It is too soon to tell what the motive was behind the accused James Holmes’ mass murder in a movie theater in Aurora, Colorado, especially now that he has stopped talking to the authorities in charge of his case. Reports about his personality, thoughts, and behaviors from friends, fellow students, professors, and the police are conflicting. He was smart, brilliant in fact. No, he wasn’t; he was a sub-standard student who dropped out of his doctoral program at the University of Colorado after failing a preliminary exam. He was a quiet man who said nothing to indicate he was on the verge of cracking. Also not true; he left an incoherent and rambling voice message on the phone service of a gun club he wanted to join, the owner of which noted: “It was this deep, guttural voice, rambling something incoherent. I thought, ‘What is this idiot trying to be?’.” He rigged his apartment with explosive devices but then warned the police about them after his capture. Initial reports described the event as spontaneous and random, but he mailed a notebook to his psychiatrist at his university describing in detail with diagrams precisely what he (pre)planned to do.

It may be months before we have any clue to his mind and motive. And short of something obvious like a brain tumor pressing against his amygdala (the brain’s emotion center)—similar to that in the brain of Charles Whitman, the University of Texas bell tower shooter who in 1966 killed 14 people and wounded 49, including himself, after leaving a note to authorities to autopsy his brain because he felt there was something wrong—we may never know the motive behind James Holmes murderous actions.

We do know something for certain, however, and that is that this will happen again…and again and again. The reason is the law of large numbers that I will outline below that are disturbing enough that it really is now time to rethink our gun-control laws to include the prohibition of semi-automatic assault rifles like those Holmes’ allegedly used to murder 12 and wound another 58 in a matter of seconds. Had he not had such weapons—possessing, say, only a pistol purchased for self-defense—the tragedy would surely have been lessened. Thus, even though I am a life-long libertarian who champions freedom in all spheres of life and has previously opposed gun-control measures in principle (I do not personally enjoy hunting or recreational gun shooting), I now believe that the freedom of a few people to own WMMs (Weapons of Mass Murder) conflicts with the freedom of the rest of us to enter the public sphere without the chance of our ultimate freedom of life itself being cut short. Here are a few figures that should give even the most freedom-loving libertarian and conservative pause.

First, there’s a good chance that James Holmes is schizophrenic, suffered from severe depression, or is a psychopath. According to the National Institute of Mental Health, Schizophrenics account for about 1.1 percent of the U.S. population over the age of 18, with the onset of occurrence most likely in the early to mid 20s. Major depressive disorders strike about 6.7 percent of Americans over the age of 18. Psychopathy is a personality disorder characterized by lacking empathy and guilt, shallow emotions and cold-heartedness, impulsivity and antisocial behaviors, and most notably criminality. According to University of Cambridge psychologist Kevin Dutton, author of the forthcoming book The Wisdom of Psychopaths: What Saints, Spies, and Serial Killers Can Teach Us About Success (Farrar, Straus and Giroux, October 16, 2012), whom I queried for this article, “estimates of the incidence of psychopathy tend to vary from 1–3 percent in men to 0.5–1 percent in women,” and in prison populations “around 50 percent of the most serious crimes on record—crimes such as murder and serial rape, for instance—are committed by psychopaths.”

As a back-of-the-envelope calculation, let us employ a figure of 2 percent across these three disorders (Schizophrenia, major depression, and psychopathy) for men only (since such mass murders are almost always committed by men)—by the law of large numbers the following calculations indicate that the Aurora tragedy is by no means a one-off event and that it will happen again:

The current U.S. population is approximately 314 million, about half of which are males, so if 2% of the 157 million American men suffer from one of these severe disorders, this results in a figure of 3,140,000. Most of these men are not violent; in fact, recent studies on psychopathy, for example, show that many are successful CEOs, politicians, and Wall Street traders and executives who employ their psychopathic personality traits of tough-minded and emotionless impulsive decision making to great effect in the rough-and-tumble world of business and politics. And most Schizophrenics and sufferers of severe depression are not violent. So let’s conservatively estimate that if only 1% of these 3,140,000 men commit any kind of violent act, this results in 31,400 acts of violence per year, a nontrivial number.

If only 1% of those violent acts involve murders, this leaves us with 314 unnecessary tragic deaths caused by psychopaths. And, finally, if only 1% of those murderous violent acts involves killing multiple people at once, this results in a rate of 3.14 Aurora-size mass murders per year in America, which is actually lower than the rate of around a dozen per year that we have been averaging the past half century, depending on what constitutes a mass murder (school-shootings alone that amount to more than one killed in one event happen on average once a year in the U.S.).
 
Again, it’s too early to say whether or not Holmes was a Schizophrenic, suffered from severe depression, or was a psychopath, and the specific figures of how many mass murders there are per year vary across different data sets, but my point is a larger one: A large-numbers analysis allows us to understand on a societal-level scale why such events happen randomly and without any specific cause common to all (drugs, gangs, bullying, depression, psychopathy, psychosis, violent video games, and the like). History and population demographics for rates of mass murder show that Aurora-size events are going to happen again and again and again, and there is no way to predict who is going to do it, where, or when. (With the possible exception of a national database that tracks and alerts authorities to the purchase of mass quantities of guns and ammunition by private citizens.) All we know is that it will happen again—for certain.

Thus, damage control is the only option we have, if we want to do something about this tragic social problem. And by damage control I mean gun control. Specifically, I mean outlawing all automatic and semi-automatic assault rifles for anyone who is not in law enforcement or the military. When the Second Amendment was written stating that citizens have a right to “keep and bear arms,” rifles took over a minute to load one bullet at a time. The most crazed 18th century American could not possibly commit mass murder because no WMMs existed at the time.

My fellow libertarians are likely to see this as another loss of freedom, but I disagree. The principle of freedom states that all people are free to think, believe, and act as they choose, so long as they do not infringe on the equal freedom of others. But the freedom for me to swing my arm ends at your nose. The freedom for you to own any gun you like is in conflict with my freedom to interact freely with my fellow citizens in public spaces when so many madmen mingle among us. We should ban assault weapons of all kinds. We already disallow private citizens to own nuclear weapons, missiles, grenade launchers, and the like. WMMs that can be secreted into a movie theater should be categorized among those we can no longer tolerate. This is no loss of freedom. It is, in fact, an increase in freedom—the freedom to move about our living spaces without fear of being gunned down in cold blood.

If you think I am exaggerating, or that my calculations are nothing but mathematical hyperbole, just consider the case of Aurora victim Jessica Ghawi, who was almost gunned down in a shopping mall in Toronto in another public shooting the month before, after which she reflected on her blog: “I was shown how fragile life was on Saturday. I saw the terror on bystanders’ faces. I saw the victims of a senseless crime. I saw lives change. I was reminded that we don’t know when or where our time on Earth will end. When or where we will breathe our last breath.”