Plato's Theory of Ideas: Understanding the Absolute

Plato's Theory of Ideas

The Theory of Ideas is the foundational element of Platonic philosophy. In essence, it defends the existence of the absolute, which stands in opposition to the corporeal, mortal, and relative world.

Unlike personal thought, the absolute that Plato refers to is impersonal. Plato maintained that reality is divided into two main realms: the Sensible World and the Intelligible World, or World of Ideas. The absolute he refers to is precisely that realm of reality. The Sensible World is the set of entities accessible to the senses—realities that are changing, multiple, born, and die—and are captured through the senses. The Intelligible World, or World of Ideas, is populated by entities that are absolute, universal, independent, eternal, and immutable. These entities are beyond time and space and are known by the most excellent part of the soul: the rational part. In this second realm, the most valuable reality is the Idea of Good.

The task of philosophy is to ascend from the Sensible World to the World of Ideas and contemplate this idea of property. This theory is primarily an ontological theory, but it has clear implications for other areas.

Although some authors note the influence of religious elements, such as the Pythagoreans, or the political motivations behind Plato's postulation of the theory, we must not forget that the most important motivation is philosophical.

Theory of Reminiscence

In the "Meno", during the study of virtue, Plato introduces the Theory of Reminiscence. This theory is summarized in the idea that knowing is remembering. Plato certainly did not defend this point of view regarding expertise and factual knowledge, but rather on strict knowledge endowed with universality and necessity, such as mathematical knowledge, which can be discovered through dialectic. Plato believed that this kind of knowledge cannot be explained solely through empirical or perceptual experience. He advocated a peculiar nativist vision: when we know truths of this kind, we are not really learning anything new, but our soul remembers a truth it had access to before becoming flesh and living in this material world. Our soul remembers something it encountered while living in the World of Ideas. The Theory of Reminiscence defends the intriguing argument that the soul lives without the body in the World of Ideas, perceives the various ideas and their relationships, becomes embodied, forgets that knowledge, and, thanks to the intervention of a teacher, manages to remember this forgotten knowledge. The Theory of Reminiscence is the complement of the Socratic theory of knowledge and education: teaching is not about introducing knowledge into the mind of a subject, but rather encouraging the student to discover the truth within themselves.

Participation Theory

How does the world of sense link to the intelligible world, by which physical things have a certain being and intelligibility?

Plato believed that true self belongs to the ideas and the entire intelligible world. However, unlike what Parmenides appears to defend, he does not deny all reality to physical or perceptible things or to the Sensible World. Visible things have being, but not a perfect or genuine one; they are shadows of true reality. Worldly things are truly sensitive to the extent that they somehow embody or concretize universal entities or ideas. This loose talk is intentional and acknowledges the difficulty recognized by Plato in explaining how physical things are linked with ideas, and how the latter provide being and intelligibility to the former. Plato uses two expressions to indicate the link between the two worlds: in some texts, he tells us that the sensible world "participates" in the being of the intelligible world, and in others, that it "imitates" such a being. In several dialogues, particularly in "Parmenides," he laments the inevitable and perhaps unsolvable problem of this obscurity.