irritable reaching after justification

I’ve noticed that poets whose work is nowhere near as clear and as comprehensible as Keats’ poetry, will often cite his ‘negative capability’ in their own defense.

individual, intelligible, inner need

The absence of any one of these conditions excludes a work form the category of art and relegates it to that of art's counterfeits. If the work does not transmit the artist's peculiarity of feeling and is therefore not individual, if it is unintelligibly expressed, or if it has not proceeded from the author's inner need for expression - it is not a work of art. If all these conditions are present, even in the smallest degree, then the work, even if a weak one, is yet a work of art.

—Leo Tolstoy, "What Is Art?" (translation by Alymer Maude, 1899)