Plato's theory of forms: a critical analysis

This dissertation critically examines the charge, advanced in Aristotle's Metaphysics and in Plato's own work, the Parmenides, that Plato's theory of forms involves an infinite regress.

Some preliminary problems regarding the chronological order and interpretation of the dialogues as well as "the Socratic problem" are discussed in Chapter One.

Chapter Two provides a complex description of the theory of forms. This description traces various aspects of the theory through each dialogue and the Seventh Letter. The following aspects are considered: the ontological status of the forms; the stability, uniqueness, singularity and reality of the forms; the various functions of the forms including their function as universals, as objects of knowledge, as paradigms, as perfect particulars and as causes; the different kinds of forms; predication including participation, the combination of forms and self-predication; and methods of apprehending the forms including anamnesis, definition, hypothesis, analogy, example, collection and division. A central point developed in Chapter Two is that the theory of forms is internally consistent.

In the third and final chapter, the arguments from Aristotle's Metaphysics and Plato's Parmenides that the theory involves an infinite regress are examined and evaluated. A contemporary analysis of the infinite regress arguments in the Parmenides by Gregory Vlastos, "The Third Man Argument in the Parmenides," is also examined and evaluated.

The principal contention of the writer is that certain of the assumptions upon which these arguments are based, although widely accepted, are, nonetheless, mistaken. It has been too easily assumed that in the first part of the Parmenides Plato is rejecting outright the theory of forms of the Phaedo and the Republic, and that Plato made the so-called "self-predication assumption." This dissertation interprets the arguments at Parmenides 132 A-B and 132 D- 133 A⁶ as reductio ad absurdum arguments by means of which Plato is rejecting certain undesirable misinterpretations of the theory of forms, rather than the theory itself.