Clement of Alexandria’s Protreptikos or Exhortation to the Greeks, written in the late second century, begins with an elaborate story of a song that lures fish, and a cicada that jumps up to fill in for the broken string of a lyre, scraping away with perfect pitch. I have long thought this was odd. The ancient genre of protreptic offered a kind of professional calling card, an introduction to speakers’ cultural sophistication, the strength of their argument and teaching, and a demonstration of their ability to argue for the superior form of philosophy-theology.