 Alexander of Aphrodisias |  Aristotle |  -->Chrysippus--> |  -->Epicureanism--> |  Epicurus |  epistemology: virtue |  knowledge: analysis of |  Plato |  Plato: middle period metaphysics and epistemology |  Plotinus |  Socrates |  Stoicism |  -->Xenophon--> |  -->Zeno of Citium--> 