to have died at approximately the age of 70, after 40 years as a practising Sophist. His death, then, may be presumed to have occurred circa 420 BC, but is not known for certain, since assumptions about it are based on an apparently fake story about his trial for asebeia (impiety) in Athens. Plutarch wrote that Pericles and Protagoras spent a whole day discussing an interesting point of legal responsibility, that probably involved a more philosophical question of causation: "In an athletic contest, a man had been accidentally hit and killed with a javelin. Was his death to be attributed to the javelin, to the man who threw it, or to the authorities responsible for the conduct of the games?" Philosophy Even though he was mentored by Democritus, Protagoras did not share his enthusiasm for the pursuit of mathematics. "For perceptible lines are not the kind of things the geometer talks about, since no perceptible thing is straight or curved in that way, nor is a circle tangent to a ruler at a point, but the way Protagoras used to say in refuting the geometers" (Aristotle, Metaphysics 997b34-998a4). Protagoras was skeptical about the application of theoretical mathematics to the natural world; he did not believe they were really worth studying at all. According to Philodemus, Protagoras said that "The subject matter is unknowable and the terminology distasteful". Nonetheless, mathematics was considered to be by some a very viable form of art, and Protagoras says on the arts, "art (tekhnê) without practice and practice without art are nothing" (Stobaeus, Selections 3.29.80). Protagoras also was known as a teacher who addressed subjects connected to virtue and political life. He especially was involved in the question of whether virtue could be taught, a commonplace issue of fifth century BC Greece, that has been related to modern readers through Plato's dialogue. Rather than educators who offered specific, practical training in rhetoric or public speaking, Protagoras attempted to formulate a reasoned understanding, on a very general level, of a wide range of human phenomena, including language and education. In Plato's Protagoras, he claims to teach "the proper management of one's own affairs, how best to run one's household, and the management of public affairs, how to make the most effective contribution to the affairs of the city by word and action". He also seems to have had an interest in "orthoepeia"—the correct use of words—although