Friedman continues his debate with Matt Zwolinski over property rights.

David D. Friedman, son of Nobel laureate Milton Friedman, is a leading proponent of anarcho-capitalism, the theory that the state is an unnecessary evil and that all services, including the law itself, can be provided by voluntary cooperation in the private economy.
While Friedman holds a Ph.D. in physics from the University of Chicago, he is chiefly known for his scholarly contributions to economics and law. He is the author of five books of non-fiction as well as the novels Harald and Salamander. In The Machinery of Freedom: Guide to a Radical Capitalism, Friedman argued that an economic analysis of impact of state action points to an anarchist conclusion. In Law's Order: What Economics Has to Do with Law and Why It Matters, he shows how directing the law to seek economic efficiency can lead to the achievement of justice.
Friedman stands in contrast to many other anarchists because of his "consequentialist" approach. Rather than argue that humans have inviolable natural rights which it is always wrong to violate, he uses cost-benefit analysis to assert that a world without government is measurably better than one ruled by states.

I have been arguing that Matt blurs together the kind of property which does raise problems for libertarians, property in land, which is an uncreated resource, with the kind of property which does not raise such problems, property created by human action. In his most recent post, he writes:

Both Herbert Spencer and G.A. Cohen claim that property rights interfere with freedom because property rights are (moral or legal) licenses to coerce. If I own a piece of land, I may legitimately use physical force to keep you off it.

That is indeed Spencer’s position. But Cohen, who Matt quoted earlier, wasn’t talking about land but about property in general. In making his argument, Matt is now limiting himself to the case of land and writing as if that was the subject of Cohen’s claim. If I have convinced him that property in land really is a special case, he should perhaps have said so. If not, he ought to be willing to defend his claim in the general case instead of limiting his examples to the case where I have already agreed that it is defensible.

Matt writes:

If I was convinced that it really was the case that a system of private property led to the oppression of workers, I would have second thoughts about defending such a system.

So would I.

But I am convinced that a system of private property leads to restrictions of the freedom, in Matt’s sense of the term, of rapists, sadists, and would-​be slave owners. That does not give me second thoughts about defending such a system—rather the opposite. Yet, according to Matt, the freedom of those people to do what they want has the same status in the argument as any other sort of freedom, is, in his earlier phrase, “the kind of negative freedom that libertarians purport to be concerned with.”

Is that really his position?