Abstract

The dissertation critically examines the problem of acting rationally. I orient the study to an analysis of reasons for action, which reveals the problem of accounting for the possibility that reasons can explain and justify action simultaneously. An intentional act is rational if it is done on behalf of a reason that explains teleologically why the agent acted and justifies the action so performed. It is not evident how a reason can accomplish both functions; more specifically, it is not evident how motivation and justification are correlated together. In short, the explanatory and the normative dimensions of reasons can come apart. How they come undone and how they come together defines the problem of rational action. ;I argue that there are three theoretical alternatives to addressing this problem. Non-cognitivism defines a practical reason in terms of the standard desire-belief model of intentional action; cognitivism argues that the agent's rational capacities provide him with a sui generic source of motivation that underwrites his intentional conduct; and externalism distinguishes between reasons that explain and justify and the class of pure normative reasons that justify only. The heart of the dissertation involves a comparative study of the merits of each alternative. I argue that non-cognitivism fails to make sense of how reasons justify intentional conduct. With the demise of noncognitivism externalism is also undermined, as it presupposes the validity of the former. The study concludes with an examination of the resources contained in cognitivism. The most promising line of research lies in the model of communicative rationality developed by Jurgen Habermas. The last chapter formulates the implications of this model for solving the problem of rational action and applies these results to discourse ethics. ;I employ a method of argumentation that internally links together the dialectically opposed positions. The critique of non-cognitivism leads to cognitivism as its natural alternative. And the examination of the respective cognitivist possibilities leads to the model of communicative rationality as their more perfect fulfillment.