That _Agere_ and _Pati_ (with the illustrations which he himself gives thereof--_urit_, _uritur_) may be ranked as varieties under the generic Category of Relation or Relativity, can hardly be overlooked. The like is seen to be true about _Ubi_ and _Quando_, when we advert to any one of the predicates belonging to either; such as, _in the market-place_, _yesterday_.[80] Moreover, not merely the last six of the ten Categories, but also the second and fourth (_Quantum_ and _Quale_) are implicated with and subordinated to Relation. If we look at _Quantum_, we shall find that the example which Aristotle gives of it is [Greek: tripê=chus], tricubital, or three cubits long; a term quite as clearly relative as the term [Greek: dipla/sios] or double, which he afterwards produces as instance of the Category _Ad Aliquid_.[81] When we are asked the questions, How much is the height? How large is the field? we cannot give the information required except by a relative predicate--_it is three feet_--_it is four acres_; we thereby carry back the mind of the questioner to some unit of length or superficies already known to him, and we convey our meaning by comparison with such unit. Again, if we turn from _Quantum_ to _Quale_, we find the like Relativity implied in all the predicates whereby answer is made to the question [Greek: Poio\s ti/s e)sti?] _Qualis est_? What manner of man is he? _He is such as A, B, C_--persons whom we have previously seen, or heard, or read of.[82] [Footnote 80: The remarks of Plotinus upon these four last-mentioned Categories are prolix and vague, but many of them go to shew how much [Greek: to\ pro/s ti] is involved in all of the four (Ennead. vi. 1, 14-18).] [Footnote 81: Trendelenburg (Kategorienlehre, p. 184) admits a certain degree of interference and confusion between the Categories of _Quantum_ and _Ad Aliquid_; but in very scanty measure, and much beneath the reality.] [Footnote 82: The following passages from Mr. James Mill (Analysis of the Phenomena of the Human Mind, vol. ii. ch. xiv. sect. ii. pp. 48, 49, 56, 1st ed.) state very clearly the Relativity of the predicates of Quantity and Quality:--