After surveying Western ideas of reason from the ancient Greeks through Kant, Hegel, and Marx, Jay engages at length with the ways leading theorists of the Frankfurt School--Horkheimer, Marcuse, Adorno, and most extensively Habermas--sought to salvage a viable concept of reason after its apparent eclipse. They despaired, in particular, over the decay in the modern world of reason into mere instrumental rationality. When reason becomes a technical tool of calculation separated from the values and norms central to daily life, then choices become grounded not in careful thought but in emotion and will--a mode of thinking embraced by fascist movements in the twentieth century.

Is there a more robust idea of reason that can be defended as at once a philosophical concept, a ground of critique, and a norm for human emancipation? Jay explores at length the ommunicative rationality advocated by Habermas and considers the range of arguments, both pro and con, that have greeted his work.