Plato vs. Materialists Plato was concerned with Epistemology. Epistemology deals with the possibilities and limits of human knowledge. It tries to arrive at a knowledge of knowledge itself. It tries to answer such questions as: Is the world as people perceive it the basic reality, or do people perceive only appearances that conceal basic reality? Knowledge may be regarded as having two parts. There is, first of all, what one perceives using the five senses. Next there is the way these perceptions are organized by the mind to form ideas or concepts. The problem of epistemology is based on how philosophers have understood the relationship of the mind to the rest of reality.