man or biped, and the servant may still continue.[98] You cannot know the _Relatum_ determinately or accurately, unless you know the _Correlatum_ also; without the knowledge of the latter, you can only know the former in a vague and indefinite manner.[99] Aristotle raises, also, the question whether any Essence or Substance can be described as _Ad Aliquid_.[100] He inclines to the negative, though not decisively pronouncing. He seems to think that Simo and Davus, when called men, are Essences or Substances; but that when called master and slave, they are not so; this, however, is surprising, when he had just before spoken of the connotation of man as accidents ([Greek: sumbebêko/ta]) belonging to the connotation of master. He speaks of the members of an organized body (wing, head, foot) as examples of _Ad Aliquid_; while in other treatises, he determines very clearly that these members presuppose, as a _prius naturâ_, the complete organism whereof they are parts, and that the name of each member connotes the performance of, or aptitude to perform, a certain special function: now, such aptitude cannot exist unless the whole organism be held together in co-operative agency, so that if this last condition be wanting, the names, head, eye, foot, can no longer be applied to the separate members, or at least can only be applied equivocally or metaphorically.[101] It would seem therefore that the functioning _something_ is here the Essence, and that all its material properties are accidents ([Greek: sumbebêko/ta]). [Footnote 95: Categor. p. 6, b. 12, p. 11, a. 24; Topic. iv. p. 124, b. 16. Compare also Topica, iv. p. 121, a. 1, and the Scholia thereupon, p. 278, b. 12-16, Br.; in which Scholia Alexander feels the difficulty of enrolling a generic term as [Greek: pro/s ti], while the specific terms comprised under it are not [Greek: pro/s ti]; and removes the difficulty by suggesting that [Greek: e)pistê/mê] may be at once both [Greek: poio/tês] and [Greek: pro/s ti]; and that as [Greek: poio/tês] (not as [Greek: pro/s ti]) it may be the genus including [Greek: mousikê\] and [Greek: geômetri/a], which are not [Greek: pro/s ti], but [Greek: poio/têtes].] [Footnote 96: Categor. p. 6, b. 30, p. 7, b. 12.] [Footnote 97: Categor. p. 7, a. 5. [Greek: e)ni/ote de\ o)nomatopoiei=n I)/sôs a)nagkai=on, e)a\n mê\ kei/menon ê)=| o)/noma pro\s o(\ _oi)kei/ôs_ a)\n a)podothei/ê.]]