After students earlier this spring at a handful of American colleges and universities formally requested that faculty warn them in syllabi about course content that might “trigger” difficult, dangerous or traumatic feelings, an intriguing educational-cultural debate has been bubbling along nicely — and the battle lines over “trigger warnings” have been drawn in fairly predictable ways.

On one rampart you have critics like American essayist Joseph Epstein who, in a recent Wall Street Journal column, denounces such “syllabus alerts” as symptomatic of the malaise of political correctness and identity politics afflicting higher education. In a distant trench, the foot soldiers of various interest groups and demographic subsets argue that particular sensitivities, as well general human frailty, warrant these early warning beacons.

It’s not clear why this topic has emerged now in quite this fashion, but as colleges fill up with returning war veterans — a group with officially recognized psychological needs — and pay closer attention to the needs of students who have suffered sexual assaults, this might be the moment to analyze the trigger-warning phenomenon.

What critics like Epstein fail to distinguish is the use of a reasonable instructor’s teaching tool — the preview of course content — from what he describes as an ignoble desire to “protect the minority of the weak, the vulnerable, the disheartened or the formerly discriminated against, no matter what the price in civility, scholarly integrity and political sanity.”

So I guess we could start by saying that many hardline opponents of the trigger warning are lucky. They have not, apparently, experienced the slings and arrows of the outrageous fortunes which assail others and which generate feelings of — gasp! — vulnerability and weakness.

Good teachers know their students bring to the classroom many intellectual, emotional, spiritual and moral conditions. Good teachers also explain quickly — in syllabi, course guides or introductory lectures — a course’s focus, scope, themes and methodologies. No professors worth their salt pull unadvertised rabbits out of pedagogical hats. Courses labeled as Shakespearean comedy don’t feature “King Lear” and “Macbeth,” nor do botany courses produce trays of frogs for dissection.

Trigger warnings are merely fashionable micro-management versions of what careful instructors do already. Students not liking the preview may choose to withdraw from the course. Once students are permanently signed up and unable to leave, there is still a place to avoid inflicting unnecessary misery while maintaining or even strengthening intellectual heft. Some version of the trigger warning is entirely appropriate here.

Material addressing combat, madness, sexual violence, harrowing death or torture, for example, might needlessly re-traumatize those still struggling with painful memories or aggravate the burdens of their present experiences.

Trigger warnings allow students to consider their options. After all, in ordinary social life, we would not blithely recommend books or movies about death, sickness, battle, bankruptcy or any other awful event to someone we knew to be closely touched by such things. Why not warn a bereaved friend about the harrowing death scenes of the hero’s mother in D. H. Lawrence’s novel “Sons and Lovers”? Or a recovering alcoholic about the Nicolas Cage character’s struggles in “Leaving Las Vegas”?

These alerts are surely indicators of the very civility opponents believe is threatened. We should extend the same politeness to our students.

Of course, no smart instructor allows any student to frivolously claim special privileges to lighten the workload or to escape the toils of class discussion. But alternative materials, relevant and valuable, may be assigned; the negotiation itself should help teach tough, reasoned discourse.

And, as many have noted, the trigger warnings at the center of this little cultural eddy are merely extensions of the usual reviews, movie ratings and “back-cover” categorizations by publishers. They are not instruments of censorship, unless we equate the instructor’s very selection of materials for academic study as sinisterly restrictive.

Trigger warnings — and this whole debate — show that we are more astute than we used to be in parsing the fascinating and delicate relationships between instructors and students; that we are thinking more carefully about the shared intellectual and moral responsibilities of the classroom; and that we are better attuned to at least some of the mysterious forces that shape different people’s responses to the things they read, watch and hear.