5) The author (as a principle for the grouping of discourses, a principle of unity and origin of their signification, as a focus of coherence) is another "principle of rarefaction" in discourse. The name of the author has a different use and value in scientific discourse and in literary discourse; these two types of discourse have exchanged their faith in the author since the Middle Ages. Scientific authors are no longer treated as authorities, but in literature "The author is what gives the disturbing language of fiction its unities, its nodes of coherence, its insertion of in the real" (58). The individual in question receives his modes of behaviour from the author-funciton as it is defined in his age, "or as he modifies it in his turn