Formal literary, should be used in criticism focuses mainly on the clarity, quality and complexity of the writing of the subject. A formal critic looks primarily at syntax, literary devices, and the flow of the writing. Formalist literary criticism can be divided into two categories: descriptive and prescriptive.
Descriptive formalism focuses on the technical analysis of the literary and linguistic devices in texts, with especial regard for how these make a text 'literary' i.e. how the text uses language in a special way which sets it apart from everyday discourse. Prescriptive formalists advocate a style of literary writing which is as distinct as possible from everyday discourse, as they believe that it is the responsibility of literary writers to make readers see things in a new way.
Prescriptive formalism is often associated with Marxism; the early Soviet critic Shlovsky argued that the function of literature was to "make the stone stonier" i.e. to use the alienating effect of challenging devices in order to avoid offering up an immediate, transparent meaning to readers so that they would have to engage actively with texts and discover new meanings from them, in a way analogous to the development of political consciousness. Bertold Brecht argued that such literary forms as satire operate through a 'Verfremdungseffekt' - i.e. they present the familiar in unfamiliar ways and therefore arouse readers' and audiences' awareness of the ideological nature of their assumptions.
Descriptive formalism was at the heart of the New Criticism school which emerged at Cambridge in the 1930s under F.R. Leavis, William Empson and Cleanth Brooks, and which encouraged students to engage in 'practical criticism', looking at literary texts as self-contained artefacts which should be explained on their own terms rather than by reference to external information such as biographical and historical details. This approach, encouraging close analytical reading, was very similar to that of the structuralist school which emerged after the Second World War and was advocated by figures such as Roland Barthes, Lacan, Bhaktin and Levi-Strauss.
Post-structuralism and deconstructionism emerged from the structuralist school but criticised structuralism's analytical approach as being reductive and simplistic. Post-structuralists drew attention to the relationships between texts and their referents and to the limitless possibilities of reading as a creative process, seeing texts not just as self-contained structures but as structures sitting within the larger meta-structures of society and ideology, with readers equally forming their readings from within these structures. Deconstructionists similarly see textual interpretation as a process which can never arrive at a final, fixed 'authoritative' reading of any text because it takes place within the constraints of readers' ideological assumptions, and also draw attention to the contradictions within texts and to the flawed ideological assumptions of their authors. Derrida, Foucault and Culler are some well-known critics in this field.