"Simplicius attributes to him a work on Opposites, to which he says that Aristotle was indebted for what he says on this subject in his Categories. His Harmonicon is quoted by Nicomachus in his Arithmetic. ...Fragments of the works attributed to him "On the Good and Happy Man," and "On Wisdom," are... extant. ...A letter of Archytas to Plato and Plato's reply are preserved by Laertius."