cs, physics,
or engineering--at least not now. Whether it ever will be cannot be
foretold. The reason that strategy (like medicine and most other
sciences concerning human beings) is not an exact science is simply
because it involves too many unknown quantities--quantities of
which our knowledge is too vague to permit of our applying exact
methods to them, in the way in which we apply exact methods to the
comparatively well-known quantities and elements in the so-called
"exact sciences." But a science may be a science even if it is
not an exact science; we may know certain important principles
sufficiently well to use them scientifically, even if we do not
know them with sufficient exactness to permit us to use them as
confidently as we should like. We may know, for instance, that it
is folly to divide a military force in the presence of an active
enemy into such small forces, and at such distances apart, as to
let the enemy defeat each small force, one after the other, even
if we do not know exactly how far it would be safe to separate
two forces of a given size, in the presence of an enemy of a given
power. It is well to know a fact in general terms, even if we do
not know it in precise terms: it is well to know in general terms
that we must not take prussic acid, even if we do not know exactly
how much is needed to kill.

So the studies and problems instituted by Von Moltke, and copied
in all the armies and navies of the world, have brought about a
science of strategy which is real, even though not exact, and which
dwells in the mind of each trained strategist, as the high tribunal
to which all his questions are referred and by whose decisions he
is guided; just as the principles of medicine are the guide alike
of the humblest and the most illustrious practitioner, wherever
the beneficent art of medicine is practised.

It is clear that, in order to be skilful in strategy (in fact,
in any intellectual art), not only must a man have its scientific
principles firmly imprinted on his mind, but he must make its practice
so thoroughly familiar to his mental muscles that he can use strategy
as a _trained_ soldier uses his musket--automatically. Inasmuch as
any man requires years of study and practice--say, of chess--in
order to play chess well enough to compete successfully with
professional chess-players, it seems to follow that any man must
require years of study and practice of the more complicated game
of strategy,