[303] Topic. VI. vii. p. 146, a. 6-20: ἔδει δ’ ἀμφότερα μᾶλλον τῷ αὐτῷ ὑπάρχειν, εἴπερ ταὐτὰ ἦν, &c.
16. Again, you will be able to object, if the definition enunciate references to two distinct correlates, severally or alternately: e.g., The beautiful is that which affords pleasure either through the eye or through the ear; Ens is that which is capable either of suffering or acting. You may show that, according to this definition, beautiful and not beautiful, or that Ens and Non-Ens, will coincide and be predicable of the same subjects.[304]
[304] Topic. VI. vii. p. 146, a. 21-32.
The definition here given of Ens appears in the Sophistes of Plato, p. 247, E. The definition of the beautiful (τὸ καλόν) appears in the Hippias Major of Plato (p. 298, E, seq.), where it is criticized by Sokrates.
17. When the definition is tendered, you ought to examine and define its own terms, which, of course, profess to enunciate genus and differentia of the definiend.[305] You will see whether the definitions of those defining terms are in any way inapplicable to the definiend.
[305] Ibid. a. 33-35.
18. If the definiend be a Relatum, the definition ought to enunciate its true correlate, or the true correlate of the genus to which it belongs. You must examine whether this is done, and whether the correlate enunciated be an ultimate end, as it ought to be (i.e. not merely a means towards something ulterior). If the correlate enunciated is a generation or a process, this will afford you an argument against the definition; for all generation or process is a means towards some ulterior end.[306]
[306] Ibid. viii. p. 146, a. 36-b. 19. This is a subtle distinction. He says that desire must be defined (not desire of the pleasurable, but) desire of pleasure: we desire the pleasurable for the sake of pleasure. He admits, however, that there are cases in which the argument will not hold: σχεδὸν γὰρ οἱ πλεῖστοι ἥδεσθαι μᾶλλον βούλονται ἢ πεπαῦσθαι ἡδόμενοι· ὥστε τὸ ἐνεργεῖν μᾶλλον τέλος ἂν ποιοῖντο τοῦ ἐνηργηκέναι.
19. The definition ought not to omit any of the differentiæ of the definiend; if any be omitted, the real essence is not declared. Here then is a defect in the definition, which it is your business always to assail on its defective side.[307] Thus, if the definiend be a relatum corresponding, not to some correlate absolutely but, to some correlate specially quantified or qualified, the definition ought to enunciate such quantification or qualification; if it does not, it is open to attack.
[307] Ibid. b. 20: πάλιν ἐπ’ ἐνίων εἰ μὴ διώρικε τοῦ πόσου, ἢ ποίου, ἢ ποῦ, ἢ κατὰ τὰς ἄλλας διαφοράς, — ἀπολείπων γὰρ διαφορὰν ἡντινοῦν οὐ λέγει τὸ τι ἦν εἶναι· δεῖ δ’ ἀεὶ πρὸς τὸ ἐνδεὲς ἐπιχειρεῖν.