The core instrument of Postmodern Critic is Deconstructivism. Their epistemological roots goes beyond Michel Foucault, back to the Russian Formalist and Piercean Pragmatics. Its political implications where first recognised by Marxist Critics  and nowdays is a common instrument for general social movements. Its domains of use are as wide as Learning Theory  and Gene Therapy .
 Marxism and the Philosophy of Language by V.N. Volosinov
 I should put a reference here or explain the crazy invention!
 Biosemiotic School.