The age in which this postulate, this universally valid element, was at its strongest was the most recent one, when war attained the absolute in violence. But it is no more likely that war will always be so monumental in character than that the ample scope it has come to enjoy will again be severely restricted. A theory, then, that dealt exclusively with absolute war would either have to ignore any case in which the nature of war had been deformed by outside influence, or else it would have to dismiss them all as misconstrued. That cannot be what theory is for. Its purpose is to demonstrate what war is in practice, not what its ideal nature ought to be. So the theorist must scrutinize all data with an inquiring, a discriminating, and a classifying eye. He must always bear in mind the wide variety of situations that can lead to war. If he does, he will draw the outline of its salient features in such a way that it can accommodate both the dictates of the age, and those of the immediate situation.
We can thus only say that the aims a belligerent adopts, and the resources he employs, must be governed by the particular characteristics of his own position; but they will also conform to the spirit of the age and to its general character. Finally, they must always be governed by the general conclusions to be drawn from the nature of war itself.
Source of English translation: Carl von Clausewitz, On War (1832), edited and translated by Michael Howard and Peter Paret. Princeton, NJ: Princeton University Press, 1976, pp. 285-91, 319-24, 372-76, 588-94.
PARET, PETER; ON WAR.
© 1976 Princeton University Press, 2004 renewed PUP Reprinted by permission of Princeton University Press.