Phaedo of Elis and Plato on the soul

Phado of Elis was well-known as a writer of Socratic dialogues, and it seems inconceivable that Plato could have been innocent of intertexualitiy when, excusing himself on the grounds of illness, he made him the narrator of one of his own: the "Phaedo". In fact the psychological model outlined by Socrates in this dialogue converges with the evidence we have (especially from fragment of the "Zopyrus") for Phaedo's own beliefs about the soul. Specifically, Phaedo seems to have thought that non-rational desires were ineliminable epiphenomena of the body, that reason was something distinct, and that the purpose of philosophy aws its 'cure' and 'purification'. If Plato's intention with the "phaedo" is to assert the separability and immortality of "reason" (whatever one might think about desire and pleasure), the Phaedo provides a useful standpoint for him. In particular, Phaedo has arguments that are useful against the 'harmony-theorists' (and are the more useful rhetorically speaking since it is only over the independence of reason that Phaedo disagrees with them). At the same time as allying himself with Phaedo, however, Plato is able to improve on him by adding to the demonstration that reason is independent a proof that it is actually immoral.