[393] Ibid. a. 7-12: οὐ δεῖ δὲ τὸ συμπέρασμα ἐρώτημα ποιεῖν· εἰ δὲ μή, ἀνανεύσαντος οὐ δοκεῖ γεγονέναι συλλογισμός.
[394] Topic. VIII. ii. p. 158, b. 34-p. 158, a. 2.
You must not persevere long in the same line of questions. For, if the respondent answers them all, it will soon appear that you are in the wrong course, since your syllogism, if you can get one at all, will always be obtained from a small number of premisses; and, if the respondent will not answer them, you have no alternative except to protest and desist.[395]
[395] Ibid. p. 158, a. 25-30.
The theses that are most difficult to attack are also most easy to defend; and these are the highest universals, and the lowest particulars. The highest you cannot deal with, unless you can get a definition of them; which is sometimes impossible and always difficult; since the respondent will neither define them himself nor accept your definitions. Those which are next to the highest are also difficult to impugn, because there are few intermediate steps of proof. Again, the lowest particulars are also difficult for the contrary reason, that there are so many intermediate steps, and it is tedious to enumerate them all continuously; while, if any are omitted, the demonstration is incomplete, and the procedure will appear sophistical.[396] The most difficult of all to impugn are definitions framed in vague and unintelligible terms, where you do not know whether they are univocal or equivocal, literal or metaphorical. When the thesis tendered to you presents such difficulty, you may presume that it is affected with the obscurity of terms here indicated; or, at any rate, that its terms stand in need of definition.[397] In geometrical construction, as well as in dialectical debate, it is indispensable that the principia or primary terms should be defined, and defined properly; without this, neither the one nor the other can be pursued.[398]
[396] Ibid. iii. p. 158, a. 31, seq. ἢ σοφισματώδη φαίνεται τὰ ἐπιχειρήματα.
[397] Ibid. iii. p. 158, b. 8-23; p. 159, a. 3: οὔκουν δεῖ λανθάνειν, ὅταν δυσεπιχείρητος ᾖ ἡ θέσις, ὅτι πέπονθέ τι τῶν εἰρημένων.
[398] Ibid. p. 158, b. 24-p. 159, a. 2.
Sometimes the major and minor premisses of your syllogistic conclusion are more difficult to establish — more beyond the level of average intelligence — than the thesis itself. In such a case some may think that the respondent ought to grant these premisses, because, if he refuses and requires them to be proved, he will be imposing upon the questioner a duty more arduous than the thesis itself imposes; others may say that he ought not to grant them, because, if he did, he would be acknowledging a conclusion derived from premisses requiring proof as much or more than itself.[399] A distinction must here be made. If you are putting questions with a view to teach, the learner ought not to grant such premisses as those above described, because he is entitled to require that in every step of the process he shall be inducted from what is more knowable to what is less knowable. Accordingly, when you attempt to demonstrate to him something which he knows little, by requiring him to concede something which he knows still less, he cannot be advised to grant what you ask. But, if you are debating with a companion for the purpose of dialectical exercise, he ought to grant what you ask whenever the affirmative really appears to him true.[400]
[399] Topic. VIII. iii. p. 159, a. 4-11. ὅταν δ’ ᾖ πρὸς τὸ ἀξίωμα καὶ τὴν πρότασιν μεῖζον ἔργον διαλεγῆναι ἢ τὴν θέσιν, διαπορήσειεν ἄν τις πότερον θετέον τὰ τοιαῦτα ἢ οὔ· &c.