Plato’s Theory of Forms and Knowledge: Exploring Reality
The Theory of Ideas
In Plato’s view of reality, he distinguishes between two worlds: the world of Ideas, which is truly real, and the sensible world, composed of things we perceive through our senses, which are copies of Ideas. Ideas are therefore the true reality and their features are like the being of Parmenides: eternal (always existing), unchanged (immutable), and intangible (no material component). They are the models from which the Demiurge constructs the sensible world, imitating the Ideas.
These two worlds are composed of entities with different characteristics: while Ideas are unique, eternal, immutable, and intangible, sensible things are multiple, perishable, changeable, and material. This explains the infinite variety of people existing in the sensible world; they are copies and imitations of the Idea of a person, a human being, which is unique and unchanging. The Idea gives things their being, essence, and the possibility of knowing them.
Moreover, the world of Ideas has a hierarchy: at its lowest level are mathematical Ideas, then Ideas of beauty and justice, culminating in the Idea of Good. Plato compares the Idea of Good to the sun, as it gives life to sensible things. Therefore, it is the ultimate principle of reality and the basis of knowledge.
Knowledge
Plato opposed the Sophists, who defended knowledge based on appearances. To truly know things, we must apply a method, dialectic, which leads us from knowledge of the sensible world to knowledge of the real world of Ideas.
Considering the division between the world of Ideas and the sensible world, Plato distinguishes between two types of knowledge: episteme (science) and doxa (opinion). Science provides objective knowledge of Ideas and leads to absolute and unquestionable truth, as it shares the characteristics of Ideas (eternal and immutable). Opinion, conversely, refers to the changing and perishable, and its validity is variable and relative.
Within science, there are different degrees, corresponding to the hierarchical structure of Ideas, from knowledge of mathematical Ideas to knowledge of other Ideas, culminating in the Idea of Good. Similarly, there are two levels of knowledge of the sensible: conjecture and belief.
Plato’s Anthropology
Since true knowledge is knowledge of Ideas, Plato explains how this is possible if humans, as told in myths, are within the sensible world and ignore the existence of the intelligible world. His theory proposes reminiscence (for Plato, true knowledge is not learning much, but remembering what we already knew). Reminiscence is recalling the Ideas.
To understand this, we must first grasp Plato’s conception of humans. A human is a dual reality where the world of Ideas and the sensible world converge: the unity between body and soul. The body belongs to the sensible world and has its own characteristics, while the soul belongs to the world of Ideas (both are immortal). When the soul is incarnated in the body, it forgets the existence of the world of Ideas and falls into ignorance. The body is the soul’s prison, but the soul, sharing the characteristics of Ideas, has known them, although it has forgotten after its union with the body. Therefore, it is necessary to embark on a path, based on observation of sensible things (which reflect Ideas and are copies of them), leading the soul to recall the Ideas, culminating in the Idea of Good. Knowledge is not, therefore, learning new things, but remembering (recollecting) Ideas that were already known.