Bobby is a brilliant scientist. So brilliant, in fact, that he builds a functional atomic bomb in his garage. Of course, Bobby strictly adheres to the non-aggression principle, so he has no plans to use his bomb to attack others. But he’s proud of his scientific accomplishment and hangs the bomb on his fireplace mantel as a trophy.

Should Bobby be permitted to possess this atomic bomb? Surely not. The reason is simple: the risk to others is simply too great.

So what’s the point of this parable? It offers a reductio ad absurdum of the typical rights-based arguments that libertarians make against gun control. The first such argument asserts that gun control deprives people of a means of self-defense. That’s certainly true. But bomb control—depriving Bobby of his bomb—deprives Bobby of a means of self-defense.

To see why, suppose Bobby posts a sign on his front lawn alerting potential intruders that he’ll bomb them should they enter his house. That’s a pretty effective means of defending himself. (You’re probably thinking that this is a bad way of defending himself, since he’ll die too. Fair enough. But just imagine that he can run into a bomb shelter before the bomb detonates. Or just change the example: to defend himself, he releases into the atmosphere a synthetic, lethal, airborne disease to which he is immune.). Nevertheless, depriving Bobby of this means of self-defense is justified on the grounds that not depriving him of this means of self-defense would mean tolerating intolerably high risks to others.

Another libertarian objection to gun control is that it deprives individuals of their private property. But bomb control deprives Bobby of his private property. Bobby justly acquired all of his materials, mixed his labor with them, and produced the bomb. On a Lockean story, Bobby privately owns the bomb. Nevertheless, depriving Bobby of this bit of private property is justified on the grounds that not depriving him of this bit of private property would mean tolerating intolerably high risks to others.

The final objection I’ll consider is that gun control opens the door to state tyranny. Gunless citizens are less equipped to resist abuses of state power. But an atomic bomb is at least as effective in deterring state oppression as a handgun. Nevertheless, depriving Bobby of this means of deterring tyranny is justified on the grounds that not depriving him of this means of deterring tyranny would mean tolerating intolerably high risks to others.

To be clear: my argument is not that gun control is justified. I take no stand on the issue. In fact, that’s pretty much my point: the case for or against gun control shouldn’t be made on the basis of philosophical arguments about rights. Instead, the issue should be decided on the basis of a cost-benefit analysis: e.g., does robust access to guns increase or decrease the general risk of violent crime, death, etc? That’s a social scientific question. What I do claim is that the kinds of rights-based arguments against gun restriction that libertarians often make are unsuccessful.