In my contribution What Libertarianism Is in the Hoppe Festschrift, Property, Freedom and Society, I included a very long footnote (23) critiquing the mutualist “occupancy” view of property rights and, specifically, Kevin Carson’s contention that this is compatible with libertarianism. A edited excerpt from the article on this issue is provided below.
Why is appropriation the relevant link for determination of ownership? First, keep in mind that the question with respect to such scarce resources is: who is the resource’s owner? Recall that ownership is the right to control, use, or possess, while possession is actual control—“the factual authority that a person exercises over a corporeal thing.” The question is not who has physical possession; it is who has ownership. Thus, asking who is the owner of a resource presupposes a distinction between ownership and possession—between the right to control, and actual control. And the answer has to take into account the nature of previously-unowned things: to-wit, that they must at some point become owned by a first owner.
The answer must also take into account the presupposed goals of those seeking this answer: rules that permit conflict-free use of resources. For this reason, the answer cannot be whoever has the resource or whoever is able to take it is its owner. To hold such a view is to adopt a might makes right system where ownership collapses into possession for want of a distinction. Such a “system,” far from avoiding conflict, makes conflict inevitable.
 A.N. Yiannopoulos, Louisiana Civil Law Treatise, Property (West Group, 4th ed. 2001), § 301 (emphasis added); see also Louisiana Civil Code, Art. 3421 (“Possession is the detention or enjoyment of a corporeal thing, movable or immovable, that one holds or exercises by himself or by another who keeps or exercises it in his name”; emphasis added).
 This is also, incidentally, the reason the mutualist “occupancy” position on land ownership is unlibertarian. As mutualist Kevin Carson writes:
For mutualists, occupancy and use is the only legitimate standard for establishing ownership of land, regardless of how many times it has changed hands. An existing owner may transfer ownership by sale or gift; but the new owner may establish legitimate title to the land only by his own occupancy and use. A change in occupancy will amount to a change in ownership. . . . The actual occupant is considered the owner of a tract of land, and any attempt to collect rent by a self-styled [“absentee”] landlord is regarded as a violent invasion of the possessor’s absolute right of property.
Kevin A. Carson, Studies in Mutualist Political Economy (Self-published: Fayetteville, Ark., 2004), chap. 5, sec. A (emphasis added). Thus, for mutualism, the “actual occupant” is the “owner”; the “possessor” has the right of property. If a homesteader of land stops personally using or occupying it, he loses his ownership. Carson contends this is compatible with libertarianism:
[A]ll property rights theories, including Lockean, make provision for adverse possession and constructive abandonment of property. They differ only in degree, rather than kind: in the “stickiness” of property. . . . There is a large element of convention in any property rights system—Georgist, mutualist, and both proviso and nonproviso Lockeanism—in determining what constitutes transfer and abandonment.
Kevin A. Carson, “Carson’s Rejoinders,” Journal of Libertarian Studies 20, no. 1 (Winter 2006): 133 (emphasis added). In other words, Lockeanism, Georgism, mutualism are all types of libertarianism, differing only in degree. In Carson’s view, the gray areas in issues like adverse possession and abandonment leave room for mutualism’s “occupancy” requirement for maintaining land ownership.
But the concepts of adverse possession and abandonment cannot be stretched to cover the mutualist occupancy requirement. The mutualist occupancy view is essentially a use or working requirement, which is distinct from doctrines of adverse possession and abandonment. The doctrine of abandonment in positive law and in libertarian theory is based on the idea that ownership acquired by intentionally appropriating a previously unowned thing may be lost when the owner’s intent to own terminates. Ownership is acquired by a merger of possession and intent to own. Likewise, when the intent to own ceases, ownership does too—this is the case with both abandonment of ownership and transfer of title to another person, which is basically an abandonment of property “in favor” of a particular new owner. See Kinsella, “A Libertarian Theory of Contract,” pp. 26–29; also Louisiana Civil Code, Art. 3418 (“A thing is abandoned when its owner relinquishes possession with the intent to give up ownership”) and Art. 3424 (“To acquire possession, one must intend to possess as owner and must take corporeal possession of the thing”; emphasis added).
The legal system must therefore develop rules to determine when property has been abandoned, including default rules that apply in the absence of clear evidence. Acquisitive prescription is based on an implicit presumption that the owner has abandoned his property claims if he does not defend it within a reasonable time period against an adverse possessor. But such rules apply to adverse possessors—those who possess the property with the intent to own and in a sufficiently public fashion that the owner knows or should know of this. See Yiannopoulos, Property, § 316; see also Louisiana Civil Code, Art. 3424 (“To acquire possession, one must intend to possess as owner and must take corporeal possession of the thing”; emphasis added) and Art. 3476 (to acquire title by acquisitive prescription, “The possession must be continuous, uninterrupted, peaceable, public, and unequivocal”; emphasis added); see also Art. 3473. The “public” requirement means that the possessor possesses the property openly as owner, adverse or hostile to the owner’s ownership—which is not the case when, for example, a lessee or employee uses an apartment or manufacturing facility under color of title and permission from the owner. Rules of abandonment and adverse possession are default rules that apply when the owner has not made his intention sufficiently clear—by neglect, apathy, death, absence, or other reason.
(In fact, the very idea of abandonment rests on the distinction between ownership and possession. Property is more than possession; it is a right to possess, originating and sustained by the owner’s intention to possess as owner. And abandonment occurs when the intent to own terminates. This happens even when the (immediately preceding) owner temporarily maintains possession but has lost ownership, as when he gives or sells the thing to another party (as I argue in Kinsella, “A Libertarian Theory of Contract ,” pp. 26–29).)
Clearly, default abandonment and adverse possession rules are categorically different from a working requirement, whereby ownership is lost in the absence of use. See, e.g., Louisiana Mineral Code, § 27 (“A mineral servitude is extinguished by: . . . prescription resulting from nonuse for ten years”). Loss of ownership is not lost by nonuse, however, and a working requirement is not implied by default rules regarding abandonment and adverse possession. See, e.g., Louisiana Civil Code, Art. 481 (“The ownership and the possession of a thing are distinct. . . . Ownership exists independently of any exercise of it and may not be lost by nonuse. Ownership is lost when acquisitive prescription accrues in favor of an adverse possessor”; emphasis added). Carson is wrong to imply that abandonment and adverse possession rules can yield a working (or use or occupancy) requirement for maintaining ownership. In fact, these are distinct and independent legal doctrines. Thus, when a factory owner contractually allows workers to use it, or a landlord permits tenants to live in an apartment, there is no question that the owner does not intend to abandon the property, and there is no adverse possession (and if there were, the owner could institute the appropriate action to eject them and regain possession; see Yiannopoulos, Property, §§ 255, 261, 263–66, 332–33, 335 et pass.; Louisiana Code of Civil Procedure, Arts. 3651, 3653 & 3655; Louisiana Civil Code , Arts. 526 & 531). There is no need for “default” rules here to resolve an ambiguous situation. (For another critique of Carson, see Roderick T. Long, “Land-Locked: A Critique of Carson on Property Rights,” Journal of Libertarian Studies 20, no. 1 (Winter 2006): 87–95.)
A final note here: I cite positive law here not as an argument from authority, but as an illustration that even the positive law carefully distinguishes between possession and ownership; and also between a use or working requirement to maintain ownership, and the potential to lose title by abandonment or adverse possession, to illustrate the flaws in Carson’s view that an occupancy requirement is just one variant of adverse possession or default abandonment rules. Furthermore, the civilian legal rules cited derive from legal principles developed over the ages in largely decentralized fashion, and can thus be useful in our own libertarian efforts to develop concrete applications of abstract libertarian principles. See Stephan Kinsella, “Legislation and the Discovery of Law in a Free Society,” Journal of Libertarian Studies 11, no. 2 (Summer 1995): 132–81; also idem, “Knowledge, Calculation, Conflict, and Law,” pp. 60–63 (discussing Randy Barnett’s views on the distinction between abstract legal rights and more concrete rules that serve as guides to action).