ic (Plato's supreme philosophical achievement, which is a detailed discussion of the nature of justice).The works of the later period include the Theaetetus (a denial that knowledge is to be identified with sense perception), Parmenides (a critical evaluation of the theory of Forms), Sophist (further consideration of the theory of Ideas, or Forms), Philebus (a discussion of the relationship between pleasure and the good), Timaeus (Plato's views on natural science and cosmology), and the Laws (a more practical analysis of political and social issues).Theory of FormsAt the heart of Plato's philosophy is his theory of Forms, or Ideas. Ultimately, his view of knowledge, his ethical theory, his psychology, his concept of the state, and his perspective on art must be understood in terms of this theory.Theory of KnowledgePlato's theory of Forms and his theory of knowledge are so interrelated that they must be discussed together. Influenced by Socrates, Plato was convinced that knowledge is attainable. First, knowledge must be certain and infallible. One consequence of this view was Plato's rejection of empiricism, the claim that knowledge is derived from sense experience. Furthermore, the objects of sense experience are changeable phenomena of the physical world. Hence, objects of sense experience are not proper objects of knowledge.Plato's own theory of knowledge is found in the Republic, particularly in his discussion of the image of the divided line and the myth of the cave. In the former, Plato distinguishes between two levels of awareness: opinion and knowledge. Claims or assertions about the physical or visible world, including both commonsense observations and the propositions of science, are opinions only. The higher level of awareness is knowledge, because there reason, rather than sense experience, is involved. The myth of the cave describes individuals chained deep within the recesses of a cave. The shadowy environment of the cave s...
