... Many professors have run across more than their share of [disturbed students who scare them]. At least one Virginia Tech professor noticed that Cho Seung-Hui, who killed 32 people on campus on Monday, was potentially dangerous and did her best to warn the administration and the police. (So did at least two female students.) But there is only so much a teacher can do — “students have rights, too.” [This is what an administrator at Oakley's university told her when she complained about one such student.]

It’s a simple fact that, for every deranged murderer like Mr. Cho there are thousands more oddballs just below the breaking point. I know one quasi-psychopathic incompetent, for example, who remained on the campus payroll for over a dozen years simply because his supervisor was afraid of being killed if he was fired.

It’s long been in fashion to believe that people are innately good, and that upbringing and environment are responsible for nasty personalities. But research is beginning to show that mean, sometimes outright evil behavior has a strong genetic component. Some of us, in other words, are truly born bad.

Researchers at King’s College London have recently determined that if one identical twin shows psychopathic traits, the other twin, who coincidentally shares precisely the same set of genes, has a very high probability of having the same psychopathic traits. But among fraternal twins, who share only half their genes, the chance that both twins will show psychopathic traits is far smaller. In other words, there is something suspiciously psychopath-inducing in some people’s genes.

What could it be? Medical images of the brain give tantalizing clues — the amygdala, the “fight or flight” decision-making center of the brain, may be smaller than usual, or some areas of the brain may glow only dimly because of low serotonin levels. We may not know precisely what set Mr. Cho off, but we are beginning to home in on the unusual differences in certain neurochemistries that can make people act in bizarre and dysfunctional ways.

Still, the Virginia Tech shootings have already led to calls for all sorts of changes: gun control, more mental health coverage, stricter behavior rules on campuses. Yes, in a perfect world, there would be no guns, no mental illness and no Cho Seung-Huis. But the world is very imperfect. Consider that Britain’s national experiment with gun-free living is proving to be a disaster, with violent and gun crime rates soaring.

In other words, most of the broad social “lessons” we are being told we must learn from the Virginia Tech shootings have little to do with what allowed the horrors to occur. This is about evil, and about how our universities are able to deal with it as a literary subject but not as a fact of life...