Introduction to the Philosophy and Writings of Plato

Let us then consider body—that is, a triply extended substance A substance that has the three dimensions of length, breadth, and depth.—which is endowed with quality; for this is the first thing we can describe and perceive with our senses. Is this, then, the ultimate principle of all things? No, for it is composed of two things: the body itself, and the quality that exists within that body as its subject. Which of these, therefore, is naturally prior? Both are indigent From the Latin 'indigens,' meaning lacking, needy, or dependent on something else for its existence. of their own parts; and that which exists within a subject is dependent upon that subject. Shall we say then that body itself is the principle of the first essence? That is impossible. For, in the first place, a true principle does not receive anything from that which comes after it. But body, as we have said, is the recipient of quality. Therefore quality (and the state of existing alongside it) is not derived from the body, since quality is present in the body as something distinct. Secondly, body is divisible in every way; its various parts depend on each other, and the whole depends on all its parts. Because it is dependent and is completed by things that are themselves dependent, it cannot be entirely self-sufficient.

Furthermore, if a body is not a single unit but merely a collection of parts joined together, it requires—as Plato says—a "connecting one" to hold it together. It is also something common and formless, acting as a kind of raw matter. It requires, therefore, "ornament" and the possession of a "form" so that it is not merely "body," but a body with a specific quality—such as a fiery body, or an earthly body; in short, a body adorned and clothed with a particular character. Thus, the things that join with it serve to finish and beautify it. Is that joining element, then, the primary principle? This is also impossible. For it does not stand on its own, nor does it exist in isolation, but lives within a subject on which it depends.

However, if someone were to argue that "body" is not a subject but rather one of the basic elements within a thing—for example, the "animal" element found in both horses and men—then each would still be dependent on the other (the subject and that which is inside it). Or rather, the common element ("animal") and the specific traits (being "rational" like a human or "irrational" like a horse) would be dependent on one each other. Elements are always dependent on one another, and anything composed of elements is dependent on those elements.

In short, this physical nature that is so obvious to us is neither "body" (for body by itself does not move the senses) nor "quality" (for quality does not possess a physical interval In this context, "interval" refers to physical extension or spatial dimension. that the senses can measure). Therefore, the thing we actually see is neither just body nor just color; rather, it is a "colored body," or "color made physical," that triggers our sight. Universally, the "sensible" object—which is a body with a specific quality—is what moves our senses. From this, it is clear that the thing which actually excites our senses is something incorporeal. For if it were merely "body," it would not yet be an object of sense. Body requires the incorporeal, and the incorporeal requires body. An incorporeal nature is not, by itself, perceivable by the senses. It is, however, different from body because these two have different powers, and neither exists before the other; rather, as elements of one physical thing, they are present together. The one gives physical extension to that which has no extension, while the other introduces a variety of shapes and forms to that which was formless.

Thirdly, these two together are not the principles of reality, since they are not self-sufficient. They need their own elements and something to guide them toward the creation of a single form. Body cannot do this, as it is inherently powerless; nor can quality, since it cannot exist apart from the body. Therefore, the "composite" (the thing made of both) either produces itself—which is impossible, as it is scattered and divided—or it is produced by a higher principle that existed before it.

Let us then suppose this principle to be what we call Nature, which is the source of motion and rest in things, existing essentially within them rather than by accident. This is something simpler and is the "builder" of composite forms. However, if this "Nature" exists only within the things it builds and does not exist separately from them or prior to them, it is not truly self-sufficient—even though it has a superior power to shape and build them. It exists only alongside them and is inseparable from them; when they exist, it exists, and when they perish, it perishes. This is because it is completely "leaning towards" them and cannot maintain its own independent existence. For the power of increasing, nourishing, and generating similar things—and the principle prior to these three, which is Nature—is not entirely incorporeal. It is almost like a certain quality of the body, differing only because it allows the composite thing to be moved or stay at rest from within. The "quality" of a physical thing provides what is visible in matter, but Nature provides an internal, natural energy, whether in terms of movement through space, or...