In Chapter 3 § 3 we examine a text concerning dialectic in Memorabilia IV.5–6 where the influence of Plato is, I believe, unmistakable. But this is not an isolated case. I consider here a number of parallel texts to demonstrate how pervasive is Xenophon's dependence on Platonic material.

The importance of this Platonic influence on Xenophon must not be exaggerated. His use of Platonic texts is essentially superficial, almost cosmetic in nature. Xenophon seems to have had no real sympathy with Plato's portrayal of Socrates. Thus his Symposium, though no doubt inspired by Plato's dialogue and largely devoted to the same theme, is as different from that work in tone and substance as anything one can well imagine. As von Fritz pointed out, it would be a mistake to think of Xenophon as trying to compete with Plato; he simply rejects and hence ignores the spiritualized view of Socrates that Plato presents. In Antisthenes and Aeschines, on the other hand, Xenophon found more congenial representations of Socrates that he could to some extent absorb into his own portrayal.

A full study of the parallels between Xenophon and Plato would call for a separate monograph. What follows makes no claim to completeness. I simply note some eight or ten passages from the Memorabilia where the direct literary dependence of Xenophon upon Plato seems to me at least probable, and two from the Symposium where it seems certain.

(Mem. 1.6.14)

As for myself, just as someone else takes pleasure in a good horse or dog or bird, in the same way and even more so do I take pleasure in good friends.

I offer here an interpretation of Plato's early and middle dialogues which aims to do justice to the genius of Plato not only as a thinker but also as a writer. For Plato is the only major philosopher who is also a supreme literary artist. There is no writer more complex, and there is no other philosopher whose work calls for so many levels of interpretation. Plato was the first author to offer a systematic definition of the goals and methods of philosophy. But he was also a social reformer and an educator, whose conception of philosophy entailed a radical transformation of the moral and intellectual culture of his own time and place. Much of his writing is designed to serve this larger cause. Hence a perceptive interpretation of Plato's dialogues calls for attention to his revolutionary cultural enterprise as well as to the literary and philosophical dimensions of his work.

My understanding of Plato reflects three quite different traditions. As a student at the University of Chicago, I learned from David Grene to read Plato as a great dramatist who belongs in the company of Shakespeare and the Attic tragedians. As a doctoral student in Classics at Columbia University, I was initiated into the mysteries of historical philology by Ernst Kapp and Kurt von Fritz. There I came to see Plato's dialogues as central texts for Greek culture of the fourth century BG, in the perspective of the great Plato commentaries of John Burnet and E. R. Dodds.

TRANSITION TO DIALECTIC AND THE FORMS

At this point our study undergoes a change of pace as well as a change in theme. Instead of moral psychology and the theory of virtue we turn now to the more technical heartland of Platonic philosophy: the concept of dialectic and the theory of Forms. This means moving also from the threshold dialogues to the Phaedo and Republic. It is Plato's own argument that has led us in this direction. In the last three chapters we have been following a line of thought that connects the beneficial knowledge of good and evil (as introduced in the Laches and Charmides) with the twin Socratic paradoxes familiar from the Gorgias, Protagoras, and Meno: that no one does evil voluntarily and that the moral virtues are somehow unified in wisdom or knowledge. But the problem remains: how can knowledge of the good guarantee right action? I have argued that Plato's conception of erōs, as a passionate desire for the good-and-beautiful, is the essential key to a Platonic understanding of these paradoxes. No one does evil willingly because our most fundamental passion is a desire for the good, a desire understood transparently or de re as a desire for what is truly good, and not merely a pursuit of what we happen to think is good. (This distinction is explicitly drawn by Plato in Rep. vi, 505D 5–9.) If we in fact pursue a goal or activity which is not really good, that can only be out of ignorance.

The task of philosophy, then, is to lead us to knowledge of the good.

A SURVEY OF THE CHARMIDES

The Charmides presents itself as a kind of companion piece to the Laches: an unsuccessful attempt to define temperance (sōphrosunē) matching the unsuccessful attempt to define courage in the Laches. In fact the two dialogues are very different from one another, and the Charmides poses many problems of its own.

A central thread connecting the Charmides with the other threshold dialogues is reflection on the parallel themes of knowledge in the strict sense, as technē, and virtue or moral excellence (aretē). The Charmides pays little attention to the topic of the teaching of virtue, which occupies center stage in the Laches, Protagoras, and Meno, as later in the Republic. The primary concern of the Charmides is to interpret temperance as a beneficial form of knowledge, the kind of knowledge that can make us “do well” (eu prattein) and lead a happy life. The chief peculiarity of the Charmides (aside from the choice of interlocutors) is its preoccupation with the ambiguous claim that temperance must be knowledge-of-knowledge or self-knowledge, not knowledge of anything else.

To the delight of scholars, Aristotle's surviving writings are both extensive and obscure. One of the sources of this obscurity is familiar to us from scholastic philosophy: the arguments often seem to meander through a nearly featureless theoretical countryside. In this barren realm we find few familiar landmarks, so that even with the road map provided by the arguments, we are often unable to tell where we are headed or why we have taken a turn.

The first part of this chapter briefly sketches out some important features of the theoretical road map as it is presented in Aristotle's earlier, logical works, the Organon. This is not intended as a primary study of those features. Those seeking that can find other, far more detailed, discussions. My purpose is to introduce some key notions and to point out their limitations.

In the second I turn to the Physics and to questions about the geography and population of the landscape there. Some of these features are quite basic to Aristotle's philosophical concerns yet are never explicitly discussed by him; others he touches upon only tangentially or in unexpected contexts; still others he discusses over and over again. None of them is in any way esoteric: they are all homely features of the world that have been noted by ten year olds throughout history – things like spiderwebs, earth, houses, sheep, and ponds. To understand Aristotle's system, we need to see how these things fit into it.

Aristotle's elements, we saw in Chapter 2, have a bipolar constitution: on the one hand, each element has an Internal Principle of Change (IPC) in virtue of which it is disposed to be what it is; on the other hand, each element can be driven by external forces from what it is, lose its nature, and perish. The first of these possibilities it owes to its form; the second its owes somehow to its matter.

In the last chapter we were primarily concerned with elemental motion and alteration. In this we turn to the role of these two factors (form and matter) in two basic processes: elemental transformation, which Aristotle holds is the coming-to-be and perishing of elements; and the creation of homogeneous compounds out of elements, which he holds does not involve the coming-to-be and perishing of elements. I conclude by showing how dispositional essentialism can help with some puzzles regarding the difference between these two processes.

Change and Continuity

Prime Matter

For a quarter-century Aristotle's interpreters have disagreed over his doctrine of prime matter. One school contends that Aristotle is not committed to prime matter; the other, that he is committed to it. The issue has been put with admirable clarity by H. M. Robinson:

In Chapter 1 we saw Aristotle introduce the Internal Principle of Change Principle (IPCP), but it remained rather abstract and we did not see how Aristotle applies it to actual cases. In this chapter I discuss his use of the principle in his accounts of elemental motion and alteration. This develops the notion of an Internal Principle of Change (IPC) and, I argue, leads him to the view that things need not always possess all their essential properties, though they must by nature be disposed toward possessing them. We can think of this as a principle of essentialist generosity, balancing his tendency to a restricted and elitist essentialism mentioned in the Introduction. (On the one hand, some plebeian things do not have essences; on the other, things that have essences get credit for trying, even if they fail.) In Chapter 5 I return to this theme.

Aristotle's Elements

In On the Heavens III, 3, Aristotle gives the following definition: “An element … is a body into which other bodies may be analyzed, present in them potentially or actually … and not itself divisible into bodies different in form” [302a16–18]. He then goes on to say that fire and earth are potentially present in flesh and wood, for they can be drawn out of flesh and wood, but that flesh and wood are neither potentially nor or actually present in fire, for they cannot be drawn out of fire.

The Unity of Definition

Nominal Essences

We saw in Chapter 1 that, in On Interpretation and in the Posterior Analytics, Aristotle wonders how the differentia and the genus make up a unity and questions Plato's method of division. When one is asked whether man is a terrestrial or nonterrestrial animal, the method of division leads one to answer that man is a terrestrial animal. But, asks Aristotle, “what prevents all this from being true of man yet not making clear what a man is or what it is to be a man?” Man is a terrestrial animal, but the method of division gives us no reason to think that being a terrestrial animal is part of man's essential nature. Mere truth is a necessary but not a sufficient condition for a formula's expressing an essential nature; there must be something more, but what? Some interpreters have thought that the missing element must be meaning-equivalence: that if “man” means “terrestrial animal,” then “man is a terrestrial animal” states the essence of man. But Aristotle has something else in mind. In a previous article I called his answer to this problem “the doctrine of proper differentiae.”

In the Metaphysics VII, 4, Aristotle says that “the essence of each thing is what it is said to be in virtue of itself [kath' hauto]. For being you is not being musical; for you are not musical in virtue of yourself. What, then, you are in virtue of yourself is your essence.”

I know twenty or thirty people who, given the chance, could come up with a vastly improved Aristotle. I count myself among this group, and if we had ever formed a committee to do the job, I know the assignment I would have wanted: inserting texts in which Aristotle says that as a given thing can survive without a certain characteristic, the characteristic is not essential to the thing.

Aristotle does, from time to time, invoke the survivability criterion, or what amounts to the same thing – most typically, in claiming that living things and their parts are essentially animate. And in the Metaphysics VII, 15, he criticizes those who would define the sun as “going round the earth”: “they err … by adding attributes after whose removal the sun would still exist.” On their view, if the sun were to stand still, it would no longer be the sun – a strange consequence, “for ‘the sun’ means a certain substance” [1040a28–33]. Outside of a biological context this sort of statement is rare, and at crucial junctures where a quick invocation of the survivability criterion would seem appropriate, Aristotle refrains.

In Metaphysics VII, 4, he addresses the question of whether an essence corresponds to “pale man” by asking whether “pale man” involves one thing's being said of another. How much easier it would have been to point out that, if the pale man spends some time in the sun, he will tan: that paleness is an attribute loss of which people survive each summer.

Plotinus adheres to the classical Greek tenet that we understand and explain something's nature by knowing and articulating its causes, and he articulates the order of causes which explains physical reality as a metaphysical procession whose first principle is his One. Here, though, I shall focus on some main features of Plotinus's analysis of physical reality which prepare the way for relating it to his metaphysical principles.

Plotinus thinks of physical reality, first and foremost, as the domain of coming-to-be (genesis). His analysis of coming-to-be focuses on the coming-to-be of particular things - for example, particular plants or animals or human beings and, in so doing, he intends to continue Plato's project of assuring and explaining the real existence of those particulars and of their comings-to-be. Plotinus does so, in part, by incorporating into his analysis the notion of substance (ousia), which Aristotle introduced to denote the proper subject)s) for assertions of real existence or ascriptions which presuppose real existence; but he considers the notion of substance to be by itself insufficient for his explanatory task.