Abstract

This dissertation provides the first detailed treatment of the philosophical history of the development of a notion of practical reason in the thought of Plato , Isocrates , and Aristotle . It argues that the conception of practical reason we find in Aristotle's Ethics emerges from and is shaped by problems that first arise in Plato's dialogues regarding the nature of wisdom, its relationship to deliberation, and the value that wisdom and deliberation possess. ;Plato conceives of wisdom as knowledge of general principles that are worth knowing for their own sake and for the sake of their role in guiding deliberation and action. In so doing, he encounters difficulties justifying the claim that wisdom ensures excellent deliberation. As Isocrates rightly argues, excellent deliberation primarily requires perceptiveness and case-specific judgment concerning particulars---capacities which cannot be acquired through or replaced by knowledge of general principles. ;In response, Aristotle draws a sharp distinction between theoretical knowledge of principles , on the one hand, and knowledge concerned with deliberation , on the other. Phronesis includes capacities for perception and case-specific judgment about particular circumstances. However, I reject the view of John McDowell and Sarah Broadie that phronesis is to be assimilated to these capacities, on the grounds that such an assimilation would undermine the rationality of practical reason as Aristotle conceives of it. ;Phronesis also includes the capacity for true hypolepsis of ends, which forms a non-deductive basis for determining the general ends that serve as the starting-points of means-end deliberative reasoning. True hypolepsis also forms the basis for the agent's understanding, in general terms, of the value of the ends he rationally desires and pursues in action. ;By drawing a sharp distinction between theoretical wisdom and phronesis to resolve Platonic difficulties, Aristotle opens up space for the further important question concerning the value practical reason has in its own right. I argue that Aristotle grounds the value of practical reason primarily in the reflective understanding associated with phronesis and its exercise.