Western countries will adopt (or consider adopting) state-mandated “medical passports”—so-called green passes—meant to prevent covid-19’s spread. They will compel private individuals to carry such passports if they want access to certain facilities or events (restaurants, theaters, concert arenas, etc.), I often hear libertarians—or people just sympathetic to libertarianism—supporting such state interventions with the following argument: “The green pass is compatible with libertarianism, because it directly stems from the nonaggression principle; in fact, if you do not have the green pass—and hence are (potentially) infectious—by infecting other people, you would be aggressing against them.”
My point is not so much that “infection” does not necessarily equate to “aggression,” but that when it comes to airborne communicable diseases, the simple fact of two people—A and B—agreeing to occupy the same room (or any kind of physical space where it is physically impossible for them not to breathe the same air) is sufficient to rule out the possibility of aggression. I think failing to understand this argument reveals a deep misunderstanding of what libertarianism is about—property rights and nonaggression.
My argument is twofold. First, I will briefly define what I believe libertarianism to be about. Second, by consistently applying the notions of “property” and “aggression,” I will argue the following: if A and B agreed to share a physical space wherein it is physically impossible for the two of them not to breathe the same air, then it would make no sense to classify A infecting B (or vice versa) as aggression.