  Since that which essence is depends on essence itself, while the fact of being an essence derives from a formal dependence (similitudo) on God, it follows that within essence itself there is a composition prior to the one so far described between essence and existence. Even in essence, in other words, we can distinguish between an id quod est and a quo est, in the classic Boethian formulation. Quo est is obviously esse essentiae. It is not so easy, however, to identify id quod est. It is certainly not essence itself, since essence is the result of the composition, not one of its component parts. Yet neither is it strictly speaking a res a reor reris, even though Henry himself had entertained this possibility on one occasion at least (Summa, art. 28, q. 4). In the denomination res a reor reris are included all those essences effectively constituted as such and also figments devoid of any objective content. Consequently, res ratae are more a subcategory of res a reor reris, rather than the possible result of the composition between the latter and esse essentiae. The distinction between res a reor reris and res a ratitudine seems to have mainly an epistemological utility: it corresponds to the scientific progression (mentioned above, §2) from a purely nominal knowledge of a thing (res a reor reris as pure quid nominis) to the recognition of its essential reality (the verification of esse essentiae, quaestio si est de incomplexo), and finally to the determination of its objective content (quid rei, res a ratitudine), according to Henry's essentialist reinterpretation of the scheme of the Posterior Analytics in his Summa (art. 24, q. 3).