The Many Moral Rationalisms

Abstract

This volume of thirteen original essays investigates the four core theses of moral rationalism: (i) the psychological thesis that reason is the source of moral judgement; (ii) the metaphysical thesis that moral requirements are constituted by the deliverances of practical reason; (iii) the epistemological thesis that moral requirements are knowable a priori; and (iv) the normative thesis that moral requirements entail valid reasons for action. The essays explore a variety of interpretations of these core theses, offer new arguments in their favour, and explore challenges to the rationalist project. The five essays in Part I (“Normativity”) offer contemporary defences or reconstructions of Kant’s attempt to ground the normative thesis, that moral requirements entail valid reasons for action (thesis iv), in the nature of practical reason and practical rationality. Some, but not all, rely on constructivist commitments about the metaphysical dependence of moral requirements on practical reason (thesis ii). The four essays in Part II (“Epistemology and Meaning”) consider the viability of claims to a priori moral knowledge (thesis iii). The authors of all four essays are sympathetic to a realist moral metaphysics and thus forgo the straightforward constructivist road to a priority. The four essays in Part III (“Psychology”) each grapple with the implications for rationalism of the role of emotions and unconscious processes in moral judgement and action (thesis i). The volume demonstrates that moral rationalism identifies not a single philosophical position but rather a family of philosophical positions, which resemble traditional rationalism, as exemplified by Kant, to varying degrees.