Originality.

Literature is not merely language.  It is also will to figuration, the motive for metaphor that Nietzsche once defined as the desire to be different, the desire to be elsewhere. This partly means to be different from oneself, but primarily, I think, to be different from the metaphors and images of the contingent works that are one's heritage: the desire to write greatly is the is the desire to be elsewhere, in a time and a place of one's own, in an originality that must compound with inheritance, with the anxiety of influence.

Harold Bloom