Beverly Cleary, whose early works were among the first chapter books I discovered in my elementary school library, is now 103. Back when I wrote The Washington Post’s Young Bookshelf column during the 1980s, she actually sent me an inscribed copy of her memoir “A Girl From Yamhill.” It seemed strange and wonderful that the writer whose tales of Henry Huggins had taught me to read was now asking me to review one of her books.

Starting with her first novel, Cleary introduced even third-graders to aesthetic and moral complexity. The 8-year-old hero of “Henry Huggins” encounters a starving dog, takes it home, cares for Ribsy — as he names the stray — and the two quickly become inseparable. In the final chapter, however, Ribsy’s former owner appears — and turns out to be a personable young man who loves the dog as much as Henry does.

By refusing to cast Ribsy’s earlier owner as an abusive master, Cleary complicates an already heartbreaking dilemma: To whom does the dog belong? The decision finally rests with Ribsy, who is placed halfway between Henry and the nice young man. Both then call the dog to come, the former owner using his pet’s old name. After considerable waffling, Ribsy finally trots over to Henry.

This scene proved a major turning point in my intellectual life. For the first time, I realized that stories didn’t invariably close with a Disneyish happy ending. Even though Henry got to keep his dog, the nice young man lost his (though he was granted weekend visiting privileges). Because of “Henry Huggins,” I began to understand that there were situations in life without easy or even wholly satisfying solutions. As the years passed, I grew especially wary of binary thinking, of any attitude of “us vs. them,” of rabid adherence to ideologies that valued abstract principles over real-life people. A supple, graduated response to others and their actions struck me as the hallmark of a humane and civilized intelligence.

Zealotry, after all, doesn’t deal in nuance, and it seldom cuts anyone a bit of slack. Devotees of social media, in particular, regularly flout Anton Chekhov’s profound dictum that, above all else, people must never be humiliated. No one ever forgives being insulted and demeaned. Yet just think of the indefensibly vicious tweets emitted by the smug, temporary resident of the White House. Would you want your children to talk and act so cruelly?

Absolutism, whether political, aesthetic or religious, leads to favoring those who conform to our beliefs and condemning everyone else. In the arts, this can result in near hysteria at the discovery of sexism, racism or exoticism in the masterpieces of earlier ages. Consider an example from recent literature: I find Vladimir Nabokov’s “Lolita” funny, complex, beautifully written, endlessly rereadable. Through the power of Nabokov’s art, the book’s narrator, a middle-aged man fixated on a pubescent girl, does all he can to present himself as the besotted victim in a doomed romance. In fact, the novel offers — among much else — a critique of the privileged status that Western society has accorded to romantic passion since the Middle Ages. In our cultural mythology, love doesn’t just conquer all, but it justifies all sorts of bad behavior, too. Not for Nabokov. Being in love is ultimately no excuse for monstrous actions, even if Humbert Humbert insists on his pitiable and helpless thralldom to a middle-school dame sans merci. Nabokov quietly lets us know that Lolita cries herself to sleep every night.

Still, some people now reflexively anathematize this brilliant novel because its self-justifying, unreliable narrator is a pedophile. (For that matter, he’s also a murderer.) Is subtlety, then, to be outlawed from fiction? Must every book wear its meaning on its sleeve? In that case, get ready for 21st-century analogues to the noble tractor drivers and self-sacrificing factory workers of 1930s Soviet Realism. Totalitarians invariably attack any art that fails to conform to some approved political or cultural agenda. The Nazis slapped the label “Entartete Kunst” — degenerate art — on scores of modernist masterpieces largely because the creators were Jewish.

Yet, however one defines the terms, do we really want our books to be safe and wholesome? “In the destructive element, immerse” has been the credo of many great writers besides Joseph Conrad. Try to name a major 19th-century novel whose protagonist doesn’t violate one or more of the Ten Commandments. Yes, there are a few, but for every perfect Elizabeth Bennet there’s an errant Hester Prynne, Emma Bovary, Effi Briest and Anna Karenina; for every Huckleberry Finn there’s a Captain Ahab, Count Dracula, Raskolnikov or Dorian Gray. The arts always thrive best when they are free to go too far. Alas, Mrs. Grundy and Thomas Bowdler are always lurking nearby, quick to censor and chastise.

Whenever I visit my eldest son and his family in Cleary’s hometown of Portland, Ore., I often stop by the city’s main public library. I’m usually on my way to that celebrated emporium, Powell’s City of Books, where I generally spend three or four hours searching for quaint volumes of forgotten lore. En route, I like to pay homage to Henry Huggins’s creator, so I step into the stately old building on 10th Avenue where one finds, along with adult books, the Beverly Cleary Children’s Library. On a recent trip, I bought a T-shirt from the gift shop for my 5-year-old granddaughter; it’s emblazoned with a line attributed to J.K. Rowling’s Hermione Granger: “When in doubt, go to the library.”

This is a wise and pragmatic bit of advice, even if it slightly sidesteps the importance of doubt, the skeptical, questioning mental bent instilled by reading as widely as possible. As a critic, I aim to be — in Henry James’s phrase — “someone on whom nothing is lost” and yet I never end any review without wondering if I might be wrong.

Michael Dirda reviews books each Thursday in Style.