Abstract

This dissertation is a study of Plato's Theaetetus . I argue that the Theaetetus is fundamentally an extended reductio of a radical materialist view---the view that the only things that there are perceptible, material particulars with no properties or relations. Based on evidence from the Sophist---the sequel dialogue to the Theaetetus---I show that, according to Plato, this radical materialism results from ignoring the intelligible Forms and the participation of things in them. The radical materialist ontology also implies a certain view of judgments and statements, essentially the view that judging or stating is naming or identifying the thing that is judged or stated. ;I read the discussion of the thesis that knowledge is true judgment in the second part of the Theaetetus as, first illustrating difficulties that the radical materialist view gives rise to in explaining the possibility of false judgment, but then indicating how false judgment can occur on that view, only to show that the radical materialist cannot give an account of simple arithmetical mistakes on his assumptions. ;The third part of Theaetetus, dealing with the thesis that knowledge is true judgment with an account, concentrates on the implications of radical materialism for the unity and complexity of objects; the radical materialist cannot give an account of how there can be a whole with parts. He also cannot explain the possibility of systematic knowledge and expertise in a field, such as arithmetic or grammar, because of his commitment to the particularity of what there is, and therefore, of what is known