During a graduate-school lecture on “Lolita,” my professor stood up in front of a crowded classroom and said something I have never been able to shake: “When you read ‘Lolita,’ keep in mind that what you’re reading about is the systematic rape of a young girl.”

I had read “Lolita” in high school and then again in college, when it became my personal literary liquor store—whenever I got stuck in a scene, or whenever my prose felt flat or typical, I’d open “Lolita” to a random page and steal something. My professor’s pronouncement felt too didactic, too political, and, although I tried to put it out of my mind and enjoy “Lolita” ’s cunning, surprising games with language, I could no longer pick up the book without feeling the weight of his judgment. The professor wasn’t wrong to point out the obvious about Humbert and Dolores Haze, and I don’t believe—at least not completely—that literature should only be examined as an object unto itself, detached from time and history, but I haven’t read “Lolita” since.

I thought of that professor and his unwelcome intrusion when I read a page-one story in last week’s Times about how several colleges across the country have considered placing “trigger warnings” in front of works of art and literature that may cause a student to relive a traumatic experience. For example, a student might be forewarned that J. M. Coetzee’s “Disgrace” details colonial violence, racism, and rape with a note on the class syllabus that would read something like “Trigger Warning: This book contains scenes of colonialism, racism, and rape, which may be upsetting to students who have experienced colonialism, racism, or rape.”

The story’s headline, “WARNING: THE LITERARY CANON COULD MAKE STUDENTS SQUIRM,” and the inclusion of some seemingly innocuous titles, like “The Great Gatsby,” as candidates for such warnings, dredged up all my distaste for my professor’s prescriptive reading of “Lolita.” If he could produce such a chilling effect, what harm could a swarm of trigger warnings—each one reducing a work of literature to its ugliest plot points—inflict on the literary canon? What would “Trigger Warning: This novel contains racism” do to a reading of Ralph Ellison’s “Invisible Man”? What would “Trigger Warning: Rape, racism, and sexual assault” do to a reading of Toni Morrison’s “Beloved”?

Social media, which mostly acts as an agreement machine whenever the liberal consensus squares off with a more radical cousin, seemed to confirm my annoyance. The novelist Darin Strauss tweeted, “Trigger Warning: All human experience.” Matt Bai, a national columnist for Yahoo News, added, “Maybe the entire Web should have ‘trigger warning’ so I never have to feel uncomfortable or challenged.” Colson Whitehead joined in: “Your face should have a trigger warning for reminding me you exist.” There were dozens of other examples, from jokey to dire, and, by the time the news cycle kicked up on Tuesday, op-eds questioning the use of trigger warnings had been published in the Guardian, the Atlantic, and Mother Jones.

Out on the far end of the agreement machine, feminist writers and academics defended the use of trigger warnings, and tried to explain their utility and their history. The modern iteration of “trigger warning,” or “TW,” as it’s commonly written, came out of the feminist blogosphere, and, like many other terms used within insular, politically active communities, addressed a specific need. Roughly ten years ago, editors at feminist and progressive Web sites realized that they needed a way of encouraging frank and candid conversation about sexual assault without catching readers unaware. Many survivors of sexual assault experience symptoms of post-traumatic stress; graphic depictions of rape or violent attacks can trigger flashbacks, nightmares, and crippling anxiety. The editors theorized that a warning posted before disturbing narratives could allow readers to prepare for what might be an upsetting but, ultimately, necessary conversation.

“Censorship was never the point,” Alexandra Brodsky, an editor at the Web site Feministing, told me. “We knew that violent and traumatic narratives could have a grave effect on the reader, so we, working together as a community, created guideposts for people to navigate what has always been a tricky terrain.” Those guideposts helped. Trigger warnings “made people feel like they could write explicitly and honestly about things that they may have not written about under different circumstances,” Brodsky said. “They let people know that this was going to be a different type of conversation.”

That logic eventually found its way into the academy. Last year, Bailey Shoemaker-Richards, a master’s student at the University of Findlay, in Ohio, started using trigger warnings in her academic presentations on cyber sexism and online abuse. The warning, she said, takes up roughly fifteen seconds at the start of a talk, and serves only as a reminder that those who are uncomfortable discussing online abuse are free to leave the room. “I don’t think a trigger warning will prevent conversations that may be upsetting,” Shoemaker-Richards told me. “But they might force people in the class to think through their reactions a little more.” Shoemaker-Richards’s use of trigger warnings largely mirrors the way that they have been implemented in classrooms across the country, and, although the term itself sounds forbidding and censorious, in practice these warnings are meant to protect students from public traumatic flashbacks. “If you know you’re about to read a graphic depiction of state racism, and you know that you’d rather be at home than in the library, the trigger warning is just information you need to make that decision,” Brodsky explained.

Brodsky feels conflicted about university-mandated trigger warnings for potentially troubling works of art and literature, as do other feminist thinkers I spoke to, but she still thinks that they should be used in the classroom. “You can’t copy the language from a Jezebel post and paste it onto a syllabus,” Brodsky explained. “With that being said, literature is important, and has effects beyond momentary pleasure and discomfort. ‘Trigger Warning: Colonialism,’ seems a bit reductive, but there should be a way that we acknowledge that what we’re going to read will have a significant impact.” The expansion of higher education onto the Internet has depersonalized the classroom, Brodsky argued, and with fewer settings in which a professor can adequately prepare a class for a potentially disturbing work of literature or art, trigger warnings could stand in, at least in part, for a nuanced and sensitive introduction.

It should be noted that none of the schools cited in the Times article have actually implemented a policy that would mandate trigger warnings, and that college classrooms have often served as testing grounds for vital policies that might at first have seemed apocalyptic or Pollyannaish. Trigger warnings could eventually become part of academic environments, as unobtrusive and beneficial as wheelchair ramps and kosher toaster ovens.

Many of the op-eds and articles on trigger warnings published this week have argued on behalf of the sanctity of the relationship between the reader and the text. For the most part, I have agreed with them. A trigger warning reduces a work of art down to what amounts to plot points. If a novel like José Saramago’s “Blindness” succeeds because it sews up small yet essential pockets of human normalcy against a horrific backdrop, a preëmptive label like “Trigger Warning: Violence and internment” strips it down to one idea.