Part one of this series can be found here.

Part two of this series can be found here.

Plato, however, does not simply divide reality into the transcendent world of Being and the physical world of Becoming. He further divides his two worlds in what has become known as the “divided line” in book six of the Republic.¹ The divided line analogy not only seeks to provide a rational description of reality but also has epistemological implications. First, Plato gives this description:

Now take a line which has been cut into two unequal parts, and divide each of them again in the same proportion, and suppose the two main divisions to answer, one to the visible and the other to the intelligible, and then compare the subdivisions in respect of their clearness and want of clearness, and you will find that the first section in the sphere of the visible consists of images. And by images I mean, in the first place, shadows, and the second place, reflection in water and in solid, smooth and polished bodies and the like. (386 – 387)

In this part of book six of the Republic, Plato divides all reality into four sections, not two. Plato gives us a description of a line which itself attempts to divide metaphysics from epistemology. The line is then divided into four sections. This line still represents Plato’s hierarchy of reality but interestingly, he begins his presentation at the bottom of his hierarchy with the realm of images. Images such as shadows and reflections have the least degree of reality. The next section in the world of Becoming is the sensible objects of this world, which partake of a slightly stronger degree of reality. The next section divides Being from Becoming and is the section of mathematical Forms. Above the sections of mathematical Forms are the higher Forms. Plato, in this passage, does not define the “higher Forms,” but from a general reading of Plato, one would guess that he has the Forms of Goodness, Truth, or Justice in mind. All reality and knowledge is a hierarchy for Plato, and Plato has Socrates provide an epistemological understanding of his divided line:

You have quite conceived my meaning, I said; and now, corresponding to these four divisions, let there be four faculties in the soul – reason answering the highest, understanding to the second, faith (or conviction) to the third, and perception of shadows to the last – and let there be a scale of them, and let us suppose that the several faculties have clearness in the same degree that their subjects have truth. (387)

In this analogy and throughout various passages of Plato, Becoming epistemically corresponds to Opinion and Being to Knowledge. The realm of Opinion is divided into Imagination as the lowest and Perception as the higher category. In the transcendent world, Knowledge is divided into Reason as the lowest realm and Understanding as the ultimate. While Plato does not always explain how clearly divided these categories are to be, he does indicate that the realm of Being somehow emanates into the world of Becoming and somehow participates in it. In the Phaedo, Plato speaks of the Form as participating in the sensible world and the source of causation. In the Euthephro, however, Plato speaks as if sensible objects are copies or imitations of the Forms. In this way, Plato resolves the problem of the One and the Many. The Forms in the transcendent world (the One) emanate and participate in the world of Becoming (the Many).

The question remains, why was the problem of the one and the many so important to Plato? First, Plato understands that things that are Becoming cannot be their own causes; to become is to pass from non-Being to Being and non-Being cannot be a cause². If non-Being cannot be a cause, Plato needs to find a source of change and cause in this world. Plato attempts to resolve this with his theory of Forms. The Forms participate in the world of Becoming and are the source of change and causation. As Socrates explains in the Euthephro, there must be some kind of standard to decide ethical decisions. Similarly, there must be some kind of standard for logical discourse if our thinking and discourse are to be meaningful. Plato posits the Forms as a kind of unchanging standard for meaningful discourse and ethical and moral actions. A world of only flux, change, and Becoming is a world of chaos. Furthermore, Plato also understands that the question of metaphysics is a basic one. How one views the world will determine how one views a variety of other things. If one believes the universe is simply governed by matter and mechanical causes, one could make a pretty good guess about what he or she believes about many other things. If, however, one believes in a transcendent standard of reality that is universal and unchanging, one could guess his or her understanding of things would be very different. In this way, metaphysics is a basic question and probably the reason why Socrates was so interested in examining the nature of reality and connecting it to ethics. For Plato, the transcendent realm of the Forms and their interaction with the world was his way of attempting to resolve these difficult philosophical matters.

As so often is the case in intellectual history, not everyone is convinced that Plato resolved the problem of the one and the many. Although most believe that his discovery of Form is very significant in one way or another. In our next post, I hope to explore how Aristotle, Plato’s greatest student, approached the problem of the one and the many and Aristotle’s contribution to metaphysics.

1 The divided line passage is too long to quote in its entirety, but I will summarize it here and point out the primary sections of his argument.

2 Plato explores this theme in the Timeaus and Parmenides among other places.

Works cited

Plato. The Dialogues of Plato. Trans. Benjamin Jowett. Great Books of the Western World. Vol. 6. Chicago: Encycyclopedia Britannica, Inc., 1996.