The ally of reason: Plato on the spirited part of the soul

My dissertation aims to provide an explicit and detailed account of the role of thumos in Plato's moral philosophy and, in doing so, to defend Plato's commitment (both in the Republic and beyond it) to including thumos in his moral psychological picture and to the theory of tripartition as a whole. I argue that Plato's primary motivation for introducing the theory of tripartition was neither a rhetorical one nor (as has often been assumed) the result of his thinking about akrasia, but rather that he saw a crucial role for thumos and spirited desires to play in early moral education and the virtue of individuals. In Chapter 1 I examine the nature of spirited desire and offer an account of how the primitive spirited desires that Plato attributes to non-human animals and infants evolve into the more mature spirited desires that he attributes to adult human beings. I argue that for Plato, what is essential to mature spirited desire is the desire to be kalos -- admirable or beautiful. In Chapter 2 I take a detailed look at the program of early education that Plato proposes in Republic 2 and 3 and argue that musical education as Plato conceives it (in addition to gymnastic education) is primarily directed at the spirited part of the soul. I also address important ways in which early education is directed at the reasoning part of the soul and suggest why Plato does not seem to direct moral education at the appetitive part of the soul. In Chapter 3 I provide an account of the amicable relationship between thumos and reason that explains both how intra-psychic communication between the two takes place and why thumos responds to reason's judgments, desires, and commands in the special way that it does. Finally, in Chapter 4 I confront and reject the recent proposal that Plato abandoned the theory of tripartition in his later dialogues, and I offer an interpretation of crucial passages from the Laws that suggest, on the contrary, that Plato maintained his commitment to that theory in his later works.