Libertarianism is the view that agents initially morally fully own themselves and have certain moral powers to acquire property rights in external things. It can be understood as a basic moral principle or as a derivative one. For example, it can be advocated as a natural rights doctrine (e.g. Nozick 1974) or defended on the basis of rule consequentialism (e.g. Epstein 1998; Shapiro 2007) or rule contractarianism (e.g. Narveson 1988; Lomasky 1987). For concreteness, I shall here interpret libertarianism as a natural rights doctrine. For a full discussion of libertarianism, see Vallentyne (2010). For critical discussion of Nozick’s version of libertarianism, see Vallentyne (2011).

Although it has a long history (e.g. at least back to Locke 1960 [1689]), libertarianism was not widely discussed by political philosophers prior to Nozick (1974). Rawls, for example, does not explicitly discuss it at all in TJ and only briefly discusses it in PL (262–265). Nonetheless, Rawls’s discussion of the entitlement to one’s natural endowment is highly relevant to libertarianism’s assertion of self-ownership, and we shall focus on that issue.

Philosophers, unfortunately, use “justice” to mean several different things. Rawls used this term to mean, roughly, the moral permissibility (rightness) of basic structures, or social institutions creating profound and unavoidable effects on individuals’ lives (TJ 3–6, 93–98). By contrast, Nozick (1974, e.g. 52), and libertarians generally, tend to use “justice” to mean, roughly, infringes no one’s rights. Thus, it’s not clear that they are addressing the same topic.

In Anarchy, State, and Utopia (ASU), Robert Nozick sketches and motivates a libertarian theory of justice and then uses it to argue that a minimal state, but nothing stronger, can be just. In this chapter, I focus on explaining and assessing his libertarian theory. My focus will be on laying out the basics and identifying how they can be challenged. I shall not address his argument for the minimal state.

JUSTICE

Although Nozick frequently (and confusedly) writes of (moral) justifiability, permissibility, and legitimacy, it is clear that his main focus in the book is on justice. He never, however, explains the concept of justice. We shall therefore start by clarifying the concept of justice relevant to Nozick's theory. What is his theory about?

The term “justice” is used in many different ways by philosophers: as fairness (comparative desert), as moral permissibility (or justifiability) either of distributions of benefits and burdens or of social structures (e.g., legal systems), as enforceable duties (duties that others are permitted to enforce), as the duties that are owed to individuals (as opposed to impersonal duties, owed to no one), and as the enforceable duties owed to individuals. It is clear that Nozick restricts justice to the fulfillment of the duties owed to individuals, but it is unclear whether he restricts it only to enforceable duties.

INTRODUCTION

Amartya Sen's contributions to moral philosophy have been enormous. He has made seminal contributions to the measurement of freedom, the measurement of equality, the measurement of poverty, the debate over the kind of equality that is relevant to justice, and the debate over the respective roles of liberty, efficiency, and equality in a theory of justice. I shall here focus on Sen's work on distribution-sensitive principles of justice, and more specifically on his work on (1) sufficientarian principles, which require promoting the adequacy of benefits (nonpoverty), (2) prioritarian principles, which require the promotion of individual benefits, but with some kind of priority for the worse off, and (3) egalitarian principles, which require the promotion of equality of benefits.

Sen's work in this area tends to focus on the development of a framework of investigation rather than an extended defense of any particular principles. My goal here will therefore be to present Sen's work, and related work by others, in an intuitively accessible manner that highlights its importance for existing philosophical debates on the topic. The presentation will mainly be a survey, with critical comments being only suggestive rather than fully defended.

BACKGROUND

Justice, as we shall understand it, is concerned with what benefits (net of specified burdens) we owe others. We shall leave open the nature of the relevant benefits (which might be income, wealth, well-being, or anything else).