In Plato's Ion (ˈaɪɒn; Ἴων) Socrates discusses with the titular character, a professional rhapsode who also lectures on Homer, the question of whether the rhapsode, a performer of poetry, gives his performance on account of his skill and knowledge or by virtue of divine possession. It is one of the shortest of Plato's dialogues.
Socrates, the Greek philosopher. In this dialogue, he questions the nature of art and of divine inspiration.
Ion of Ephesus, the rhapsode. In poetry, he specialized in the works of Homer. The city of Ephesus was under Athenian control at this time and Athens had lost many of its beloved generals in the recent Sicilian expedition. Athens was in the process of hiring foreign mercenaries so Socrates' suggestion that Ion should serve as a general to the Athenian soldiers is not the non-sequitur it may at first appear when these circumstances are taken into account.
Ion has just come from a festival of Asclepius at the city of Epidaurus, after having won first prize in the competition. Socrates engages him in discussion and Ion explains how his knowledge and skill is limited to Homer, whom he claims to understand better than anyone alive. Socrates finds this puzzling as to him it seems that Homer treats many of the same subjects as other poets like Hesiod, subjects such as war or divination, and that if someone is knowledgeable in any one of those he should be able to understand what both of these poets say. Furthermore, this man is probably not the poet, like Ion, but a specialist like a doctor, who knows better about nutrition.
Socrates deduces from this observation that Ion has no real skill, but is like a soothsayer or prophet in being divinely possessed:
"For not by art do they utter these things, but by divine influence; since, if they had fully learned by art to speak on one kind of theme, they would know how to speak on all.