In this Essay, I consider the relevance of this behavioral research to normative issues in property law. Along the way, I discuss the broader issue of the potential relevance of biological facts about human behavior to the law. I argue that facts about actual human behavior, like those discussed in Friedman & Neary’s research, are potentially relevant to property and other legal issues. In contrast, I argue that evolutionary arguments like those made by Stake are not relevant to property or other legal issues. I criticize Stake’s evolutionary argument on two levels. First, I argue Stake’s evolutionary claims lack evidentiary support and fail to connect in subtle but important ways with substantive property law. Second, drawing in part on arguments recently developed by Brian Leiter and Michael Weisberg, I argue that evolutionary facts, even if scientifically well founded, have little or no relevance to normative legal issues, in property or otherwise.

This short encyclopedia entry focuses on the first category – those legal protections that give special protection to possessory rights in a home. It first elaborates on the distinction between rules favoring possession and the other two types of special legal protections given to homes. It then discusses various types of legal rules that give additional protection to possession of a home, including homestead rules favoring homeowners over creditors and tenure rules favoring renters over their landlords. Finally, it discusses theoretical issues related to the protection of possessory rights in homes, and considers open questions about whether this special protection is justified.

The recent increase in federal regulation notwithstanding, the regulatory takings doctrine is primarily the product of challenges to state police power regulations. But despite the centrality of the police power to the problem of regulatory takings, an observation made nearly one hundred years ago still holds true today: No phrase is more frequently used and at the same time less understood. Contemporary regulatory takings jurisprudence is plagued by misunderstandings about the police power, in part because no one has seriously attempted to analyze or define the police power since 1907 - fifteen years before the landmark regulatory takings case Pennsylvania Coal v. Mahon was decided by the United States Supreme Court.

The uncertainty and confusion over the police power, however, is unnecessary. The term police power was introduced and defined by the Supreme Court, and has a clear meaning as a concept of American constitutional law - though one that unfortunately has been ignored in contemporary takings jurisprudence. The purpose of this Article is to explore the precise nature of the police power and its lessons for clarifying the regulatory takings debate.

Part I of this Article addresses the question: What is the police power? It begins by discussing the early federalism cases in which the Supreme Court introduced and defined the phrase police power to be synonymous with the entirety of the states' sovereign power. It then examines the practical development of police regulations in the state courts, including the landmark decision Commonwealth v. Alger and the evolution from community-based common-law regulation toward the modern regulatory state. Finally, it discusses various attempts to limit the scope of the police power, from Lochner-era substantive due process to various academic definitions of the police power based on political theory. Part I concludes that the police power, as a concept of American constitutional law, is synonymous with the entirety of the sovereign power of the states that remained after the constitutional grant of limited powers to the federal government.

Part II discusses the interaction between the police power and the Just Compensation Clause. It begins with the ambiguous foundation of modern regulatory takings, Justice Holmes's cryptic opinion in Pennsylvania Coal v. Mahon. Placing the holding in Mahon in the context of Holmes's prior writings on the police power and his substantive due process dissents shows that Holmes understood the broad scope of the police power while at the same time rejected the formalistic rule that exercises of the police power could never be takings. Part II then examines the historical record and text of the Just Compensation Clause, and concludes that the central holding in Mahon - that exercises of the police power can in some circumstances be takings - is correct when an exercise of the police power renders the property in question valueless, but not when the exercise of the police power results in a lesser diminution of the property's value.

Part II then looks to the nature and scope of the police power, and the history and text of the Just Compensation Clause, to make a few observations that help to clarify the regulatory takings problem. Much of the confusion in regulatory takings is due to a misunderstanding of the nature and scope of the police power, which has led to the regulatory takings question being framed in incorrect terms. Most significantly, recognition that the broad scope of the police power is not tied to the prevention of harm helps demonstrate that the character of the government act in question should have no place in the regulatory takings inquiry, and that its central role in contemporary regulatory takings cases is misplaced. When properly stated, the regulatory takings question should simply ask whether the government act has rendered the property in question valueless - if the answer is yes, then compensation is due. Finally, Part II concludes that despite their analytical incoherence, the Supreme Court's contemporary takings cases have reached results that are consistent with both the historical record and text of the Just Compensation Clause.

The article concludes that homes are different from other types of property and give rise to legal interests deserving of special legal protection, but that these interests can be outweighed by competing interests in particular legal contexts. The result is that in many contexts special legal treatment of homes is justified. In other contexts, for example residential rent control, the strength of competing interests means that the law overprotects the home. In still other contexts, for example eminent domain law as embodied by the Supreme Court's recent decision in Kelo v. New London, the law tends to underprotect the home.

This essay addresses a subset of this larger debate. It looks to recent social science research to explore how and why group size and diversity impact cooperation and other prosocial behaviors. It then considers how to take the results of this research into account in designing legal structures, either by placing people into contexts that foster cooperation or by taking affirmative steps to mitigate the negative impacts of increases in group size or diversity. Increases of group size and diversity tend to undercut the informal mechanisms that communities use to encourage cooperation, and in many circumstances these mechanisms can be replaced by legal structures. To illustrate the potential for using the design of legal structures to encourage prosocial behavior, the essay draws on examples including residential community organizations, the management of natural resources, corporate boards, and the private microlending groups organized by the Nobel-Peace-Prize-winning Grameen Bank.

In this Essay, I argue against both sides of this intractable debate. Property and freedom are inextricably linked, but a strong relationship between property and freedom does not immunize property from government interference. To support these positions, I shift the discussion of property and freedom away from debates about the inviolability of property, and focus instead on the institutional relationship between property and freedom. Accordingly, I focus on two questions that have often been neglected in the heat of the debate over government interference with property: to what degree does the institution of private property protect individual freedom, and to what degree is individual freedom possible without the institution of private property?

Property as an institution promotes individual freedom in three ways: by creating a zone of individual autonomy and privacy; by distributing power; and by providing access to the resources that people need to be free. The discussion of these institutional connections between property and freedom draws out three important substantive points. First, individual freedom depends, in an institutional sense, on private property. Second, because the relationship between property and freedom is complex, different types of property (e.g., land versus money) and different aspects of property ownership (e.g., the ability to exclude others versus the ability to transfer to another owner) promote freedom in different ways. Third, and most importantly, the relationship between property and freedom in this context may be used to support, rather than oppose, arguments for the redistribution of property. Indeed, a strong connection between property and freedom can be maintained without any reference whatsoever to libertarian or other theories that hold that property rights should be immune from state interference.

Using these relationships between property and freedom, I then critique two of John Rawls's positions on property. Rawls asserted that the basic liberties protected by his First Principle of Justice include the right to hold personal property, but not productive property; and that either a property-owning democracy or a liberal socialist regime could comport with his two principles of justice. In my critique of Rawls, I first explain why the concept of freedom embodied by the First Principle of Justice provides a better defense of private property than the inequality allowed by the so-called difference principle in the Second Principle of Justice. I then use the connections between property and freedom discussed earlier in the Essay, and Rawls's own positions on freedom, to argue that Rawls's positions on property are wrong, that the First Principle must include the right to hold productive property, and that therefore only a property-owning democracy would satisfy the requirements of the two principles of justice.