Plato is one of the most important philosophers in history. At the heart of his philosophy is his “theory of forms” or “theory of ideas.” In fact, his views on knowledge, ethics, psychology, the political state, and art are all tied to this theory.
According to Plato, reality consists of two realms. First, there is the physical world, the world that we can observe with our five senses. And second, there is a world made of eternal perfect “forms” or “ideas.”
What are “forms”? Plato says they are perfect templates that exist somewhere in another dimension (He does not tell us where). These forms are the ultimate reference points for all objects we observe in the physical world. They are more real than the physical objects you see in the world.
For example, a chair in your house is an inferior copy of a perfect chair that exists somewhere in another dimension. A horse you see in a stable is really an imperfect representation of some ideal horse that exists somewhere. In both cases, the chair in your house and the horse in the stable are just imperfect representations of the perfect chair and horse that exist somewhere else.
According to Plato, whenever you evaluate one thing as “better” than another, you assume that there is an absolute good from which two objects can be compared. For example, how do you know a horse with four legs is better than a horse with three legs? Answer: You intuitively know that “horseness” involves having four legs.
Not all of Plato’s contemporaries agreed with Plato. One of his critics said, “I see particular horses, but not horseness.” To which Plato replied sharply, “That is because you have eyes but no intelligence.”