Clockwise from top left: Socrates, Michel de Montaigne and Henry David Thoreau.

ILLUSTRATION: JOHN CUNEO
By Eric Weiner, WSJ

Thanks to the pandemic and its economic fallout, we are all philosophers now. The “slow cure,” as philosophy has been called, is exactly what we need. This is philosophy not as metaphysical musing but as originally conceived by the ancient Greeks: practical, therapeutic medicine for the soul.

Philosophy helps us to untangle the knotty ethical questions raised by the pandemic, but it can also help us to answer far more personal but equally urgent quandaries. How to endure the unendurable? How to find certainty in an uncertain universe? Philosophy provides no easy answers, but it reframes our questions and alters our perspectives—a skill that is helpful during good times and invaluable during bad ones.

Philosophy is well acquainted with bad times. Many of history’s greatest thinkers did their most lasting work during pandemics, economic upheaval and social unrest. Theirs is an earned wisdom—and a portable one. Unlike information or technology, wisdom is never rendered obsolete. Philosophy’s insights are more relevant than ever.

Covid-19 has humbled us, unmoored us. Nothing seems certain anymore. Good, Socrates would say. Western philosophy’s patron saint and first martyr would surely recognize our plight. He lived during Athens’ decline as a great power, a fall accelerated by military adventurism and the bubonic plague.

Yet Socrates saw opportunity in his troubled times. He buttonholed revered Athenians, from poets to generals, and soon discovered that they weren’t as wise as they thought they were. The general couldn’t tell him what courage is; the poet couldn’t define poetry. Everywhere he turned, he encountered people who “do not know the things that they do not know.”

Likewise, today’s lockdowns (partial or full) force us to pause and question assumptions so deeply ingrained that we didn’t know we had them. This, said Socrates, is how wisdom takes root. We crave a return to “normal,” but have we stopped to define normal? We know these times demand courage, but what does courage look like? Already, we’ve expanded our notion of “hero” to include not only doctors and nurses but grocery clerks and Grubhub couriers. Good, Socrates would say: Now interrogate other “givens.”

In 19th-century America, Henry David Thoreau leveraged his troubled times—a country marching toward civil war—to find beauty in the imperfect. Gazing at Walden Pond one calm September afternoon, he noticed that the water was marred by motes speckling the surface. Where others might see blemishes, Thoreau saw something “pure and beautiful like the imperfections in glass.”

He observed Walden from various vantage points: from a hilltop, on its shores, underwater, by daylight and moonlight. He would even bend over and peer through his legs, marveling at the beautiful inverted landscape. If you can’t change the world, Thoreau counsels, change how you see it—even if that means contorting yourself. Museums and theaters may be closed, but beauty has not absconded. Viewed at the right angle, said Thoreau, “every storm and every drop in it is a rainbow.”

Michel de Montaigne was an expert contortionist, only it was himself, not ponds, that he yearned to see more clearly. He lived in France in the 16th century, when death was in the air—“gripping us by the throat,” he said. The plague killed nearly half the residents of Bordeaux, where he served as mayor in the 1580s. Grief over the death of his closest friend propelled Montaigne up three winding flights of stairs to the top floor of a red-roofed tower, perched high atop a hill and exposed to the winds, where he penned his brilliant essays. From great suffering, great beauty arises.

Alone in his tower, Montaigne cleaved himself from the world out there and, in a way, from himself too. He took a step back to see himself more clearly, the way that one half-steps away from a mirror. He would advise us to do the same: Use the pandemic as an opportunity to see the world, and yourself, a bit differently. For instance, maybe you have always considered yourself an extrovert but find that you actually enjoy the forced solitude. Welcome this different version of yourself, Montaigne urges.

Philosopher and novelist Albert Camus

PHOTO: CECIL BEATON/CONDE NAST/GETTY IMAGES

Stoicism was born of disaster—its founder Zeno established the school of thought in 301 B.C. after he was shipwrecked near Athens—and it has been dispensing advice on coping with adversity ever since. No wonder it’s enjoying a resurgence, one that began before the pandemic.

Stoic philosophy is neatly summed up by the former slave turned teacher Epictetus: “What upsets people is not things themselves but their judgments about things.” Change what you can, accept what you cannot, a formula later adopted by Alcoholics Anonymous and crafty T-shirt hawkers.

A good Stoic would have prepared for the pandemic by practicing premeditatio malorum, or “premeditation of adversity.” Imagine the worst scenarios, advised the Roman senator and Stoic philosopher Seneca, and “rehearse them in your mind: exile, torture, war, shipwreck.” A modern Stoic’s list looks a bit different—a screaming child, unpaid bills, a worrisome fever—but the idea is the same. By contemplating calamity, we rob future hardships of their bite and appreciate what we have now. Adversity anticipated is adversity diminished.

“ The pandemic has made a mockery of our grand plans. Graduations, weddings, job prospects—poof, gone, rolling back down the hill like Sisyphus’s boulder. ”

Albert Camus experienced more than his share of adversity: growing up poor in Algeria, enduring a world war and, later, intellectual fisticuffs with his fellow philosophers, before dying in a car accident in 1960 at the age of 46. Camus is the ideal pandemic philosopher, although not for the reasons you might think. It isn’t his oft-cited novel “The Plague” that most fully explains our predicament but his lesser-known essay “The Myth of Sisyphus,” about the sad figure from Greek mythology, condemned by the gods to push a boulder up a hill only to watch it roll down again and again.

The pandemic has made a mockery of our grand plans. Graduations, weddings, job prospects—poof, gone, rolling back down the hill like Sisyphus’s boulder. Yet we must persevere, said Camus. Our task, he said, isn’t to understand the meaning of catastrophes like Covid-19 (there is none) but to “imagine Sisyphus happy.” How? By owning the boulder. By throwing ourselves into the task, despite its futility, because of its futility. “Sisyphus’s fate belongs to him,” said Camus. “His rock is his thing.”

Are you working on a seemingly fruitless project, a dissertation or a marketing strategy, forever delayed, buffeted by the gales of circumstance? Good, Camus says, you’ve begun to grasp the absurdity of life. Invest in the effort, not the result, and you will sleep better. His prescription is our challenge in the age of Covid-19: staring down the absurdity of our predicament but stubbornly persisting rather than yielding to despair. Just like a good philosopher.

—Mr. Weiner is the author, most recently, of “The Socrates Express: In Search of Life Lessons from Dead Philosophers,” published Aug. 25 by Avid Reader Press.