Perhaps too the thesis may enunciate the Definition as if it were a Proprium; which is another ground for objecting that the proprium is not well set out. Thus, the thesis may enunciate, as proprium of man, that man is a land animal walking on two feet. Here what is given as proprium is the essence of man, which never ought to be affirmed in the proprium. To set out the proprium well, the predicate ought to reciprocate and to be co-extensive with the subject, but it ought not to affirm the essence thereof. A good specimen of proprium well set out is the following, Man is an animal by nature gentle; for here the predicate is co-extensive with the subject, yet does not declare the essence of the subject.[218]
[218] Ibid. b. 37-p. 132, a. 9.
Lastly, the proprium, to be well set out, though it does not declare the essence of the subject, yet ought to begin by presupposing the generic portion of the essence, and to attach itself thereunto as a constant adjunct or concomitant. Thus, suppose the thesis to enunciate, as proprium, Animal is that which has a soul; this will not be well set out, for the predicate is not superadded or attached to the declared generic essence of animal. But, if the thesis enunciates, as proprium of man, Man is an animal capable of acquiring cognition, — this will be a proprium well set out, so far as the present objection is concerned. For here the predicate declares first the generic essence of the subject, and then superinduces the peculiar adjunct thereupon.[219]
[219] Topic. V. iii. p. 131, a. 10-21.
Thus far Aristotle has pointed out certain conditions to be attended to in determining whether a Proprium is well set out or described, without determining whether it be really a Propium or not. It may perhaps be truly predicated of the subject, and may even admit of a better description which would show it to be a proprium of the subject; but the description actually set out is defective, and the assailant is entitled to impeach it on that ground. He now proceeds to a larger discussion: What are the conditions for determining whether the supposed Proprium be really a Proprium at all, in respect to the subject of which it is predicated? Assuming that the description of it is not open to impeachment on any of the grounds above enumerated, are there not other real grounds of objection, disproving its title to the character of Proprium?[220]
[220] Ibid. p. 132, a. 22-27. πότερον μὲν οὖν καλῶς ἢ οὐ καλῶς ἀποδέδοται τὸ ἴδιον, διὰ τῶνδε σκεπτέον· πότερον δ’ ἴδιόν ἐστιν ὅλως τὸ εἰρημένον ἢ οὐκ ἴδιον, ἐκ τῶνδε θεωρητέον.
The distinction here noted by Aristotle (between the two questions:— (1) Whether the alleged Proprium is well set out or clearly described? (2) Whether the alleged Proprium is a Proprium at all?) is not carried out, nor indeed capable of being carried out, with strict precision. The two heads of questions run together and become confounded. Alexander remarks (Scholia, p. 284, b. 24-46, Br.) that the three or four last-mentioned loci under the first head embrace the second head also. He allows only three loci as belonging peculiarly to the first head — τοῦ μὴ καλῶς ἀποδεδόσθαι τὸ ἴδιον:— (1) Equivocal terms; (2) Predicate not reciprocating or co-extensive with subject; (3) Predicate not more knowable than subject. The other loci (besides these three) enumerated by Aristotle under the first head, Alexander considers as belonging equally to the second head. But he commends Aristotle for making a distinction between the two heads: οὐ γὰρ πᾶν τὸ ἀπηλλοτριωμένον τούτων, καὶ μὴ ἔχον ὁμωνύμους φωνὰς ἤ τι τῶν εἰρημένων, καὶ ἴδιον ῥητέον ἐξ ἀνάγκης. The manner in which M. Barthélemy St. Hilaire explains this nice distinction is not clear to me (Note to his translation of Topica, p. 177).
1. Suppose your respondent to set up A as a proprium of B: you will examine first whether A can be truly predicated of B at all; next, if it can so be, whether it is truly predicable of B quâ B, or of every thing that comes under B quâ B. Thus, if he contends that not to be deceived by reason is a proprium of scientific men, you will be able to show that this does not hold in geometry, since geometricians are deceived by pseudographemes or scientific paralogisms. Or, should the respondent deny that A is a proprium of B, you will succeed in refuting him, if you can prove that A is truly predicable of every B and quâ B. Thus, it is a proprium of man to be an animal capable of acquiring knowledge; because that attribute is truly predicable of every man quâ man.[221]
[221] Topic. V. iv. p. 132, a. 27, seq.
2. Again, suppose your respondent affirms a given proprium A of B: you will examine whether A can be truly predicated of every thing called B, and whether B can be truly predicated of every thing called A; if not, the alleged proprium will not hold. Thus the affirmation, A god is an animal participant of knowledge, is a true affirmation; but it would not be true to say, A god is a man: wherefore, to be participant of knowledge is not proprium of man; and, if this be the proprium which the respondent undertakes to maintain, you will be able to refute him. On the other hand, if what he undertakes is the negation of a proprium (A is not a proprium of B), you will establish the affirmative against him by showing that of every thing respecting which A can be truly affirmed B can be affirmed also, and vice versâ. You will thus show that A is a true proprium of B.[222]