Matt Zwolinski is Professor of Philosophy at the University of San Diego and director of USD’s Center for Ethics, Economics, and Public Policy. He is the editor of Arguing About Political Philosophy and, with Benjamin Ferguson, The Routledge Companion to Libertarianism and Exploitation: Philosophy, Politics, and Economics (both in progress). He is currently writing a book on the history of libertarian thought with John Tomasi, and a book on the idea of a Universal Basic Income with Miranda Perry Fleischer.

In my previous essay on this topic, I argued that property rights restrict liberty. A property right in a piece of land, or a car, or a piece of bread, is a license to interfere coercively with those who would use those items without your consent. For Herbert Spencer, this consideration was a good reason to reject claims of private property in land. For G.A. Cohen, it was reason to reject claims of private property altogether.

I think that both Spencer and Cohen draw the wrong conclusions from a true premise. Property rights really do restrict liberty, but that isn’t enough to conclude that they should be rejected. It does, I think, shift the burden of justification onto those who wish to defend the morality of property rights. But this justificatory hurdle is one that libertarians have long recognized and tried – successfully, I think – to clear.

Consider, for example, John Locke. As most readers of this blog are aware, Locke held that individuals could come to acquire property rights in previously unowned goods by “mixing their labour” with it, “for this labour being the unquestionable property of the labourer, no man but he can have a right to what that is once joined to” (II. 5, 27). But while Locke clearly thought that labor mixing was necessary to acquire previously unowned resources, he apparently did not think it was sufficient. Why, after all, should the fact that you spent some time working on some land give me a reason to respect your right to exclusive use of it? Before your act of appropriation, I was free to use that land too. Now that you’ve claimed it as your exclusive possession, I’m less free than I was before. What gives you the right to do that to me, and to everyone else born and yet‐​to‐​be‐​born?

Locke thought that this challenge could be met if it could be demonstrated that an act of appropriation was not “any prejudice to any other man” (II. 5, 33). If my claiming a piece of land as my own doesn’t make you any worse off, in other words, then you don’t have any real grounds for complaint. And so long as my act of appropriation satisfies the so‐​called “Lockean proviso” of leaving “enough, and as good, in common for others,” Locke thought that this condition would be satisfied (II. 5, 27).

This “Lockean proviso” has been thought by many to be difficult, if not impossible, to meet. How could any act of appropriation leave as much and as good for others, when natural resources are finite? Locke seems aware of this challenge, and so takes great pains to show that the conversion of resources from the common stock to private use characteristically does not set back the interests of other human beings, but rather advances them.

He who appropriates land to himself by his labour, does not lessen, but increase the common stock of mankind: for the provisions serving to the support of human life, produced by one acre of inclosed and cultivated land, are (to speak much within compass) ten times more than those which are yielded by an acre of land of an equal richness lying waste in common. And therefore he that incloses land, and has a greater plenty of the conveniencies of life from ten acres, than he could have from an hundred left to nature, may truly be said to give ninety acres to mankind: for his labour now supplies him with provisions out of ten acres, which were but the product of an hundred lying in common (II. 5, 37).

One finds a strikingly similar kind of argument in the work of Robert Nozick, who drew heavily from Locke to create an explicitly libertarian theory of property rights and the minimal state. Nozick accepts a formulation of Locke’s proviso which holds that “a process normally giving rise to a permanent bequeathable property right in a previously unowned thing will not do so if the position of others no longer at liberty to use the thing is thereby worsened” (178). But, apparently like Locke, Nozick believes that “the free operation of a market system will not actually run afoul of the Lockean proviso” (182).

How is this possible? Nozick justifies this claim by appealing to

the various familiar social considerations favoring private property: it increases the social product by putting means of production in the hands of those who can use them most efficiently (profitably); experimentation is encouraged, because with separate persons controlling resources, there is no one person or small group whom someone with a new idea must convince to try it out; private property enables people to decide on the pattern and type of risks they wish to bear, leading to specialized types of risk bearing; private property protects future persons by leading some to hold back resources from current consumption for future markets; it provides alternate sources of employment for unpopular persons who don’t have to convince any one person or small group to hire them, and so on (177).

In some ways, this passage is a puzzling one. For, it looks as though Nozick, the paradigmatic proponent of natural rights, is making a straightforwardly consequentialist argument in favor of property rights. But if this is really what he’s doing, then his argument is doomed to failure. This is because anyone who opposes private property on the ground that it restricts liberty is likely to be (and should be) unmoved by mere appeals to the beneficial social consequences of property. If we have a right to liberty, then this right cannot be infringed simply because the overall effects of doing so will be positive.

But there is more to Nozick’s argument (and to Locke’s) than meets the eye. In my next essay, I will show how these arguments provide the basis for a genuinely liberty‐based defense of private property, one that can stand up to the criticisms of Cohen and Spencer.