The Idea of Justice by the economist Amartya Sen is a critique and revision towards the philosopher John Rawls’s A Theory of Justice (1971). Amartya Sen drew extensively upon Rawls’s work, mostly composed while the former was a Professor in India. Amartya Sen was not a student of John Rawls. Rather, Rawls drew upon the work of Harsanyi and Amartya Sen.

As might be expected of anything written by Sen, this is a book of immense depth, detail, and range. The title itself is immediately suggestive: although it clearly echoes Rawls, the ‘idea’ indicates that it is not intended as a similar work of grand theory; it also echoes Collingwood (although imperfectly because it is not an account of the development of the concept). The tentative nature of the title indicates the author’s starting point—arguing from our understanding of instances of injustice and securing agreement on them, rather than developing an overarching theory and reasoning forward from that.

The Idea of Justice is ambitious in scope and it is not possible here to do more than summarize a few key points and to articulate the beginnings of a critique. The four parts of the book comprise considerations of the demands of justice, forms of reasoning about the materials of justice, and public reasoning and democracy. Anyone familiar with the author’s previous work will not find many surprises here—in fact, the book as a whole in many ways is a useful summary and drawing together of much of his work. The first part on the demands of justice focuses on reason, objectivity, and impartiality and raises many interesting questions in relation to Rawlsian and other approaches.

The second part focuses on how we might reason about justice in practice and includes a discussion of the plurality of reasons which is of the utmost importance. The third part (dealing with what Sen terms ‘the materials of justice’) is perhaps most familiar as it deals with the capabilities approach: I certainly do not intend to criticize this here, as it is a helpful and persuasive approach to major issues in justice, rights and development quite independently of the other strengths or weaknesses of this book. By concentrating on what people are able to do rather than what they possess, or on the definition of needs or wants in an abstract sense, it illuminatingly cuts through many of the debates surrounding the subject.

The final part of the book addresses public reasoning and democracy and is an interesting examination of the intertwining of democracy and public reasoning and their relation to justice, the distribution of goods (which includes a discussion of Sen’s well-known position on famine) and human rights.

One of the key parts of the author’s argument is that rather than working from a single principle or criterion, we should consider the possibility of multiple grounds for reasoning and decision-making: ‘what is important to note here, as central to the idea of justice, is that we can have a strong sense of injustice on many different grounds, and yet not agree on one particular ground as being the dominant reason for the diagnosis of injustice’. This, of course, has to be distinguished from a sort of evidence-giving which amounts to no more than the accumulation of plausible but unrelated circumstantial evidence adding up to nothing. And this raises the issue of whether there has to be some sort of criterion which can be invoked to say that this, but not that, set of multiple grounds is reasonable or adequate.

But, given his approach, the author has impaled himself on the horns of a small dilemma here. Can he provide a criterion for coherence and for taking ‘plural grounding’ seriously? After all, merely noting that we often proceed this way in practice might be true, but it does not amount to epistemological justification. Or do we have to sense it on each occasion? Does it become a sort of moral intuitionism or particularism? One might argue the case for this, but at the same time, it is open to rather obvious objections. And if on the other hand, a criterion is to be given, whence do we derive it? Does it come from a theory, and if so, can and should the author give us that theory? But he seems to have committed himself to deny that any such theory is possible.