Wordsworth's Preface to the Lyrical Ballads outlines a theory of the nature and effect of poetry based on the concept that poetry is the "the spontaneous overflow of powerful feeling" from the poet. Through poetic activity, the poet trains, strengthens and refines his sensibility. Following the French philosopher Jean Rousseau, Wordsworth sees civilization as corrupting and distorting the sensibility, and feels that only by examining and portraying pastoral life may the poet recapture authenticity of emotion.
IN his analysis of reader response, Wordsworth assumes a sympathy of sentiment whereby the reader, as he reads the poem, vicariously experiences a similar strengthening and refining of the sensibility through sympathy with the emotions of the poet.
This notion of poetry as training and refining the emotions was a commonplace of neo-Aristotelian literary theory of the 18th century (Dacier, Moor, Twining, Pye, etc.). The novelty in Wordsworth is synthesis of Aristotelian poetic theory with the individual Romaniticism and pastoralism of Rousseau.