Set forth below is a brief description of the origins and substance of this doctrine; it is far from comprehensive, and is intended only as an introduction.
If natural rights libertarianism had a Shema, I believe it would be the first two sentences of Anarchy, State, and Utopia: “Individuals have rights, and there are things no person may do to them (without violating their rights). So strong and far-reaching are these rights that they raise the question of what, if anything, the state and its officials may do” (ASU, ix). This declaration properly highlights the moral dimension of rights: the existence of a right in one person implies that all other people, acting individually or through the state, have a corresponding duty not to interfere with its exercise.
Like virtually all modern doctrines, the claim for natural rights has its origins in antiquity. John Locke’s famous Two Treatises of Government [circa 1689], from which the passages quoted below are taken, is generally thought to represent the first systematic effort to develop this notion into a recognizably modern political philosophy. I will not belabor here Locke’s profound influence on the Founding Fathers and on subsequent generations of American leaders.
Locke starts his analysis by imagining a world devoid of political authority, what he called a “state of nature.” Even such a pre-political society is governed by a law of nature “which obliges every one: Reason, which is that Law, teaches all Mankind, who will but consult it, that being all equal and independent, no one ought to harm another in his Life, Health or Possessions.” If an individual or group threatens to aggress against a person’s property (broadly construed), the innocent party has an inherent right to defend himself and punish the offender. Thus, Locke conceived of natural liberty primarily as the right to be free from the predations of others.
In order to enhance their security, those living in a state of nature may conditionally surrender to the state their right to enforce justice for themselves. The state’s obligation, then, is to establish the conditions that enable people to “pursue happiness” without undue fear of aggression. If the ruler fails to perform this function but instead acts as a tyrant, the populace is (according to Locke) justified in “appealing to Heaven,” i.e. invoking its natural rights and revolting against him.
Locke did not distinguish, as is fashionable today, between so-called property or economic rights and other, supposedly more exalted ones. To the contrary, he spoke in one breath of a liberty to dispose as he likes of one’s “person, actions, possessions, and his whole property.” For Locke, natural law not only authorizes but favors the creation of private property:
God, who hath given the World to Men in common, hath also given them reason to make use of it to the best advantage of Life and convenience. The Earth, and all that is therein was given to Men for the Support and Comfort of their being. And though all the Fruits it naturally produces, and Beasts it feeds, belong to Mankind in common…there must of necessity be a means to appropriate them some way or other before they can be of any use.
His justification of individual ownership starts with the seemingly self-evident proposition that “every Man has a Property in his own Person.” From this premise he reasons that self-ownership extends to the work of a person’s hands, i.e. we are entitled to retain the fruits of our labor, including the “privatization” of land by enclosing and working it. According to Locke, such claims do not violate the legitimate rights of others because due to the efficiency of private property, “he who appropriates land to himself by his labor does not lessen but increases the common stock of mankind.”
Locke is here making an important point, one missed or ignored by Marx and those on whom he continues to exert his baleful influence: individuals who accumulate wealth by means of the institution of private property do not do so at the expense of others. To the contrary, full capitalist property rights establish the preconditions for economic vitality generally, creating opportunity for all.
The freedom to pursue happiness requires only that other people not interfere with our activities, subject only to the condition that we do not seek to rob, steal or otherwise aggress against them. Philosophers refer to such rights as negative rights. On the other hand, if we are entitled to happiness, and we cannot obtain it by our own efforts, then other people may be legitimately compelled to provide it to us, even if this requires a substantial sacrifice on their part. Rights of this sort are called positive (or welfare) rights may be understood as any right that would, in John Hospers’ words, require “not only noninterference, but also some positive action on the part of others.” The distinction between these two conceptions of rights, and the (general) recognition of the moral legitimacy of only the former, lies at the heart of contemporary libertarian philosophy.
As noted above, Locke claimed to derive rights from the dictates of natural law, a medieval doctrine closely associated with Aquinas whose central thesis is, per Richard Wollheim, that: “phenomena are divided into natural kinds, that each natural kind is distinguished by the possession of an essence, that the essence stipulates an end, [and] that virtue and goodness are necessarily linked with the fulfillment of these ends.” Locke equivocated between the idea that natural law can be deduced by human reason and that it had to be accepted simply as the Creator’s will. While the latter derivation may satisfy those holding a particular theological perspective, it has nothing to say to those demanding a philosophical justification.
Even if we interpret Locke as proceeding under the former assumption, he never shows that his particular understanding of rights can be derived from the precepts of natural law. Thus, as Nozick concludes, he failed to “provide anything remotely resembling a satisfactory explanation of the status and basis of the law of nature in his Second Treatise” (ASU, 9). As a consequence, modern libertarian philosophers have felt compelled to offer a more systematic and coherent justification for natural rights than is found in Locke.
The most successful effort in this direction, in my judgment, is the one outlined by Nozick in ASU. He does not attempt to derive libertarian rights in a top-down fashion from an overarching normative theory that delineates virtue and vice. Instead, he offers what is essentially a political doctrine, i.e. a theory regarding the limits of legitimate state authority, that takes the form of an intuitionist, Kantian-based argument in support of “side constraints.” Nozick’s strategy is based on the claim that only his conception of rights as near absolute prohibitions against aggression is compatible with our pre-theoretical beliefs regarding the moral status of persons.
He introduces the idea of side constraints in the course of considering the extent to which the fundamental interests of individuals may justly be sacrificed for the “greater good” (see ASU, 28-30). At one extreme would be the view that the rights of particular individuals have no special moral significance and must always yield if they stand in the way of achieving a greater benefit for others. A second, intermediate position is that while individual rights should generally be respected, they may be overridden when required to minimize the total number of rights violations.
This program would commit us to a form of consequentialism, where the good to be promoted is the minimization of rights violations. Accordingly, on this view, we would be permitted to violate one innocent person’s right of free expression if this would (somehow) preserve the comparable rights of a larger number of people. Nozick rejects this idea in favor of the view that respect for rights should not be a mere goal, but a virtually absolute limitation on our conduct.
Here, he appeals to Kant’s notion of humans as “ends in themselves,” quoting Kant’s second formulation of the categorical imperative: “Act in such a way that you always treat humanity, whether in your own person or in the person of any other, never simply as a means, but always at the same time as an end.” (ASU, 32). An appropriate commitment to human dignity implies, says Nozick, that “individuals are inviolable;” that is, violations of their rights are unconditionally prohibited (see ASU, 28-35). Thus, the sacrifice of an individual’s rights, even if required to prevent a greater number of violations, still uses that person solely as a means to an end, and is impermissible. He expressly leaves open the question of whether side constraints must be relaxed in order to avoid “catastrophic moral horror” (ASU, 30n).
It is clear that most people do hold a side constraint view of how persons may be treated, at least up to a point. We can pose the issue of the inviolability of rights quite starkly: suppose that a terrorist organization seizes a group of five innocent hostages and threatens to kill them unless our society executes another innocent person of greater interest to them. Let us further imagine that because of this organization’s past history, information from our intelligence agencies or for other reasons, we have almost total certainty that the terrorists will take the threatened action against the five hostages if we refuse, but will release them if we comply. And, suppose we have similarly persuasive evidence that making the proposed exchange will not encourage any future hostage-takings. Should we give in?
I believe that the vast majority of both academic philosophers and ordinary people would reject this “devil’s bargain.” If we were to make this exchange we would, in Nozick’s phrase, be adopting a “utilitarianism of rights” where our goal is merely to minimize the total violation of rights (see ASU, 28-29). Accordingly, our commonsense morality endorses the “inviolability” of rights in the sense described by Nozick.
He attributes our intuitive embrace of side constraints to our possession of certain unique, so far as we know, characteristics. Chief amongst these is our ability to understand and conform our conduct to the moral law, and to guide our lives according to values of our own selection (“rational agency”) (see ASU, 48-9). Nozick offers us what philosophers refer to as an “argument from the best explanation” for this conclusion.
In simplest terms, when we seek to explain a particular phenomenon, the theory that best fits the evidence is probably true. For example, from ancient times physicians have observed that under certain conditions people become ill. As Louis Pasteur (and other pioneers in microbiology) hypothesized, the existence of something called “germs” is the best explanation of this fact. Because the germ theory of disease best fits the facts, it is probably true. By the same logic, the best explanation of our strong intuitive commitment to the inviolability of rights is our underlying commitment to the view that people are rational agents (ASU, 34).
From here, Nozick is able to argue that since humanity owes its special status to this attribute, other people are obligated to respect it by refraining from the use of force or coercion against innocent persons, i.e. those who are not themselves engaged in aggression against others. In my book, Nozick’s Libertarian Project: An Elaboration and Defense, I present a much more detailed and rigorous reconstruction of Nozick’s reasoning, and try to anticipate and respond to possible objections. I believe that his argument has been misunderstood and underappreciated by most theorists because he elects not to present it in a formal, linear fashion with supporting argumentation for each step. Nevertheless, I contend that his approach is plausible when evaluated by the standards typically applied to moral/political theories.