What can classical political philosophy teach us about international relations, and about the causes and preconditions of conflict between nations? Is Thucydides merely a historian in the conventional modern sense, or is he a political philosopher? Moreover, is Thucydides correctly identified by present-day political scientists with the “realist theory” of international relations, or does he offer some alternative approach to politics besides those we are familiar with today?
In his ambitious first book, Thucydides on the Outbreak of War, S.N. Jaffe engages all of these important questions with marvelous results—producing in the process one of the best available philosophical commentaries on Thucydides. Jaffe’s study offers a detailed, penetrating, and highly original interpretation of Book I of Thucydides’ History of the Peloponnesian War. His particular focus is what the history teaches about the causes of conflict between Athens and Sparta. But Jaffe’s larger aim, as he states in the introduction, is to lay bare the underlying logic of these two great city-states’ motivations, and thus to explore the causes of war as such.
An assistant professor of political science and international affairs at John Cabot University, Jaffe brings a careful attention to detail, oriented toward understanding both the intricate structure and the substantive teaching of Book I, as well as its role in the overall arc of the narrative. In the introduction, he claims that his interpretation “attempts to follow Thucydides’ own textual indications” and to provide an “internal reading” of the History that reveals Thucydides’ “authorial intention.” Guided by Thucydides’ own statement that he wished to leave behind a “possession for all times,” Jaffe considers Thucydides to be not merely a historian, but a political philosopher who “is interested in human nature.” Thus, “key episodes in the History are intended to disclose characteristic phenomena” and “universal themes” of humanity and politics: “Thucydides asserts the timelessness of his work on the ground that the future will resemble the past, because the men of the future will resemble those of the past.” Accordingly, underlying the Thucydidean approach to the study of history is the presupposition that there are universal and unchanging characteristics of human nature that animate all politics in all times and places.
Thucydides’ view of human nature is “largely psychological,” understood not in the “contemporary” sense but instead as a foundational set of dispositions and beliefs (including especially beliefs about justice, morality, and piety) that inform and animate the actors of his history. This psychological outlook shapes Thucydides’ perspective on the “necessity” or “compulsion” that operates in international relations and in politics more generally. By “necessity,” he doesn’t mean primarily external compulsion or the “efficient causes” that operate deterministically in the political world. Instead, Thucydidean necessity is disclosed by the matrix of “rational” choices that each actor considers to be most conducive to his or her self-interest or to the priorities of his or her regime. As Jaffe states elsewhere, necessity in Thucydides “is the necessity of pursuing the advantageous things.” The compulsion of necessity can operate even through an irrational set of judgments about what is “advantageous,” since irrational people characteristically believe their goals to be rational—and are no less compelled by them than are the more truly rational.
Jaffe begins illustrating this insight in Chapter 1 through his account of the conflict between the naval power Corinth and her rebellious colony, Corcyra. Somewhat counter-intuitively, the appeal to justice in this instance is made by the stronger power (Corinth) in the name of maintaining Athenian neutrality and non-intervention. This “first quarrel” provides the initial spark which ignites the broader regional conflict between Athens and Sparta. In trying to win over Athens as a naval ally against Corinth (a member of the Spartan League), Corcyra must reject the Corinthian emphasis on justice in favor of the view that “all cities seek the advantageous things, and therefore none should be blamed for doing so.” Corcyra’s claim is therefore that it is in Athens’s interest to ally with her because, given the doctrine of necessity that governs all cities, war with Sparta is inevitable. Through this interpretation, Jaffe can helpfully prepare the groundwork to show how Corcyra anticipates the infamous “Athenian thesis” which prioritizes advantage above anything else. At the same time, however, he also introduces the theme of justice, disabusing the reader of the naïve expectation that justice for Thucydides is merely the refuge of the weak. The moral force of justice is one of the things in nature that can exercise compulsion on human beings—even on those who are powerful.
Among other things, this account of necessity complicates the view—influentially advanced as the “Thucydides trap” theory in Graham Allison’s 2017 book, Destined for War—that Thucydides considered the war between Athens and Sparta a simple “inevitability.” Jaffe also liberates the great historian from the “realist” cage to which he has been consigned by modern students of international relations. Thus, in Chapter 2, we see that Thucydidean “necessity” is multi-dimensional rather than flat, and robust enough to accommodate a “tripartite” conception of human striving that transcends simple advantage. In their speech at the Spartan Congress, the Athenian envoys claim that they did not “assume the mantle of their empire by force,” but rather were invited to do so both by their allies and by circumstances—in particular, by the strategic withdrawal of Sparta after the defeat of the Persian army. Jaffe emphasizes that the Athenians, having taken on the leadership of the Hellenic League, believed they were subsequently “forced to grow powerful” by “fear, honor, and profit”—motives which they considered so universal and reasonable that they “compel the behavior of all cities,” thus rendering the growth of Athenian hegemony blameless and even just. Thucydides may be a realist, but he is not narrowly focused on power or national interest. His treatment of human nature and of politics is much richer and more complicated than the contemporary paradigms will allow.
Throughout the book, Jaffe helpfully demonstrates that Thucydides himself endorses crucial elements of the “Athenian thesis” as a reflection of both human nature and political reality, even if he does not embrace or recommend its implications for politics and empire without qualification. Indeed, precisely by endorsing the insights of this thesis, the Thucydidean historian or political scientist appreciates more fully the importance of regime types and of differences between the constitutions, laws, attitudes, and traditions of particular political actors. Therefore, “the national characters of Athens and Sparta are essential for understanding the war’s outbreak.” In other words, Thucydides provides an account of phusis (nature) and nomos (convention) as they manifest themselves in Athens and Sparta.
Although Sparta and Athens appear to represent two polar opposite regime types—the former displaying piety, morality, and justice; the latter freedom, daring, innovation, and self-interest—Jaffe argues that according to Thucydides “the observable differences between Sparta and Athens” are partially the result of the “different prioritization of fear, honor, and profit.” The truest prophasis, or cause, of the war is the Spartan fear of growing Athenian power (rather than the professed reasons about the violation of the Thirty Years’ Peace and about Athenian religious pollution). What this means is that Sparta, just as much as Athens, cares for advantage; thus it too is governed by the “the universal doctrine of necessity” that informs the “Athenian thesis” of the envoys. These universal drives, however, are shaped and expressed (and, most importantly, articulated in speech) differently in and by each of the two regimes, through the “distinctive way that Athens and Sparta express human nature.” Thus, Sparta’s conception of advantage is also bound up with the gods, who ensure a harmony between justice and advantage by punishing wrongdoers.
Jaffe supplies the crucial evidence for these provocative claims in his treatment of Athens and Sparta in Chapters 3 and 4, respectively. In Chapter 3, he lays out a careful interpretation of both the Pentecontaetia (the 50 years that preceded the outbreak of war) and the Archaeology (the long introduction in which Thucydides describes the early history of human society). Jaffe focuses on these sections in order to reveal the true source of Athenian hegemony—its growth under the leadership of Themistocles after the Persian retreat, and its eventual transformation into an empire.
The apparent mirror opposite of this Athenian daring and self-interest is found in Chapter 4 with Jaffe’s treatment of Sparta’s “greatest prophasis for the war”—the professed causes of the war that are advanced by Sparta. Here, he interprets Sparta’s emphasis on piety and concern for legal justice as “Herodotean,” so that in presenting it “Thucydides has deftly situated [a] mythical account within his own truer account of the war’s outbreak.” As convincing as Jaffe is on this point, the reader wonders why Thucydides bothers with such mythology in the first place, and whether Sparta’s concern for justice and piety is merely a product of its unique conventions. Perhaps Thucydides presents Sparta’s mythologizing account “of the cosmos populated by gods” because he himself judges it to be necessary for humanity, even if not ultimately true. Sparta’s piety may reflect deeper requirements of human nature that the Athenian empire tried deliberately (and hubristically) to overcome. If so, then the Athenian empire’s tragic arc in the History makes us wonder whether the Spartans were right all along—whether cosmic justice is supported, if not by actively ruling gods who punish wrongdoers, then at least by nature itself, and by the limits she has set to human politics.
S.N. Jaffe’s book is an excellent scholarly and philosophical resource, an exemplar of serious and original scholarship from which Thucydides scholars, classicists, political theorists, and students of international relations can learn. The manuscript is one of the most wide-ranging and clearly-conceived interpretations of Thucydides to be published in the last two decades, and it will demand continuous engagement and study from serious readers. It may not always be easy to digest for those unfamiliar with the history of the Peloponnesian War, but the book’s difficult arguments reward careful examination and reexamination for anybody interested in politics or the causes of war.