 This brings us back to Ip9 and the other objectionable aspect of (16). Why should perfection or reality and strength of reason to exist correspond to possessing a greater number of attributes? Spinoza does not offer any explicit defense of this correlation. The demonstration of Ip9 simply refers readers back to the definition of an attribute (see also Ep9). Here is one possible way Spinoza might motivate the correlation between number of attributes and perfection / reality for existing. The principle in Ip9 may be that to the extent to which a single thing [unaquaeque res] can be expressed by a greater number of attributes, to that extent it is more perfect, and hence is more real (IId6) and has greater reason for existing (Ip11s). Spinoza’s emphatic “unaquaeque” may point to the idea that perfection involves both unity and diversity. To the degree to which one and the same thing can sustain a greater variety of expressions of it, to that extent it is more perfect. The maximal perfection and reality of God, on this account, is partly constituted by the fact that God’s self-identity is compatible with a plentitude of incommensurable expressions – infinitely many attributes – of it. This view of metaphysical perfection, one which tries to maximize both identity and diversity, is very similar to Leibniz’s account of perfection as harmony, a principle that Leibniz explains as “diversity compensated by identity.”[6] On this reading, God’s metaphysical perfection for Spinoza is the perfection of Leibniz’s most harmonious world, the perfection of maintaining both the one and the many (Newlands 2010a).