This essay is adapted from a contribution to Property, Freedom, and Society.
Property, Rights, and Liberty
Libertarians tend to agree on a wide array of policies and principles. Nonetheless, it is not easy to find consensus on what libertarianism’s defining characteristic is, or on what distinguishes it from other political theories and systems.
Various formulations abound. It is said that libertarianism is about individual rights, property rights, the free market, capitalism, justice, or the nonaggression principle. Not just any of these will do, however. Capitalism and the free market describe the catallactic conditions that arise or are permitted in a libertarian society, but do not encompass other aspects of libertarianism. And individual rights, justice, and aggression collapse into property rights. As Murray Rothbard explained, individual rights are property rights. And justice is just giving someone his due, which depends on what his rights are.
The nonaggression principle is also dependent on property rights, since what aggression is depends on what our (property) rights are. If you hit me, it is aggression because I have a property right in my body. If I take from you the apple you possess, this is trespass — aggression — only because you own the apple. One cannot identify an act of aggression without implicitly assigning a corresponding property right to the victim.
So capitalism and the free market are too narrow, and justice, individual rights, and aggression all boil down to, or are defined in terms of, property rights. What of property rights, then? Is this what differentiates libertarianism from other political philosophies — that we favor property rights, and all others do not? Surely such a claim is untenable.
After all, a property right is simply the exclusive right to control a scarce resource. Property rights specify which persons own — that is, have the right to control — various scarce resources in a given region or jurisdiction. Yet everyone and every political theory advance some theory of property. None of the various forms of socialism deny property rights; each version will specify an owner for every scarce resource. If the state nationalizes an industry, it is asserting ownership of these means of production. If the state taxes you, it is implicitly asserting ownership of the funds taken. If my land is transferred to a private developer by eminent domain statutes, the developer is now the owner. If the law allows a recipient of racial discrimination to sue his employer for a sum of money, he is the owner of the money.
Protection of and respect for property rights is thus not unique to libertarianism. What is distinctive about libertarianism is its particular property assignment rules: its view concerning who is the owner of each contestable resource, and how to determine this.
Property in Bodies
A system of property rights assigns a particular owner to every scarce resource. These resources obviously include natural resources such as land, fruits of trees, and so on. Objects found in nature are not the only scarce resources, however. Each human actor has, controls, and is identified and associated with a unique human body, which is also a scarce resource. Both human bodies and nonhuman, scarce resources are desired for use as means by actors in the pursuit of various goals.
Accordingly, any political theory or system must assign ownership rights in human bodies as well as in external things. Let us consider first the libertarian property assignment rules with respect to human bodies, and the corresponding notion of aggression as it pertains to bodies. Libertarians often vigorously assert the "nonaggression principle." As Ayn Rand said, "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." Or, as Rothbard put it:
The libertarian creed rests upon one central axiom: that no man or group of men may aggress against the person or property of anyone else. This may be called the "nonaggression axiom." "Aggression" is defined as the initiation of the use or threat of physical violence against the person or property of anyone else. Aggression is therefore synonymous with invasion.
In other words, libertarians maintain that the only way to violate rights is by initiating force — that is, by committing aggression. (Libertarianism also holds that, while the initiation of force against another person’s body is impermissible, force used in response to aggression — such as defensive, restitutive, or retaliatory/punitive force — is justified.)
Now in the case of the body, it is clear what aggression is: invading the borders of someone’s body, commonly called battery, or, more generally, using the body of another without his or her consent. The very notion of interpersonal aggression presupposes property rights in bodies — more particularly, that each person is, at least prima facie, the owner of his own body.
Nonlibertarian political philosophies have a different view. Each person has some limited rights in his own body, but not complete or exclusive rights. Society — or the state, purporting to be society’s agent — has certain rights in each citizen’s body, too. This partial slavery is implicit in state actions and laws such as taxation, conscription, and drug prohibitions.
The libertarian says that each person is the full owner of his body: he has the right to control his body, to decide whether or not he ingests narcotics, joins an army, and so on. Those various nonlibertarians who endorse any such state prohibitions, however, necessarily maintain that the state, or society, is at least a partial owner of the body of those subject to such laws — or even a complete owner in the case of conscriptees or nonaggressor "criminals" incarcerated for life. Libertarians believe in self-ownership. Nonlibertarians — statists — of all stripes advocate some form of slavery.
Self-ownership and Conflict-avoidance
Without property rights, there is always the possibility of conflict over contestable (scarce) resources. By assigning an owner to each resource, legal systems make possible conflict-free use of resources, by establishing visible boundaries that nonowners can avoid. Libertarianism does not endorse just any property assignment rule, however. It favors self-ownership over other-ownership (slavery).
The libertarian seeks property assignment rules because he values or accepts various grundnorms such as justice, peace, prosperity, cooperation, conflict-avoidance, and civilization. The libertarian view is that self-ownership is the only property assignment rule compatible with these grundorms; it is implied by them.