Aristotle proceeds to say that this Subject--the Subject for all Predicates, but never itself a Predicate--cannot be the genuine [Greek: ou)si/a], which must essentially be [Greek: chôristo\n kai\ to\ to/de ti] (p. 1029, a. 28), and which must have a [Greek: ti/ ê)=n ei)=nai] (1029, b. 2). The Subject is in fact not true [Greek: ou)si/a], but is one of the constituent elements thereof, being relative to the Predicates as _Correlata_: it is the potentiality for Predicates generally, as _Materia_ is the potentiality for Forms.] The logical aspect of Ontology, analysing _Ens_ into a common Subject with its various classes of Predicates, appears to begin with Aristotle. He was, as far as we can see, original, in taking as the point of departure for his theory, the individual man, horse, or other perceivable object; in laying down this Concrete Particular with all its outfit of details, as the type of _Ens_ proper, complete and primary; and in arranging into classes the various secondary modes of _Ens_, according to their different relations to the primary type and the mode in which they contributed to make up its completeness. He thus stood opposed to the Pythagoreans and Platonists, who took their departure from the Universal, as the type of full and true Entity;[122] while he also dissented from Demokritus, who recognized no true _Ens_ except the underlying, imperceptible, eternal atoms and vacuum. Moreover Aristotle seems to have been the first to draw up a logical analysis of Entity in its widest sense, as distinguished from that metaphysical analysis which we read in his other works; the two not being contradictory, but distinct and tending to different purposes. Both in the one and in the other, his principal controversy seems to have been with the Platonists, who disregarded both individual objects and accidental attributes; dwelling upon Universals, Genera and Species, as the only real _Entia_ capable of being known. With the Sophists, Aristotle contends on a different ground, accusing them of neglecting altogether the essential attributes, and confining themselves to the region of accidents, in which no certainty was to be found;[123] in Plato, he points out the opposite mistake, of confining himself to the essentials, and ascribing undue importance to the process of generic and specific subdivision.[124] His own logical analysis takes account both of the essential and accidental, and puts them in what he thinks their proper relation. The Accidental ([Greek: sumbebêko/s]), concomitant, _i.e._ of the essence) is _per se_ not knowable at all (he contends), nor is ever the object of study pursued in any science; it is little better than a name, designating the lowest degree of _Ens_, bordering on _Non-Ens_.[125] It is a term comprehending all that he includes under his nine last Categories; yet it is not a term connoting either generic communion, or even so much as analogical relation.[126] In the treatise now before us, he