Analyzing the Philosophical Perspectives on War

Why do nations go to war? This question has occupied philosophers, generals, and political theorists for centuries, and the answers reveal as much about how we understand human society as they do about conflict itself. Some thinkers locate the roots of war in human nature, others in the way states are organized, and still others in the structure of the international system. Two figures stand out for shaping how we think about war today: Kenneth Waltz, who built a framework for classifying its causes, and Carl von Clausewitz, who argued that war is fundamentally a political act. Alongside them, a broader set of philosophies treats war as politics, as destiny, or as catastrophe. Understanding these perspectives is essential for anyone studying peace and conflict, because how we explain war directly shapes how we try to prevent it.

Kenneth Waltz and the three images of war 🔗

In 1959, Kenneth Waltz published Man, the State, and War, a work that became foundational to modern international relations theory. Rather than offering a single explanation for war, Waltz organized the existing theories into three broad categories he called “images,” each representing a different level of analysis. His central argument was that no single image, taken alone, can fully explain why wars happen.

Waltz drew on classic political philosophers such as St. Augustine, Hobbes, Kant, and Rousseau to build each image, examining both what each level claims about the causes of war and the limitations of that claim. This systematic approach is what made his work stand out and established him as a founder of the neorealist school of international relations.

The first image: human nature 🔗

The first image locates the cause of war in human beings themselves, whether in the flawed nature of particular leaders or in human nature more broadly. Thinkers like Thucydides, Machiavelli, and Hobbes argued that humans are driven by greed, fear, and vanity, and that these passions inevitably draw them into conflict. In this view, if individuals could be reformed or educated, peace would follow. As Waltz summarized it, the evil or improper behaviour of people leads to war, while universal individual goodness would mean peace.

Waltz himself was skeptical of this image. His key objection was that human nature is constant, yet war is not. Wars come and go, but human nature does not change, so the cause of something variable cannot lie in something fixed. Whether one even reads humans as inherently violent or essentially peaceful depends on the theory one already holds, which makes the first image difficult to test.

The second image: the internal structure of states 🔗

The second image shifts attention from individuals to the internal organization of states. Here, war is explained by how states are constituted internally. Some versions argue that “bad” states, such as autocracies or militaristic regimes, cause wars, while “good” states, such as democracies or egalitarian communities, are more peaceful. Other versions suggest that states facing internal strife may pursue war abroad to manufacture unity at home.

The third image: international anarchy 🔗

The third image, which Waltz emphasized most, locates the cause of war at the systemic level. According to this image, the root cause of war is the anarchic structure of the international system. Importantly, “anarchy” here does not mean chaos or disorder. It means the absence of any sovereign authority standing above states to govern their interactions. In the domestic sphere, government can resolve disputes; in the international sphere, no such overarching authority exists.

Waltz captured this idea with a memorable line borrowed from Rousseau: wars occur because there is nothing to prevent them. He often used Rousseau’s parable of the stag hunt to illustrate the problem. Several hunters must cooperate to catch a stag, but if one spots a rabbit he can grab for himself, he may betray the group to satisfy his immediate hunger, leaving everyone else worse off. In a system with no enforcer, even rational actors who would prefer cooperation cannot trust one another, and conflict becomes likely.

Yet Waltz did not claim the third image alone explains everything. His enduring conclusion was that all three images must be combined for a complete analysis. The third image describes the framework within which states act, while the first and second images explain the forces that shape the policies states actually pursue. Relying on any one image distorts the other two.

Carl von Clausewitz and war as a political instrument 🔗

If Waltz gave us a framework for classifying the causes of war, Carl von Clausewitz gave us perhaps the most influential definition of what war fundamentally is. A Prussian general and veteran of the Napoleonic Wars, Clausewitz set out his ideas in his unfinished masterwork On War (1832). His thinking continues to dominate military education and realist thought to this day.

War as the continuation of policy 🔗

Clausewitz is most famous for his dictum that war is the continuation of politics, or policy, by other means. The full passage is more precise than the popular shorthand. He wrote that war is not merely a political act but a real political instrument, a continuation of political dealings carried out through different methods. The crucial point is that war is never an end in itself. It is always a tool used to achieve some political objective.

This insight has powerful consequences. As scholars at the US Army War College note, Clausewitz is often reduced to this single quotation, which obscures the depth of his work. But the dictum itself integrates all the tools of statecraft into a single coherent whole. Military force is one instrument among several, and it derives its meaning entirely from the political ends it serves. War divorced from political reason becomes unintelligible and, often, self-defeating.

The remarkable trinity 🔗

Clausewitz also described war as a “remarkable trinity,” one of his most discussed concepts. According to the classic translation, war as a total phenomenon is always composed of three tendencies that pull against one another.

Primordial violence, hatred, and enmity: These passions function as a blind natural force and mainly concern the people, in whom such emotions must already be present for war to take hold.

Chance and probability: This is the realm of uncertainty, luck, and friction in which creative skill operates, and it belongs primarily to the commander and the army.

Reason and subordination to policy: This is war’s element of rational calculation, the business of government alone, which sets the political aims.

The genius of the trinity is that these three elements interact dynamically, and their balance shifts with the character of each particular war. The National Defense University describes the trinity as a kind of complex system, where passion, chance, and reason continually influence one another. This is why Clausewitz compared war to a chameleon: its underlying nature stays the same, but its appearance adapts to each situation.

Three philosophies of war: political, eschatological, and cataclysmic 🔗

Beyond Waltz and Clausewitz, the scholar Anatol Rapoport offered a influential typology that classifies how people fundamentally conceive of war. In his introduction to a widely read edition of On War, Rapoport distinguished three philosophies, which the philosophy of war often summarizes through a striking comparison: in the political view, war resembles a game of strategy like chess; in the eschatological view, it resembles a mission or the climax of a drama; and in the cataclysmic view, it resembles a fire or an epidemic.

The political philosophy of war 🔗

The political philosophy is essentially the Clausewitzian view. War is a rational instrument of state policy, deliberately chosen to achieve calculated goals. Like a game of chess, it is played by rational actors who weigh costs and benefits, and it can in principle be controlled, limited, and ended once its political purpose is served. Rapoport identified Clausewitz as the model representative of this conception. According to one detailed account drawing on Rapoport, this philosophy treats the state as the ultimate reference point, and it dominated European thinking in the long era between 1648 and 1914.

The eschatological philosophy of war 🔗

The eschatological philosophy treats war as a grand, final struggle that fulfils some design in history and ushers in a permanent new order. It can take sacred or secular forms. In some religious traditions, a final war precedes the establishment of a new moral or divine order. A secular version appears in certain revolutionary ideologies, where, for instance, a global conflict is expected to transform into a class struggle that, after victory, establishes a world from which war has been abolished. The essential feature is that war is not merely instrumental but transformative, a mission with a destined endpoint.

The cataclysmic philosophy of war 🔗

The cataclysmic philosophy conceives of war as a catastrophe that befalls humanity, much like a natural disaster, a fire, or a disease. In this view, no one is truly responsible and no one ultimately benefits. War is something that simply happens to people, often striking the innocent alongside the guilty. As a survey of these philosophies explains, the global variant treats war as a calamity affecting the entire human race. Because it sees war as a disaster rather than a tool, this philosophy directs attention toward prevention, focusing on uncovering the causes of war and inventing institutionalized methods of conflict resolution.

A shifting balance after 1914 🔗

These philosophies are not just academic categories; their relative influence has shifted with history. The political philosophy reigned supreme from the era of the Peace of Westphalia until the First World War. But the catastrophe of 1914 dealt severe damage to the idea of war as a normal, controllable instrument of statecraft. In the aftermath, the eschatological and cataclysmic philosophies gained ground. The arrival of nuclear weapons and the dissolution of the clear “battlefield” central to Clausewitz’s thinking further challenged the purely political view, even though it remains alive and well in military academies. This typology has continued to prove useful for analysts, who have applied it, for example, to interpret how different communities understand contemporary conflicts as either calculated military-political ventures or as existential, world-altering struggles.

Why these perspectives matter 🔗

These frameworks are not competing claims about a single right answer so much as different lenses that illuminate different aspects of war. Waltz reminds us that the causes of war operate at multiple levels at once, from the individual to the structure of the entire international system. Clausewitz insists that war, however violent and chaotic, remains tied to political purpose and to the interplay of passion, chance, and reason. Rapoport’s typology shows that how a society conceives of war, as a game, a mission, or a catastrophe, shapes whether it tries to win wars, wage them as crusades, or prevent them altogether.

For students of peace and conflict, the practical payoff is clear. Every theory of why wars happen contains, often implicitly, a theory of how peace might be achieved. If the cause lies in human nature, we look to education and reform. If it lies in the structure of states, we look to political institutions. If it lies in international anarchy, we look to building cooperative structures above the state. And if we see war as a catastrophe rather than a clever instrument, we devote our energy to prevention and to the machinery of conflict resolution.

What do you think? Among these perspectives, which best explains the conflicts you see in the world today, and does the way we choose to understand war ultimately determine our ability to prevent it?

References

1. https://cup.columbia.edu/book/man-the-state-and-war/9780231188043/
2. https://www.e-ir.info/2012/07/18/anarchy-and-war-a-critique-of-waltzs-third-image/
3. https://en.wikipedia.org/wiki/Man,_the_State,_and_War
4. https://oll.libertyfund.org/pages/clausewitz-war-as-politics-by-other-means
5. https://warroom.armywarcollege.edu/articles/grand-strategy-clausewitz/
6. https://www.clausewitz.com/mobile/HPtrinity.htm
7. https://ndupress.ndu.edu/Media/News/News-Article-View/Article/2076059/clausewitzs-wondrous-yet-paradoxical-trinity-the-nature-of-war-as-a-complex-ada/
8. https://en.wikipedia.org/wiki/Philosophy_of_war
9. https://is.mendelu.cz/eknihovna/opory/zobraz_cast.pl?cast=69572
10. https://www.tandfonline.com/doi/full/10.1080/01402390.2024.2379395