 Nevertheless, composition is not the result of an addition. The quiddity or essence of a thing is not in its turn a “thing” with its own mental existence so that, once added to (real) existence, it could become a real thing (Lizzini 2014). This would not only lead to infinite division (in the quiddity one would again distinguish quiddity from existence), but also—as Avicenna notes—to Platonism (Ilāhiyyāt, V, 1, 204, 4–5; cf. VII, 2–3; Marmura 2006; Porro 2002, 2011a). But here lies the problem: the distinction between essence and existence cannot obviously lead to the conclusion that essence is simply non-existent (no affirmative statement about the absolutely non-existent is possible: Ilāhiyyāt, I, 5, 32, 12–13; cf. 15–16). What Avicenna states by distinguishing quiddity and existence in what exists either in the mind or in reality is that quiddity does not coincide with the existence of the thing: neither with its mental existence, which is related but does not correspond to universality, nor with its concrete existence (fī l-ʿayān), which implies individuality. On this point there are two fundamental if problematic sections of Ilāhiyyāt (V 1–2) where Avicenna outlines the so-called theory of the “indifference of essence”: in itself quiddity is only quiddity (equinity is only equinity: fa-l-farasiyya fī nafsi-hā farasiyya faqaṭ or, according to the celebrated Latin formula, equinitas ergo in se est equinitas tantum). The same logical consideration (iʿtibār) that Avicenna applies to the existence of God and existence in general serves here to explain the separation of quiddity from existence: the animal that is not on condition of something other is the animal in its reality or quiddity; it can exist either in the mind or in the concrete world but only if it is accompanied by some fulfilled conditions; the animal on condition of not (i.e., of not being accompanied by any other), is the abstract form that results from a mental consideration (Ilāhiyyāt, V, 1, 203, 15–204, 13). Indeed, when it is considered either in intellectu or in re, quiddity is accompanied by existence and by the quantitative determination that belongs to it: it is then either universal or particular, although in itself it is neither universal nor particular and is nothing but quiddity. When it is considered with a quantitative determination, quiddity is thus no longer considered as it is in itself (Alexander of Aphrodisias’ Quaestiones I.3 and I.11 have been indicated as the source of this distinction: Menn 2013; cf. de Libera 1999; Benevich 2019). Every intention (maʿnā), that of universality—which is the inherent non-impossibility of a multiple predication (Ilāhiyyāt, V, 1, 195, 4–196, 3)—and those of particularity or unity, accompanies quiddity in existence (mental or real); in Avicenna’s technical terminology they are attributes (ṣifāt) or necessary concomitants (lawāzim) of the quiddity of the thing, not identical with it. Quiddity (e.g., equinity) is not the universal (of horse): 