Writing not quite a century later, T. S. Eliot set out his measurements of a classic as “maturity of mind, maturity of manners, maturity of language, and perfection of the common style.”

It’s easy to see that neither of these definitions will really suit our current understanding of the word. Eliot thought that a classic, in the strictest sense, was a work that apotheosized a great civilization at its zenith; so exacting (or, if you like, priggish) are his standards that literally the only writer to entirely fulfill them is Virgil. He thought Chaucer and Shakespeare were a little too rough around the edges, Goethe too provincial, Pope too mannered. Except for a passing mention of Henry James, he doesn’t even bother to mention the existence of American letters.

Sainte-Beuve is more flexible and encompassing, but he stipulates that a classic can only be truly distinguished by readers who have enjoyed a lifetime of learning and have staked out the leisure to devote themselves to their libraries. It exists as a concomitant to the salon and the ivory tower.

So if Eliot is imperialist and Sainte-Beuve is aristocratic, we need some idea of what makes a classic in a democracy. For that, we could do worse than to turn to Sainte-Beuve’s contemporary Alexis de Tocqueville, who has always seemed to have the new world’s number. In “Democracy in America,” de Tocqueville observed that Americans esteemed the arts and sciences more for their practical applications than for their abstract value—hence the popularity of newspapers, religious treatises, and self-help books. Reading itself was not done for the purposes of something as perversely theoretical as enlarging one’s soul; it needed to have some tangible function in the here and now: “Democratic nations may amuse themselves for a while with considering the productions of nature; but they are excited in reality only by a survey of themselves.”

A look through the Classics section of bookstores—in America or any of the Western democracies—bears out de Tocqueville’s instincts. The offerings are wide-ranging, tilting toward diversity and inclusion. But, more to the point, artistic brilliance is no longer the most important determining factor. What makes a classic today is cultural significance. Authors are anointed not because they are great (although many of them are) but because they are important.

In other words, the current criteria for classics are more a matter of sociology than of aesthetics. That’s why prose-toilers like George Orwell and Aldous Huxley are securely fixed in the canon while masters such as Frank O’Connor and Eudora Welty could easily be left out. “1984” and “Brave New World” are embedded in the weave of language and history, but what does Welty have going for her apart from stylistic perfection? Henry Miller survives—and will continue to survive—because the country once found him shocking enough to censor. (Likewise, D. H. Lawrence might very well be a footnote if not for “Lady Chatterley’s Lover.”) There’s better prose in the average issue of Consumer Reports than in most Upton Sinclair novels, but “The Jungle” triggered actual legislative reform and will therefore last as long as the United States does.

If there was once a notion of immortal writers from across the eons orbiting together in an artistic cosmos, contemporaneous in their timelessness, the ways that the Great Books are presented on school curricula today underscore a perceived domino effect of historical necessity. The Greeks and Romans are important because they influenced the Renaissance. The Renaissance is important because it diminished the hegemony of the church. It also gave us the Enlightenment, which gave us the modern democracies, which brings us back to the present. There’s always an element of pragmatic self-interest in the way these books are elevated. Imprints devoted to reissuing classics—like Penguin, Oxford, Virago, and New York Review Books—are magnificent boons to readers, the best things to come of the democratization of the classic. But these places have bills to pay, and it does them no good to overly refine their standards—they’re geared to call a book a classic under any plausible pretext they can find.

Just think how literary critics must feel about these developments! They have become effectively superseded in a process they once regulated. Yet that fact also gives them an exhilarating kind of freedom. Parallel to the, shall we call it, mercantile nature of the classic is a wide-open field in which critics can argue for or against the literary merits of just about anything. No one can hope to force “The Grapes of Wrath” out of high-school syllabi—it’s the answer to S.A.T. questions about the Great Depression, after all. But critics could, if they were so inclined, contend that it’s an objectively bad book. Once a fundamental faith in the artistic quality of classics disappeared, the Western canon became the Wild West. Want to make the case that the Bible is an overrated mishmash of philosophically confused codes and folklore? You’ll get a hearing. Want to stand up in public and declare that Milton was a simpleton? You might get tenured.

Of course, it can be pretty unseemly. There’s a brilliant chapter in Vance Bourjaily’s (dare I say it, classic) novel “Now Playing at Canterbury” called “Fitzgerald Attends My Fitzgerald Seminar.” In it, a washed-up literature professor recounts one of his recurring nightmares: He’s leading his graduate class on modern literature when, unnoticed by his students, F. Scott Fitzgerald walks in and takes a seat in the back. The students begin to give their oral presentations on some of Fitzgerald’s early stories, and they’re merciless—they mock his mannerisms, his overreaching prose, his outré gender politics. The professor, who grew up adoring Fitzgerald, is horrified. He glances to the back to see his idol—this is the author post-“The Crack-Up”—looking wounded and perplexed.

So might he appear now, upon discovering his third novel, very much a transitional work, being panned in a feature article in New York magazine eighty-eight years after he wrote it. Yet what Bourjaily’s professor also understands is that his students, however callow and showoffy, are also passionate about literature and what they believe it should stand for. The truth, with all due deference to Joyce Carol Oates, is that we don’t read classics as though they’re monuments like the Grand Canyon. (Speaking as someone who has joyfully expectorated into it on numerous occasions, we don’t even treat the Grand Canyon like the Grand Canyon.) It’s not the way of egalitarian societies. And that willingness to subject legends to the same hazing as any eager tyro fresh from a writing program is what gives the criticism of our age its vulgarity but also its vitality.

This means, then, that it’s no good airily dismissing a wrongheaded dismissal. If some marauding Philistine attacks a book you love, you have no choice but to gird your loins and fight for it. Because the only time the classics can expect to find peace is when the dreaded day comes that nobody is reading them.

Sam Sacks writes the Fiction Chronicle for the Wall Street Journal and is an editor at Open Letters Monthly.

Illustration by Kris Mukai.