Aristotle’s defense of poets and painters acknowledges their imperfections but stresses their positive accomplishments. In Part XXV of Poetics, Aristotle addresses the “critical difficulties” that artists are bound to encounter and addresses the kinds of faults that occur within the art of poetry. Maintaining that all artists are imitators, he places poets and painters together in this group, but his commentary primarily addresses the poet’s actions and their consequences. He mentions that he is addressing “the objections raised by the critics,” but does not identify those critics.

For Aristotle, imitation is a positive quality. He breaks poetic imitation into three categories or “objects,” which consist of things as they are, as they are said to be, and as they ought to be. By making these distinctions, he shows that his concept of imitation is not limited to an effort to reproduce reality. In conceding that poets do make mistakes, Aristotle claims that not all errors are consequential. To him, it matters more if the poet is capable of successful imitation or if they simply make “a wrong choice” that does not affect the poem’s essence.

Another quality of poetic error, which he finds less excusable, relates to the three objects. The poet should not, in his view, try to represent something that is “impossible.” Such an error could be excused if the poet claims they are representing things as they ought to be. He allows that a poet may succeed by writing about a "probable impossibility."