Abstract

The dissertation is a detailed philosophical interpretation of the entire text of Plato's Sophist. In addition to extended analysis of the argument and discussion of many current interpretations, special attention is given to the following themes as they occur in other Platonic dialogues as well as the Sophist: ; Plato's theory of Knowledge: What is it that can be known? And how does one get to know it? Do the Sophist and other late dialogues show a change in Plato's views, or an elaboration of views he held when he wrote such works as the Phaedo and the Republic? ;: these fall into three types: those with propositional structures, those which are structured like descriptions, i.e. denoting complexes, and definitions, which are denoting complexes of a special sort. Each of these types is discussed, and the role of definitions in Plato's theory of knowledge is explained. ; Judgments: what is a judgment, or opinion? How does a judgment come to be made? Plato distinguished questions about the internal structure of judgments or opinions from questions about what is involved in a person's coming to judge, or believe, or opine something. Both sorts of questions are discussed in the dissertation. ; Truth and falsity: two notions of truth, together with corresponding notions of falsity, are distinguished. One is a notion of truth as predicated of propositionally structured simpliciter. This is the notion which plays a dominate role in the Sophist. The other notion, which rears its head in the Cratylus and a short section of the Phaedrus, if a notion of true of as predicted of names and and what they are said of. Both notions, and other notions of truth held by Plato's philosophical opponents, are explained and discussed. ; Negation: What is the problem about being and not being^which arises in the Sophist? How is it related to the problem raised^as to how false judgments and are possible? Plato believed^that Parmenides made a mistaken assumption about negation, and^that that assumption could be used by sophists such as Protagoras^and Gorgias to undermine the thesis that mistaken judgments and^false occur. The central pages of the Sophist are devoted to^uncovering Parmenides' error, and to offering a replacement for the^assumption which Plato rejects. Plato then shows how the replacement he suggests can beused in an analysis of true and false and judgments. ;Numerous other themes arise in the course of the analysis of the argument--Plato's notions of time and change, of images, of explanation, etc. These, too, are discussed. There are twenty one appendices containing discussions of points of translation, alternative interpretations of key passages, formal proofs not appropriate for inclusion in the main body of the text and too extended for footnotes, and remarks on various passages occurring in other Platonic dialogues helpful in glossing the Sophist