330? BCE - 270? BCE: Age 60?
Philetas of Cos was poet and critic in Alexandria during the 4th century BCE. We don't know much about him, but one story is that he was always getting teased for being thin. He was so thin, people said, that he put lead in his shoes to avoid getting blown away.
According to Athenaeus of Naucratis, Philetas worried so much about the Liar paradox that he died of insomnia. His epitaph was: "Philetas of Cos am I; It was the Liar who made me die, and the bad nights caused thereby." — in Greek, of course.
To understand the Liar Paradox, cast your mind back to the original Star Trek: Captain Kirk and Harry Mudd use the Liar Paradox to defeat Norman the evil android.
Kirk: Everything Harry tells you is a lie — remember that! Everything Harry tells you is a lie!
Mudd: Now listen to me carefully, Norman laddie: I - am - lying!
Norman: You lie, but if everything you say is a lie then you must be telling the truth, but you cannot be telling the truth because everything you say is a lie... you lie, you tell the truth, you– Illogical! Illogical! Please explain! You are human! Only humans can explain their behavior! Please explain!
Sources: Wikipedia, Memory Alpha, the Star Trek Wiki