Abstract

My dissertation is an examination of Plato's epistemology and ontology in the Theaetetus and Sophist. Through this examination I advance the following views. First, in the last part of the Theaetetus, Plato comes to be aware of epistemological and semantic difficulties with his earlier theory of Forms. The difficulties are: that simple Forms as well as their composites cannot be known, and that we cannot make any meaningful statement about Forms. Second, Plato overcomes these difficulties in the Sophist by attributing to each Form a dunamis, capacity to combine with some others. Third, an epistemological implication of this revised ontology is that on Plato's view one knows all or nothing, i.e., that to know anything one ought to know the whole reality. ;I begin my dissertation with an interpretation of Socrates' dream in the last part of the Theaetetus. In Chapters 1 and 2, I argue that primary elements in the dream are Forms and that logos there is any meaningful statement. With this interpretation, it is suggested that Plato's concern in the dream is the impossibility not only of defining Forms but, more fundamentally, of talking about them. In Chapters 3 and 4, I discuss two assumptions underlying the dream theory. Chapter 3 deals with the first of the two assumptions that Forms cannot combine with one another, and I try to show that this impossibility is entailed by Plato's view on the nature of Forms. Chapter 4 is concerned with the second of the two assumptions and is also an interpretation of the sumploke eidon passage in the Sophist. Chapter 5 is an investigation of how Plato handles in the Sophist the difficulties pointed out in the Theaetetus. My suggestion is that Plato resolves the difficulties by attributing a dunamis to each Form. With this suggestion, I examine the 'Vowel-Form Interpretation,' according to which in the Sophist Plato distinguishes between two kinds of Forms. In the last Chapter, I propose with the aid of the ontological discussions in Chapters 3-5, a conception of knowledge Plato is working toward in the Theaetetus and Sophist. The Epilogue is a comparison of Plato's conception of knowledge with modern one. A brief remark is made on the relevance of Plato's view to modern discussion of knowledge