[cross-posted in L & P comments section]
Wendy McElroy argues that while isolating a Typhoid Mary may be justified, it cannot be justified according to libertarian principles.
I disagree. I don’t define aggression as an intentional action; as I see it, what makes an action a rights-violation has more to do with what a person does than with why she does it. Only overt acts fall under the jurisdiction of the law – not inner thoughts; hence there’s no basis for treating intentional violations differently from unintentional ones. (That’s also why I’m against punishment, i.e., any coercive treatment that goes beyond what’s needed for restraint and restitution.)
If I assault someone while sleepwalking or hypnotised, they have as much of a right to defend themselves as if I’d acted deliberately. If I unknowingly walk off with a valuable document because it’s stuck to my shoe, you have as much right to demand it back from me as if I’d voluntarily stolen it. If I break your vase, I owe you compensation whether I did it accidentally or deliberately.
So likewise, if by entering a room I will thereby unintentionally cause people to die, they have as much right to defend themselves against me, to confine me, as if I were a cold-blooded killer. (Of course they don’t have a right to subject me to cruel or degrading treatment; but they don’t have a right to do that to the cold-blooded killer either, IMHO.) Hence I can’t see that isolating a Typhoid Mary poses any problem for libertarian rights theory.