The object of defense is preservation; and since it is easier to hold ground than to take it, defense is easier than attack. But defense has a passive purpose: preservation; and attack a positive one: conquest.... If defense is the stronger form of war, yet has a negative object, it follows that it should be used only so long as weakness compels, and be abandoned as soon as we are strong enough to pursue a positive object.

In the whole range of human activities, war most closely resembles a game of cards.

War is the realm of uncertainty; three-quarters of the factors on which action in war is based are wrapped in a fog of greater or lesser uncertainty. ... war is the realm of chance. No other human activity gives it greater scope; no other has such incessant and varied dealings with this intruder. Chance makes everything more uncertain and interferes with the whole course of events.

Our knowledge of circumstances has increased, but our uncertainty, instead of having diminished, has only increased. The reason of this is, that we do not gain all our experience at once, but by degrees; so our determinations continue to be assailed incessantly by fresh experience; and the mind, if we may use the expression, must always be under arms.

Lastly, the great uncertainty of all data in War is a peculiar difficulty, because all action must, to a certain extent, be planned in a mere twilight, which in addition not unfrequently — like the effect of a fog or moonshine — gives to things exaggerated dimensions and an unnatural appearance.

War is regarded as nothing but the continuation of state policy with other means.

With uncertainty in one scale, courage and self-confidence should be thrown into the other to correct the balance. The greater they are, the greater the margin that can be left for accidents.