The present theory will therefore treat the combat as the real contest, marches, camps, and cantonments as circumstances which are more or less identical with it. The subsistence of the troops will only come into consideration like other given instances in respect of its results, not as an activity belonging to the combat.

The art of war thus viewed in its limited sense divides itself again into tactics and strategy. The former occupies itself with the form of the separate combat, the latter with its use. Both connect themselves with the circumstances of marches, camps, cantonments only through the combat, and these circumstances are tactical or strategic according as they relate to the form or to the signification of the battle.

No doubt there will be many readers who will consider superfluous this careful separation of two things lying so close together as tactics and strategy, because it has no direct effect on the conduct itself of war. We admit, certainly, that it would be pedantry to look for direct effects on the field of battle from a theoretical distinction.

But the first business of every theory is to clear up conceptions and ideas which have been jumbled together, and, we may say, entangled and confused; and only when a right understanding is established, as to names and conceptions, can we hope to progress with clearness and facility, and be certain that author and reader will always see things from the same point of view. Tactics and strategy are two activities mutually permeating each other in time and space, at the same time essentially different activities, the inner laws and mutual relations of which cannot be intelligible at all to the mind until a clear conception of the nature of each activity is established.

He to whom all this is nothing, must either repudiate all theoretical consideration, or his understanding has not as yet been pained by the confused and perplexing ideas resting on no fixed point of view, leading to no satisfactory result, sometimes dull, sometimes fantastic, sometimes floating in vague generalities, which we are often obliged to hear and read on the conduct of war, owing to the spirit of scientific investigation having hitherto been little directed to these subjects.