This book examines the issue of rational cooperation, especially cooperation between people with conflicting moral commitments. Can such cooperation--the choice made by a group and the decision by each member to contribute to that choice-- be understood as guided by reason? Can the activity of reasoning itself take a cooperative form? The book is distinctive in offering an account of what people can accomplish by reasoning together, of the role of deliberation in democratic decision making, and of the negotiation of the proper use of concepts.

This book examines the ways in which reasonable people can disagree about the requirements of political morality. Christopher McMahon argues that there will be a 'zone of reasonable disagreement' surrounding most questions of political morality. Moral notions of right and wrong evolve over time as new zones of reasonable disagreement emerge out of old ones; thus political morality is both different in different societies with varying histories, and different now from what it was in the past. McMahon explores this feature of his theory in detail and traces its implications for the possibility...