Defending the Non-​Aggression Principle: A Reply to Matt Zwolinski Part 5

According to Zwolinski, the non-​aggression principle (NAP) “holds that aggression against the person or property of others is always wrong, where aggression is defined narrowly in terms of the use or threat of physical violence.”

As I noted in Part 1 of this series, “the NAP usually is (and should be) expressed in terms of physical force, not violence.” A possible distinction between these two terms may be illustrated as follows: Suppose a large man physically blocks the doorway of an old lady’s house and will not allow her to enter. We might say that this is not literally a violent act, since the man never comes into contact with the lady. And even if we agree that his action should reasonably be interpreted as an intent, or threat, to use violence should she attempt to enter her own house, it is the blocking of the entrance by physical means that qualifies as a violation of her property rights. Thus, in this as in many other cases, it seems more appropriate to speak of physical force rather than of violence per se.

Given that Murray Rothbard often framed the NAP in terms of “violence,” Zwolinski cannot be faulted for following his lead. But it should be kept in mind that many (and perhaps most) libertarians follow Ayn Rand in framing their fundamental political principle as the non-​initiation of physical force (often abbreviated NIOF), rather than speaking of violence. As Rand wrote in “Man’s Rights”:

Similarly, in “The Nature of Government,” we find this formulation:

In Part 3, I discussed how Rothbard applied the NAP to the issue of fraud. That Rand applied her NIOF principle in essentially the same manner-​-​as well as to other problems, such as breach of contract-​-​is clearly indicated in this passage from “The Nature of Government.”

Thus, as Rand put it in “Galt’s Speech”: “So long as men desire to live together, no man may initiate – do you hear me? no man may start--the use of physical force against others.”

Although Rothbard’s usage may be confusing at times, three things should be noted. First, his use of “violence” is consistent with a legalistic meaning, according to which violence is regarded as the unjust or unlawful use of physical force. The entry on “violence” in Black’s Law Dictionary reads, in part: “Force, physical force, force unlawfully exercised, the abuse of force, that force which is employed against common right, against the laws, and against public liberty.”

Second, that Rothbard intended his non-​aggression principle to be identical with prohibiting the initiation of physical force may be seen in the fact that he sometimes used the latter phrasing-​-​as we see in his article “Law, Property Rights, and Air Pollution, in which he depicts “the basic axiom of libertarianism” as “no initiation of force against person or property.”

Third, throughout the history of classical liberalism we sometimes see the terms “force” and violence” used more-​or-​less interchangeably. For example, in The Constitution of Liberty F.A. Hayek wrote that “the threat of force or violence is the most important form of coercion.”

At times, Rothbard used neither “violence” nor “force” when formulating the fundamental libertarian principle. In Man, Economy, and State, for instance, he focused on the libertarian prohibition of “invasive action,” which he defined as follows:

While conceding that Rothbard formulated the NAP in various and sometimes imprecise ways, I think it is clear what he meant. Another potential source of confusion is Rothbard’s use of “axiom” in regard to the NAP. Since Rothbard attempted to provide a moral justification for the NAP (especially in The Ethics of Liberty), by “axiom” he obviously did not mean a fundamental moral principle, much less a self-​evident moral principle. Rather, he used “axiom” to signify the fundamental political principle of a free society. Whether this was a judicious use of “axiom” is something I will leave for readers to decide.

As with many earlier libertarian thinkers, regardless of the terms they used, both Rothbard and Rand attempted to justify a theory of rights, and they then used that foundation to distinguish between voluntary and coercive interaction. As Rothbard wrote in Power and Market, “liberty is defined as freedom to control what one owns without molestation by others.” (This notion of “freedom” was squarely in the Lockean tradition, as I discussed in an earlier essay.)

Rothbard, who was well-​versed in the history of libertarian ideas, often used “property” in the older, classical sense to mean moral jurisdiction over something. It was with this meaning in mind that James Madison spoke of property in one’s time, and an earlier Lockean, William Wollaston, spoke of property in one’s happiness. This was what Rothbard meant when, following the lead of the nineteenth-​century libertarian Auberon Herbert, he defended “self-​ownership” as the fundamental human right.

Rand, in contrast, preferred to speak of “the right to life” instead of “self-​ownership,” while reserving the word “property” to denote external goods. Nevertheless, she occasionally reverted to the classical meaning of “property,” according to which to own x, or to have property in x, means to have sovereign jurisdiction over x, i.e., the right to use and dispose of x as one sees fit. In “What is Capitalism?” Rand put it this way:

Despite the linguistic differences between Rothbard and Rand, both emphasized consent as a fundamental condition of justice in human relationships. As Rothbard put it in The Ethics of Liberty, after explaining the nature of “the free society, the society of peaceful cooperation and voluntary interpersonal relations”:

Disagreements over how certain key words should be used are nothing new; we find similar discussions throughout the history of classical liberalism. An interesting and useful analysis appears in an unpublished manuscript by Jeremy Bentham (1748-1832). After dividing coercive laws into two broad categories, commands and prohibitions. Bentham continued:

Bentham concluded:

F.A. Hayek, among other classical liberals, agreed that “to be precise, we should probably define liberty as the absence of restraint and constraint”--so long as it is understood that these terms refer to the actions of human beings rather than to natural phenomena.

We now arrive, at long last, to the only point by Zwolinski that I have not yet considered, viz., pollution. Zwolinski writes:

In an earlier article, “Libertarianism and Pollution,” Zwolinski explores in greater detail the possible implications of the NAP for pollution, and he cites in passing Rothbard’s most complete treatment of this issue, “Law, Property Rights, and Air Pollution,” which was originally published in the Cato Journal (Spring 1982).

At the risk of ending this series with a whimper rather than a bang, I’m afraid I have little to say about pollution and the problems it creates for the NAP. For one thing, I have not given this issue much thought over the years; for another, I think Rothbard deals quite well with the problems in his article in the Cato Journal, though I might take issue with a few minor points.

I will concede that Zwolinski is justified in raising the problem of pollution. Of his six objections to the NAP, this is the only one that is credible, in my view. But I see no justification for rejecting a strict interpretation of the NAP on the basis of one difficulty.

All general theories, including those in the hard sciences, confront unresolved problems and unanswered questions. Libertarian theory is no exception. But to call for a radical paradigm shift because of such problems, as Zwolinski does with the NAP, cannot be justified unless the dominant paradigm (to use Thomas Kuhn’s expression) experiences drastic failures in a number of areas, and unless a more satisfactory paradigm is offered in its place.

Should Zwolinski ever decide to explain his own paradigm, then we may examine its strengths and weaknesses and thereby compare it to a strict interpretation of the NAP. But no such comparative analysis is possible in a theoretical vacuum. Merely to claim that there are exceptions to the NAP does not come close to telling us what we need to know. Unless we accept Zwolinski and his fellow Bleeding Hearts as the final arbiters in this matter, we will need clearly defined criteria by which we can identify legitimate exceptions to the NAP, and distinguish them from purported exceptions that cannot be justified. Again, it will not do for Zwolinski (or anyone else) to proclaim that x is an exception to the NAP unless he also explains and justifies the criteria we should use to distinguish between legitimate and illegitimate exceptions.

Meanwhile, until this groundwork has been laid and justified, I will continue to view pollution as merely one among numerous problems in libertarian theory that requires additional work.