Plato's Ion and Ovid's usus

When Ovid calls himself vates, he is taking a term that had sacred connotations, but then had "fallen into "contempt," according to Lewis and Short, until Virgil had restored some of the luster of the oracle, the prophet. 

 In the Ars Amatoria, the term can't be so solemnly Virgilian:

Non ego, Phoebe, datas a te mihi mentiar artes,     
Nec nos aëriae voce monemur avis,
Nec mihi sunt visae Clio Cliusque sorores     
Servanti pecudes vallibus, Ascra, tuis:
Usus opus movet hoc: vati parete perito;
     Vera canam: coeptis, mater Amoris, ades!

Phoebus, I won't pretend that you've endowed me with arts,
     nor is my source the voice of high-flying birds,
nor did Clio and Clio's sisters appear to me,
     Ascra, as I tended my flocks in your valleys.
Experience is what inspires this work! Obey the skilled prophet:
     I'll sing truths. Be present, Mother of Love, for my project! 

                                                                         (AA I.25-30)

As suggestive as it might be to ponder this differentiation of human usus - experience - from divine inspiration -- Apollonian on one hand, Hesiodic on another -- we'll stipulate that the source of inspiration is the experience of Amor, and that this is sufficient to qualify the singer as a vates.

For now I simply offer one of Plato's great passages about poetic inspiration, quoted in this excellent post on Sententiae Antiquae:

Plato’s Ion 533d-534e

“ . . . talking well about Homer is not some skill (τέχνη) within you—as I was just saying—but it is a divine power that moves you (θεία δὲ δύναμις ἥ σε κινεῖ), just as in that stone which Euripides calls a ‘Magnet” but which most people call Herakleian. For this stone not only moves iron rings but it also imbues the rings with the same power so that they can do the same thing as the stone in turn—they move other rings and as a result there is a great chain of iron and rings connected to each other. But the power from that stone runs through them all. In this way, the Muse herself makes people inspired, and a linked chain of inspired people extend from her. 

"All the good poets of epic utter those beautiful poems not because of skill but because they are inspired and possessed—the good lyric poets are the same, just as the Korybantes do not dance when they are in their right minds, so too the lyric poets do not compose their fine lines when they are sensible, but when they embark upon their harmony and rhythm, they are in revelry and possessed. They are just like the bacchants who draw honey and milk from rivers when they are possessed, not when they are in their normal state of mind. The soul of the lyric poets does this too, which they themselves admit: for they claim, as I see it, that they bring to us their songs by gathering from the honey-flowing springs from certain gardens and glades of the Muses like bees—and they fly too! 

And they speak the truth. For a poet is an empty thing—winged, and sacred and not capable of composing before it is inspired and out of mind, when thought is no longer inside. Until one has gained this state, every person is incapable of composing or giving oracles. Because they compose not by skill—when they say many fine things about their subjects—but by divine dispensation, as you do about Homer, each is only capable of composing well in the arena where the Musa compels—one person composes dithyramb, one encomia, another dance songs, another epic and another iambic poetry. But each is useless in the other genres."

535e-536a

“Do you understand that the audience is the last of the rings which I was describing as transmitting through one another the power from the Herakleian stone and that you are the middle as the rhapsode and interpreter—that the poet himself is the first ring? The god moves the soul of all of these people wherever he wants, stringing the power from one into another.” 

English translation of Ovid from J.D. Hejduk's The Offense of Love