Here there is a basic distinction between two kinds of projects: one, modeled on linguistics, takes meanings as what have to be accounted for and tries to work out how they are possible. The other, by contrasts, starts with forms and seeks to interpret them, tot ell us what they really mean. Poetics starts with attested meanings or effects and ask how they are achieved. Hermeneutics, on the other hand, starts with texts and asks what they mean, seeking to discover new and better interpretations. Hermeneutic models come from the fields of law and religion, where people seek to interpret an authoritative legal or sacred text in order to decide how to act.
Literary criticism often combine poetics and hermeneutics, asking how a particular effect is achieved or why an ending seems right, but also asking what a particular line means and what a poem tells us about the human condition. But the two projects are different. Taking meanings or effects as the point of departure is fundamentally different from seeking to discover meaning.
]If literary studies took linguistics as a model, its tasks would be to describe the literary competence that readers of literature acquire. A poetics describing the literary competence would focus on the conventions that make possible literary structure and meaning.
The analogy between poetics and linguistics may seem misleading, for we don’t know the meaning of a literary work and therefore can’t take meaning as a given but have to seek it. This is certainly one reason why literary studies in modern times have favored hermeneutics over poetics. But poetics does not require that we know the meaning of a work; its task is to account for whatever effects the reader can attest to. Moreover, a crucial part of poetics is an account of how readers do go about interpreting literary works.
Culler, Jonathan. Literary Theory: A Very Short Introduction. Oxford U Press: New York, 1997.