In discriminating and arranging the Ten Categories, Trendelenburg supposes that Aristotle was guided, consciously or unconsciously, by grammatical considerations, or by a distinction among the parts of speech. It should be remembered that what are now familiarly known as the eight parts of speech, had not yet been distinguished or named in the time of Aristotle, nor did the distinction come into vogue before the time of the Stoic and Alexandrine grammarians, more than a century after him. _Essentia_ or _Substantia_, the first Category, answers (so Trendelenburg thinks[128]) to the Substantive; _Quantum_ and _Quale_ represent the Adjective; _Ad Aliquid_, the comparative Adjective, of which _Quantum_ and _Quale_ are the positive degree; _Ubi_ and _Quando_ the Adverb; _Jacere_, _Habere_, _Agere_, _Pati_ the Verb. Of the last four, _Agere_ and _Pati_ correspond to the active and passive voices of the Verb; _Jacere_ to the neuter or intransitive Verb; and _Habere_ to the peculiar meaning of the Greek perfect--the present result of a past action. [Footnote 128: Trendelenburg, Kategorienlehre, pp. 23, 211.] This general view, which Trendelenburg himself conceives as having been only guiding and not decisive or peremptory in the mind of Aristotle,[129] appears to me likely and plausible, though Bonitz and others have strongly opposed it. We see from Aristotle's own language, that the grammatical point of view had great effect upon his mind; that the form (_e.g._) of a substantive implied in his view a mode of signification belonging to itself, which was to be taken into account in arranging and explaining the Categories.[130] I apprehend that Aristotle was induced to distinguish and set out his Categories by analysing various complete sentences, which would of course include substantives, adjectives, verbs, and adverbs. It is also remarkable that Aristotle should have designated his four last Categories by the indication of verbs, the two immediately preceding by adverbs, the second and third by adjectives, and the first by a substantive. There remains the important Category _Ad Aliquid_, which has no part of speech corresponding to it specially. Even this Category, though not represented by any part of speech, is nevertheless conceived and defined by Aristotle in a very narrow way, with close reference to the form of expression, and to the requirement of a noun immediately following, in the genitive or dative case. And thus, where there is no special part of speech, the mind of Aristotle still seems to receive its guidance from grammatical and syntactic forms. [Footnote 129: Ibid. p. 209: "Gesichtspunkte der Sprache leiteten den erfindenden Geist, um sie (die Kategorien) zu bestimmen. Aber die grammatischen Beziehungen leiten nur und entscheiden nicht." P. 216: "der grammatische Leitfaden der Satzzergliederung wird anerkannt."]