We will have so much to say to one another when the coronavirus crisis is over: distillations from solitude, in cases like mine. At seventy-eight, with bad lungs, I’m holed up with my wife at our country place until a vaccine is developed and becomes available. It’s boring. (Remember when we lamented the distracting speed of contemporary life?) On the scale of current human ordeals, as the pandemic destroys lives and livelihoods, mere isolation hardly ranks as a woe. It’s an ambivalent condition that, among other things, affords time to think long thoughts. One of mine turns to the art in the world’s now shuttered museums: inoperative without the physical presence of attentive viewers. Online “virtual tours” add insult to injury, in my view, as strictly spectacular, amorphous disembodiments of aesthetic experience. Inaccessible, the works conjure in the imagination a significance that we have taken for granted. Purely by existing, they stir associations and precipitate meanings that may resonate in this plague time.

Why does the art of what we term the Old Masters have so much more soulful heft than that of most moderns and nearly all of our contemporaries? (I place the cutoff between the murderous scourges of war that were witnessed by Francisco Goya and those that Édouard Manet, say, read about in newspapers.) I think the reason is a routine consciousness of mortality. Pandemic diseases and innumerable other causes of early death haunted day-to-day life, even for those creators who were committed to entertainment. Consider the heaps of bodies that accumulate in Shakespeare’s tragedies: catharses of universal fear. The persistence of religion in art that was increasingly given to secular motives—Bible stories alternate with spiritually charged themes of Greek and Roman mythology—bespeaks this preoccupation. Deaths of children were a perpetual bane. Paintings of the Madonna and Child, most grippingly those by Giovanni Bellini, secrete Mary’s foreknowledge of her son’s terrible fate. The idea that God assumed flesh, suffered, and died was a stubborn consolation—Mary’s to know and ours to take on faith or, if we’re atheists, at least to marvel at as mythic poetry.

“Madonna and Child,” by Giovanni Bellini, circa 1470.

An ineffably sacramental nuance in paintings from the Dutch seventeenth century, which luxuriate in the ordinary existence of ordinary people, evokes the impermanence of human contentment. Never mind the explicitness of that time’s memento mori, all the skulls and guttering candles. I am talking about an awareness that’s invisible, but palpable, in Rembrandt’s nights—his fatalistic self-portrait in the Frick Collection comes to mind—and in Vermeer’s mornings, when a young wife might open a window and be immersed in delicate, practically animate sunlight. The peculiarly intense insouciance of a Boucher or a Fragonard—the sensuous frolics of France’s ancien régime, immune to concern about absolutely anything disagreeable, including, God forbid, social unrest—protests, in favor of life, rather too much. (Young folk dallying at court provide the sole but turbulent drama in Fragonard’s “The Progress of Love,” a marvellous suite of paintings that is also at the Frick.) Only as the nineteenth century unfolds, with improvements in sanitation and other living conditions (for the rising middle classes, at least), does mortal insecurity wane—barring such episodic ravages as tuberculosis and syphilis, which, like AIDS a century later, could seem to the unaffected to be selective of their victims—and death start to become an inconvenience in the lives of other people.

Now, in our world of effective treatments for almost anything, death obtains at the extremes of the statistical and the anecdotal, apart from those we love, of course. People slip away, perhaps with the ripple of an obituary: celebrity news items. What with the dementias attendant on our remorselessly lengthened lives, many slip away before the fact. Cancer is an archipelago of hospital medicine, normalized across the land. (I have cancer, but with fading awareness of it as immunotherapy gives me an unexpected lease on continued life.) The twentieth century shifted our sense of mass death to the political: war, genocide, and other numerical measures of evil, lately focussed on terrorism, opiates, and guns. Our mourners are respected—and lavished with optimistic therapy, as an aspect of a zeal for mental hygiene that clears away each night’s corpses before every workaday morning. We may well return to shallow complacency when the present emergency passes. (There’s the baffling precedent of the 1918-19 influenza pandemic, which killed as many as a hundred million people, largely young, and left so little cultural trace.) But right now we have all convened under a viral thundercloud, and everything seems different. There’s a change, for example, in my memory of Diego Velázquez’s “Las Meninas” (1656), which is the best painting by the best of all painters.

In December, I spent most of two days studying “Las Meninas” during a visit to Madrid, when I believed that my end was near. I had set myself the task of ignoring all received theories about this voluminously analyzed masterpiece and, on the spot, figuring out its maddening ambiguities. It’s big: more than ten feet high by about nine feet wide. Its hanging in the Prado allows for close inspection. (The picture’s illusion of a space that is continuous with the one that you occupy can make you feel invited to walk into it.) The work’s conundrums orbit the question of who—situated where in space and when in time—is beholding this placid scene in a large room at the court of the Hapsburg king (and Velázquez’s employer) Philip IV which captures life-size presences with the instantaneity of a snapshot. The painter? But he’s in the picture, at work on a canvas, with its back to us, that can only be “Las Meninas.” Some characters, mildly startled, lock eyes with ours; others remain oblivious of us. (But who are we?) There’s the riddle of a distant mirror that doesn’t show what you would assume it shows.

“Self-Portrait,” by Rembrandt, from 1658.

Presuming to grasp the whole is like hazarding a unified theory of relativity and quantum physics. Despite ending as I had started—mystified—I congratulated myself on parsing evidence of the artist’s chief ingenuity: a perspectival scheme that resolves at a viewing point not centered but offset to the right, face to face with a jowly dwarf and opposite Velázquez’s rendered position to the left. (Speculations that he must have painted the scene with the aid of a large mirror requires one to believe, implausibly, that he and a number of other visibly right-handed characters were southpaws.) I was in aesthete heaven. But, three months on, marooned by fear of the virus, I’m interested by an abrupt shift in my attitude toward the painting: from lingering exhilaration to vertiginous melancholy. “Las Meninas” is tragic, as an apotheosis of confidence and happy expectation that teeters precariously—a situation that Velázquez couldn’t have known at the time but which somehow, subliminally, he wove into his vision.

At the lower middle of the painting stands the stunningly pretty five-year-old Infanta Margarita Teresa, coolly self-possessed and attended by two maids. She is a vessel of dynastic hope, which proved not to be entirely misplaced. Unlike three other children of Philip IV and his queen (and niece), Maria Anna, she survived childhood, and, unlike her remaining sibling, a younger brother, she seems to have escaped the genetic toll of Hapsburg inbreeding. (When her brother ascended the throne, as Charles II, his ruinous disabilities, impotence among them, ended the dynasty in Spain, amid the country’s steep decline as a European power.) Margarita Teresa lived to the ripe age of twenty-one, married off for diplomatic reasons, at the age of fifteen, to become the Empress of the Holy Roman Empire and to bear four children, only one of whom outlasted infancy. Her reputed charms did not include her vicious anti-Semitism. (She encouraged her husband, Leopold I, to expel Jews from Vienna and to convert the city’s main synagogue into a church.) But the glory of her promise in “Las Meninas” suddenly casts, for me, a shadow of ambient and forthcoming death and disaster. There would never be another moment in the Spanish court so radiant—or a painting, anywhere, so good. It’s the second to last of Velázquez’s greatest works. He all but discontinued painting, in favor of taking on more prestigious court duties, and died in 1660, at sixty-one. Philip IV survived him by five years.