In 1802, William Wordsworth tried to explain his views on poetry. He tried to explain how poetry functions and the nature of the craft itself. Wordsworth also attempted to qualify and explain what a true poet is. He did all of this in his "Preface to Lyrical Ballads."
Keep in mind that William Wordsworth is a poet of Romanticism. There are a lot of key characteristics of Romanticism that make it a joy to read; however, it is incredibly important to also remember that the focus of the period was on emotion and the importance of the individual. Wordsworth's definition of poetry is his definition, and he claims that good poetry is the "spontaneous overflow of powerful feelings."
Notice the emphasis on emotions. To Wordsworth, poetry is all about the internal feelings of the poet. It should not have to follow a set of strict rules, because a poet's emotional state isn't governed by rules. Wordsworth goes on to explain that while the spontaneous overflow of emotions is important, poets also have to spend time wrestling with those emotions, and emotional tranquility is another key.
It [poetry] takes its origin from emotion recollected in tranquillity: the emotion is contemplated till by a species of reaction the tranquillity gradually disappears, and an emotion, kindred to that which was before the subject of contemplation, is gradually produced.
While Wordsworth's definition is reasonable, Poe's essay "The Philosophy of Composition" presents readers with a very different picture of the poet and poetry writing. In his essay, Poe shows readers how he was able to construct a poem in a very logical format. Components of the poem were logically and intentionally chosen for their overall effect. It's a solid counterargument to Wordsworth's definition.