This study offers a new analysis of the last argument of Plato's Phaedo for the immortality of the soul. Interpretations of this argument and especially of the last section have differed considerably. Judgements on its value have usually been adverse. One scholar speaks of the ‘screen of unreal argument’ which concludes the proof, and writes that ‘from the standpoint of logic the argument has petered out into futility’. Another describes the final stage of the proof as ‘a blatant petitio principii’. (...) A third remarks that the conclusion follows ‘if we do not look too closely’. (shrink)