Surveillance camerasSurveillance camerasIn the week since the Tsarnaev brothers--19-year-old Dzhokhar and 26-year-old Tamerlan--bombed the Boston Marathon, pundits have practically inducted the two into the Islamic Terrorist Hall of Fame. But what if the Tsarnaevs' act of terror has less to do with their extreme religious beliefs, and more to do with biology? New York's Lisa Miller:

The older one looks like some kind of loser, a boxing maniac with a love for trashy Euro style. But Dzhokhar, the younger brother, well, he seems like a sweetie pie, with those moony eyes and that fuzzy halo of hair.

Which just goes to show that evil may not have a single face, but it can be reliably found within one kind of body: that of an angry man in his late teens or twenties.

Adam Lanza, Timothy McVeigh, Jared Lee Loughner, James Eagan Holmes, Seung-Hui Cho—some of these villains were afflicted with mental illness, some of them drawn to extremist ideologies. It was easy to distance ourselves from each of them with a variety of alienating labels: autistic gun nut, domestic terrorist, sociopath, embittered immigrant loser. But they have three things indisputably in common. Their gender. Their youth. And a willingness to hate, which forensic psychiatrist Michael Welner distinguishes from simple anger. “You have to be hateful of everyone to kill anyone,” he says. “A person who will undertake a spectacle crime or a mass killing, that is one of the defining qualities: They don’t care that anyone can be killed.”

Angry. Young. Men. The description doesn’t explain the motivations behind every notorious bloodbath, but it’s a place to start—perhaps the only place to start. Men have testosterone, an aggression drug, coursing through their veins; levels rise under stress, and young men have more of it than older ones.

Miller's psychobabble is a close cousin to James Livingston's post-Sandy Hook argument that industrialization makes men feel less like men, which causes them to do awful things beyond their control:

Adam Lanza can’t be accused or convicted of “unconscionable evil,” not in the court of public opinion and not by the criteria of moral philosophy. He wasn’t making a moral choice when he shot his mother in the face with her own gun, and then killed 20 defenseless children. So individual responsibility and culpability aren’t at issue, as they have not been and cannot be since Columbine.

But still. Let us also ask the obvious question. Why do these young white male people whom we routinely characterize as crazy—as exceptions to the rules of civilized comportment and moral choice—always rehearse and recite the same script? If each killer is so deviant, so inexplicable, so exceptional, why does the apocalyptic ending never vary?

The answer is equally obvious. Because American culture makes this script—as against suicide, exile, incarceration, or oblivion—not just available but plausible, actionable, and pleasurable. Semiautomatic, you might say.

But mainly to young white male people who want to kill many other white people with sophisticated weapons.

In Miller's framework, every man is a potential mass murderer because of his biology; in Livingston's, every white man without an explicit religious motivation is a potential mass murderer because of capitalism/mechanization/industrialization. I have a hard time deciding which theory is more offensive to the billions of men across the globe who don't engage in mass murder.