Trying to define poetry is probably a useless enterprise. The literature on it is vast. Most famous poets have written about it. For Alexander Pope, for example, the essence of it came from what "oft was thought but never so well expressed," for Wordsworth it was a matter of the "overflow of powerful feelings . . emotions recollected in tranquility," whereas for Shelley poets were the "unacknowledged legislators of the world." Coleridge was perhaps the most ambitious in asserting that in writing poetry the human mind imitates the divine mind in a god-like act of creation (by a kind of human fiat, which is thus an imitative repetition of its original counterpart).