I was a natural rights libertarian for some time, and even gave a defense of the natural-rights position in a previous post on this blog. However, over the last few months I’ve gradually shifted toward a more utilitarian point of view. While I’m still sympathetic to the natural rights approach (and believe that many of its critics use asinine or strawman arguments), I think it ultimately has a lot of problems.
I’ve done quite a few brain exercises with this. For instance, suppose the Marxist exploitation theory, or any other leftist exploitation theory, is in fact true. They aren’t, of course, but let’s pretend that they are. The pure deontological libertarian would then have to support capitalism anyway, even if he conceded it would mean massive exploitation, suffering and evil. This strikes me as crazy. Despite their anti-utilitarian rhetoric, I don’t think even most of the self-proclaimed natural-rights libertarians would remain so if they discovered one of these exploitation theories was true. Ludwig von Mises argued that natural-rights advocates don't really ever fully escape utilitarianism, and I think he’s right.
Consider an argument with a communist.
Communist: “Everyone has a right to have their needs fulfilled, no matter what.”
Sane person: “Even if it leads to hell on Earth and kills millions?”
Communist: “Yes. Everyone has a right to have their basic needs fulfilled.”
Obviously, I'm not claiming natural-rights libertarians are communists, but I think you get my point. So we’re supposed to only think about things in terms of “rights,” and never, ever consider the consequences or practicality of anything? While this will certainly help keep one principled (a huge plus of the natural-rights approach), it seems loaded with pitfalls.
A pure version of the NAP is also very problematic. To take one horrifying example, it would mean allowing private ownership of nukes (a position that even Rothbard rejected, though his rejection is a blatant violation of the NAP). As David Friedman has pointed out, a purist NAP would also mean breathing is immoral, since carbon dioxide is a pollutant and pollution is aggression. The infinite complexities of life can’t be reduced to a simplistic slogan like the NAP. The subjects of morality and rights in general are surprisingly complicated and exceedingly difficult to define and justify, once one really “gets into” them.
Note: While I could have easily made this post quite a lot longer, and given a lot more examples and explanations, I don’t think it’s necessary. I don't think anyone wants to read a long, rambling post anyway.