Shelley: "A Defence of Poetry"

      In this excerpt from "A defense of Poetry" by Percy Bysshe Shelley, she defends poetry as a form or art. She talks about the difference between reason and imagination, and says that "reason is the enumeration of quantities known", and "imagination is the perception of the value of those quantities" (Shelley). She goes on to say that poetry is a way to express imagination. Later, she also states that even though poetry is up to one's imagination, it also has a very certain order in which it follows. In explaining all this, she is saying that poetry is in fact a respectable and admirable form of art.
     Her idea that poetry being created by imagination, is closely related to Aristotle's statement in "from Poetics" that imaginative epics are better than real epics, in other words, fiction is better than nonfiction. This is also shown by the idea that tragics are better than epics, because they are fictional.
     Why do so many people, including present people, agree that fiction is better?