"I hate poetry! It's hard to understand, it's not relevant to me, and it doesn't even matter to anyone beside English teachers."
Well, here's an excerpt from an essay written on Shelley's "A Defence of Poetry":
In A Defence of Poetry, Shelley contends that the invention of language reveals a human impulse to reproduce the rhythmic and ordered, so that harmony and unity are delighted in wherever they are found and incorporated, instinctively, into creative activities: ‘Every man in the infancy of art, observes an order which approximates more or less closely to that from which highest delight results...’ (SPP, p. 481).This ‘faculty of approximation’ enables the observer to experience the beautiful, by establishing a ‘relation between the highest pleasure and its causes’ (SPP, p. 482). Those who possess this faculty ‘in excess are poets’ (SPP, p. 482) and their task is to communicate the ‘pleasure’ of their experiences to the community. Shelley does not claim language is poetry on the grounds that language is the medium of poetry; rather he recognises in the creation of language an adherence to the poetic precepts of order, harmony, unity, and a desire to express delight in the beautiful. Aesthetic admiration of ‘the true and the beautiful’ (SPP, p. 482) is provided with an important social aspect which extends beyond communication and precipitates self-awareness. Poetry and the various modes of art it incorporates are directly involved with the social activities of life.
For Shelley, then, ‘poets...are not only the authors of language and of music, of the dance, and architecture, and statuary, and painting; they are the instituters of laws, and the founders of civil society...’ (SPP, p. 482).