In terms of its influence upon public debate, the so-called “new natural law” theory associated with Germain Grisez, John Finnis, Joseph Boyle, and Robert George, among others, is perhaps most known for its contributions to what are conventionally labelled “social issues.” Less attention is given to the ways in which the same theory has been used to analyze questions with significant economic dimensions. These range from the nature of social justice to subjects as diverse as the welfare state, the rule of law and poverty, monetary policy, health care policy, free trade, and the economic analysis of law.

Two emphases of these writings have been, first, to identify the government’s role in the economy (and its limits), and, second, to underscore that the case for economic freedom and its concomitant institutions needs to be grounded on practical reason and a concern for human flourishing rather than simply efficiency and utility. In Property and Practical Reason, Adam MacLeod has adopted this approach to rethink a key foundation of economic liberty—private property—and thereby renew the manner in which natural law scholars have traditionally addressed this topic.

Aquinas and Beyond

Classical natural law reflection since Aquinas has generally discussed private property within the parameters of two principles: (1) that the goods of the earth are for the use of all (the principle of common use, or the universal destination of material goods); and (2) that property arrangements exist to realize this end. Following Aristotle, Aquinas identified three reasons why privately owned property is normally (though not in an absolute sense) the best way of realizing this goal. First, people tend to take better care of what is theirs than of what is common to everyone, since individuals tend to shirk a responsibility that is nobody’s in particular. Second, if everyone were responsible for everything, the result would be confusion. Third, dividing up things generally produces a more peaceful state of affairs, while sharing common things often results in tension. Individual ownership—understood as the power to manage and dispose of things—is thus justified. Aquinas insists, however, that the use of our property (including our non-surplus wealth) must serve the universal destination of material goods.

Start your day with Public Discourse

Sign up and get our daily essays sent straight to your inbox.

Most subsequent classical natural law thought on property has involved elaboration of these points. Discussion has subsequently focused on issues such as distribution, or the instances in which private property becomes “common.” All this certainly remains valuable. Yet it arguably hasn’t done justice to just how much private property helps promote human flourishing and the common good.

Explaining how property contributes to realizing these ends is central to MacLeod’s book. In addition to drawing on new natural law theory (of which he provides one of the most accessible explanations that I’ve read), MacLeod is attentive to other exponents of pluralist non-paternalistic perfectionist accounts of law, such as the liberal legal theorist Joseph Raz. MacLeod’s core thesis is summarized concisely in the second sentence of the book’s introduction: “institutions of private ownership are justified, and in many communities are required, by a basic moral principle. That principle is equal respect for human beings as agents of practical reason.”

Consistent with the broader natural law tradition, MacLeod affirms that “the moral norms underlying property are not all moral absolutes, like prohibitions against killing, raping, and maiming.” Nevertheless, MacLeod states, “the norms of property are moral foundations. They are grounded in human goods and requirements of practical reasonableness.” The purpose of MacLeod’s book is to unpack this rationale for private property and explain how it establishes (1) the rights associated with property and (2) the just limits on the exercise of these rights.

Why Utility isn’t Enough

This text subtly critiques some theories of property usually associated with particular schools of conservative and classical liberal thought. In the first place, MacLeod does not base his argument on “the [Lockean] claim that humans have natural rights in their own labor.” Instead, he maintains that property enjoys moral foundations because humans are what they are: beings who exercise practical reason.

Second, while MacLeod strongly affirms that private property arrangements normally yield more in terms of economic efficiency and growth, his account of the norms of property does not accept the consequentialist premise that one can somehow measure incommensurable goods (i.e., weigh and measure the unweighable and immeasurable). To this extent, MacLeod indirectly challenges those who support free markets but who limit themselves to variants of the utilitarian explanation for economic freedom. This underscores a wider point that cannot be repeated enough: Until more conservatives and free marketers start articulating extra-utilitarian arguments for economic liberty beyond autonomy for the sake of autonomy, they are effectively closing themselves off to the full normative apparatus underlying the case for free markets.

Here it is worth highlighting MacLeod’s point that one of the fundamental goods that underpins the justification for private property and establishes the proper parameters for its use is the basic good of practical reasonableness. Deploying the new natural law thesis that practical reasonableness is “architectonic” (i.e., the good that orders our free choices and acts vis-à-vis all other basic goods and the norms of morality and law), MacLeod claims that what he calls property in the common law tradition is unique in its capacity to facilitate the conditions that allow the ownership of things to promote pluralistic non-paternalistic perfectionism. This is especially significant, MacLeod holds (I think rightly), because “practical reasonableness has largely been overlooked relative to goods of self-preservation, fairness, and efficiency”—the goods hitherto emphasized by most natural law writers when discussing private property. This is perhaps the important innovation introduced by MacLeod into debates about private property; he steadily unpacks this insight in subsequent chapters.

Property as Mediated Dominion

So how does practical reasonableness play out with regard to private property? On one level, MacLeod carefully weaves his argument about property into new natural law’s account of how practical reasonableness allows human flourishing on the part of individuals and communities to occur. At the same time, MacLeod interprets case law and statutes to illustrate how courts and legislatures (many of which, one may assume, were not especially familiar with natural law reasoning) have invoked practical reason to address clear injustices involving private property, whether they be incursions upon the legitimate freedom conferred by property or actions that exceed this liberty’s proper limits.

This leads to another significant contribution made by MacLeod: his proposal for how we establish the moral and legal architecture for property rights. MacLeod summarizes the conditions that we need to realize under the title of “mediated dominion.” The “dominion” to be established is that which secures “domains of private ownership against outside coercion” so that people are free to deliberate and realize human flourishing, whether individually or with others. Here, MacLeod emphasizes, private property—far from leading to society’s radical atomization—enables individuals to work together freely and free from unreasonable outside interference as they pursue a rich plurality of good ends. Without such free coordination, it is difficult to see how private property could contribute to a culture of pluralist non-paternalistic perfectionism.

In this regard, MacLeod elaborates at length on what so many have forgotten: that the freedom established by private property has not only helped “countless inventors, entrepreneurs, artists, scientists, and authors to make the world a more livable, beautiful and healthy place.” The same dominion, he states, also (1) has assisted religious communities to act in accordance with the beliefs they hold to be grounded in faith and reason, and (2) was “the silent guardian” of the meetings that helped end segregation in the American South and abolish slavery throughout the British Empire. One could add that it is precisely because private property creates a sphere of liberty that limits unreasonable uses of state power that authoritarian and totalitarian regimes invariably adopt arbitrary or outright hostile approaches towards it.

Neither every use of private property nor every claim that people associate with property rights is, however, reasonable (slavery being one example). Many reasonable limits, MacLeod specifies, are mediated by the private ordering of property itself. My right not to endure someone else’s unreasonable interference with my property serves to limit another person’s use of my property, and vice-versa. In another innovation, however, MacLeod shows how “mediation” can be profitably realized through common law.

Common Law, Reason, and Property

MacLeod’s concept of common law isn’t one of a set of rules that spontaneously adapts to changing circumstances. Common law, he illustrates, embodied a strong “commitment to the norms of reason” before and after the Cromwellian and Glorious Revolutions. Again, the effect is indirectly to challenge particular schools of conservative and classical liberal thought—in this case, their often evolutionist understanding of common law—but with the intent of providing a stronger normative position for the optimality of common law vis-à-vis property.

While mediating property dominion through common law places tremendous responsibilities upon juries and judges, MacLeod doesn’t exclude governments from contributing to this process. Yet although MacLeod does not invoke the principle of subsidiarity, he does see this very much as a bottom-up process. Governments and legislatures, he indicates, should generally act to correct injustices unresolved by common law as they emerge, rather than engaging in grand master schemes or haphazard but very direct interventions into quite particular situations.

From the standpoint of practical reason, what matters above all is that the mediating occurs in a reasonable rather than an arbitrary manner. To establish the parameters according to which such reasoning should occur, MacLeod specifies what he calls the “external norms” associated with dominion, most notably self-exclusion (prohibitions against theft, trespass, necessity) and a prohibition against unreasonable interference with others’ property. There are also “internal norms.” These include liberty, in the sense of freeing people to develop and pursue plans of action either individually or together, as well as what MacLeod calls powers.

The latter is derived from awareness that no law is morally neutral. It follows, according to MacLeod, that law can encourage people to use their property in ways that further the good, but without overtly coercing them to do so. Incentivizing charitable donations is one example. MacLeod is nevertheless conscious that this power of moral persuasion through law is very susceptible to abuse. He therefore stresses that “the efficacy of powers to influence choice and action should make lawmakers circumspect,” given that such “tuning” can have far-reaching (and, economists would add, unintended) consequences.

But perhaps Property and Practical Reason’s wider significance is that it provides a template for further investigations of institutions that touch directly on economic life from the perspective of practical reason. Some obvious candidates include contract law and commercial law. There’s no reason, however, why MacLeod’s analysis couldn’t also be applied to deepening our comprehension of how, for instance, acts of human economic creativity contribute to all-round human flourishing that includes but also goes beyond material well-being.

At a time when many people believe that decidedly cavalier attitudes toward economic freedom prevail in the West, this is precisely the type of rejuvenated defense of this important liberty and its associated institutions that we need.