice, for variety) like a type of crystallisation. But it doesn’t much matter, really, because these conditions are after all artificial. To go back to our philosophy book; it is like the rules of logic or scientific laws, reality does conform to it more or less, but bear in mind that the great mathematician Poincaré is by no means certain that mathematics are strictly accurate. As to the rules themselves, which I mentioned to you, they are of secondary importance really, and besides they are altered from time to time. We cavalrymen, for instance, have to go by the