Author ORCID Identifier

Date Available


Year of Publication


Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation


Arts and Sciences



First Advisor

Dr. Eric Sanday


Being and Structure in Plato’s Sophist is a study of the metaphysical notion of being as it is at play in Plato’s dialogue the Sophist, and the senses in which Plato’s conception of being entails further accounts of ontological structure and goodness. While modern metaphysics primarily concerns existence, ancient metaphysics primarily concerns what grounds what, and in this dissertation I consider the nature and value of Plato’s understanding of being as a notion of ground rather than a principle of existence. I argue that Plato conceives of being in the fundamentally unified sense of participation, which entails a self-and-other and hence complex relation. For Plato, being must be understood in its context as one among many Platonic forms, or the network of mutually co-constitutive structures of determinacy that are the grounding stability necessary for the very possibilities of becoming, knowing, and discourse. I argue that Plato inherits his view in large part from Parmenides, and that the account in the Sophist makes explicit a previously implicit aspect of the Parmenidean tradition insofar as it involves a novel sense of nonbeing not as absolute nothingness, but instead as difference in the sense of constitutive and determinate otherness. I furthermore discuss the ways in which this account helps to show the connections between seemingly disparate elements of the dialogue like its dramatic setting, the method of division, and the discussion of the great ontological kinds. In this way, the dissertation entails a study of the entire dialogue and the interrelation of its parts, as well as its context among several other key Platonic and Parmenidean texts.

Digital Object Identifier (DOI)