Just as with JFK’s assassination and the Challenger explosion, I remember precisely where I was and what I was doing when I first heard about a school shooting. On Aug. 1, 1966, Charles Whitman collected his small arsenal and rode the elevator to the observation deck of the landmark tower on the campus of the University of Texas at Austin. Thirty-two floors above the ground, he had an excellent field of fire in all directions and, an expert marksman, went on a murderous rampage before he was fatally shot by police.

No one really knows why Whitman did it. His autopsy revealed a brain tumor that may — or may not –have affected his emotions. In any case, brain tumors can’t account for all the shooters who followed Whitman in a grisly succession of incidents and hundreds of victims.

The shooters are often alienated young men, loners with troubled backgrounds and an infatuation with guns. Some defy profiling, and their actions feel like a surprise. In retrospect, some of their behaviors may seem suspicious, but often the shooters are indistinguishable from their classmates.

This must occur to many college professors all across the country after shootings like those at Northern Illinois University on Feb. 14 or Virginia Tech last April. Every semester they develop a complicated relationship with as many as several hundred strangers with an extraordinary range of personalities and backgrounds.

Many are respectful and friendly, compliant and willing to work hard to please or for a good grade. Others are dour and sullen, but only a very few are patently belligerent. They dress informally, and many are elaborately tattooed and pierced. Some of them read books and others are addicted to violent video games. Drugs are not unheard of. In short, they’re not much different from the range of young people one would encounter in the local grocery store.

The atmosphere in many classrooms is friendly and cooperative. These days there are fewer aloof, unapproachable professors who stoop to tolerate students only during office hours. And the modern student body — larger, older and much more diverse — is less inclined to offer to professors the unquestioning, worshipful respect it might have in the past. All in all, many of us consider these changes to be good ones.

Nevertheless, every college classroom floats on a tacit current of tension. Quite a bit is at stake, not least of which is the money required for an increasingly expensive education. For many students, learning means piling up a load of debt that will last for years.

But there’s more. No matter how friendly and collegial the atmosphere that develops in the best classrooms, eventually the professor will make judgments about the quality of the students’ work that will have significant effects on their futures, as well as on their sense of competence and worth. Sometimes, those judgments may seem arbitrary and unfair.

And on top of all of the tensions of college life, many students are struggling with complicated personal lives that include long hours at menial jobs and the cares of parenthood.

Of course, shooters like Steven Kazmierczak and Seung-Hui Cho aren’t just normal students who were pushed over the edge by the pressures of college life. In fact, most students survive the pressure. Nevertheless, colleges and universities produce special tensions that challenge the most stable of psyches.

How do we make them safer? In lieu of a good answer to that question — which I don’t have –permit me to object to a solution that’s always proposed in the wake of the latest shooting: abolishment of the gun-free zones that most colleges and universities enforce.

This solution has a certain logic. But even if only a small percentage of the students in a crowded lecture hall are carrying a legally concealed handgun, the results are likely to be chaotic. Even among trained soldiers at war, “friendly fire” casualties are sometimes estimated to be as high as 25 percent.

Had I been present at Northern Illinois, would I have wanted a weapon? Of course. But do I want my students to be permitted to carry concealed weapons on campus when final grades come out? No. Deadly weapons and undisciplined shooters are a bad mix in the already volatile cauldron of college life.

(John M. Crisp teaches in the English Department at Del Mar College in Corpus Christi, Texas. E-mail him at jcrisp(at)delmar.edu.)