Joshua Rothman in The New Yorker:
When he was thirty-five, Kieran Setiya had a midlife crisis. Objectively, he was a successful philosophy professor at the University of Pittsburgh, who had written the books “Practical Knowledge” and “Knowing Right from Wrong.” But suddenly his existence seemed unsatisfying. Looking inward, he felt “a disconcerting mixture of nostalgia, regret, claustrophobia, emptiness, and fear”; looking forward, he saw only “a projected sequence of accomplishments stretching through the future to retirement, decline, and death.” What was the point of life? How would it all end? The answers appeared newly obvious. Life was pointless, and would end badly.
Unlike some people—an acquaintance of mine, for example, left his wife and children to move to Jamaica and marry his pot dealer—Setiya responded to his midlife crisis productively. In “Midlife: A Philosophical Guide” (Princeton), he examines his own freakout. “Midlife” has a self-soothing quality: it is, Setiya writes, “a self-help book in that it is an attempt to help myself.” By methodically analyzing his own unease, he hopes to lessen its hold on him.
Setiya finds that the history of the midlife crisis is both very long and very short. On the one hand, he identifies a text from Twelfth Dynasty Egypt, circa 2000 B.C., as the earliest description of a midlife crisis and suggests that Dante might have had one at the age of thirty-five. (“Midway on life’s journey, I found myself / In dark woods, the right road lost.”)
More here.