  The formation of the doctrine of the transcendentals in the 13th century introduces a class of predicates that are not discussed by Porphyry. In reaction to this absence, one can either define the transcendentals in contradistinction to universals, as witnessed in the Ars Meliduna, or extend the list of universals by including a sixth universal predicable. An instance of the first reaction we find in William of Ockham’s Commentary on Porphyry’s Isagoge, who explicitly addresses the question whether the classification of the predicables with regard to the concept of being is exhaustive (i.e. the question of the “sufficiency” of Porphyry’s division of the predicables), and distinguishes between terms that are predicates of many, the universals, and terms predicated of all, the common terms. (Ockham, Expositio in librum Porphyrii de Praedicabilibus, prooem. 2) An instance of the second reaction we find in Duns Scotus; as a consequence of his defense of the univocity of being, Scotus is prepared in his Commentary on the Metaphysics to extend the list of predicables with a sixth one, a ‘transcendental universal’ (universale transcendens), as examples of which he names ‘being’ and ‘one’. (Duns Scotus, Quaestiones super libros Metaphysicorum, IV, q. 1)