Socrates claims that Ion does not have art, but merely inspiration. But what is inspiration? Plato's Ion is often read in conjunction with Book X of the Republic, particularly in aesthetics classes. There are some remarkable similarities and differences. In both writings, the poet (and also the inspired interpreters of the poet, including the rhapsode, the critic and the actor) does not really know anything, and certainly does not know what he claims that he knows. In both writings we have a series that starts from and moves away from God. In the Republic, God is the creator of the ideal bed, the carpenter is the maker of the bed in the world of appearances, and the painter is the maker the painted bed. The painter is the imitator. (The whole account of the three beds is there to define the true imitator. Once we know how the painter, as well as the actor who pretends on stage to be, for example, a general, is to be distinguished from the creator and the true maker, then we have the "imitator" defined. "Imitator" does not mean anyone who imitates but rather someone who merely captures the surface appearance of something. Someone who holds a mirror to the world is also at this level.)
In the Ion, the God (or the Muse) is the first magnet, which then gives its power to the poet, who is the second magnet, who, in turn, inspires the rhapsode (or the actor) as well as other artists (for example dancers and stage-designers) involved in performing his work. The audience is at the fourth remove from the Muse.
The remarkable difference between the Republic account of the three beds and this is that in the Ion the poet is only two removes from reality, i.e. is in direct communication with God, and therefore takes the same place as the craftsman in the Republic. I am not going to worry, here, about which work was written first by Plato, although I should mention that the Republic is generally considered a middle and the Ion an early dialogue, which would make any change of mind on Plato's part be something that takes place after the Ion and before the Republic.
There are some differences between the actions involved in the two sequences as well: in the Republic the carpenter's bed is a copy of the ideal bed, and it in turn is imitated by the painter's bed. In the Ion, there are not two processes, but just one: inspiration, which is passed down from one magnet to the next. It is more dynamic in this way. Also, inspiration is just different from imitation. One can imitate with skill, whereas no skill is involved in inspiration qua inspiration. Inspiration is more magical: the inspired person participates in the source of inspiration, they are as if one with the source. The experience of inspiration is closer to a religious experience, whereas the act of imitation could be secular, mechanical, and solely for entertainment purposes. Imitation can involve more detachment, where only the surface form of the original is captured. Inspiration, by contrast, seems to pass on its inner essence: the poet passing his inspiration from God on to the the rhapsode, and the rhapsode doing this for the audience.
Historically, artists have found more support in Plato's theory of inspiration than in his theory of imitation. It is also interesting (and possibly contradictory for Plato) that Socrates saw himself as inspired in some way. In the Apology he often refers to a personal daemon, and there is a passage in the Symposium that implies that he is occasionally possessed by this inner spirit. Also, he praises wisdom in the Apology and says that he has no real knowledge. So, perhaps he is like Ion in being inspired by a God and in having no knowledge. (Someone who finds the Ion attractive as providing a theory of artistic creation might combine it in some way with the account of the Socratic way of life in the Apology.) However, Socrates also asserts in the Ion that, although the poets and Ion may have wisdom, he himself does not have wisdom and is only interested in truth and knowledge! This would be inconsistent with his position in the Apology that he has no knowledge, although not inconsistent with his commitment there to truth. I cannot resolve this, although perhaps scholars who know the Greek already have.
Another interesting difference between the two series (of beds and magnets) is that possession by the gods in the Ion involves a highly imaginative experience. Ion, for example, is ecstatic in the sense that he almost believes he is in ancient Troy as he recites Homer's poetry. This personal out-of-body imaginative experience is not described in the Republic account of the imitator. Many, in reading these passages in the Ion, have felt that Socrates is, here, more sympathetic to the imitative artist than he shows himself to be in the Republic.
What I would like to do, here, however (and for those of you who have read so far, this is the meat of my comment), is note the very specific quality of being "out of one's mind" described in Ion. Bear in mind that there are many ways in which one can be "out of one's mind," ranging from the relatively innocent moment of being so engaged with an aesthetic object as to forget oneself, to the more scary experiences of being deluded, obsessed, crazy, mad, or, in contemporary terms, entering into a manic-depressive or schizophrenic state. So what does Socrates mean by "out of one's mind"? He speaks of it in terms of Bacchic possession, a very specific kind of religious experience associated with intoxication, death and rebirth: "like Bacchic maidens who draw milk and honey from the rivers when they are under the influence of Dionysus but not when they are in their right mind." (I am working here from the Jowett translation at it appears in Art and Its Significance ed. David Ross, 3rd. ed., 1994, 48-9)
So, what is it to "draw milk and honey from the rivers"? I take it that this involves a kind of positive ecstatic experience when water takes on a quality that is metaphorically intensified. This is similar to the description Edward Bullough famously offered, in explicating his concept of psychic distance, of the fog at sea which I discussed in my book (245-247). He speaks of the fog as "a veil surrounding you with an opaqueness as of transparent milk, blurring the outline of things and distorting their shapes.." (759). The Bacchic maidens, in short, are "out of their minds" in the sense that they engage in a radical form of imaginative seeing of the sort described by Bullough when he describes what he calls "psychical distance."
Socrates goes further: "the soul of the lyric poet does the same, as they themselves say; for they tell us that they bring songs from honeyed fountains, culling them out of the gardens and dells of the Muses; they, like the bees, winging their way from flower to flower." (49). Socrates goes on to endorse this view of the poet, even referring to him (her) as "a light and winged and holy thing" like such a bee. Such a poet is active in the sense that he or she goes from one source of inspiration to the next (the sources here, notably, being natural and not explicitly divine) and yet holy in being able to find the divine in everyday life. So, the poet, positively understood by Socrates, is someone who is able to take a radical aesthetic approach to nature, being inspired by nature in an active way, i.e. in bringing songs from fountains and other natural phenomena which he experiences in an intensified imaginative/sensuous way (symbolized by the term "honeyed.")
Thus, contra Neitzsche, it turns out that Socrates has a Dionysian theory both of the creative process and quite possibly also of aesthetic experience. Nietzsche, of course, must have known this. He is inspired by one aspect of Socrates' theory when attacking the other. Don't forget that the surface logic of the Ion is simply that poets and rhapsodes are deceivers in pretending to have knowledge and self-knowledge, whereas they only have inspiration, a kind of second-best sort of wisdom (true wisdom would, of course, involve having true self-knowledge) that can only be held up if one seriously believes in God, something that Socrates makes rather unnecessary in some of his other arguments.
It is only at another level of reading (focusing on the milk and honey text) that Socrates becomes an advocate of Dionysian forms of experience, ones that also involve a form of active engagement that is highly imaginative, that e.g. involves encountering nature in an intoxicated or intoxicated-like way, seeing it with heightened significance, i.e. as having what, in my book, I called "aura." Moreover, this experience of water as milk and honey is a kind of entering into another world, as when Ion seems to enter into the world of Homer: a kind of magical transfer of the self. (A similar view of the creative process can be found in Lu Chi's the Wen Fu as I have argued in an unpublished paper posted on my web page.)
This, by the way, is not the same as another well-founded reading of Ion in which the inspired person simply becomes a spokesperson of the God, as like a medium in a seance. I think that this reading is intended by Plato, but is only on the surface level of the story.
For more on Ion see here