The version of libertarianism that I refer to as the hard line natural rights position holds that individuals have an absolute right to themselves and their property, hence that any violation for any purpose is wrong. Obvious implications are that it is wrong to collect taxes for any purpose or for a starving man to steal a loaf of bread. It is a position that many libertarians not only agree with but view as defining libertarianism.
I explained my reasons for rejecting that position in Chapter 41 of The Machinery of Freedom
(second edition). The Bleeding Heart Libertarians with whom I have recently been arguing reject it too. Thinking about our argument, it occurs to me that there are at least three different approaches to creating an alternative, and that part of my reason for arguing with them is that their approach strikes me as the least attractive of the three.
The first of the three approaches is to argue that the logic of libertarian rights theory leads to different conclusions than those most libertarians accept. One way of doing so is to leverage the problem of initial appropriation of unproduced resources such as land. I did not create the land my house sits on, nor did the person I bought it from or the person he bought it from, so how do I get the right to keep other people off it? It might be argued that I owe compensation to the people I am keeping off that land for violating their rights, an argument that can be used to defend forms of taxation and/or income transfer as vindications, not violations, of natural rights.
I have problems with all versions of that argument that I have seen, but I agree that there is a real problem. In the introduction to Machinery
I argued that most income in a modern society does not come from unproduced resources, hence the solution to the problem of who is entitled to collect it does not matter very much—not a very satisfactory response, but I had no better one. Since then I have managed something a little closer
to a solution, but not one I am entirely happy with. I am not convinced by the Georgists or other left-libertarians with similar approaches but I regard what they are doing as an attempt to get a modified version of libertarianism out of a solution to a real problem in the theory.
A second approach to modifying libertarian rights is the one I associate with the members of the BHL group I have been arguing with, mostly Jason and Matt. It attempts to resolve the conflict between the implications of the hard line position and their moral intuitions by importing into libertarianism ideas borrowed from modern academic philosophy. Like the first approach, the conclusion is a modified theory of rights, this time one in which the right to use force in the defense of property—this time all property, not just land—is conditional on meeting some sort of conditions of social justice.
Both approaches produce arguments that justify some amount of taxation and income transfer as compatible with rights, with the details and the justification varying within and between the approaches. The language is not identical, but if letting me use force to defend my property is unjust unless the poor are properly taken care of, then I do not have a right to both defend my property and refuse to help the poor, which makes the use of force in defense of my property a rights violation, so the essential conclusion is the same. The difference is in where they get it from.
My preference for the first approach over the second comes from my unhappiness with what I have seen of modern political philosophy, of which the work of John Rawls provides a prominent example. I have been observing it for quite a long time, having been present when the pre-publication version of one prominent variant—not by Rawls—was being presented to an audience and had the frustrating experience of trying to persuade its author to follow his logic where it led instead of where he wanted to go. I read Rawls' A Theory of Justice early on and never was able to figure out why anyone took it seriously, beyond the fact that it provided arguments for conclusions they wanted to reach. Reading modern philosophers I occasionally come across an interesting idea that is new to me, but not often enough to make me want to read much modern philosophy.
Which explains why when I see academic political philosophers trying to import into libertarianism ideas from modern "high" liberalism, ideas which I largely regard as pretentious fluff, my reaction is not positive. Even though they, like me, are trying to construct an alternative to hard line natural rights. For some of the reason I regard those ideas, nicely exemplified by Jason's "minimally decent lives," as fluff, see my previous post
Which gets me to the third approach—mine. Unlike both of the others, I am not trying to produce a modified theory of rights. Like the second group, I find some conclusions of hard line natural rights strikingly inconsistent with my moral intuitions. My conclusion is that rights are not a complete account of oughts. That an act violates a right is a strong argument against doing it, but not a conclusive argument. If, to take an old example of mine, the only way of saving the human race from destruction by an approaching asteroid requires, by some bizarre set of facts, that I steal an object worth a nickle from its rightful owner, I should do it. Doing it violates his rights, which may mean that he is morally entitled to try to stop me. But a small violation of rights is more than outweighed, in my moral calculus, by an enormous benefit in consequences.
For a more complete account of the first approach described, see:
The Origins of Left-Libertarianism
Left-Libertarianism and its Critics
both edited by Peter Vallentyne and Hillel Steiner