The writers Kazuo Ishiguro and Ursula K. Le Guin are having a highly old-fashioned debate about the distinction between literary and genre fiction. Ishiguro started it, in an interview with The New York Times about his latest novel The Buried Giant, when he asked "Will readers follow me into this? Will they understand what I'm trying to do, or will they be prejudiced against the surface elements? Are they going to say this is fantasy?" Le Guin didn't like the tone of that last remark and fired back, "Well, yes, they probably will. Why not? It appears the author takes the word for an insult." Now Ishiguro has defended himself, rather meekly, by saying, "I am on the side of the pixies and the dragons." The whole spectacle is very odd. It sounds like a debate from another era. What writer today would feel any need whatsoever to separate him or herself from fantasy or indeed any other genre? If anything, the forms of genre—science fiction, fantasy, the hardboiled detective story, the murder mystery, horror, vampire, and werewolf stories—have become the natural homes for the most serious literary questions.

Only idiots or snobs ever really thought less of "genre books" of course. There are stupid books and there are smart books. There are well-written books and badly written books. There are fun books and boring books. All of these distinctions are vastly more important than the distinction between the literary and the non-literary. Time has a tendency to demolish old snobberies. Once upon a time, Conan Doyle was embarrassed by the Sherlock Holmes stories; he wanted to be remembered for his serious historical novels. Jim Thompson's books—considered straight pulp during his lifetime—are obviously as dense and layered and confounding as great literature. Correction: They are great literature. Who really thinks, today, that Stanislaw Lem isn't a genius, that he's "just a science fiction writer"?

More recently, writers of a more explicitly literary bent have explored genre with more and more regularity. Colson Whitehead's zombie novel Zone One was both a bestseller and a critical darling. Chang-rae Lee's On Such a Full Sea is literature and genre fiction, simultaneously, with no sense of contradiction. In a self-referential move, Emily Mandel's Station Eleven, a National Book Award finalist in 2014, predicts a post-apocalyptic future in which artists treat Star Trek and Shakespeare with absolute equality. This is the future, and also to a certain extent the present.

Resistance to genre, among literary writers, has given way to eagerness to exploit its riches. The boundaries between high and low are increasingly meaningless for audiences. But there are aesthetic reasons for embracing genre as well. For novelists—and I should probably acknowledge at this point that I have a novel with werewolves out right now, The Hunger of the Wolf—generic forms offer a freedom of scope that literary realism simply no longer does.

The landscape of realism has narrowed. If you think of the straight literary novels of the past decade—The Marriage Plot, The Interestings, The Art of Fielding, Freedom—they often deal with stories and characters from a very particular economic and social position. Realism, as a literary project, has taken as its principle subject the minute social struggles of people who have graduated mainly from Ivy League schools. The great gift of literary realism has always been its characteristic ability to capture the shifting weather of inner life, but the mechanisms of that inner life and whose inner lives are under discussion have become as generic as any vampire book: These are books about privileged people with relatively small problems.

Not that these small problems can't be fascinating. It is exactly the best realist novels of our moment which are the most miniature: In Teju Cole's Open City, a man and his thoughts wander over various cities. In Adelle Waldman's The Love Affairs of Nathaniel P., the action consists of the tiny fluctuations of the inordinate vanity and self-loathing of the main character. Both novels are superb, and both are focused on the most minute of details. They draw larger significances from those details, certainly, but the constraints are ferocious. Any discussions of politics or any broader aspect of the human condition are funneled through the characters' fine judgments.

In the wide-open spaces left by the narrowing of realism, genre becomes the place where grand philosophical questions can be worked out on narrative terms. You will occasionally read about a mobile phone in a realist novel, but the technology's meaning, and consequence, are much more thoroughly handled in a book like Super Sad True Love Story. Freedom deals with the environmental crisis, it is true. But a book like Station Eleven deals with the fate of our species and the possibilities of art, ideas of a scope which the realist imagination, at least of our moment, can no longer stomach.

Properly speaking, there is no outside of genre anymore; one may choose to write vampire books or werewolf books or horror books or one may choose to write books in the genre known as "literary fiction." For most of the 20th century, literary art dreamed of an escape from genre, an escape from the restraints of type and stereotype and, above all, the market. In the 21st century, the traditional roles have now been reversed. I can only assume that Ishiguro misspoke in his Times interview, because in The Buried Giant and in Never Let Me Go, he used the forms of genre writing as beautifully and as profoundly as anyone. He knows the "literary bigots" today are the ghetto-dwellers. Realism is a closed shop. Genre fiction is open.