I haven't read Nagy a lot, but as far as I've followed his ideas on genesis of the Homeric epics, he doesn't impress me at all. I'll quote bits from Barry Powell's review of his book Poetry as Performance, Homer and Beyond (to be found in its entirety at http://bmcr.brynmawr.edu/1997/97.03.21.html). I'm not exactly a fan of Powell (he has a strange theory that alphabetic writing was invented for the express purpose of recording Homer, for one), but in this review I think he really nails it. My main difference with him in this review is that I think, following West, that "Homer" wrote and was not dictated; but that's irrelevant for evaluating Nagy's views here.As far as ideological opposition between Nagy and West, I've never read an article by Nagy that I didn't find impressive. Perhaps West deserves the regard that he holds on this forum, but what I've read of him so far (mostly his books on music, and a few articles on Homer) hasn't demonstrated genius to me yet. But by all means, I would love to be corrected if someone would like to link me to his best stuff. It's hard work publishing the vast quantities that West does, and I can certainly understand why the quality might vary.
There's a reply by Nagy, which I can't locate, and a reply to that reply by Powell (http://bmcr.brynmawr.edu/1997/97.04.24.html)
The poems of Homer (if he existed) were not taken down by dictation, but somehow were "crystallized" over a long period, especially during the sixth century BC in Athens. In this way, through "crystallization," there came into being the text we have today. Those are the big issues, as I see them, and it is here I wish to register my complaint.
Chapter I, "The Homeric Nightingale and the Poetics of Variation in the Art of a Troubadour," begins by quoting Odyssey 19. 518-523, where Penelope compares herself to a nightingale, the daughter of Pandareos, who killed her own child Itylos. A variant reading of unclear meaning, poludeukea for the vulgate poluekhea "with many resoundings" to describe the nightingale's voice, suggests to N. that we have found two "original" readings, each depending on the mutability of oral poetry and neither, therefore, more correct than the other. N. takes the obscure variation as paradigmatic of mouvance, a term he borrows from the criticism of French medieval poetry where similar variant readings appear. Implicit in N.'s long discussion is that written versions of Homer, and of other oral poets, reflect oral performance. Because we find variation in oral song, and because we find variation in the textual tradition, therefore the textual tradition reflects the variation so common in oral song and not the errors of copyists or the like. Does N. therefore think that the Iliad and the Odyssey were sung by Homer, not taken down in writing, then sung by a successor nearly verbatim (except for such minor variations as poludeukea/poluekhea), still not written down, then sung by someone else, with still more mouvance and a shifting of lines here and there, new particles creep in, then in the sixth century BC sort of written down, and then in the fifth century BC really written down, but still mouvance going on, until the Alexandrians at last established our text? Yes, N. does believe this. But the Iliad and the Odyssey that we possess are not oral poems; they are texts based on oral performance, which is not the same thing. The monumental labor and expense required to record the Iliad and Odyssey ensure for most Homerists that the poems were recorded a single time, that there was an original text. What is the problem with such an assumption? We do need to explain the small variations found in Homeric manuscripts, as we must explain those found in any text, ancient and modern. Still, from the moment that the Homeric poems were written down, they existed as texts and were subject to the vicissitudes of any text created in any fashion. Here is a cardinal element of the Parry-Lord thesis: oral poetry composed in performance is always something new, and there is no fixed text; but a written text is a fixed text. A written text is no longer oral poetry, nor subject to the rules that govern the generation of oral poetry, although it began as such.
Part of my problem with Nagy is that his writing style is opaque, and simply don't have the patience to go on reading him until I can understand what he's exactly trying to say. So for that reason I haven't read him a lot. What I've read concerns Homer, and at least there I must say that although his theories seem very nice at an abstract level, when you try to imagine what they mean concretely, you're at a loss – like, for example, the crystallization theory (discussed above): what is the exact relationship between manuscripts and performance that is proposed? Like who wrote what and why? Not clear.Chapter 5, "Multiform Epic and Aristarchus' Quest for the Real Homer," sets down what N. calls the Five Ages of Homer, a summing up of the various stages of textual fixation according to his model of the evolution of the Homeric poems. First was a fluid period, roughly 2000-800 BC; second, a "pan-Hellenic" period, still no written text, down to the middle of the sixth century; third, "potential texts in the form of transcripts," from mid-sixth to fourth centuries; fourth, a standardizing period with "texts in the sense of transcripts or even scripts" under the supervision of Demetrius of Phalerum from 317-307; finally, a rigid period "with texts as scripture," from middle of the second century BC on, beginning with Aristarchus' work around 150 BC: "In brief, then, this scheme of five periods in Homeric transmission brings into play primarily the dimension of performance, in particular the traditions of the rhapsoidoi, and, secondarily, the dimension of text as a derivative of performance, where each successive period reflects a progressively narrower concept of textuality, from transcript to script to 'scripture.'" (p. 113) The whole process N. describes as "crystallization," a word used in his earlier publications.
Here, then, is the heart of N's thesis, and of his dilemma. For a written text is not the product of a chemical reaction (and what is a "potential" text? What is the picture exactly?). In archaic Greece texts seem to have come into being in three ways. Scribes took down verses from oral poets by dictation. Why does N. not accept A. B. Lord's theory of the dictated text? N. never explains why. Aristocrats, who learned how to decipher texts that began as oral poetry, discovered how to create, in writing, new forms of poetry, lyric and choral song (how do you train a chorus without a written text?); Sappho and Euripides composed for reperformance from a written prompt in just this way. Finally, texts which originated in either way, through dictation taken from oral poets or created originally in writing, were copied when one man read aloud from a written text and another wrote down what he heard, or he copied the manuscript by eye (we're not very clear about this). Texts may be a derivative of performance, as N. puts it, when an oral poet dictates to a scribe (which N. denies happened), but when a rhapsode or actor delivers orally a memorized text, performance is derivative of text. The model seems so persuasive that I do not see why N. is determined to overthrow it. We have people dictating texts, creating texts in writing, and copying texts. "Crystallization" is an unfortunate metaphor and I cannot see why N. wants it.