Frontiers of Justice: Disability, Nationality, Species Membership (review)

The central question of Martha Nussbaum's book is, "How can we extend justice to all those in the world who ought to be treated justly?" (92) Her negative claim is that social contract theories cannot provide an adequate answer to this question, and her positive claim is that a capabilities approach can. More specifically, she argues that there are three unsolved problems of social justice: disability, nationality, and species membership. In all these cases, she says, social contract theories are inadequate: because they ground justice in mutual advantage, they cannot explain what we owe to people who have disabilities; because they take the nation-state as their basic unit, they cannot account for our duties to the distant poor; and because they give centrality to human rationality, they cannot say what is owed in justice to non-human animals. In short, social contract theory cannot "globalize."

The capabilities approach, by contrast, can explain our duties at these three "frontiers." Moreover, it can do so in a way that is consonant with the deep intuitions of contract theory. Thus "the capabilities approach and Rawlsian contractarianism are allies across a wide space of the terrain of justice, and it seems welcome that theories with somewhat different assumptions and procedures should generate closely related results" (81).

So, what are the differences between contract theory and a capabilities approach, and why do these differences make a capabilities approach superior? First, contract theory is procedural whereas a capabilities approach focuses on outcomes and, second, contract theory begins with a conception of human beings as mutually disinterested rational actors whereas a capabilities approach begins with a conception of the dignity of the human being, and of a life that is worthy of that dignity. For the contract theorist, then, a just outcome is one that has been delivered by a just procedure, whereas for a proponent of the capabilities approach, "justice is in the outcome, and the procedure is a good one to the extent that it promotes this outcome" (82).

So described, the capabilities approach sounds suspiciously like a conclusion in search of an argument. We already know, apparently, which outcomes are just, and the task is one of coming up with procedures that will most reliably deliver those outcomes. But in a world riven by deep disagreement about what justice is, and what it requires of us, this assumption appears at best optimistic and at worst positively question-begging. Indeed, the central claims of this book—that we have duties of justice to the disabled, to non-nationals, and to non-human animals—are amongst the most vigorously contested claims in modern political philosophy and there are many who acknowledge that our treatment of these groups is morally reprehensible, while nonetheless denying that it amounts to a failure of justice.

Nussbaum is alert to these difficulties, but her responses to them tend to veer between the tu quoque and the quasi-mystical. Thus, in response to allegations of intuitionism she points out that contract theory also makes appeal to intuitions, while her defence of the capabilities approach in respect of non-human animals is "animated by the Aristotelian sense that there is something wonderful and worthy of awe in any complex natural organism" (94). But the former ignores important questions about the precise role of intuitions in political theory, while the latter is neglectful of the fact that, if people really believed non-human animals to be "worthy of awe," we probably would not have a problem in the first place.

Throughout the book, Nussbaum seems unclear about whom she is addressing, or with what purpose. Much of the time she seems anxious to reassure social contract theorists that there are ways of solving the three unsolved problems while also retaining principles of justice roughly similar to the ones that contract theory itself delivers. At other times, however, she seems to have the more expansive aim of persuading people in...