Abstract

Since the early 20th century, two new disciplines emerged in the tradition of analytic philosophy: meta-ethics and political epistemology. Nevertheless, debates on such questions go back to the ancient Greeks and, in particular, to the debates between Plato and Protagoras. This article elucidates the controversy between Plato and the influential sophist Protagoras from the perspective of contemporary meta-ethics and political epistemology. It argues that the main motivation of Plato’s philosophical endeavors is to overcome Protagoras’s skeptical claims that no moral facts and no moral knowledge applicable to political issues exist. The paper defends the thesis that there exists a deep disagreement between Protagoras and Plato on the existence of moral facts and moral knowledge. A deep disagreement is a disagreement that cannot be resolved through the use of reasons and arguments. Applying the foundationalist approach Robert J. Fogelin proposes in his seminal paper “The Logic of Deep Disagreements”, this article argues that the deep disagreement between Protagoras and Plato exists because their political thought is based on “underlying principles” that clash. While Plato’s political philosophy rests on his religious and theological convictions, the political thought of Protagoras is based on his skepticism, relativism, and agnosticism.