The Problem of Separation (χωρισμός) and Participation (μέθεξις) in Plato’s Late Dialogues (Parmenides, Sophist, Timaeus)

The dissertation aims to provide a systematic investigation of two fundamental concepts of Plato’s metaphysics – separation (χωρισμός) and participation (μέθεξις), which were used by Plato to describe the relation between sensible particulars and their essences, which Plato called Forms. Such an investigation is necessary due to the importance that these concepts play in the effort to reconstruct Plato’s philosophy as a whole. The inquiry firstly proceeds via the testimonies left by Aristotle, which point to the relation between these concepts and the problem of the ontological status of mathematical objects, as well as to Plato’s dialogue Parmenides as the locus of a more thorough explication of the concepts in question. The dissertation then provides a thorough study of the Parmenides, showing that the problem of separation and participation has two main features. The first part of the Parmenides is focused on the paradoxical mereological relation between Forms and sensible particulars (it can best be described as a dianoetic problem). Meanwhile, the second part of this dialogue shows that a similar problem is true when speaking about the relation between the Forms themselves (it can be best described as a noetic problem). Both of these problems can then be shown to receive solutions in the Sophist and the Timaeus. The Sophist deals with the noetic aspect of the problem and provides an arithmological interpretation of Forms, which explains the structural relations between them in a meaningful way, while the Timaeus deals with the dianoetic aspect of the problem and shows, via the concept of space (χώρα), how Forms and sensible particulars can be meaningfully related