Plotinus himself recognizes five _Summa_ or _Prima Genera_,[136] (he does not call them Categories) _Ens_, _Motus_, _Quies_, _Idem_, _Diversum_; the same as those enumerated in the Platonic Sophistes. He does not admit _Quantum_, _Quale_, or _Ad Aliquid_, to be _Prima Genera_; still less the other Aristotelian Categories. Moreover, he insists emphatically on the distinction between the intelligible and the sensible world, which distinction he censures Aristotle for neglecting. His five _Genera_ he applies directly and principally to the intelligible world. For the sensible world he admits ultimately five Catgories; _Substantia_ or _Essentia_ (though he conceives this as fluctuating between Form, Matter, and the Compound of the two), _Ad Aliquid_, _Quantum_, _Quale_, _Motus_. But he doubts whether _Quantum_, _Quale_, and _Motus_, are not comprehended in _Ad Aliquid_.[137] He considers, moreover, that Sensible Substance is not Substance, properly speaking, but only an imitation thereof; a congeries of non-substantial elements, qualities and matter.[138] Dexippus,[139] in answering the objections of Plotinus, insists much on the difference between Aristotle's point of view in the Categoriæ, in the Physica, and in the Metaphysica. In the Categoriæ, Aristotle dwells mainly on sensible substances (such as the vulgar understand) and the modes of naming and describing them. [Footnote 136: Plotinus, Ennead. vi. 2, 8, 14, 16.] [Footnote 137: Plotinus, Ennead. vi. 3. 3. [Greek: ê)\ kai\ tau=ta ei)s ta\ pro/s ti; periektiko\n ga\r ma=llon.] His idea of Relation is more comprehensive than that of Aristotle, for he declares that terms, propositions, discourse, &c., are [Greek: pro/s ti; kath' o(\ sêmantika/] (vi. 3. 19).] [Footnote 138: Ibid. vi. 3. 8-15.]