Understanding 'On War'
Understanding 'On War'


by Bill Bentley for Canadian Military Journal (CMJ)

Does Clausewitz's 'On War' have much to say about the nature of 21st century warfare? Bill Bentley thinks so. What we may think are cutting-edge concepts (hybrid warfare, etc.) merely echo one of the Prussian general's central insights -- wars are indeed complex, non-linear things

War amongst the people, hybrid war, unrestricted warfare, counter-insurgency (COIN), stabilization operations, culture wars, new wars versus old wars, terror wars, these are examples of the conceptualization of war and conflict that have emerged in the wake of the end of the Cold War. Currently overshadowed by the contemporary security environment, there remains the historically most prevalent form of conflict; that of high intensity state-on-state war. The work of one man first published 181 years ago can be very helpful in understanding both the nature and character of all these types war and conflict in the 21st Century, regardless of how they are described and explained, however imperfectly, in today's relevant literature, military colleges, and other policy making fora. In this regard, a clear understanding of the relationship between the thought of Carl von Clausewitz and German Romanticism greatly enhances our understanding of how this Prussian military thinker constructed his unique theory of war, and what he meant by it.

As to his actual influence extending throughout the 20th Century and into the 21st Century, there are numerous testimonials to the impact and value of General Carl von Clausewitz's life-long attempt to develop a theory of war and conflict that aimed, not at prescription, but at a deep understanding of the phenomenon itself. Four will suffice here to make the point. T.E. Lawrence (of Arabia) was a great admirer of On War, finding it logical and fascinating. He considered Clausewitz the intellectual master of all writers on the subject of war.[1] More recently, H. T. Hayden, editor of Warfighting: Maneuvre Warfare in the US Marine Corps, stipulates that Clausewitz's On War is the definitive treatment of the nature and theory of war.[2] According to W. B. Gallie, a British philosopher and Second World War infantry major, the years 1818-1832 saw the writing and eventual publication of the first, and to date, the only book (On War) of outstanding intellectual eminence on the subject of war.[3] Finally, one of the leading strategic theorists still writing today has concluded that " … for as long as humankind engages in warfare, Clausewitz must rule.[4]


The subject of these accolades, Carl von Clausewitz, was born in Burg, Prussia, in 1780, and joined the Prussian army at the age of twelve. From 1792 until 1815, he fought against the French revolutionary and Napoleonic forces at the battles of Valmy, Jena, Borodino, Leipzig, and Waterloo. In 1818, he was appointed Director of the Prussian War Academy in Berlin, and for the next 12 years, devoted himself to writing about war, and especially, to the construction of his theory of war expounded in his masterpiece, On War. He joined his life-long friend and mentor, General von Gneiseneau, on campaign in Poland in 1830, where he died of cholera in 1831. The unfinished manuscript of On War was published by his wife, Marie, in 1832.

On War was translated into French in 1849 and English for the first time in 1874. It has subsequently been translated into several languages, including Russian, Japanese and Chinese. Notwithstanding its growing availability, the book was little read for 40 years after it first appeared in 1832. Rather, theorists and practitioners, such as Willison in Prussia, Camon in France, Henderson in England, and Halleck and Mahan in the United States, were more influenced by the work of Clausewitz's contemporary, Antoine Jomini, especially his Art of War. Jomini's theory drew heavily from empiricism and positivism, and sought straightforward rules and even laws of war and strategy, which Jomini believed could be applied regardless of historical or geo-political context. As will be explained herein, Clausewitz strenuously objected to this approach. Clausewitz, however, rather suddenly received widespread belated recognition after the wars of German unification against Denmark, Austria, and especially France in 1870-1871, and to a significant degree, his influence then eclipsed that of Jomini. This interest was sparked by virtue of the fact that the military architect of these startling successes, General Helmut von Moltke, frequently cited von Clausewitz's On War as one of the major intellectual and theoretical influences that shaped his strategic thinking and the associated campaigns.

Nonetheless, On War remained notoriously difficult to interpret and to fully understand. It was often misquoted and frequently referred to without having been read carefully, if at all. Except for a few dedicated, serious scholars of On War, this remains largely the case today.

A large part of the difficulty in this regard has been the failure to place Clausewitz's thought firmly in the relevant intellectual context. It is necessary to read On War, as John Lynn has recently argued, not as a work that expresses eternal truth about war, but within the intellectual context that generated it. It is a Romantic work, and like the broader intellectual and cultural movement of Romanticism, it cannot be understood apart from the intellectual paradigm that it challenged -- the dry rationalism of the Enlightenment.[5] There is no doubt that the Enlightenment was itself a very complex movement that should not be reduced to a few platitudes. Taken as a whole, the Enlightenment (circa 1687-1789) sought to establish the intellectual foundation for a political system without divine sanction, a religion without mystery, a morality without dogma. Such was the edifice the Enlightenment thinkers believed man now had to erect.

Science would have to become something more than an intellectual pastime; it would have to develop into a power capable of harnessing the forces of nature to the service of mankind. Science was the key to happiness. With respect to the material world, once it was in his power, man could order it for his own benefits and for the happiness of future generations. Such are the "notes" by which the 18th century is readily identifiable.[6] But for the Romantics, from Coleridge, Chateaubriand, Herder, and Heine, through Schelling and Hegel, a vision of the Enlightenment emerged that was as cold, timeless, monotonous, and as calculating as the bourgeois who had supposedly embraced it.[7] In their view, the Enlightenment enshrined mechanism as the model to explain all phenomena of matter, life and mind. Teleological causes, such as Thomism backed by the Catholic church, had been inverted in Bacon's terms as "barren virgins." "Any work they supposedly accomplished could be turned over to efficient mechanical causes."[8]

Romanticists, scientists, philosophers, historians, as well as artists, were reacting against what they considered the desiccated rationalism that prevailed during the Enlightenment period in Europe. Romanticism as an intellectual movement, therefore, can be understood as an overwhelming international tendency which swept across Europe and Russia at the end of the 18th Century and beginning of the 19th Century in reaction to earlier neo-classicism, mechanism, and rationalism embodied in Enlightenment thought. More than simply a return to nature, the realm of imagination or feeling, it was a synthesizing nature that transformed the entire character of thought, sensibility, and art. Romantic scientists and philosophers, especially those in Germany such as Georg Hegel, Wolfgang Goethe, Friedrich and Auguste Schlegal, and the renowned historian Leopold von Ranke, were determined to look at nature and society holistically, to see 'wholes' and relationships, rather than discrete events and phenomena. In other words, they rejected the analytical, reductionist, and linear approach to breaking things apart to study them that was so characteristic of the methodology embedded in Enlightenment philosophy.

One of the leading intellectual historians of the 20th Century, Isaiah Berlin, characterized the Romantic movement as follows:

The importance of Romanticism is that it is the largest recent movement to transform the lives and thought of the Western world. It seems to me to be the biggest single shift in the consciousness of the West that has occurred, and all of the shifts which have occurred in the course of the 19th and 20th centuries appear to me in comparison less important and at any rate deeply influenced by it.[9]

Since Clausewitz was born in 1780 and died in 1831, his life spanned almost exactly the very height of the Romantic Movement, especially in Germany where it was openly philosophical and all-embracing. Clausewitz was certainly not a professional philosopher, but he was, nonetheless, a man of a particularly philosophical bent of mind. He read voraciously and broadly, far beyond the field of military history. He was also scientifically literate, reading mathematical treatises and attending lectures just as science was turning to the serious study of biology and advances in the theories of statistics and probabilities. His major work, On War, still sought to provide a reasoned understanding of war, just as were the efforts of many of his contemporary theorists in France and England, as well as Germany. However, he insisted upon recognizing the inherent limits of analytical reason when grappling with such a dynamic and complex phenomenon as war in the same way that thermodynamicists came to trade the mechanistic claims of complete predictability for a more stochastic understanding of the natural world.[10] In fact, Clausewitz was strongly influenced by the most prominent Romantic scientists and philosophers in Germany at the time; men such as Fichte, Schelling, Goethe, and Hegel.

After the battle of Jena in October 1806, Clausewitz was interned in France, where he met and became close friends with Auguste Schlegal, one of the 'leading lights' of European Romanticism. Then, during the hiatus between Clausewitz's return to Berlin in 1808 and his entry into Russian service in 1812, he partook of the rich intellectual life of that city. Through her contacts, Clausewitz's wife Marie seems to have introduced her husband to Achim von Arnim, an important Romantic folklorist, dramatist, and poet, and Wilhelm Humboldt, a philosopher and educational reformer. These two urged Clausewitz to join the Christian-German Symposium, a group that met for discussions every two weeks. A list of its active participants reads like a 'Who's Who' of leading Berlin Romantics, including Fichte, Schliermacher, von Kleist, Muller, Brentano, and Auguste Schlegal's brother, Frederick. Later, when Clausewitz returned to Berlin in 1818 to head the War Academy, he met still other philosophers and cultural figures, and he became close friends with Georg Hegel. Von Arnim also came back into Clausewitz's life, along with his wife Bertina, a considerable Romantic author and editor in her own right.[11]

The influence that the Romantics had upon Clausewitz can be found throughout On War, but four major examples will serve to illustrate the point in this short article. First, an account of the implications of Romanticism's adherence to Idealist philosophy, as opposed to the Materialism underlying much 18th Century philosophy, and underpinning Rationalism and Empiricism. Second, the role of the political in the social life of humankind. Third, the role of history in shaping Romantic thought. And fourth, the dialectical reasoning utilized in most Romantic argumentation.

In Romantic Idealism, a Particular is first in order of existence, since to know that a thing exists, we must know something about particular or determinate things. This is because, if it exists, a Universal exists only in Particulars. A Universal, however, is first in order of explanation, because to know what a thing is, we must be able to specify some of its properties, some features that it shares in common with other things.[12] Hegel, for example, thought that Universals do not exist in the temporal world as such, but only "en re"(manifested) in particular things. He thinks that Universals only exist in things, even though their meaning is not reducible only to them.[13] Similarly, Goethe argued in the field botany that the outward forms may change in countless ways, yet the idea of a formative principle remains the same. Goethe called this formative principle the Urpflange. The archetypical plant is no specific plant anywhere in nature, nor is it to be understood temporally.[14]

For Hegel, the ultimate Universal is Absolute Spirit, consisting of the trinity of religion, art, and philosophy. These are spheres that transcend the Particular, but find their highest realization temporally in the modern state.[15] Clausewitz postulates a remarkably similar construct when it comes to war, and one that mirrors the state in terms of the people, the army, and the government. The Universal of war is described as follows:

War is more than a true chameleon that slightly adapts its characteristics to the given case. As a total phenomenon its dominant tendencies always makes war a paradoxical trinity -- composed of primordial violence, hatred and enmity, which are to regarded as a blind natural force; of the play of chance and probability within which the creative spirit is free to roam; and of the element of subordination as an instrument of policy which makes it subject to reason alone.

According to Clausewitz:

The first of these aspects mainly concerns the people, the second the commander and the army, and the third the government. The passions that are kindled in war must already be inherent in the people, the scope which the play of courage and talent will enjoy in the realm of probability and chance depends on the particular character of the commander and the army; but the political aims are the business of government alone.


These three tendencies are like three different codes of law deep rooted in their subject yet variable in their relationship to one another. A theory that ignores any one of them or seeks to fix an arbitrary relationship between them would conflict with reality to such an extent that for this reason alone it would be totally useless. Our task, therefore, is to develop a theory that maintains a balance between these three tendencies like an object suspended between three magnets. [16]

Thus, Clausewitz has established the Universal concept of war, which is eternal. Throughout history, this Universal has manifested itself in innumerable Particular wars. Hence, the nature of war does not change, but the specific character of any given Particular war will vary enormously. That is, while the outward shape and material dimensions of war may shift continuously, the essence of war remains unchanged.

Clausewitz then turns to consider real world war, and concludes that there are two kinds of war:

War can be of two kinds, in the sense that either the objective is to overthrow the enemy -- to render him politically helpless or militarily impotent thus forcing him to sign whatever peace we please; or merely to occupy some of his frontier districts so that we can annex them or use them for bargaining at the peace negotiations.[17]

Therefore, Absolute War, as it appears in On War, is an ideal, an abstraction that in turn governs reality, as do all Ideas in Idealism.

Turning to the question of policy, politics, and reason, most of the theorists and practitioners of war in the 18th Century readily acknowledged that there had to be a political objective to justify war. Here, they were reflecting a relationship identified at least as far back as Aristotle, when he wrote that " … the only merit of war is to yield a political result."[18] These theorists, however, then took considerable pains to separate politics and policy from military strategy and the conduct of war once hostilities commenced. This, Clausewitz flatly rejected. Again, the connection with Romantic thought and philosophy is clear. The Romantics were, indeed, some of the first thinkers in the modern era to reaffirm the importance of the political, to make politics again "the first science" as Aristotle once made it. In the spirit of Aristotle, Frederick Schlegal would write, "political judgement is the highest of all viewpoints."[19]

This belief leads Clausewitz to perhaps his most famous and certainly most quoted thought:

War is simply a continuation of political intercourse with the addition of other means. We deliberately use the phrase "with the addition of other means" because we also want to make it clear that war in itself does not suspend political intercourse or change it into something entirely different. In essence that intercourse continues irrespective of the means it employs. The main lines along which military events progress and to which they are restricted are political lines that continue throughout the war into the subsequent peace.[20]

According to Clausewitz, warfare has its own grammar, but not its own logic -- the latter is provided by policy. Clausewitz goes even farther to stress his point, obviously addressing those military officers who might think they can avoid political influence once war has been embarked upon.

Policy, of course, will not extend its influence to operational details. Political considerations do not determine the posting of guards or the employment of patrols. But they are the more influential in the planning of the war, of the campaign and often even the battle.[21]

In other words, there is no such thing as "a politics free zone" in war. This is a reality that modern military strategists/generals/admirals should always factor into their thinking.

The way in which Clausewitz understood history and applied it in his theory of war was also profoundly influenced by the Romantic philosophy of history. During the Enlightenment, the utility of history was viewed in two related ways. One, history was used to show how everything from antiquity onwards had slowly moved in a progressive manner to achieve the state of near perfection achieved in 18th Century Europe. Thus, each preceding era could be seen as following often imperfect steps to a teleological end-state which was the Enlightenment. Two, history could be used to discover regularities and historical laws, [22] which could then be applied and then faithfully followed.

The Romantics disputed this view of history, and their rejection of it had a profound influence upon the philosophy and practice of the discipline of history, an impact felt up to the present. That is, that although the Romantic Age did not invent history, as some scholars of Romanticism sometimes seem to suggest, it did invent Historicism. [23] Historicism is a philosophy of history that postulates that everything in the social and political domains has a history. All laws, institutions, beliefs, and practices are subject to change, and each is the result of a specific historical development. Hence, no thing in the social and political world is eternal. In this case, we should examine all human beliefs, practices, and institutions within their historical context, showing how they arose of necessity from their specific economic, social, legal, cultural, and geographic conditions. Hence, Leopold von Ranke's celebrated dictum that every age enjoys a direct relationship with God. [24] Closely associated with this position, historians of this school of history view society as an organism, an indivisible whole, whose politics, religion, morality, and legal system are inextricably intertwined.

In reference to this latter point, Clausewitz advises that in war, more than elsewhere, the part and the whole must always be thought of together. As he states: "In war, as in life generally, all parts of a whole are interconnected and thus the effects produced however small, their cause must influence all subsequent military operations and modify their outcome to some degree, however small".[25] Remarkably, here, Clausewitz has anticipated one of the significant findings of modern complexity theory -- that is, the principle of non-proportionality.

Finally, in accordance with the philosophy of Historicism, and closely following von Ranke, Clausewitz concludes:

We wanted to show how every age had its own kind of war, its own limiting conditions. Each period, therefore, would have held to its own theory of war, even if the urge had always and universally existed to work things out on scientific principles. It follows that the events of every age must be judged in the light of its own peculiarities.[26]

Here, of course, Clausewitz was not talking about the Universal concept of war, but rather of the Particular wars as they occurred throughout history.

With regard to the dialectical mode of thinking employed by Clausewitz throughout On War, we must understand that the whole drive of the Romantic orientation was to hold opposites in tension, not to submerge them into an imagined unity. It was to experience the conflicts, the contradictions of experience, not to 'think them away.' It was toward reality, not towards a metaphysical escape from reality. [27] Clausewitz expressed his own interpretation of this orientation this way:

Where two ideas form a true logical antithesis each complimentary to the other, then fundamentally each is implied in the other. If the limitations of our mind do not allow us to comprehend both simultaneously and discover by antithesis the whole of one in the whole of the other, each will, nevertheless, shed enough light on the other to clarify many of its details.[28]

We have already seen that, from the outset, Clausewitz claimed there were two kinds of Particular war, and he extracted many conclusions from a dialectical analysis of this state of affairs. Logically derived from this duality, Clausewitz discerned that there were, therefore, two kinds of strategy -- the strategy of annihilation, and the bi-polar strategy.

In the strategy of annihilation everything results from necessary causes and one action rapidly affects another; there is, if we may use the phrase, no intervening neutral void. Since the whole series of engagements is strictly speaking linked together, since in every victory there is a culminating point beyond which lies the realm of losses and defeats, in view of all these intrinsic characteristics of war we say there is only one result that counts: final victory. Until then nothing is decided, nothing won and nothing lost. In this form of strategy we must always keep in mind that it is the end that crowns the work. Within this concept strategy is indivisible and its component parts (the individual victories) are of value only in their relation to the whole.

Contrasting with this extreme view is another view no less extreme, which holds that strategy consists of separate successes each unrelated to the next, as a match consisting of several games. The earlier games have no effect on the later. All that counts is the total score and each separate result makes its contribution toward the total.[29]

This paradigm of military strategy has important implications in the modern era. The 20th Century saw two global wars prosecuted through a strategy of annihilation, and such a strategy conceivably could be employed again in the future. However, for all of the early part of the 21st Century, the appropriate strategy has been a bi-polar strategy, carefully balancing the need to go to the battle pole with a variety of actions on the non-battle pole -- economic, diplomatic, information, and so on.

Having dealt with the concept of strategy, Clausewitz then examines the relationship between a related duopoly; that between strategy and tactics. "According to our classification tactics teaches the use of armed forces in the engagement, strategy the use of engagements for the object of the war."[30] During this examination, Clausewitz concludes that engagements mean fighting. The object of fighting is the destruction or defeat of the enemy. The enemy in the individual engagement is simply the opposing fighting force. By contrast, in strategy, there is no such thing as victory. Part of strategic success lies in timely preparations for a tactical victory; the greater the strategic success, the greater the likelihood of a victorious engagement. The rest of strategic success lies in exploitation of a victory won. Thus, the original means of strategy is victory -- that is, tactical success; its ends in the final analysis are those objects which will lead directly to peace.[31]

The strategic theorist Colin Gray captures the essence of Clausewitz's conception of strategy for the modern era:

Strategy is virtual behaviour, it has no material existence. Strategy is an abstraction, though it is vastly more difficult to illustrate visually than are other abstractions like love or fear. Because strategy is uniquely difficult among the sub-systems of war and conflict few indeed are the people who can shine in the role. Their number can be increased through education, though not by training and not at all reliably by the experience of command and planning at the operational and tactical levels of warfare.[32]

Metaphorically, strategy is the mental, intellectual bridge between politics and the grammar of war -- operational art and tactics.

The next significant duality or logical antithesis is that between the attack and the defence. Clausewitz argues here that the defence is the stronger form of war with a negative aim; whereas, the attack is the weaker form of war with a positive aim. "If the defence is the stronger form of war yet has a negative object, it follows that it should be used only as long as weakness compels, and to be abandoned as soon as we are strong enough to pursue a positive act."[33] He then derives one of his most important concepts from this dialectic -- that of the culminating point.

If the superior strength of the attack -- which diminishes day by day -- leads to peace, the object will have been attained. There are strategic attacks that have led directly to peace, but these are in the minority. Most of them lead up to the point where the remaining strength is just enough to maintain a defence and wait for peace. Beyond that point the scale turns and the reaction follows with a force that is usually much stronger than that of the original attack. This is what we mean by the culminating point of the attack.[34]

The concept of the culminating point remains a critical consideration in all campaign planning at the operational level in the modern era.

The last dialectical relationship that will be dealt with in this article is that between the moral (or psychological) and the physical. As usual, Clausewitz contends that other theorists and practitioners, although aware of the element of moral(e) in war, sought to submerge this issue in their search for more scientific rules, adherence to which would reduce the potential negative impact of the psychological factor. Clausewitz would have none of that!

The effects of physical and moral factors form an organic whole which, unlike a metal alloy, are inseparable by chemical processes. One might say the physical seems little more than the wooden hilt, while the moral factors are the precious weapon, the finely honed blade.[35]

Here, Clausewitz's metaphor exquisitely captures the more prosaic axiom -- the moral is to the physical as three is to one.

Explicitly relating this relationship to his dialectical mode of thinking, Clausewitz adds:

They (other theorists) aim at fixed values, but in war everything is uncertain and calculations have to be made with variable quantities. Other theorists direct the inquiry exclusively towards physical quantities whereas all military activity is intertwined with psychological forces and effects. Other theorists consider only unilateral action whereas war consists of continuous interaction of opposites. [36]

As the conflicts of the 21st Century have amply demonstrated, Clausewitz's view of moral/psychological factors must now include what we understand as the cultural dimension of war and conflict.

The Romantic influence found throughout On War certainly extends beyond the four examples provided in this short article. On War is suffused with the understanding that every war is an inherently complex, non-linear phenomenon. In a profoundly unconfused way, Clausewitz understood that seeking exact, analytical solutions does not fit the reality of the problems posed by war and conflict. This is a quintessential Romantic position with regard to society as a whole. The theme of war as an organic, not mechanical, activity is also a central Romantic idea. Finally, the widespread use of metaphors, a very characteristic tendency in Romantic writing, helps place Clausewitz firmly in the Romantic circle.

Concluding Remarks

Carl von Clausewitz clearly has exerted an inordinate influence upon political and military thought throughout the world. In the case of the former domain, Lenin, Mao Tse-Tung, Gorbachev, and Kissinger were keen students of Clausewitz. In the latter case, to that list must be added von Moltke, Alexander Svechin, J.F.C. Fuller, Eisenhower, and Colin Powell. For many more less well known practitioners, theorists, and scholars, their thought and theoretical viewpoint were significantly shaped by exposure to On War. Very few of these individuals were thoroughly grounded in the subject of European Romanticism. Obviously then, much can be derived from Clausewitz without this background. On the other hand, a deeper understanding of why he framed his thought, precisely what he meant, and, therefore, a more philosophical appreciation of the great master's work, is only fully achieved by placing him firmly in the proper intellectual context.

A valuable by-product of this intellectual effort is to make oneself more aware that all theory and the practice it generates, is related in often ill-understood ways to the underlying intellectual, cultural, spirit of the age. Thus, the question can and should be asked: What is helping to shape military theory today? What has been the impact of the theory of relativity, quantum mechanics, complexity theory, information technology theory, advances in cognitive sciences, or the near-eclipse of Positivism in main stream social sciences, and the ascendency of interpretive sociology and Constructivism on prevailing and evolving military theory, in what has been called the post-modern era? For example, the more extreme versions of the recent Revolution in Military Affairs (RMA) could not survive the Heisenberg Uncertainty Principle and the implications of complexity theory. Similarly, the concept of Effects-Based Operations (EBO) has fallen prey to the concept of "war amongst the people," a concept derived from changes in the social sciences. The marriage of intellectual history to the study of military theory is an underestimated relationship, and much profit can be gained by working to make this relationship a much stronger partnership.








Article: Originally published in Vol. 13 No. 4 of the Canadian Military Journal

"Understanding 'On War' "




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