 Paul’s formulation of the theory of identity and distinction is a further development of Duns Scotus’ and Wyclif’s doctrines on the subject. The Italian master recognizes two main types of identity: material (secundum materiam) and formal (secundum formam). There is material identity when the material cause is the same, either in number (it is a case of the same thing called in different ways) or by species (it is a case of two objects made of the same kind of stuff). There is formal identity when the formal cause is the same. This happens in two ways: if the form at issue is the singular form of the individual composite, then there is a unique object known in different ways; if the form at issue is the common essence instantiated by the singular form, then there are two distinct objects belonging to the same species or genus (In Metaph., book V, tr. 2, chap. 3, fol. 185ra). Correspondingly, the main types of distinction (or difference) are also two: material and formal. There is material distinction when the material cause is different, so that the objects at issue are separable entities. In general, there is formal distinction when the formal cause is different. This happens in two ways: if the material cause is also different, then it is a particular case of material distinction. If the material cause is the same, then a further analysis is necessary. If the material cause is the same by species only, then it is an improper case of formal distinction; but if the material cause is the same in number, then there is properly formal distinction, since the forms at issue have different definite descriptions but share the same substrate of existence, so that they are one and the same thing in reality. For example, there is a proper formal distinction in the case of the two properties of being-capable-of-laughing (risibile) and of being-capable-of-learning (disciplinabile), which are connected forms instantiated by the same set of individual substances (In Metaph., book V, tr. 2, chap. 3, fol. 185rb).