 This means that the relationship between common natures and singulars is ultimately grounded on individuation, since no actual universality and no instantiation is possible without individuation. On this subject Paul successfully reconciles the Scotistic approach with certain Thomistic theses. Paul claims that the principle of individuation is twofold, immanent and remote. The immanent principle is the one whose presence necessarily entails the existence of the individual it constitutes, and whose absence necessarily entails the non-existence (or disappearance) of the individual. The remote principle, on the other hand, is just what the immanent principle presupposes, but whose presence and absence alone are insufficient for causing the existence or disappearance of the individual, as it continues being after the corruption of the individual. Thisness (haecceitas) is the immanent principle of individuation, whereas form, matter, and quantity are the remote principle. Thisness in turn has a twofold origin, as it derives from matter and form together in the case of corporeal substances, and as it derives from the essence (quidditas) alone in the case of angelic intelligences (SN, part VI, chap. 5, fol. 95vb). Furthermore, according to Paul there is a close similarity between the thisness, which he now calls individual difference (differentia individualis), and the specific difference. The specific difference is what differentiates the species from the genus, since it is the determination or property which, once added to the genus, results in the species. On the other hand, the specific difference is really identical with the genus, from which it is distinct only in virtue of a formal principle. The same happens to the individual difference: it is what differentiates the individual from the species; from the ontological point of view, it is really identical with and formally distinct from the species itself; and it is the formal principle in virtue of which the individual is what it is, something particular, concrete, and perfectly determined in itself (SN, part VI, chap. 5, fol. 96rb; chap. 26, fol. 112rb–va; QdU, fol. 128va; fol. 129rb; In Metaph., book III, tr. 1, chap. 1, fol. 83vb).