On War (Clausewitz, Howard, Paret, 1832, 1976, 1989)

p.94 We can see that in war many roads lead to success, and that they do not all involve the opponent's outright defeat. They range from the destruction of the enemy's forces, the conquest of his territory, to a temporary occupation or invasion, to projects with an immediate political purpose, and finally to passively awaiting the enemy's attacks. Any one of these may be used to overcome the enemy's will: the choice depends on the circumstances.

p.96 there are many reasons why the purpose of an engagement may not be the destruction of the enemy's forces, the forces immediately confronting us. Destruction may be merely a means to some other end. In such a case, total destruction has ceased to be the point... When one force is a great deal stronger than the other, an estimate may be enough. There will be no fighting: the weaker side will yield at once.

The fact that engagements do not always aim at the destruction of the opposing forces, that their objectives can often be attained without any fighting at all but merely by an evaluation of the situation, explains why entire campaigns can be conducted with great energy even though actual fighting plays an unimportant part in them.

p.97 Combat is the only effective force in war; its aim is to destroy the enemy's forces as a means to a further end. That holds good even if no actual fighting occurs, because the outcome rests on the assumption that if it came to fighting, the enemy would be destroyed. It follows that the destruction of the enemy's force underlies all military actions; all plans are ultimately based on it, resting on it like an arch on its abutment. Consequently, all action is undertaken in the belief that if the ultimate test of arms should actually occur, the outcome would be favorable. The decision by arms is for all major and minor operations in war what cash payment is in commerce. Regardless how complex the relationship between the two parties, regardless how rarely settlements actually occur, they can never be entirely absent... But of course, we can only say destruction of the enemy is more effective if we can assume that all other conditions are equal.

p.112 Circumstances vary so enormously in war, and are so indefinable, that a vast array of factors has to be appreciated - mostly in the light of probabilities alone. The man responsible for evaluating the whole must bring to his task the quality of intuition that perceives the truth at every point. Otherwise a chaos of opinions and considerations would arise, and fatally entangle judgment... Truth in itself is rarely sufficient to make men act. Hence the step is always long from cognition to volition, from knowledge to ability. The most powerful springs of action in men lie in his emotions.

p.147 Continual change and the need to respond to it compels the commander to carry the whole intellectual apparatus of his knowledge within him. He must always be ready to bring forth the appropriate decision. By total assimilation with his mind and life, the commander's knowledge must be transformed into a genuine capability.

p.149-150 In war, the will is directed at an animate object that reacts... Part of the object of this book is to examine whether a conflict of living forces as it develops and is resolved in war remains subject to general laws, and whether these can provide a useful guide to action.

p.153 Routines... represent a general way of executing tasks as they arise based, as we have said, on average probability. They represent the dominance of principles and rules, carried through to actual application. As such they may well have a place in the theory of the conduct of war... they are the best of the general forms, short cuts, and options that may be substituted for individual decisions.

p.153 Even if we did know all the circumstances, their implications and complexities would not permit us to take the necessary steps to deal with them. Therefore our measures must always be determined by a limited number of possibilities.

p.180-181 the deployment of forces at a certain point merely makes an engagement possible; it does not necessarily take place. Should one treat this possibility as a reality, as an actual occurrence? Certainly. It becomes real because of its consequences, and consequences of some kind will always follow.

p.181 In both cases [previously discussed] results have been produced by the mere possibility of an engagement; the possibility has acquired reality... the destruction of the enemy's forces and the overthrow of the enemy's power can be accomplished only as the result of an engagement, no matter whether it really took place or was merely offered but not accepted.

p.181 The possession of provinces, cities, fortresses... etc., may be the immediate object of an engagement, but can never be the final one. Such acquisitions should always be regarded merely as means of gaining greater superiority, so that in the end we are able to offer an engagement to the enemy when he is in no position to accept it. These actions should be considered as intermediate links, as steps leading to the operative principle, never as the operative principle itself.

p.182 We are constantly brought back to the question: what, at any given stage of the war or campaign, will be the likely outcome of all the major and minor engagements that the two sides can offer one another? In the planning of a campaign or war, this alone will decide the measures that have to be taken from the outset.

p.182 If we do not learn to regard war, and the separate campaigns of which it is composed, as a chain of linked engagements each leading to the next, but instead succumb to the idea that the capture of certain geographical points or the seizure of undefended provinces are of value in themselves, we are liable to regard them as windfall profits. In doing so, and in ignoring the fact that they are links in a continuous chain of events, we also ignore the possibility that their possession may later lead to definite disadvantages. This mistake is illustrated again and again in military history... By looking on each engagement as part of a series, at least insofar as events are predictable, the commander is always on the high road to his goal.

p.183 The strategic elements that affect the use of engagements may be classified into various types... It would however be disastrous to try to develop our understanding of strategy by analyzing these factors in isolation, since they are usually interconnected in each military action in manifold and intricate ways... For our part, we shall continue to examine the picture as a whole

A reserve has two distinct purposes. One is to prolong and renew the action, the second, to counter unforeseen threats... But the need to hold a force in readiness for emergencies may also arise in strategy. Hence there can be such a thing as a strategic reserve, but only when emergencies are conceivable... It is thus an essential condition of strategic leadership that forces should be held in reserve according to the degree of strategic uncertainty... We have called it an absurdity to maintain a strategic reserve that is not meant to contribute to the overall decision.

p.348 Geography and ground can affect military operations in three ways: as an obstacle to the approach, as an impediment to visibility, and as a cover from fire... this threefold effect of terrain tends to make military activity more varied, complex and skillful, because it introduces three additional elements into the combination... This influence is thus always active; its degree varies according to the nature of the country.

p.360 Only three things seem to us to produce decisive advantages: surprise, the benefit of terrain, and concentric attack... Concentric attack comprises all tactical envelopment, great or small; its effectiveness is produced partly by the double effectiveness of cross fire, and partly by the fear of being cut off.

p.580-581 It follows that war is dependent on the interplay of possibilities and probabilities... conditions in which strictly logical reasoning often plays no part at all and is always apt to be a most unsuitable and awkward intellectual tool.