Plato's Theory of Ideas: Development, Dualism, and Critical Review

The Theory of Ideas in Plato's Philosophy

All Platonic philosophy revolves around the Theory of Ideas (or Forms). However, it is not easy to interpret the exact meaning of this theory, as it is not explicitly detailed in any single dialogue.

Early Dialogues and Socratic Ethics

In the early dialogues, the Theory of Ideas was inspired by Socratic ethics: To be virtuous, it is necessary to know what each virtue is. That is, we must find out the commonality present in human actions that allows us to claim they are virtuous. That "something common" is a universal essence.

The Theory of Ideas in Maturity

In the dialogues of maturity, the Theory of Ideas underwent a significant transformation. It can be summarized as follows:

• Intelligible Essences: The Ideas are intelligible essences—that by which a thing is what it is. (E.g., the Idea of Beauty is beauty in itself, and that by which particular things are beautiful.)
• Separation: The intelligible essences exist apart from particular, sensible things.
• Object of Thought: The Ideas are the true object of thought and knowledge. Through this knowledge, sensible beings can be grasped by the understanding and named.
• World Dualism: The theory implies a doubling of the world: the visible world (a fleeting world dominated by constant change) and the intelligible world (the truly real world).
• Characteristics: Each Idea is unique, eternal, and unchanging. They can be known only through intelligence (reason).
• Modeling: The Ideas are the model (paradigm) of sensible things.

Critical Review of the Theory of Ideas

A critical review of Plato's Theory of Ideas reveals serious deficiencies. The main difficulty lies in its dualistic doctrine, which posits the existence of two separate worlds.

Key Philosophical Problems and Objections

The main problems raised against the theory include:

1. What types of Ideas exist? The theory implies an Idea for every common name. While early dialogues focused only on moral concepts, later stages added aesthetic concepts and mathematical relationships. It is critical to ask whether there were also Ideas of things. Plato suggests there is no reason to deny the existence of such ideas.
2. What is the relationship between Ideas and things? This objection examines the main difficulties against the concepts of participation and imitation used to describe the relationship between Forms and particulars.
3. Is there a hierarchy of Ideas? Plato consistently established a hierarchy within the intelligible world throughout his dialogues.

Plato's Defense of the Theory of Ideas

Despite these difficulties, Plato maintained that we must continue to admit the existence of the Ideas and uphold his theory, citing the following reasons:

• The World of Ideas is the foundation of the sensible world.
• The properties of sensible things are manifested in a limited way.
• Science (episteme) is concerned with the immutable and universal.
• No one can know the singular intellectually without referring to the universal.