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.
Carl von ClausewitzWhenever armed forces . . . are used, the idea of combat must be present. . . . The end for which a soldier is recruited, clothed, armed, and trained, the whole object of his sleeping, eating, drinking, and marching is simply that he should fight at the right place and the right time.
Carl von ClausewitzTo be practical, any plan must take account of the enemy's power to frustrate it.
Carl von ClausewitzWhat do we mean by the defeat of the enemy? Simply the destruction of his forces, whether by death, injury, or any other means-either completely or enough to make him stop fighting. . . . The complete or partial destruction of the enemy must be regarded as the sole object of all engagements. . . . Direct annihilation of the enemy's forces must always be the dominant consideration.
Carl von Clausewitz