In the section entitled ‘Dialectic method as exhibited in preceding speeches’ Hackforth writes: ‘It is in this section that Plato for the first time formally expounds that philosophic method – the method of dialectic – which from now onwards becomes so prominent in his thought, especially in the Sophist, Statesman and Philebus … The verve displayed by Socrates in his account … justifies the belief that here we have Plato’s first announcement of a new discovery to which he attaches the highest importance. We have, it is true, had a dialectical method sketched in an earlier dialogue, the Republic; but it was not the same as this, despite some points of resemblance.’ (Plato’s Phaedrus, translation and commentary R. Hackforth, Cambridge University Press, 1972, p. 134)
Hackforth finds ‘anticipatory’ points of resemblance to dialectic outlined in the Phaedrus in Republic 531 D and 537 C – ‘we have here Collection in embryo’ – and at 454 A – ‘similarly with Division’. Let me consider in this post just the first reference, Republic 531 D, which points to Socrates’ reflection on the ‘prelude’ (prooimion, 531d8) to dialectic. To make sense of Socrates’ words, I must briefly summarise the studies with which commences the way upon which true philosophers will be produced in Plato’s ideal city (engenêsontai 521c1-2), on which he reflects. It begins with arithmetic, which compels the mind to contemplate ‘the one and all number’ (to hen kai sumpas arithmos, 525a6) free from any reference to the realm of becoming apprehended by our senses, and thus leads the soul towards ‘seeing the true Being’ (epi tên tou ontos thean, 525a1). Next comes geometry, which studies ‘plain’ (epipedon, 528a9), that is figures of ‘two dimensions’ (deuteran auxên, 528b2), then stereometry, which studies figures of three dimensions (tritên auxên, 528b2), then ‘astronomy, which is motion of depth’ (astronomian, phoran ousan bathous, 528e1), that is motion of three dimensional entities, and finally harmony, which does not study ‘the numbers of syn-phonies that are heard’ (tous en tasis sumphôniais tais akouomenais arithmous, 531c1-2), but ‘inquires which numbers are syn-phonic and which are not (episkopein tines sumphônoi arithmoi kai tines ou), and for what reason (kai dia ti hekateroi, 531c3-4).
On this ‘prelude’ (prooimion) to dialectic Socrates remarks: ‘And I think (Oimai de ge) that the road of all these studies that we went through (kai hê toutôn pantôn hôn dielêluthamen methodos), if it reaches the point of their inter-communion (ean men epi tên allêlôn koinônian aphikêtai) and connection with one another (kai sungeneian), where their mutual affinities will be embraced in thought (kai sullogisthê̢ tauta hê̢ estin allêlois oikeia), then the pursuit of them will contribute to our preoccupation (pherein ti autôn eis ha boulometha tên pragmateian), and our labour will not be wasted (kai ouk anonêta poneisthai), but if not, (ei de mê) it will be wasted (anonêta, 531c9-d4).’
In Hackforth’s view, these words anticipate ‘Collection’, with which the outline of dialectic in the Phaedrus commences: ‘The first is that in which we bring a dispersed plurality under a single form, seeing it all together (Eis mian te idean sunorônta agein ta pollachê̢ diesparmena), the purpose being to define so-and-so (hina hekaston horizomenos) and thua to make plain (dêlon poiê̢) whatever may be chosen as the topic for exposition (peri hou an hekastote didaskein ethelê̢, 265d3-5, tr. Hackforth).
Viewing the Phaedrus as Plato’s first dialogue, I agree with Hackforth that in it ‘Plato for the first time formally expounds that philosophic method – the method of dialectic’, but I cannot see Republic 531 D as an anticipation of ‘Collection’ in the Phaedrus; ‘Collection in embryo’, as he puts it. On the contrary, I see Republic 531c9-d4 as a very telling instance of ‘Collection’ outlined in the Phaedrus.
To resolve this controversy, we must look at the framework within which Plato introduces dialectic in the Phaedrus; for in it he introduces it as subservient to the true rhetoric. Persuading the audience of whatever one wants was the common aim of all rhetoric, but as Plato argues in the Phaedrus, only a man who knows the truth can achieve the desired persuasion with certainty, scientifically: ‘The man who does this scientifically (ho technê̢ touto drôn) will make the same thing appear to the same people at one time just (poiêsei phanênai to auto tois autois tote men diakion), but at any other time he wishes (hotan de boulêtai), unjust (adikon) … to the city he will make the same things appear at one time good (tê̢ polei dokein ta auta tote men agatha), at another the opposite (tote d’ au t’anantia)’ (261c10-d4). He cannot acquire this knowledge ‘if he is ignorant of the truth of each thing (alêtheian agnoôn hekastou, 262a9): ‘Anyone who does not know the truth, but has made it his business to hunt down appearances, will give us a science of speech which is, so it seems, ridiculously unscientific (Logôn ara technên ho tên alêtheian mê eidôs, doxas de tethêreukôs, geloian tina, hôs eoike, kai atechnon parexetai, 262c1-3).’ To know the truth, one needs dialectic.
It is for this purpose that one needs dialectic within the framework of Socrates’ outline of true rhetoric in the Phaedrus. I can understand why Plato introduced dialectic in this role in a dialogue written in 405, that is in the days when his desire to pursue a political career within the framework of the Athenian democracy was most acute, but I don’t see how he could introduce it in this manner in any dialogue that followed the Republic, that is after he renounced on any political aspirations in the city of Athens.