You wish to know if leadership can infallibly determine the success of
the war; look at the most extreme case, the most opposed situations, in
which leadership alone will infallibly triumph. The enemy's army is
forced to pass through a deep mountain gorge; your general knows it: he
makes a forced march, he takes possession of the heights, he holds the
enemy shut in a pass; they must either die or surrender. In this extreme
case, luck cannot have any part in the victory. It is therefore
demonstrated that skill can determine the success of a campaign; from
that alone is it proved that war is an art.

Now imagine an advantageous but less decisive position; success is not
so certain, but it is always very probable. You arrive thus, step by
step, to a perfect equality between the two armies. What will decide
then? luck, that is to say an unforeseen event, a general officer killed
when he is on his way to execute an important order, a corps which is
shaken by a false rumour, a panic and a thousand other cases which
cannot be remedied by prudence; but it still remains certain that there
is an art, a generalship.

As much must be said of medicine, of this art of operating on the head
and the hand, to restore life to a man who is about to lose it.

The first man who at the right moment bled and purged a sufferer from an
apoplectic fit; the first man who thought of plunging a knife into the
bladder in order to extract a stone, and of closing the wound again; the
first man who knew how to stop gangrene in a part of the body, were
without a doubt almost divine persons, and did not resemble Molière's
doctors.