 The most important feature of Burley’s early ontology is his claim that the being (esse) of universals coincides with the being of their instantiations as particulars, so that universals can be said to be everlasting because of the succession of these particulars, not because of a peculiar kind of esse (TsP, ch. se substantia, ed. Conti, p. 34; see also Ean, the question in book I, utrum universale habeat esse extra  animam—whether what is universal has real being outside the  mind—,fols. 9ra–11ra). In his middle commentary on the De interpretatione (pp. 53–56) Burley also speaks of mental universals, i.e., the concepts through which our mind relates general names to their significata. We might sum up his position on universals in these texts as follows: (1) universals exist in a twofold way, as common natures in extramental reality and as concepts in our minds; (2) real universals are naturally suited to be present in many things as their primary metaphysical components; (3) mental universals are partially caused in our minds by common natures existing outside our minds; and (4) real universals have no being (esse) outside the being of their particular instantiations.