Read the excerpt from "A Defence of Poetry.” There is this difference between a story and a poem, that a story is a catalogue of detached facts, which have no other connexion than time, place, circumstance, cause and effect; the other is the creation of actions according to the unchangeable forms of human nature, as existing in the mind of the Creator, which is itself the image of all other minds. The one is partial, and applies only to a definite period of time, and a certain combination of events which can never again recur; the other is universal, and contains within itself the germ of a relation to whatever motives or actions have place in the possible varieties of human nature.

In this excerpt, Shelley conveys the central idea that poetry

exists only in one’s mind.
contains a wealth of facts.
expresses a universal truth.
describes a specific event.