Plato and Parmenides

Parmenides was likely written within the last two decades preceding Plato's death in 347 BCE. Despite two millennia of documented commentary, scholars struggle to make sense of it. Almost every major discussion of the Parmenides in this century has begun with some remark about its extraordinary difficulty & no interpretation has yet been offered that a majority of commentators find persuasive. The main interpretative problem of is what to make of the treatment of the several hypotheses that constitutes the 2nd portion (Stephanus 137C-166C, referred to as P2). One source of perplexity is that this latter portion fails to exhibit continuity of subject matter with the 1st part (P1), making it difficult to determine what the whole is about. To make matters worse, the argumentation of the 2nd part is so extremely condensed that it sometimes appears incoherent. As a result, not only are individual arguments hard to decipher, but moreover it's unclear what Plato was trying to accomplish with these arguments in the 1st place.
Two major lines of interpretation were established by the time of Proclus' Parmenides Commentary in the 5th century, both with prominent followers. As Proclus notes in his 1st book, some readers view the dialog as a logic exercise. Some read P2 as a polemical tour-de-force in which methods of argument derived from Zeno are turned against their originator to show that Zeno's own monistic views lead to absurdities of the very sort he purports to demonstrate against pluralism's champions. Others read the 2nd part at face value, as a demonstration of a logical method that will enable Socrates to avoid the pitfalls in his Form theory exposed by Parmenides in the 1st part of the dialog. In either case, readers of this persuasion view the dialog primarily as a dialectical exercise without positive metaphysical content.
The 2nd major interpretative line identified by Proclus assigns P2 a metaphysical purpose. An early version of this approach, associated with Origen, identifies the topic as the Being of the historical Parmenides, with the consequence that the exclusively negative results of the 1st hypothesis come to be viewed as adding to the pluralistic list of features denied of the singular Being in Parmenides' poem. The tradition of interpretation with which Proclus himself agrees, on the other hand, is that beginning with Plotinus & moving thru Porphyry to lamblichus & Syrianus. As Proclus puts it, commentators of this group take the subject to be "all things that get their reality from the One," which he identifies with the Republic's Good. Keying upon the conclusion at Parmenides 142A that the One can be neither expressed nor conceived, Proclus reads the 1st hypothesis' results as a demonstration of the ineffable transcendence of this Supreme Principle.--Plato's Parmenides & the Dilemma of Participation (edited)