The problem is that a proper appreciation of externalities is radically anti-property. Property law can’t take most externalities into account for practical reasons, but the externalities exist regardless.

Libertarians are blasé about natural resource constraints. For some products, resources are not the constraint. Capitalism has been very good at creating more value out of the same resources, e.g. iPhones. But for other products, such as food, or oil, more people can make them more expensive. I.e. more people are a negative externality to me. The idea that someone who doesn’t “aggress” against me doesn’t harm me is not necessarily true.

If you take externalities seriously, you cannot be a libertarian.

***

The non-aggression principle also doesn’t work for another reason. It assumes there is a “neutral” distribution of property rights, and any deviation from these is aggression. But in fact any distribution of property rights is possible. If you have the right to consume pornography in private on your property, and I stop you, that is aggression. But if you don’t have the right to consume pornography in private, yet do so, and I stop you, you are the aggressor.

What counts as aggression is not an objective fact: it depends on the prior distribution of property rights.

This is a similar argument to Nick Szabo’s “The Coase theorem is false“.

Another fake libertarian, whatever.

Uh. Not here in Maine. Does he have a reference for that?

Libertarianism works fine as a low-priority set of guidelines added onto some otherworldly set of principles.

E.g. if you are a poorly educated Catholic, and you are very unworldly in your pursuit of sanctifying grace, then by all means use the Z. A. P. as a supplement to solve short-term questions.

If you are a well-educated Catholic, you might come to the same conclusions as the Z. A. P. for any given challenge, but you will be able to reason without using the Z. A. P.

I have never had a lot of respect for the Z. A. P. I have always had a lot of respect for the philosophy of minarchism — the notion that government should be minimized.

However, at some point, “small government conservative” became unfashionable and “libertarian” was the term that everyone recognized, so people called me a libertarian or an anarchist.