Plato's Theory of the Idea of Good Explained

Chapter 18: Plato and the Idea of Good

Socrates and Glaucon on Knowledge

Plato, through the dialogue between Socrates and Glaucon, presents the point of view regarding the Idea of Good. They humble themselves, relying on the fact of not knowing anything or merely holding a distorted or false opinion.

The Idea of Good as Illumination

This dialogue refers to the Idea of the Good as that which makes other ideas accessible. In the intelligible world, the Idea of Good enlightens the other Ideas, similar to how the sun illuminates the visible world.

• With the help of sunlight, we see objects clearly.
• Without sufficient light, our vision becomes distorted and false.

Plato notes many similarities between these concepts. Material and visible things can be perceived by all senses, not just sight. However, there is an eternal reality, unique and unchanging, that unites them, called "what is." Therefore, "unity" corresponds to the Ideas. He gives the example of Beauty or Justice, which cannot be perceived by any sense but only by intelligence.

Ideas Versus Visible Aspects

The various aspects of the visible world are "multiple," attempting to imitate or copy the Ideas, often imperfectly.

Chapter 19: The Necessity of the Good

Exhibition of Understanding

Plato, again through Socrates and Glaucon, continues the discussion on the Idea of Good. The fragment serves as an exhibition, showing the need for a third element to properly understand things. Senses alone cannot attain complete sight.

The Sun Analogy Revisited

Plato compares the Sun with the Idea of Good; without the latter, everything visible is distorted or negligible. The Idea of Good gives rise to other ideas, providing understanding to visible things. The Idea of Good, in turn, cannot be seen except through itself.

Chapter 20: Division of Reality

Socrates Explains Reality's Structure

Chapter 20 is an expository text where Socrates attempts to explain the division of reality to his interlocutor. This division separates the visible world from the intelligible world, sorting them from lowest to highest reality.

The Visible World Division

The lower part (visible world) splits into two:

1. Images, which are mere reflections or appearances.
2. Natural and artificial things in the visible world.

The Intelligible World Ascent

The main idea of this fragment concerns the way the soul ascends:

• Mathematical objects are based on assumptions to fill the soul until the end.
• The soul reaches the highest level with the help of Ideas, neglecting mere images.