The Dialectic of Essence: A Study of Plato's Metaphysics

Introduction

How ought one to live? I take this question to be the starting point for Plato's philosophy, his Platonism. No doubt others before him asked it: Soc-rates for one. But it is not the mere posing of the question that makes it so special. Rather, it is the manner in which Plato considers it. In his hands it calls for reflection, and reflection of a certain, increasingly systematic variety. Plato thinks that systematic reflection, what he and we call "philosophy," shows that this question can be answered. Indeed, philosophical reflection reveals that philosophy itself, the practice of philosophizing, is the answer to the question.

From this starting point spring his ethics, epistemology, and metaphysics. For Plato, these domains are interdependent. Plato is rightly honored for his synoptic vision, his power to see systematic connections between different parts of life, science, the arts, and philosophy. If the question is, broadly speaking, part of ethical inquiry, his answer requires the development of much of his metaphysics and epistemology.

My aim in this work is to explore Plato's metaphysics. The book has three parts, modeled on what I believe to be the three key elements of his metaphysics: the Theory of Forms; the account of particulars; and the nature of metaphysical theory itself.

At the core of Plato's entire philosophy is the Theory of Forms. For Plato, Forms are both the goal and the grounds of philosophical inquiry. In seeking to answer the question of how ought one to live, Plato thinks that we come ineluctably to recognize their presence, in part through the realization that they are needed if one is to engage in any inquiry at all.

Thus while I will try to steer clear of most of his ethics and much of his epistemology, I cannot avoid the epistemology entirely. The fact that reflec-tion is a critical component of the best way to live ensures that epistemology will be in play from the outset. The capacity for reflection is distinctive of humans. Reflection presupposes that we take objects or states of affairs, including our own mental states, e.g., beliefs, perceptions, or feelings, as fixed in some sense, so that we may examine and think about them. The assumption that the world is a certain determinate way, constant and fixed to some degree, was as much a part of the Greek worldview as it is of our own. Plato's philosophy is predicated on the notion that the cosmos of which we are an integral part is rationally ordered and (therefore) in principle intelligible to us.1 But this is not to say that every Greek thinker accepted that the world was fixed and determinate. Perhaps its most problematic aspects are properties such as good and bad, right and wrong, or justice and injustice. Heraclitus, Gorgias, and Protagoras, thinkers whom Plato regarded as rivals, and no doubt countless tragedians, historians, and politicians challenged assumptions about the universality and sameness of ethical notions. Plato sees that reflection is a source of anxiety for humans. For us alone constancy is an issue, since only humans, it seems, have the ability to raise issues about it in our everyday thought and talk. And yet, aware of the challenges posed by reason, Plato concludes that in order to save the phenomenon of reason there must be stable, determinate Forms.

Part and parcel, then, of the reflective inquiry into the question of how ought one to live is this issue of fixity and stability. Socrates claims, against the sophists and others, that there are objective ethical values. Plato recognizes that Socrates' method of argumentation presupposes determinate concepts and beliefs that can be juxtaposed with other beliefs and concepts and judged to be compatible or incompatible, consistent or inconsistent with one another. Because there are these fixed, determinate contents, it is possible for one to deny the same judgment or statement that another asserts. Plato's Doctrine of Forms is the crystallization of his insight that there must be fixity or constancy, both in the world and in our thoughts. Indeed, I take this intuition to be at the heart of Realism or Platonism, Platonic or otherwise. Forms are the preconditions of an ordered, intelligible cosmos. They are principles of fixity, stability, and changelessness. Forms have a distinctively philosophical legacy. They are universals. They are objective, mind-independent entities. Among their heirs are Frege's sharp borders2 and the rules of Wittgenstein's Investigations. Let us refer to these fixed entities as "properties." The guiding insight, then, into the Theory of Forms is that properties cannot change their nature or properties. In my view, Plato's primary metaphysical goal is to explore and analyze this bedrock intuition that properties or Forms are the source and principles of stability in nature.