It is in keeping with this conception of the relations between history and poetry, that Castelvetro should differ not only from Aristotle, but from most of the critics of his own time, in asserting that the order of the poetic narrative may be the same as that of historical narrative. "In telling a story," he says, "we need not trouble ourselves whether it has beginning, middle, and end, but only whether it is fitted to its true purpose, that is, to delight its auditors by the narration of certain circumstances which could possibly happen but have not actually happened."[78] Here the only vital distinction between history and poetry is that the incidents recounted in history have once happened, while those recounted in poetry have never actually happened, or the matter will not be regarded as poetry. Aristotle's fundamental requirement of the unity of the fable is regarded as unessential, and is simply observed in order to show the poet's ingenuity. This notion of poetic ingenuity is constant throughout Castelvetro's commentary. Thus he explains Aristotle's statement that poetry is more philosophic than history--more philosophic, according to Castelvetro, in the sense of requiring more thought, more speculation in its composition--by showing that it is a more difficult and more ingenious labor to invent things that could possibly happen, than merely to repeat things that have actually happened.[79] III. _The Function of Poetry_ According to Strabo, it will be remembered, the object or function of poetry is pleasurable instruction in reference to character, emotion, action. This occasions the inquiry as to what is the function of the poetic art, and, furthermore, what are its relations to morality. The starting-point of all discussions on this subject in the Renaissance was the famous verse of Horace:-- "Aut prodesse volunt aut delectare poetae."[80] This line suggests that the function of poetry may be to please, or to instruct, or both to please and instruct; and every one of the writers of the Renaissance takes one or other of these three positions. Aristotle, as we know, regarded poetry as an imitation of human life, for the purpose of giving a certain refined pleasure to the reader or hearer. "The end of the fine arts is to give pleasure ([Greek: pros hedonen]), or rational enjoyment ([Greek: pros diagogen])."[81] It has already been said that poetry, in so far as it is an imitation of human life, and attempts to be true to human life in its ideal aspects, must fundamentally be moral; but to give moral or scientific instruction is in no way the end or function of poetry. It will be seen that the Renaissance was in closer accord with Horace than with Aristotle, in requiring for the most part the _utile_ as well as the _dulce_ in poetry.