Thucydides wrote only one work, the remarkable History of the Peloponnesian War. His History is a painstaking description of the events of the war between Athens and Sparta, which he describes as the greatest and most terrible war known to him (I.I, I.23).

If we compare Thucydides’ History with the classic of political philosophy, Plato’s Republic, we may be struck by the gulf that seems to separate them. The Republic deals chiefly with the best political order, the best regime. This orientation leads to the deprecation of actual political life, since this life, when seen in the light of the best regime, cannot but appear deficient. Thucydides, however, examines political life on its own terms and examines actual cities, primarily Athens and Sparta. Consequently his cities are not so harmonious as those we find in the descriptions of the best regimes in Plato’s Republic, or Laws and in Aristotle‘s Politics. What we are presented with in the pages of Thucydides is actual cities engaged in “real” or ”power” politics.

Thucydides’ History and Political Philosophy

Thucydides sometimes seems to suggest that he is a historian only in the sense that he is a “chronicler.” Thucydides speaks of such a chronicler, Hellanicus (I.97), whose work is not detailed enough, and Thucydides says that what Hellanicus has neglected, he himself will cover sufficiently. Perhaps, then, Thucydides is only an especially precise historian. But even in this context he makes clear that he has a broader and more comprehensive intention than merely to chronicle: his History is meant to be “a possession for all time” (I.22.4). Thomas Hobbes, who translated Thucydides into English, ranks Thucydides’ achievement as a historian with that of Homer as a poet, Aristotle as a philosopher, and Demosthenes as an orator. “For he setteth his reader in the assemblies of the people and in the senate, at their debating; in the streets, at their seditions; and in the field, at their battles.” If the reader is a “man of understanding” he may “from the narrations draw out lessons to himself.

Thucydides, under the cloak of being just a chronicler, provides the reader with a basis for statesmanship and philosophizing. An ordinary historian might select only the events such as decisive battles that were important for the course of the war but Thucydides has also selected events that did not affect the course of the war, but throw light on the war as a whole or, indeed, any war. The scope of history, according to Hobbes is “profit by writing truth.” Hobbes elaborates:

“Digressions for instruction’s cause, and other such open conveyances of precepts which is the philosopher’s part, he never useth; as having so clearly set before men’s eyes the ways and events of good and evil counsels, that the narration itself doth secretly instruct the reader, and more effectually than can possibly be done by precept.”

Thucydides’ History teaches only by narrative, but it is a narrative that tells us more than the story of the Peloponnesian War. It tells us about man and politics in general. In this sense, Thucydides’ intention and practice go beyond those whom we today call historians.

The Greatness of the Peloponnesian War

Thucydides narrated the Peloponnesian War not merely because he happened to live at the time, but because the war was singularly memorable. Why? It was, so to speak, the first universal war, and not only the most memorable Greek war.

Thucydides proves this assertion in his long introduction, the “archaeology.” Thucydides argues there that the most famous Greek war, the Trojan War, is memorable only because of the power of poetry. The Persian War would seem to have been a more impressive conflict because it involved both barbarians and Greeks, but Thucydides points out that it was resolved “speedily” compared to the war between Sparta and Athens, after just two land battles and two sea battles.

Thucydides describes the slow increase in civic wealth and power through the ages, culminating in the great power and wealth of the Athenians at the beginning of the Peloponnesian War. There was also an advance from original, universal barbarism, to the distinction between barbarism and what we may call Greekness, or civilization. Thus, the war, which affects the only two parts of the human race, Greeks and barbarians, may be called “universal” because the human race has two poles: barbarism and Greekness. Thucydides knew of other advanced civilizations such as the Egyptians, but he wants to convey a fundamental problem: the human race has two poles, barbarians and Greeks; and the Greeks in turn have two poles, Sparta and Athens.

Sparta and Athens were at their height when the war broke out. For any people to be at their highest point in regard to war presupposes that they must have lived for a long time unperturbed by wars. The highest point in regard to war presupposes the highest point in regard to peace. If we assume then, that not only Sparta and Athens are the fundamental opposites, but also war and peace (or motion and rest), then the Peloponnesian War is the climactic war that reveals these opposites at their highest point.

Athenian Imperialism and the Problem of Justice

Thucydides’ central theme is Athenian imperialism. Repeatedly in his pages we hear Athens’ spokesmen defend the city’s imperialism by denying that “right” or justice has any role in relations between cities. According to the Athenians, it has always been established for the weaker to be kept down by the stronger; no one who can acquire something by force is dissuaded by the argument that it is unjust to do so; justice has no place, unless between equals in power (I.76.2; 5.89). The Spartans and their allies claim to wage war against Athens in order to save Greece from Athens’ tyrannical ambitions. They claim to wage a just war, which is, as such, supported by the gods. In fact, most Greeks sided with the Spartans at the beginning of the war, believing that they were fighting a war of liberation, with the gods’ promises of assistance. In the end, of course, the Spartans do win the war.

Thucydides’ pages thus give voice to two opposing theses about justice. According to the Athenians, justice has no place in power politics, while according to the Spartans, justice does have power in the world. Thucydides’ narrative investigates these two theses, and the ways of life, politics, piety, and individuals to which they give rise.

The “Realistic” Thesis of the Athenians

On the eve of the war’s outbreak, the Athenian envoys at Sparta claim that Athens cannot be blamed for having acquired its empire because they were compelled to do so by “the greatest things,” including “fear, honor, and interest.” Fear, honor, and interest are irresistible impulses felt by all political communities; the Athenians are thus like all others overcome by the desire for empire; and none who can acquire has yet been dissuaded by argument that it is unjust to do so (I.75–76.2). According to the Athenians, interest compels and excuses no less than fear. So, self-interested behavior is above reproach. But if any self-interested action by a political community is compulsory, and hence cannot be condemned, what remains blameworthy? It is not so much that the Athenian envoys argue that might makes right, as that right has no place in international relations.

The Athenians restate their thesis in Book V in the famous “Melian Dialogue.” The Athenian ambassadors this time do not even deign to defend the justice of their empire or decision to attack Melos, because justice has no power except between equals (5.89). But the Melians refuse to abide by the Athenian understanding and instead advocate the Spartan position. The Melians believe that the gods will come to their defense because they “are pious men who stand against men who are unjust” (5.104).

In this way the Melians challenge the Athenians. For to the extent that the Athenians argue that justice has no power in the world, they assume that the world is fundamentally indifferent to it, and hence that there are no divine powers that enforce justice by rewarding the just and punishing the unjust. Thucydides forces the reader to wonder how the Athenians or anyone else can know that there is no moral order, and thus be confident about their thesis about justice.

The Athenians respond to the Melians’ argument by denying the Melian assumption that there are just gods who reward and punish human beings. Moreover, the Athenians argue that precisely on the basis of the Melians’ own assumptions, such gods do not exist. Rather, all human beings are compelled by a necessity of their nature to want what is good for themselves, and pursue the power that is in their interest, without regard to justice. All are compelled to care more about self interest than justice. The Melians are not morally superior to the Athenians—they are simply weaker. If there are gods as the Melians claim, they too cannot favor one side over the other, because both parties are equally self-interested.

The “Moralistic” Thesis of the Spartans

Thucydides does not directly address the Athenian argument at Melos, but perhaps indicates that what proved to be the Melians’ fruitless resistance to the Athenians was imprudent or even reckless. We therefore must consider his presentation of the Spartans’ views. Sparta, while a great power, is not an expansive imperialist polis. Spartan spokesmen repeatedly make the case that the war is fought to liberate the Greek cities from Athenian tyranny. We can see this in the presentation of the Spartan general Brasidas, praised for both his virtue and intelligence (4.81.2–3), on an expedition to liberate Athens’ northern Greek subjects (4.78 ff.). At first blush, Sparta seems to contradict the Athenian assertion that all cities are compelled only by self interest above all. For Sparta seems to care about the freedom of her fellow Hellenes.

But is the Spartan way so different from the Athenian? Are they motivated more by justice than by fear and self-interest? Thucydides says (in his own name) that the truest cause for the Spartans going to war was of fear of growing Athenian power. Moreover, they are not above violating sacred oaths in pursuing their interest. Later in the war, when they agree to the Peace of Nicias, they not only abandon their war against Athens, but also abandon the very Greek cities that Brasidas had liberated, in exchange for 300 prisoners. Indeed, the purpose of Brasidas’ foray was to trade the liberated cities for a peace settlement favorable to Sparta (4.81.2, 4.117). Finally, the reason the Spartans had refrained from an expansive imperial policy was their hidden slave-empire at home. They feared that the Helots, whom they had conquered in the past, would rise up in rebellion. Perhaps the Spartans dared not send so many troops abroad for fear of losing power at home. Perhaps Thucydides’ portrayal of Sparta in fact serves to reinforce the Athenian understanding of justice and self-interest.

The Melian Dialogue and the Mytilenean Debate

The Melians would rather fight the unjust Athenians than live as slaves under their unjust imperial rule, and express the pious hope that the gods will come to their aid in their fight against the Athenians and reward their justice. Nonetheless, the Melian Dialogue is followed by the slaughter and enslavement of the Melians. The Athenian position on justice and self-interest thus seems to lead to great inhumanity. Yet, the Athenians’ action is not a necessary consequence of their argument in all, or even most, circumstances. In fact, throughout the war, the Athenians, while acting according to their amoral thesis, are more humane than the Spartans. Could it be that the Athenian thesis, rightly understood, might issue in a greater allowance for gentleness?

The Spartans, convinced of the justice of their cause, the liberation of Greece, assume all who oppose them must be unjust. Consequently, they do not hesitate, time and again, to condemn and execute those whom they conquer or take prisoner. The Spartans simply assume that justice coincides with the interests of Sparta; therefore all human beings have an obligation to promote the interests of Sparta. Anyone who opposes Sparta must be willfully unjust, hence deserving of punishment.

The Athenians, however, who believe that all human beings are compelled by natural necessity to pursue their own interest, see them as doing what they cannot help but do. They therefore cannot be reasonably blamed or punished for seeking what they perceive as good for themselves. The Athenian understanding excuses those who would resist Athenian imperial tyranny as much as it excuses the pursuit of that empire by Athens.

The Athenians evince humanity and gentleness in their treatment of the Mytileneans, and Thucydides affords us a powerful glimpse of the difference between Athens and Sparta in their deliberations and deeds on that occasion. The city of Mytilene has revolted against Athenian rule, attempting to defect to the Spartan side. At first, the Athenians are enraged, because they have treated the Mytileneans mildly, and the timing is precarious. The Athenians put down the rebellion and resolve in an angry fit to put to death all Mytilene’s male citizens and enslave her women and children. But the next day the Athenians change their minds, believing it savage to destroy the whole city when only the leaders are responsible for the rebellion (3.3.1, 3.36). They hold a second assembly to reconsider the fate of the Mytileneans.

In this second assembly Thucydides presents “the most violent Athenian citizen,” Cleon, who argues that it is both in Athenian self-interest and just to demand the punishment of all Mytilene. Meanwhile, Diodotus, whose name means “gift of god,” who is the only participant unknown outside the pages of Thucydides, and who appears just this one time, argues that the majority of the Mytileneans should be spared. Diodotus argues according to the Athenian thesis: because all human beings are compelled to pursue self-interest regardless of the demands of justice, the Mytileneans cannot be blamed for rebelling against Athenian rule. The Athenians should thus not consider justice, but only their interest. Thus does Diodotus convince the Athenians that it is not in their self-interest to kill all the Mytileneans. By appealing to the Athenians’ reason and encouraging them to consider their self-interest calmly, Diodotus frees them, on this occasion at least, from the spell of their moral indignation and its punitive passions.

Thucydides’ View of Athenian Imperialism

How, then, should we appraise Thucydides’ view of the Athenian empire and its thesis? Just as Sparta is hypocritical in Thucydides’ portrayal, so, too, Athens is portrayal as openly amoral. Thucydides’ portrayal of Athens seems to suggest that no political community can successfully conduct its foreign policy on such an openly amoral basis. Some version of Spartan moralism, despite its hypocrisy, is a sounder basis.

Indeed, Thucydides suggests that even the Athenians are unable to live by their thesis. He presents many examples of the Athenians failing to treat conquered peoples according to their own self-interest; they often give in to righteous anger and the desire for vengeance by slaughtering and enslaving those they regard as traitorous— e.g., the Scioneans and the Melians. Indeed, while they claim that all nations are compelled by nature to pursue what they deem their self interest, they also claim that they are righteously superior to other nations. Because they possess a noble superiority to mere considerations of interest, they think they deserve to hold their empire and the glory it affords (1.76.3–1.77; 4.122.5–6, 5.32.1, 5.116.3–4). The Athenian leader Pericles goes so far as to speak of the Athenians’ moral superiority in terms of their superior generosity to others without calculation of profit or loss, and because of the sheer grandeur of their ambition: they seek an unlimited empire despite the great dangers and terrible misfortunes it risks. The imperial ambition itself is a sign of their noble superiority to mere calculation. So, while the Athenians may claim not to care more about justice than self interest, they do claim to deserve imperial success and “eternal fame.” They, like the Melians, implicitly believe in the power of justice. To assert that they deserve the rewards of empire and glory is to believe and hope that they will receive what they deserve.

Despite the Athenians’ constant derision of pious hopes in the name of amoral and imperial realism, they cannot suppress such hopes within themselves (5.10, 5.111). On more than one occasion they seek to purify the sacred island of Delos to win favor with the gods; in the end their attempt to suppress pious hope leads to a religious explosion, so extreme and destructive that it leads to disaster and defeat in the pivotal expedition to Sicily that Thucydides describes. One should also reflect on the possible effect of the Athenian thesis on the Athenians’ treatment of each other. Justice is a concern that no state can or should avoid (7.18).

Thucydidean Wisdom

Thucydides reveals himself as one devoted solely to the truth (1.20.3), whose work will benefit its readers, not by teaching them how to gain power empire, or glory, but by teaching them to understand the truth about human affairs. Thucydides intends his work to be a possession for all times: this suggests that the truth about political life is more enduring than the glories of Athens and her empire. Thucydides, in the subtle presentation of his own progress in wisdom and understanding, lets us see the excellence of a life that seeks to understand the truth.

For further introductory reading, see:

Clifford Orwin, The Humanity of Thucydides, Princeton: 1994.

David Bolotin, “Thucydides” in History of Political Philosophy, Eds. Strauss and Cropsey, Chicago: 1987.