 The main feature of this metaphysical conception is Burley’s claim that universals fully exist outside the mind and are really distinct from the individuals in which they are present and of which they are predicated. According to him, if universals are no longer actual constituent parts of their particulars, then the inconsistencies pointed to by Ockham vanish. Furthermore, from a metaphyisical point of view, causes must be proportional to their effects. But the causes of a particular thing must be particular, whereas those of a common nature must be universal. Therefore, individual substances cannot be composed of anything except particular forms and matter, whereas universals are composed of a genus and specific difference as well as by any other universal form above the genus. Consequently, the lowest species is not a constitutive part of the individuals in which it is present and of which it is predicated, but only a form coming together with their essences, making their metaphysical structure known (EP, ch. de substantia, fol. 23rb–va). Hence, Burley sharply distinguishes between two main kinds of substantial form: one singular (forma perficiens materiam) and the other universal (forma declarans quidditatem). The former affects (a particular) matter and, together with it, brings the substantial composite (or hoc aliquid) into existence. The latter, the lowest species, discloses the nature of the particular substance in which it exists and of which it is predicated, but it is not one of its constituent parts. So particular substances are in and of themselves really distinct from their species and from each other. Every individual really differs from its species because the latter is not part of its essence, but a form existing in it, as well as really distinct from other individuals belonging to the same species because of its own particular form and matter (EIs, ch. de specie, fol. 10va; EP, chs., de substantia, fol. 23va–b; de quantitate, fol. 31rb; see also Tractatus de formis, pp. 9–10). Secondary substances belong to the category of substance only insofar as they are predicated of the essence of particular substances (in quid) (EP, ch. de substantia, fol. 22ra), whereas particular substantial forms and particular matter do not properly belong to the category of substance because they do not fulfill the above conditions for being a substance (EP, ch. de substantia, fol. 22ra). Burley’s exposition here amounts to equating the essence of a thing, its forma totius (qua really different from the forma partis), and its universal (or secondary) substance (namely, the species of the thing at issue) with one another. The essence so viewed includes substantial form and matter in equal measure. It is interpreted as the main common, immanent form of a certain set of individuals and represents the unchanging and basic properties of that set of things. Although the essence is one and the same item in all the singulars of which it is predicated, it is not one in number, but one according to the species (una et eadem res secundum speciem). It has some sort of unity and identity other than numerical, specifies Burley. As a consequence, it can be present in different places, say in Rome and in Oxford, at the same time, since this is compatible with its other-than-numerical unity. The unity of the essence is a transcendental (and so trans-categorial and merely intelligible) and not a numerical (i.e, quantitative) unity. Therefore, universal essences cannot be counted with their individuals.