This essay examines two different modes of reasoning about justice: an individual mode in which each individual judges what we all ought to do and a social mode in which we seek to reconcile our judgments of justice so that we can share common rules of justice. Social contract theory has traditionally emphasized the second, reconciliation mode, devising a central plan to do so. However, I argue that because we disagree not only in our judgments of justice but also about (...) the degree of reconciliation justice calls for, the social contract presupposes a single, controversial, answer to the proper degree of reconciliation. In place of the social contract’s ‘top-down’ approach, this article explores the idea of self-organizing moral systems, in which each individual, acting on her own views of justice, responds to the decisions of others, forming systems of shared justice. Several basic agent-based models are explored to begin to understand the dynami... (shrink)

The paper deals with the methodological clash between idealism and anti-idealism in political philosophy, and highlights its importance for public reason (PR) and public justification (PJ) theorising. Upon reviewing the broader context which harks back to Rawls’s notion of a realistic utopia, we focus on two major recent contributions to the debate in the work of David Estlund (the prototypical utopian) and Gerald Gaus (the cautious anti-utopian). While Estlund presents a powerful case on behalf of ideal theorising, claiming that motivational (...) incapacity and other non-ideal features of “human nature” – the so-called bad facts – do not normally refute the desirability of highly utopian theories of justice, we show that Gaus is correct in stressing the importance of feasibility considerations, including empirical knowledge about human societies. Because moral disagreement is to be expected even among cognitively and morally excellent reasoners, we argue that Estlund’s search for Truth about justice must idealise away normative diversity as just another bad fact. This methodological dispute has important ramifications for current debates about PR and PJ as the grounds of liberal legitimacy. Because consensual approaches rely on strong idealisation which results in exclusion of numerous comprehensive doctrines from consideration, we conclude that convergence-based liberal political theory has distinct advantage as regards exploiting normative diversity to the advantage of everyone. (shrink)