Why Intellectual Property Rights? A Lockean Justification

Today, the dominant justification for intellectual property (IP) rights is a broadly framed utilitarian theory.[1] But this was not always the case, and nor should it be. Both utilitarian and labor-desert theories offer robust normative justifications for IP rights, and historically they were both called upon by courts and commentators.[2]

Unfortunately, widespread misunderstanding about labor-desert theories abounds today, especially in IP scholarship (see here and here). This essay thus details how a moral theory that justifies the right to property according to productive, value-creating labor equally justifies IP rights as property rights. This is John Locke’s property theory, and while his property theory is not the only labor-desert theory, for ease of reference, I shall refer to it as the “Lockean theory.”

Of course, in a short essay, one cannot explicate every premise or respond to every reasonable counterpoint deserving of a response, and thus what follows is only an outline of the Lockean justification for IP rights. It will also detail how this theory guides the design and application of the legal rules and institutions charged with the protection of IP rights in civil society, just as it did historically (see, for example, here, here, and here), despite incorrect claims to the contrary.[3]

A Brief Sketch of a Lockean Theory of IP

One of the strengths of the Lockean property theory is that it recognizes that IP rights are fundamentally the same as all property rights in all types of assets—from personal goods to water to land to air to inventions to books. These and many other type of goods are the byproduct of an individual’s value-creating, productive labor that creates them, acquires them, transforms and uses them, and ultimately disposes of them in voluntary transactions with other people in civil society. This is why Locke himself expressly recognizes that copyright is property. He also wrote approvingly of inventions and the technical arts as exemplars of the value-creating, productive labor that creates all property (contrary to oft-repeated, mistaken claims about Locke’s view of IP rights by some scholars today[4]).

The key moral insight in Locke’s Two Treatises of Civil Government is that all property arises from the fact that individuals must produce the values required for a flourishing human life. Accordingly, property rights define the sphere of liberty required for an individual to create, use, and dispose of these values.

As I have explained, this is the essence of Locke’s “mixing labor” argument for property in the Two Treatises.[5] Here, “mixing labor” is a metaphor that refers to the productive labor that creates the physical goods required for a flourishing human life. Philosopher Stephen Buckle, for instance, writes that, for Locke, “labour is the improving, value-adding activity required by the duty to preserve oneself and others.”[6]

Locke is absolutely clear about the meaning of value: “the intrinsick value of things . . . depends only on their usefulness to the Life of Man.” (TT II.37)[7] In this important respect, the concept of value in Locke’s labor theory of value and in his broader property theory is not economic or materialistic; as I have explained, it is a moral concept that refers to the intellectual and physical values that one creates to live a flourishing life, or what Locke repeatedly refers to in the Two Treatises as the “conveniences of life” (TT II.26, II.34, II.37, II.36, II.48).  This is unsurprising given Locke’s commitment to classical natural law ethical theory and its moral ideal of a flourishing life, consisting of both mental and physical values.[8]

This important point is often missed by legal scholars and philosophers who read only the Second Treatise, or perhaps only just Chapter 5 (“Of Property”) of the Second Treatise, and thus fail to recognize the broader philosophical framework in which Locke situates his political theory generally and his property theory in particular.

In the First Treatise, for instance, Locke explains that it is man’s nature as “an intellectual Creature” that makes him “capable of Dominion.” (TT I.30) A flourishing human life requires both intellectual and physical labor—the production of the intellectual and physical values that serve the “conveniences of life” through the uniquely human capacity for rationally guided action. In brief, “mixing labor” occurs when a rational person engages in value-producing labor, and he creates property—dominion in the Latin of the Roman Law and of modern political philosophy.[9]

These foundational ideas from Locke’s ethical theory explain why his examples of value-creating labor in the Second Treatise consist mostly of the “Industry” of technological inventions, such as the bread made by the “Mill [and] Oven,” the “Plough” that tills the soil, and “all the Materials made use in the Ship,” among others. (TT II.43) And we must not forget the conceptual skills of artisans that made possible “the Labour of those who broke the Oxen, who digged and wrought the Iron and Stones, who felled and framed the Timber.” (TT II.43)

This is what Locke means when he writes that “the ordinary Provisions of Life, through their several progresses, before they come to our use, … receive of their value from Human Industry.” (TT II.42) (original emphasis) Locke’s own explanation of his property theory is replete with examples of his moral approval of how technological inventions secure for an individual the “conveniences of life”—a flourishing human life.

What to make of this deeper moral insight embedded in Lockean property theory, especially in justifying IP rights? Two important points are worth noting.

First, it shows how legal scholars and philosophers have misconstrued Locke’s famous farming examples in the Second Treatise (TT II.32, II.37, II.40, II.43, II.48) in claiming that his property theory is restricted to only physical parcels of earth or goods. Those who assert that Lockean property theory establishes that property is solely about resolving conflicts over a preexisting physical resource (like the land used for a farm) have taken a premise from Locke’s explanation for the formation of civil society and grafted it onto Locke’s entirely separate explanation for why property is justified. Locke’s farming examples are illustrations of value-creating, productive labor because they are replete with conspicuous references to the intellectually-driven, technological inventions that make possible farming in the first place.

Second, and directly related to the first point, it explains why Locke himself expressly justifies copyright as “property” and approvingly refers to “Inventions and arts” in his summation of his theory that property arises from value-creating, productive labor that supports the “conveniences of life” in § 44 of the Second Treatise. In 1690, the legal concept of patents (property rights in inventions) did not exist yet,[10] and so this is an explicit indication of Locke’s willingness to include what would later become the legal concept of patents within his property theory.

With respect to copyright, which was slowly coming into existence as a legal concept in the late 17th century, Locke expressly endorses it as a property right in 1695. In an essay on the statutory printing monopoly granted to the Stationers Company by Parliament, Locke condemns such monopolies as violating the “property” in creative works that “authors” rightly claim for themselves.[11] In what might be a further surprising claim for many today who think copyright terms are too long, Locke writes in this 1695 essay that authors should have their property rights secured to them for their lifetimes or after first publication plus “50 or 70 years.”[12] The current copyright term is life of an author plus 70 years, which was set in 1998 by the much-maligned Copyright Term Extension Act.[13]

And to be clear that Locke believes that it is authors who should have a property right in their literary works that can be freely alienated in the marketplace, he further proposes an amendment to Parliament that any new printing statute should expressly “secure the author’s property in his copy, or to his whom he has transferred it.”[14]

The natural law ethical theory that informs Locke’s argument for property rights explains why he thinks his property theory applies to inventions and books. In § 34 of the Second Treatise, Locke explains that the world exists for “the use of the Industrious and Rational” who obtain the “greatest Conveniences of Life they were capable to draw from it” by the “Labour [that] was to be his Title to it.” (original emphasis) It is man’s rational nature as an “intellectual Creature” (TT I.30) that is the source of both the moral ideal (a flourishing life) and the means to that end (value-creating, productive labor). It is not lions, tigers, bears, or other “dangerous and noxious Creatures” (TT II.16) who invented the plough, the mill, and ships. Such inventions represent the rationally-guided, value-creating, productive labor that serves a flourishing human life in civil society, and this is why Locke highlights them as exemplars of his property theory.

Lockean Theory in Modern American IP Law

The genius and success of Anglo-American property law is that it has recognized and applied the central idea from Lockean property theory that property rights secure values, not just physical objects. As James Madison explains in a 1792 essay, property is more than just “a man’s land, or merchandize, or money,” as it has a “larger and juster meaning, [in which] it embraces everything to which a man may attach a value and have a right.”[15] Madison thus concluded that “a man has a property in his opinions” and even that he has “a property in his rights.”[16] This explains the hoary metaphor that the law should secure the fruits of one’s labors.[17] Just as with Locke’s “mixing labor” metaphor, the “fruits of one’s labors” is a metaphor that refers to the use and profit that one enjoys from laboring on one’s property.

Of course, the idea that property rights secure justly deserved profit from the use of property was not novel to Locke; in 1628, for example, Lord Coke posited the rhetorical question, “What is the land but the profits therefrom?”[18] But Locke’s genius is to give this idea its moral import.  It is also the genius of early American courts that they applied this moral principle in the law. American courts recognized that “property … may be violated without the physical taking of property” following any act that “destroys it or its value.”[19]

While there have always been scholars, judges, and even some prominent American Founders who thought otherwise about patents and other IP rights, the dominant approach among American courts was to secure patents, copyrights, and other IP rights as fundamental property rights. As I have explained in my scholarship, for instance, patents were defined as civil rights securing fundamental property rights, and thus identified at the time by the legal term of art, “privilege” (see here). American legislators and courts thus secured property rights in novel and useful inventions, creative works, trademarks, and trade secrets—securing the right to make, use, and profit from the value created by one’s productive (inventive) labors.

For the sake of brevity, a few illustrative quotes must suffice. In a patent lawsuit in 1845, an American judge wrote that “we protect intellectual property, the labors of the mind, productions and interests as much a man’s own, and as much the fruit of his honest industry, as the wheat he cultivates, or the flocks he rears.”[20] This 1845 judicial opinion appears to be the first use of the phrase “intellectual property” in the official American legal records.

In his famous 1826 treatise, Commentaries on American Law, Chancellor James Kent classifies copyrights and patents under the title, “Original Acquisition by Intellectual Labor.” Here, Kent argues for the Lockean principle that “It is just that [authors and inventors] should enjoy the pecuniary profits resulting from mental as well as bodily labor.”[21]

As 19th century judges were wont to say, the patent laws ensured that an inventor would “enjoy the fruits of his invention.”[22] Even more explicitly invoking the Lockean theory I described earlier, one judge in 1843 explained that it is “difficult to draw a distinction between the fruits of mental and physical labor” and that this is a key reason why the patent laws provide that “a man should be secured in the fruits of his ingenuity and labor.”[23] These are only a few examples from a historical legal record of IP rights that are permeated with references to Lockean theory.[24]

But many scholars today reject such evidence as mere “rhetoric.” The conventional wisdom is that, while such sentiments were perhaps widespread given American exceptionalism, they had no real impact in the creation and enforcement of IP rights in actual legal doctrine.[25]

This is wrong for several reasons. I cannot address them all in a short essay here, but I will identify a couple to make the case that Lockean theory was determinative in designing novel legal protections for IP rights in the early American Republic.

First, as a preliminary matter, my colleague, Eric Claeys, has shown that this critique results in part from foisting on Lockean property theory a deontological framework that is alien to Locke’s ethical and political theory. It was also alien to the American legal actors who understood Lockean theory and implemented it in the law. Thus, this indeterminacy critique is really a strawman attack on Lockean theory.

Such deeper philosophical concerns, including a deeper conceptual dispute about what comprises the concept of property itself,[26] are beyond the scope of this essay. Here, it is sufficient to explain that Lockean theory was determinative in designing IP law, and in fact it drove the creation and application of many doctrines that have come to be settled IP law in the United States, at least with respect to legally securing patented innovation.

To understand this point, though, one must first understand how legal doctrines are generally construed and applied by courts and other legal actors. As a general matter, the law functions through presumptions that are built into a legal doctrine according to the normative theory that justified the doctrine when it was created. According to Lockean political theory, the law functions by securing the rights to life, liberty, and property, which are limited by the equal protection of other people’s rights or by the rights-holder’s own default on his moral claims.

To give a noncontroversial example: Adults have the constitutional right to vote in the United States, unless of course one commits a felony and is currently residing in prison. A right defines the scope of one’s liberty and the law implements this through the default rules and rebuttable presumptions that constitute much of the work of legal analysis.

There are too many complexities to show how this works for all IP rights and so this essay will focus on early American patent law. As shown above, many legislatures and judges recognized that patents are property rights in innovation resulting from value-creating, productive labor. Accordingly, this defined the nature of the legal presumptions the courts applied in securing patents to their owners.

This is evident in some of the basic doctrinal requirements in patent law. For instance, Lockean theory justifies the uniquely American approach of securing patents to the “first inventor,” which is a presumption that could be rebutted by the inventor’s own actions resulting in a default on his claim to a patent. This default occurs, for instance, when a first inventor publicly uses or sells an invention and thus creates moral interests and reasonable expectations secured under the law to third parties to its ongoing, unfettered use.[27]

Furthermore, the doctrinal requirement that patents may issue only for technological innovation that is useful, and not for just abstract ideas, is also justified by Lockean property theory’s basic premise that productive labor creates the useful real-world values that serve a flourishing life.[28]

Lastly, Lockean theory justifies the longstanding doctrinal presumption that an inventor is entitled to a patent unless it can be proven that his application fails the various doctrinal requirements for a valid patent (that the invention is novel, useful, and fully disclosed).[29]

Beyond these basic doctrinal requirements for obtaining a valid patent, the justification of patents as property rights according to Lockean theory had additional and far-reaching practical effects in the law. It led judges to fashion other crucially important doctrinal presumptions, such as adopting the interpretative canon taken from common law judges’ interpretation of title deeds that patents should be construed liberally in favor of the inventor (we now refer to this as the presumption of validity, which is expressly provided for in the patent statutes).[30]

This made sense to early American judges, who legally classified patents as “title” deeds[31] and who further defined patent rights according to concepts from common law property doctrines, such as identifying multiple owners of patents as “tenants in common.”[32] The policy justification that courts should secure to innovators the fruits of their inventive labors was embedded in the conceptualization of patents as property rights in the early American political and legal system.

For similar reasons, Lockean theory inexorably led American judges to extend constitutional protections to patents under the Constitution, which directly contrasted with denials of similar protections for monopoly franchise grants. American judges often contrasted American property rights with the franchise grants in inventions in other countries, such as in England.[33] This was a point of difference often highlighted by American judges as to the superior treatment of American innovators—here, inventors received proper protection for the fruits of their inventive labors under the American laws that secured property rights in innovation.[34]

Last, and certainly not least, the protection of patents as fundamental property rights justified by Lockean theory led courts to craft the important legal protections for patent owners in alienating their property rights in the marketplace. Courts expressly incorporated into patent law the common law property doctrines securing the right to freely transfer one’s property rights in the marketplace. Courts even adopted the same concepts used to describe such transfers by common law property owners—patent owners transfer their rights via “assignments” or “licenses.”[35]

Award-winning economic historians like Zorina Khan and others have shown that this led to an explosion in commercial transactions in the United States, as inventors and capitalists embraced the efficiencies of the division of labor and market specialization.[36] This important economic activity was made possible in part by courts securing patents as property rights, applying Lockean property theory’s normative presumption in favor of private ordering of the marketplace through freedom of contract.

The protection of IP rights as property rights under Lockean theory in early American law was not limited to patents, as scholars have shown for trademark and copyright.[37] It is undeniable that there were judges and even some Founders, such as Thomas Jefferson, who believed that IP rights were special grants of monopoly privileges. But their views were absent when courts crafted the key legal doctrines that defined American IP rights and secured these property rights against widely reviled “pirates.”[38] The intellectual history of IP rights, at least from the 18th century onward, is one in which the legal doctrines securing patents, copyrights, and trademarks were conceived as property rights and applied in real-world cases under the guidance of Lockean property theory. As Circuit Justice Bushrod Washington explained in 1817: patent infringement is “an unlawful invasion of property.”[39]

A Response to Critics

It has become fashionable of late, especially for some vociferous libertarians, to reject IP rights as unjustified monopoly grants that are destructive of rights to liberty and property. This conclusion often but not always rests upon at least one of two premises. One is a mistaken historical claim about the nature of so-called “common law property” secured by judges versus IP rights created only in statutes. The second is a mistaken normative claim that the moral justification for property rights is that they resolve conflicts over limited, scarce resources.

There are other critiques of IP rights. But for the sake of brevity, I will address only these two claims, as they tend to be the most prominent in the critique of IP rights by those who are committed to limited government and the free market.

First, the criticism that IP rights arose historically solely from statutory (monopoly) grants, as distinguished from “common law” court decisions securing proper property rights in land (real estate) is really myth masquerading as history (as I extensively detail here and here). Historically, property rights in land and in IP were first defined by a mixture of statutes enacted by the British Parliament and later by American legislatures and common law court decisions. Legislators and judges alike were motivated by Lockean property theory in securing IP rights as fundamental property rights.

For example, Daniel Webster, the famous Whig politician known as the Great Orator, introduced legislation in the U.S. House of Representatives in 1824 to secure patent rights to all first inventors regardless of their national citizenship. Webster said that this was justified because

at this time of day, and before this Assembly, . . . he need not argue that the right of the inventor is a high property; it is the fruit of his mind—it belongs to him more than any other property—he does not inherit it—he takes it by no man’s gift—it peculiarly belongs to him, and he ought to be protected in the enjoyment of it.[40]

Even Webster’s opponent in this legislative debate agreed with Webster that the law should “protect the just rights of patentees” by securing “the property which an inventor has in that which is the product of his own genius.”[41]

As for the courts, as we have seen, they were largely responsible for first crafting the specific legal doctrines governing how patents are secured, used, and ultimately sold in the marketplace.

The historical record is absolutely clear that the institutional provenance of IP rights is found in both statutes and court decisions alike, just as property rights in land as well.

The second critique of IP rights starts from the premise that property rights are justified as a solution to disputes over scarce goods, and thus if there is no scarcity (such as in new inventions or books that are nonrivalrous and nonexclusive) there are no conflicts that justify granting property rights.

But Lockean theory reveals that this is not the right premise from which to begin the moral justification for property rights. To begin the moral justification for property rights from the economic concept of scarcity begs the question: why is producing values morally justified and whence do these values come?

Of course, property is a moral standard for resolving disputes, but as Locke recognized, this is a logical corollary of the preceding moral justification for property rights: the fruits of productive labor should be secured to their creators because this is a necessary prerequisite for a flourishing human life. This moral principle then serves as the basis for legally resolving disputes when they do arise: the doctrinal presumption that one should be secured in one’s property rights given the equal protection of others’ rights and the absence of a default by the property-owner.

This naturally leads to a final observation: Given differences in produced values in the world, such as a water well, domesticated animals, a fecund farm, the desert sand used to make silicon for computer chips, air, broadcast spectrum, corporations, stock, credit, future interests, inventions, business plans, books, paintings, songs, and myriad others, the specific legal doctrines that protect these values will vary. As Locke first explained, property is fundamentally justified and defined by the nature of the value created and secured to its owner, and not by the disputes that might follow after this productive labor creates a new valued asset in the world. To wit, different types of property rights are defined and secured differently under the law.

This is important, because some IP critics believe that unique limits on IP rights, such as term limits for patents and copyrights, prove that they are not property rights. But term limits are of no import in distinguishing patents or copyrights from real estate for the same reason that there are similar, significant differences in legal limits that exist for all types of property rights. For example, property rights in water are not the same as property rights in land, and there are even illuminating doctrinal similarities between water rights and patents, as I have explained. Of course, these differences between property doctrines should be explained and justified, but the fact of the difference itself is morally immaterial. In fact, as I have explained elsewhere, many legal scholars make basic conceptual and empirical errors in comparing property rights in inventions (patents) to property rights in land (see here and here).


Lockean theory provides a conceptual explanation and normative justification for all property rights—property rights secure the rights to acquire, use and dispose of assets in the world that arise from value-creating, productive labor. One of its virtues is that it makes clear that IP rights are not a special or even troublesome case to justify as property rights. The productive labor that produces a farm is morally equivalent to the productive labor that produces the technical inventions used in farming, such as the plow and mill. Both are the proper subject of property rights, and their owners should be secured in the fruits of their productive labors.


[1] See, for example, John Duffy, “Rethinking the Prospect Theory of Patents,” University of Chicago Law Review 71 (2004): 439.

[2] See Eldred v. Ashcroft, 537 U.S. 186, 212 footnote 18 (2003) (noting the “complementary” relationship between utilitarian and labor-desert policies as long-established justifications for copyright).

[3] See, for example, F. Scott Kieff, Pauline Newman, Herbert F. Schwartz and Henry Smith, Principles of Patent Law (Foundation Press, 2011), 45, who assert that “Locke’s natural rights theory and its impact with respect to intellectual property is dubious.”

[4] Tom  W. Bell, for instance, asserts that “copyright and patent protection contradicts Locke’s justification of property.” See Tom W. Bell, “Indelicate Imbalancing in Copyright and Patent Law,” Copy Fights: The Future Of Intellectual Property in the Information Age, edited by Adam Thierer and Clyde Wayne Crews, Jr. (Cato Institute, 2002): 4.

[5] See Adam Mossoff, “Locke’s Labor Lost,” University of Chicago Law School Roundtable 9(1) (2001): 155-164; Adam Mossoff, “Saving Locke from Marx: The Labor Theory of Value in Intellectual Property Theory,” Social Philosophy and Policy 29 (2012), 294-307.

[6] Stephen Buckle, Natural Law and the Theory of Property: Grotius to Hume (Clarendon Press, 1991): 151.

[7] References to Locke’s writings will be made in the main text using the following convention: “TT II.37” refers to John Locke, Two Treatises of Government, Peter Laslett ed. (Cambridge Univ. Press, student ed. 1988), second treatise, section 37.

[8] See Mossoff, “Saving Locke from Marx,” 294-307.

[9] There is an ambiguity in the Latin dominion, which also refers to political authority (see, for example, TT II.4, II.90 II.120), but Locke’s usage of this term in the context of discussing property rights is consistent with other modern natural law philosophers who also referred to property as dominion. (TT I.29, I.39, II.26, II.35) This explains William Blackstone’s reference to “the rights of dominion, or property,” in discussing the views of “writers on natural law.” It also explains his famous definition of “the right of property; or the sole and despotic dominion which one man claims and exercises over the external things of the world, in total exclusion of the right of any other individual in the universe.” William Blackstone, Commentaries on the Laws of England, vol. 2 (Chicago: The University of Chicago Press, 1979): 1-2.

[10] See Adam Mossoff, “Rethinking the Development of Patents,” 1255-1322.

[11] See Mark Goldie, ed., John Locke: Political Essays (Cambridge: Cambridge University Press, 1997): 337. Professor Justin Hughes first raised attention about this forgotten essay in 2006, and he situates it within the context of the time in which references to “property” in written works as an intangible right were becoming commonplace. See Justin Hughes, “Copyright and Incomplete Historiographies: Of Piracy, Propertization, and Thomas Jefferson,” Southern California Law Review 79 (2006): 1011-13.

[12] Goldie, John Locke: Political Essays, 337.

[13] See 17 U.S.C. § 302(a).

[14] Goldie, John Locke: Political Essays, 338.

[15] James Madison, “Property,” National Gazette (March 29, 1792), James Madison Writings, edited by Jack N. Rakove (Library of America, 1999), p. 515.

[16] Ibid.

[17] Justice William Patterson writes in Vanhorne’s Lessee v. Dorrance in 1798 that “No man would become a member of a community, in which he could not enjoy the fruits of his honest labour and industry.” 2 U.S. (2 Dall.) 304, 310 (1795).

[18] See Eaton v. Boston C. & M. R.R., 51 N.H. 504, 512 (1872) (quoting from the 1628 treatise, Coke on Littleton).

[19] In re Jacobs, 98 N.Y. 98, 105 (1885). See also Wynehamer v. People, 13 N.Y. 378, 433 (1856) (“A man may be deprived of his property in a chattel, therefore, without its being seized or physically destroyed, or taken from his possession. Whatever subverts his rights, in regard to it, annihilates his property in it.”).

[20] Davoll v. Brown, 7 F. Cas. 197, 199 (C.C.D. Mass. 1845).

[21] James Kent, Commentaries on American Law, vol. 2 (Little, Brown & Co., 12th edition, 1873): 474.

[22] Hawes v. Gage, 11 F. Cas. 867, 867 (C.C.N.D.N.Y. 1871) (No. 6237).

[23] Brooks v. Bicknell, 4 F. Cas. 247, 251 (C.C.D. Ohio 1843) (No. 1944).

[24] For many, many more examples, see Mossoff, “The Use and Abuse of IP at the Birth of the Administrative State,” 2022-2024; Mossoff, “Who Cares What Thomas Jefferson Thought About Patents?,” 990-998; Mossoff, “Patents as Constitutional Private Property,” 705-707 & 718-719.

[25] See, for example, footnotes 4-5.

[26] See, for example, Eric R. Claeys, “Property 101: Is Property a Thing or a Bundle?,” Seattle University Law Review 32(3) (2009): 617; Adam Mossoff, “Exclusion and Exclusive Use in Patent Law,” Harvard Journal of Law & Technology 22(2) (2009): 1; Eric R. Claeys, “Private Law Theory and Corrective Justice in Trade Secrecy,” Journal of Tort Law 4 (2011): 1; Adam Mossoff, “The False Promise of the Right to Exclude,” Econ Journal Watch 8(3) (2011): 255.

[27] See Pennock v. Dialogue, 27 U.S. (2 Pet.) 1, 23 (1829) (Story, J.) (holding that “that the first inventor cannot acquire a good title to a patent; if he suffers the thing invented to go into public use, or to be publicly sold for use, before he makes application for a patent”). This foundational court decision in American patent law, which officially creates what are now-known as the public-sale and public-use bars for obtaining a patent, is rife with fundamental property concepts and Lockean theory, as I discuss in “Who Cares What Thomas Jefferson Thought About Patents? Reevaluating the Patent ‘Privilege’ in Historical Context,” 995-996. In fact, Justice Story even refers to the unauthorized stealing of an invention as “piracy.” Pennock, 27 U.S. at 12.

[28] See 35 U.S.C. § 101 (“Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title.”).

[29] See, for example, 35 U.S.C. § 102 (“A person shall be entitled to a patent unless” it can be shown that the invention is not novel or that the inventor defaulted on a rightful claim to the patent.).

[30] See Adam Mossoff, “Who Cares What Thomas Jefferson Thought About Patents? Revaluating the Patent ‘Privilege’ in its Historical Context,” 989-1009.  As I explain in this article, this presumption was adopted before the examination system for patent applications was adopted in the Patent Act of 1836.

[31] See, for example, Evans v. Kremer, 8 F. Cas. 874, 875 (C.C.D. Pa. 1816) (No. 4,565) (Washington, Circuit Justice) (noting that the patentee must always “be prepared to maintain his title, in relation to the question of original discovery”). For a lengthy listing of judicial opinions reflecting this common practice, see Adam Mossoff, “Who Cares What Thomas Jefferson Thought About Patents? Revaluating the Patent ‘Privilege’ in its Historical Context,” 994, footnote 194.

[32] See Adam Mossoff, “Who Cares What Thomas Jefferson Thought About Patents? Revaluating the Patent ‘Privilege’ in its Historical Context,” 994-995.

[33] See Adam Mossoff, “Who Cares What Thomas Jefferson Thought About Patents? Revaluating the Patent ‘Privilege’ in its Historical Context,” 989-1009; Adam Mossoff, “Patents as Constitutional Private Property: The Historical Protection of Patents under the Takings Clause,” Boston University Law Review 87, no. 3 (2007): 689-724; Adam Mossoff, “Commercializing Property Rights in Inventions: Lessons for Modern Patent Theory from Classic Patent Doctrine,” Competition Policy and Patent Law under Uncertainty: Regulating Innovation, eds. Geoffrey A. Manne & Joshua D. Wright (Cambridge: Cambridge University Press, 2011): 345-376.

[34] See, for example, McKeever v. United States, 14 Ct. Cl. 396 (1878).

[35] See Adam Mossoff, “Exclusion and Exclusive Use in Patent Law,” Harvard Journal of Law & Technology 22 (2009): 321-79.  See also Adam Mossoff, “Commercializing Property Rights in Inventions: Lessons for Modern Patent Theory from Classic Patent Doctrine,” 345-76.

[36] See B. Zorina Khan, The Democratization of Invention: Patents and Copyrights in American Economic Development, 1790-1920 (Cambridge University Press, 2005).  Khan writes that “The analysis [in this book] emphasizes the role that patents and copyrights played in the securitization of ideas through the creation of tradable assets: intellectual property rights facilitated market exchange, a process that assigned value, helped to mobilize capital, and improved the allocation of resources. … Extensive markets in patent rights allowed inventors to extract returns from their activities through licensing and assigning or selling their rights.” Ibid., 9-10.  See also B. Zorina Khan, “Trolls and Other Patent Inventions: Economic History and the Patent Controversy in the Twenty-First Century,” George Mason University Law Review 21 (2014): 825; Naomi R. Lamoreaux, Kenneth L. Sokoloff, and Dhanoos Sutthiphisal, “Patent Alchemy: The Market for Technology in US History,” Business History Review 87 (Spring 2013): 3.

[37] See Justin Hughes, “Copyright and Incomplete Historiographies: Of Piracy, Propertization, and Thomas Jefferson,” Southern California Law Review 79 (2006): 993; Mark P. McKenna, “The Normative Foundations of Trademark Law,” Notre Dame Law Review 82 (2007): 1839.

[38] Ibid., 993.

[39] Gray v. James, 10 F. Cas. 1019, 1021 (C.C.D. Pa. 1817) (No. 5,719).

[40] Annals of Congress 41 (1824): 934.

[41] Ibid., 936 (Rep. Buchanan).

Adam Mossoff

Adam Mossoff is Professor of Law at George Mason University School of Law, and he is a Senior Scholar at the Center for the Protection of Intellectual Property, which he co-founded at Mason Law in 2013.

About the Author

Recent Popular Posts

Related Posts


  1. says

    Awesome article. Note that all property rights have term limits. Dead people cannot have property rights. Wills and intestate transfers are more about a first right of refusal and orderly transfers than perpetual property rights as Rand points out.

  2. Sothyvon Eng says

    Hello author,

    I am a Master student doing LL.M in IP. I have come across your article during my research for some questions.
    It is a magnificent article elaborating the theories justifying IP by John Locke. However, it has been and still is my doubt why all other IP rights require registration except for Copyright for most countries. Is there anything to do with Lockean natural rights theory? or any other theories?

    Many thanks for your kind attention given to my comments/question.


    I look forward to your response.


  1. […] Why Intellectual Property Rights? A Lockean Justification, by Professor Adam Mossoff, is probably one of the most important papers written on property rights in over a century.  The point of the paper is to show Locke’s labor (physical and especially mental) theory of property rights provides the moral justification for intellectual property (copyrights and patents). […]

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>