His 1998 Nobel prize may have been in economics, but people also call him an exceptional polymath. Whether talking the language of mathematics or economics or political theory or philosophy, Amartya Sen has held onto a fondness for the dialogic tradition. Four years ago, in The Argumentative Indian, he wrote both that voice is a crucial component of the quest for social justice and that the argumentative tradition, if used with deliberation and commitment, can help defend against social inequalities, poverty and deprivation. Rejecting the claim that analytical reasoning and critique are quintessentially Western or European, he highlighted how texts like the Mahabharata (in the larger context of the Bhagavad Gita) are oriented to debate, the idea that two contrary arguments can coexist in a world of reason, with even the ?defeated? argument retaining life. That would be Arjuna questioning whether his duty to promote just cause could supersede slaughter ? even of family members.

In the idea of justice that Sen sketches in his latest book, reasoned engagement emerges as a hero once again. Anne, Bob and Carla are at the heart of a wonderful fable, setting up his complex argument cleanly. All the kids are claiming ownership of a flute. Anne?s claim is that she is the only one who knows how to play it, Bob?s that he is the only one too poor to purchase one and Carla?s that she is the one who has laboured to put it together. In different contexts, these are all legitimate claims. No single model of a perfectly just society ? what Sen calls transcendental intuitionalism and ascribes to the likes of Immanuel Kant, Jean-Jacques Rosseau and John Locke ? can accommodate all of them. In contrast, there is what he calls realisation-focused comparison, where a plurality of reasons can pose a definite challenge for how social institutions should be constructed (as opposed to imagining ideal ones as goals in themselves). Sen sort of sees the Bhagwad Gita and Kant as cousins insofar as they give priority to (abstract) duty over (lived) consequence.

?Let justice be done, though the world perish,? proclaimed a Holy Roman emperor of the sixteenth century whom Sen quotes only to rebut. Looking to the Mahabharata?s end, with its desolate landscape of funeral pyres and weeping women, he says: ?If indeed the world does perish, there would be nothing much to celebrate in that accomplishment, even though the stern and severe niti leading to this extreme result could conceivably be defended with very sophisticated arguments of different kinds.? The point is, instead of seeking the perfectly just, to prevent manifestly severe injustices. No wonder it is people like Mary Wollstonecraft who emerge as key heroes in Sen?s text. He acknowledges her as one his main influences.

Wollstonecraft?s pleas for the rights of men and women, Sen argues, were based on a strong appeal to reason as well as against a specific injustice. He quotes A vindication of the rights of woman: ?When your constitution is revised the Rights of Woman may be respected, if it be fully proved that reason calls for this respect, and loudly demands JUSTICE for one half of the human race.? Here, he also raises the question of why justice should seek a popular endorsement. Why should people actually agree that it?s being done? Simple answer: there is an obvious link between the objectivity of a judgment and its ability to withstand public scrutiny. This then brings us to the role of media.

In different sections, whether he is writing on human rights or famines or the November attacks on Mumbai, Sen repeatedly says that the media is essential to the pursuit of public reasoning. His thesis on how a major famine cannot occur in any functioning democracy with ? among other characteristics ? a relatively free media is very well known by now. How powerful an impact the Bengal famine of 1943, which he watched from Shantiniketan, has had on his thinking is equally well known. In revisiting that seminal crisis in this book, Sen also pulls the rug on theories that pit democracy against development, contending that public reasoning is deeply interrelated to economic performance and social opportunity.

What about happiness? Taking off from the fact that economics is often referred to as a dismal science, Sen questions those who claim happiness as a self-evident good. He is neither a killjoy nor does he long for pain rather than pleasure. And he has seen famine victims who feel a positive ecstasy when they get their relief supplies, an ecstasy that appears unassailable. Nonetheless, he points to problems with the alleged insignificance of everything else. There is also the example of the domestic servant who feels wonderfully well off on this day off. Because a person has adapted to deprivation, that?s no reason not to take an accounting of that deprivation. And an interactive public discussion is critical to tackling chronic deprivation.

In a passing reference, Sen also emphasises the role of public reasoning in preventing community-based violence: ?The fact that, after the murderous attacks in Mumbai in November 2008 by terrorists from a Muslim background (and almost certainly of Pakistani ancestry), the much-feared reaction against Indian Muslims did not emerge was to a great extent due to the public discussion that followed the attacks, to which both Muslims and non-Muslims contributed richly.? As did the media.

For those who might yet be churned up about how those attacks have been tackled, here is an axiom: ?Outrage can be used to motivate, rather than to replace, reasoning.? Finally there is this thought: it is bad enough that we live in a world with deprivations, tyrannies and injustices; how much worse would it be if we couldn?t even engage in debate, altercate but still communicate?

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