It was shortly after this that the son of one of the other couples arrived, right at the end of the summer. He was about 20, and seemed old to me, not only because he was a grown-up, but because he was very withdrawn, barely speaking to other people; he seemed to spend the greater part of the day throwing a bowie knife at the ground, which invariably landed blade down despite the twirl he gave it. I asked my mother at one point why he was so strange, and she explained that he had been in the war and seen things he couldn’t talk about. I think I intuitively understood what she meant; in any case, the episode has stayed with me until today.

This was my first experience, indirect as it was, of what is today called combat trauma, but was then, I think, still known as shell shock. Years later, after an aborted career plan as an astronaut and a professional degree in classics, I found myself studying up close two cultures—ancient Greece and Rome—in which war was a permanent condition of life, and virtually no citizen escaped the duty of military service. Like most of my peers, I was impressed by the depth and beauty of classical literature and philosophy, and didn’t wonder at the connection this might have with the unrelenting violence they experienced at firsthand. I had read, for example, the passage in Plato’s Republic, in which he recognizes how difficult it will be to train the guardians of his ideal state to be aggressive toward strangers and yet mild toward their own people. Socrates asks his interlocutor Glaucon, who in real life was one of Plato’s brothers, how people who have such fierce characters will “not be savage toward each other and their fellow citizens?” “It won’t be easy,” Glaucon replies. “And yet,” Socrates says, “they must be gentle toward their own, but rough toward their enemies. Otherwise, they won’t wait for others to destroy them but will do it first themselves” (Republic 2, 375B5–C6). Plato’s answer is to adduce the example of guard dogs, which can be trained to protect their own but attack anyone they don’t recognize. It never occurred to me, or, it seems, to Plato, to wonder whether war itself might brutalize these guardians—a nicely sanitized word for what was in fact a military caste—and increase the danger that they might turn their belligerence against their own families upon returning home.

It is remarkable, and has indeed been remarked, that the Greeks and Romans seem never to have identified the pathology of combat trauma explicitly.¹ Not that they were alone in having this blind spot: it was really only with World War I that such effects of battle began to be observed and identified as a disorder, and more recently still that post-traumatic stress in general has been classified as a medical condition. When I first read the Iliad and Odyssey in Greek, in graduate school, it was during the heyday of the New Criticism, and we were attuned to finding deep meanings in the texts we admired. No longer did we view Homer as a primitive poet; his epics touched on grand themes of fate and freedom, collective identity versus individualism. We—or some of us—interpreted Achilles’ refusal to fight after he had been insulted by Agamemnon, and his declaration that his honor came not from the king but from Zeus, as a sign of a new conception of personal autonomy, an internalization of values that was the harbinger of a modern sense of morality and responsibility. We puzzled over how characters could assign to Zeus’ scales the outcome of a battle between warriors, and wondered whether this was merely a metaphor or an indication of a pre-moral fatalism. Even then, I recall thinking that a tendency to see the hand of destiny behind life-and-death events was not foreign even today, and that in time of war men and women seeking to brace themselves for battle often say things like “if that bullet has my name on it,” or imagine that there is a day appointed for their death and there’s no avoiding it when it comes, but till then they are safe. But these thoughts were marginal to my appreciation of the poem as an exploration of ethics and human consciousness.

Then I encountered Jonathan Shay’s remarkable book, Achilles in Vietnam.² I confess it was a student who urged me to read it, since I might have put off examining a volume with such a title. Shay, a psychiatrist who had worked with traumatized veterans of the war in Vietnam, saw a deep similarity between the experiences of his patients and that of Achilles, as narrated in the poem. Very summarily, Shay found there were two conditions that, in combination, were catalysts for combat trauma: first, a loss of faith in the commanding officer or other representative of the system, and hence in the justification for the war; and second, the death in battle of an especially close friend, invariably described as gentle or loving, however murderous he might have been on the battlefield. When Agamemnon humiliates Achilles by taking his war prize, the captured girl Briseis, he loses Achilles’ respect not only for his authority but also for the motive of the entire war, which was the theft, as the Greeks saw it, of Menelaus’ bride Helen. If Agamemnon, Menelaus’ brother and the leader of the expedition to recover Helen, can take away Achilles’ girl with impunity, why should Achilles risk his life to rescue his tramp of a sister-in-law? Then, as a result of Achilles’ abstention, his dearest friend Patroclus enters the battle in his stead, and is slain. The consequence of such a double whammy, Shay explained, is often a period of manic battle frenzy, in which the person feels unusually powerful and invulnerable, or at any event indifferent to death, and wreaks havoc upon the enemy, just as Achilles does, until he slays Hector, the man responsible for his comrade’s death. If he survives, he may then experience a range of post-traumatic symptoms, including flashbacks, trouble sleeping, and a generalized rage or hostility that may express itself in unmotivated aggression against others.

Of course, there is no indication that Achilles suffers from such a syndrome at the end of the Iliad. True, he senselessly abuses the body of Hector, but he eventually agrees to return it to Hector’s father for a whopping ransom; he remains his violent self, at one point threatening old Priam, but he is not represented as mentally disturbed in the aftermath. Shay was aware of this and suggested that the elaborate rituals by which Achilles honored his friend and committed his corpse to the pyre might have helped him to recover his sanity. In Vietnam, when a soldier was killed his body was often whisked away as quickly as possible and his mates were urged to get over their grief, and so found no healthy means of working it through. This is, I think, a weak point in Shay’s argument, for reasons I will indicate in a moment. But what I most took away from Shay’s book—and this changed my whole view of the epic—was the sense that Homer knew what war was about, and was writing for an audience who did as well. The Iliad is first and foremost a brilliant study in how people behave under the stress of battle. It is not a mere repository of traditional motifs, organized so as to tell a great story or to illustrate timeless ethical issues, though it is those things too, of course. But it is, above all, a poem of war.

Now, Achilles is not the only hero to go on a rampage. It happens all the time in the Iliad, and even has a technical name in Greek: it is an aristeia, deriving from the Greek word meaning “best.” Heroes, like athletes, have their sudden moments of perfect coordination and exhilaration, and for a while they are invincible. From the ancient Greek point of view, these episodes of elation are not signs of mental disorder, but the highest manifestation of a fighter’s excellence. All the heroes can’t all be suffering from combat trauma—or can they? Might it be that the Greeks and Romans did not isolate such a syndrome in their soldiers precisely because it was so common, so practically universal, that it didn’t stand out? Can we speak of a culture of trauma?

Let me offer anothe...