Edward Feser has written a long and fascinating blog post on his road from libertarianism to conservatism. An excerpt:
At the core of (Robert) Nozicks and (Murray) Rothbards critiques of taxation, and of my own thinking about libertarianism, was the thesis of self-ownership, which holds that each of us is his or her own property, and thus that each of us has rights over ourselves of the sort that are typically associated with property. Hence you have the right to decide what to do with your body and its parts and with your talents and labor power, and (so the argument goes) by extension have the right to determine what will be done with the fruits of your labor, such as your income . . . . I thought the conception of natural rights embodied in the thesis of self-ownership — which I took to be independently plausible and which was the very heart of my own libertarianism — fit in naturally with the Aristotelian-Thomistic (A-T) natural law approach to ethics that had become my settled view by the early 2000s.
I was dead wrong. There are two main problems with the idea of self-ownership — the self part, and the ownership part. (Eric) Macks work got me on the road to seeing this, though that was hardly what he intended. In his Social Philosophy and Policy article The Self-Ownership Proviso: A New and Improved Lockean Proviso, (Eric) Mack had put forward what seemed (and still seems) to me powerful arguments to the effect that we cannot plausibly be said to own ourselves in a substantive way if the right to self-ownership protects us only from the skin inward and says nothing about whether we may bring our powers to bear on the world. Suppose, for example, that you and I are castaways and wash up on some tiny island upon which no human beings have ever trod. You immediately pass out on the beach, while I get to work constructing a bamboo fence whose perimeter happens entirely to enclose your body. Upon waking, you accuse me of imprisoning you and thereby violating your self-ownership rights, and demand to be released. Suppose I then respond as follows: I have not imprisoned you at all! Ive simply homesteaded all the land around you — which you had no right to, since it was virgin territory — and Ive built a fence around it , to make sure you dont come onto my land and take any of the resources Ive justly acquired. True, youve got nothing in the way of resources in the seven-foot by four-foot plot of sand Ive left you, but thats not my fault. Thats just your bad luck, sorry. I suppose it would be nice of me to give you some of mine, but at most Id be unkind rather than unjust if I decide not to do so. And I was very careful not to touch you as I built my fence. I do respect your right of self-ownership, after all!
Now even though I would not have directly harmed you in any way — I havent so much as touched your body, nor (so the argument goes) taken anything that belonged to you, since it was virgin territory and up for grabs — there is still an obvious sense in which I have harmed you indirectly . For part of what you own by virtue of being a self-owner are powers that are of their nature world-interactive (as Mack puts it) and I have effectively nullified your ability to bring those powers to bear on the world. And precisely by doing so I have, you might say, respected the letter but not the spirit of the thesis of self-ownership. To respect others rights of self-ownership in a substantive and not merely formal way, then, we have in Macks view to avoid using our property in a way that effectively nullifies others ability to bring their world-interactive powers to bear on the world.
That is just a brief sketch of Macks point; I develop and defend it at length in my article There is No Such Thing as an Unjust Initial Acquisition, which I linked to above. But it is a point that any Aristotelian-Thomistic natural law theorist has to take very seriously, for two reasons. First of all, the A-T ethicist grounds morality in a teleological conception of human nature, and cannot fail to agree with Mack that many of our powers are inherently world-interactive. In particular, no A-T natural law theorist can fail to agree that our realizing what is good for us, our flourishing as the kinds of beings we are, requires that we be able to bring those powers to bear on the world. Secondly, for those A-T theorists who are open to the idea of natural rights, those rights have themselves a teleological foundation. We have the natural rights we have precisely as a means of safeguarding our ability to flourish as the kinds of beings we are, to pursue what nature has determined is good for us and perfects us. So, if an A-T approach to natural rights could ground the thesis of self-ownership, it would have to ground something like Macks self-ownership proviso as well. So far so good, I concluded at the time I wrote the There is No Such Thing article.
But no sooner had I finished writing up that article than I could see that the implications of this conclusion were very far-reaching indeed.