At the center of Aristotle's Poetics is the contention that nothing can be understood separately from it purpose (telos). He states that the goal of poetry is a certain type of pleasure; likewise tragedy provides the purging of emotions, which provides well-being for humans. These forms of art, like all arts have as their basis mimesis, or imitation. In Poetics 4, Artistole explains that art, thus, informs,
Thus the reason why men enjoy seeing a likeness is, that in contemplating it they find themselves learning or inferring, and saying perhaps, ‘Ah, that is he'
Further, Aristotle argues that there are three differences in artistic imitation: "the medium, the objects, and the manner." Of course, in Aristotle's time, the medium was limited to poetry or drama; the objects are men in action, who may be noble or villainous. These men in action, however, are subordinate to the plot which is essential to all imitative works. Finally, manner refers to narration. That is, in Homer's poetry, for instance, the voice of the narrator can be his own, or he can assume another voice.
Perhaps, the most important and largest part of his Poetics is Aristotle's discussion of tragedy (the section on comedy has been lost) as the dramatic form that imitates a serious and complete action that arouses pity and fear, leading to a catharsis, or purging of emotions. This imitation of life is both pleasurable and instructive. The elements of tragedy are discussed in the order of their importance:
- plot - "the soul of tragedy"
- character - personages who further the action of the plot
- thought -dialogue that is "possible and pertinent"
- diction - "the expression of the meaning in words"
- embellishments - song is the most important of these