The first question is, How does strategy arrive at a complete list of these things?  If there is to be a philosophical inquiry leading to an absolute result, it would become entangled in all those difficulties which the logical necessity of the conduct of War and its theory exclude.  It therefore turns to experience, and directs its attention on those combinations which military history can furnish.  In this manner, no doubt, nothing more than a limited theory can be obtained, which only suits circumstances such as are presented in history.  But this incompleteness is unavoidable, because in any case theory must either have deduced from, or have compared with, history what it advances with respect to things.  Besides, this incompleteness in every case is more theoretical than real.

One great advantage of this method is that theory cannot lose itself in abstruse disquisitions, subtleties, and chimeras, but must always remain practical.

38.  How far the analysis of the means should be carried.

Another question is, How far should theory go in its analysis of the means?  Evidently only so far as the elements in a separate form present themselves for consideration in practice.  The range and effect of different weapons is very important to tactics; their construction, although these effects result from it, is a matter of indifference; for the conduct of War is not making powder and cannon out of a given quantity of charcoal, sulphur, and saltpetre, of copper and tin:  the given quantities for the conduct of War are arms in a finished state and their effects.  Strategy makes use of maps without troubling itself about triangulations; it does not inquire how the country is subdivided into departments and provinces, and how the people are educated and governed, in order to attain the best military results; but it takes things as it finds them in the community of European States, and observes where very different conditions have a notable influence on War.

39.  Great simplification of the knowledge required.

That in this manner the number of subjects for theory is much simplified, and the knowledge requisite for the conduct of War much reduced, is easy to perceive.  The very great mass of knowledge and appliances of skill which minister to the action of War in general, and which are necessary before an army fully equipped can take the field, unite in a few great results before they are able to reach, in actual War, the final goal of their activity; just as the streams of a country unite themselves in rivers before they fall into the sea.  Only those activities emptying themselves directly into the sea of War have to be studied by him who is to conduct its operations.

40.  This explains the rapid growth of great Generals, and why A general is not A man of learning.