In response to my article on ‘Socrates in the Phaedrus’, in his letter of December 31, 1980 Richard Sorabji insisted that I separate my researches on Plato ‘from any connection with Diogenes Laertius’ claim that the Phaedrus was Plato’s earliest writing’: ‘My reasons have to do with the central philosophic doctrines of the Phaedrus … Let me start with some examples of central philosophic doctrines. 1) The 3-partite soul: Plato feels it necessary to argue that the soul has 3 parts in the Republic, after having treated it earlier in the Phaedo as unitary. Yet in D. L’s view, he would earlier still, in the Phaedrus myth, have treated it as having 3 parts without any argument at all, subsequently reverting in Phaedo to making it unitary, and then arguing all over again in Republic for its having 3 parts. Nor is the tripartite structure in the Phaedrus a mere accident. It is vitally required to give an account of the conflict involved in erotic passion. Is this a sensible sequence?’
In Republic X Socrates reflects on the tripartite division of the soul as follows: ‘We cannot believe (mȇte touto oiȏmetha) – reason will not allow us (ho gar logos ouk easei) – the soul, in her truest nature, to be a thing (tȇi alȇthestatȇi phusei toiouton einai psuchȇn) full of variety and internal difference and dissimilarity (hȏste pollȇs poikilias kai anomoiotȇtos te kai diaphoras gemein auto pros hauto).’ – Glaucon: ‘What do you mean (Pȏs legeis;?’ – Soc. ‘It is not easy (Ou raidion) for that thing to be immortal which is a compound of many elements not perfectly adapted to each other (aidion einai suntheton te ek pollȏn kai mȇ tȇi kallistȇi kechrȇmenon sunthesei), as the soul has appeared to us to be (hȏs nun hȇmin ephanȇ hȇ psuchȇ).’ (611a10-b7, tr. Jowett)
Adam notes appositely: ‘hȏs nun hȇmin ephanȇ hȇ psuchȇ [‘as the soul now has appeared to us to be’] refers to the tripartite division of soul in IV 435 A ff. … Now that he has proved the soul to bee immortal, Plato takes the opportunity to suggest a revision of the psychology of Book IV, in which soul was treated as composite: for nothing that is composite can well be immortal. According to the theory that is rather suggested (612 A) than fully worked out in this chapter, the so called lower ‘parts’ are not of the essence of soul at all, but only incidental to its association with the body, and consequently perishable. Cf. Phaedo 66 C ff., 79 C, D and the thnȇton eidos psuchȇs [‘the mortal form of the soul’] of Timaeus 69 C ff. Plato expresses himself with great reserve (612 A), but apparently intends us to believe that soul in its truest nature is logistikon [‘intellect’], and that the logistikon alone is immortal.’ (Jams Adam, The Republic of Plato, 1902, digitally printed 2009, vol. II, p. 427)
At 611d7-612a6 Socrates says: ‘There, Glaucon, there we must look (alla dei, ȏ Glaukȏn, ekeise blepein).’ – Glaucon: ‘Where then (Poi)?’ – Soc. ‘At her love of wisdom (Eis tȇn philosophian autȇs) … then you would see her as she is (kai tot’ an tis idoi autȇs tȇn alȇthȇ phusin), and know whether she have one shape only or many (eite polueidȇs eite monoeidȇs), or what her nature and state may be (eite hopȇi echei kai hopȏs) Of her affections and of the forms which she takes in this present life (nun de ta en tȏi anthrȏpinȏi biȏi pathȇ te kai eidȇ) I think (hȏs egȏimai) that we have now given a very fair description (epieikȏs autȇs dielȇluthamen).’ (Tr. Jowett)
In the Phaedrus the tripartite division is descriptive of the soul in its immortality: ‘As to soul’s immortality then we have said enough (Peri men oun athanasias autȇs hikanȏs), but as to its nature there is this that must be said (peri de tȇs ideas autȇs hȏde lekteon): what manner of thing it is (hoion men esti) would be a long tale to tell, and most assuredly a god alone could tell it (pantȇi pantȏs theias einai kai makras diȇgȇseȏs); but what it resembles (hȏi de eoiken), that a man might tell in brief compass (anthrȏpinȇs te kai elattonos): let this therefore be our manner of discourse (tautȇi oun legȏmen). Let it be likened to the union of powers in a team of winged steeds and their winged charioteer (eoiketȏ dȇ sumphutȏi dunamei hupopterou zeugous te kai hȇniochou). Now all the gods’ steeds and all their charioteers are good, and of good stock (theȏn men oun hippoi te kai hȇniochoi pantes agathoi te kai ex agathȏn); but with other beings it is not wholly so (to de tȏn allȏn memeiktai). With us men, in the first place, it is a pair of steeds that the charioteer controls (kai prȏton men hȇmȏn ho archȏn sunȏridos hȇniochei); moreover (eita) one of them is noble and good, and of good stock (tȏn hippȏn ho men autȏi kalos te kai agathos kai ek toioutȏn), while the other has the opposite character, and his stock is opposite (ho d’ ex enantiȏn te kai enantios). Hence the task of our charioteer is difficult and troublesome (chalepȇ dȇ kai duskolos ex anankȇs hȇ peri hȇmas hȇniochȇsis).’ (246a3-b4, tr. R. Hackforth)
Just as Republic I implicitly corrects the Phaedran presentation of Polemarchus, so Republic X implicitly corrects the image of the immortal soul presented in the Phaedrus.