ABSTRACT
His first argument against the doctrine of specific forms, however, was quite unoriginal. It was simply, in effect, the doctrine of abstraction in its ancient role of a theory of universals. Essentially similar arguments can be found in philosophers as diverse as Descartes and Hobbes. As Descartes argued, all universals are simply modes of thought; or, as Locke put it, 'General and Universal, belong not to the real Existence of Things.' Distinctions between universals, such as the distinctions among the five predicables (at any rate as.applied to particular sorts of substances), are also mind-dependent. The hierarchy of genera and species, ascending to the various categories of being, arises only because the mind ascends by abstraction from man and horse to animal, vivens, body, substance 'and at last to Being, Thing, and such universal terms which stand for any of our Ideas whatsoever'. Thus 'this whole mystery
of Genera and Species' is 'nothing else but abstract Ideas, more or less comprehensive, with names annexed to them'. The 'Rule, that a Definition must consist of Genus and Differentia' is rejected. The method of division of the genus by the difference merely extracts an arbitrarily chosen element from the abstract idea of the species, one property out of all those which are contained in the complex nominal essence." A further point brought against the tree of Porphyry seems to be this: that hierarchy would have to be founded in the form or essence of the individual, since universals exist for the Aristotelian only in individuals. Consequently there must be a corresponding complexity or layering in the individual. Thus the Aristotelian must 'think Nature to be very liberal of these real Essences, making one for Body, another for Animal and another for a Horse, and all these Essences liberally bestowed upon Bucephalus'. This is to mistake the 'artificial Constitution of Genus and Species' for the 'real Constitution of things' .93
