 The thesis (which he shares with Wyclif and his followers) of the composition of potency and act proper to all categorial items (universal and individual substances, and universal and individual accidents – see SN, pars vi, ch. 4, fol. 95rb) is in accord with this approach. In Paul’s opinion, each categorial item is act, and hence form, with respect to the entity that according to the high-low direction immediately precedes it in the categorial line (linea praedicamentalis), and in potency, and hence matter, with respect to the entity that immediately follows it – taking the terms ‘matter’ and ‘form’ in a broad sense (communiter), since ‘matter’ stands for any potential nature and ‘form’ for any act (or form) contracting some given nature (cf. ibidem). For instance, the highest genus of the category of substance is immediately composed of act and potency; intermediate genera and lowest species immediately of genus and difference, and mediately of act and potency (because of the supreme genus, which is the original constitutive element of their natures); and individuals immediately of essence and being (that is to say, as Paul puts it, of specific nature and an individuating principle, or ratio individualis, and mediately of genus and difference (because of the lowest species), and of act and potency (because of the highest genus) (SN, pars vi, ch. 4, fol. 95rb; In Metaph., V, tr. 2, ch. 2, fol. 184ra; and book XII, tr. 1, ch. 4, fols. 433va and 434ra-b; In Cat., cap. de substantia, fols. 54vb, 55ra, and 55rb-va).Thus, for example, mammal is in act with respect to animal, of which it actualises a potentiality, and in potency with respect to feline, which in turn actualises a potentiality of mammal. The Porphyrian (see Isagoge, chs. on genus and on species) and neo-Platonic idea of potentiality as a productive capacity reinforces this interpretation. As a result, what is potential, because it is more universal, comes first and is more important than what is actual, and therefore real (In Metaph., V, tr. 2, ch. 4, fol. 193ra) – a scale of values that overturns the Aristotelian one. As is evident, the notions of act and potency are central to Paul’s ontology, since potency and act constitute the first, basic, and most universal type of composition of created beings. Every other type of composition somehow presupposes it.