One could say that what differentiates ancient from modern philosophy is the fact that, in ancient philosophy, it was not only Chrysippus or Epicurus who, just because they had developed a philosophical discourse, were considered philosophers. Rather, every person who lived according to the precepts of Chrysippus or Epicurus was every bit as much a philosopher as they.
"La Philosophie comme manière de vivre: Entretiens avec Jeannie Carlier et Arnold I. Davidson" by Pierre Hadot, Jeannie Carlier, Arnold I. Davidson, Paris: Albin Michel, translated by Michael Chase, (p. 272), 2001.
