§1.1.14Ὅταν οὖν τὸ παντὶ τῷ Β ἐνδέχηται καὶ τὸ Β παντὶ τῷ Γ, συλλογισμὸς ἔσται τέλειος ὅτι τὸ Α παντὶ τῷ Γ ἐνδέχεται ὑπάρχειν.
When, therefore, it is possible for A to belong to all B and B to all Γ, there will be a perfect syllogism that it is possible for A to belong to all Γ.
τοῦτο δὲ φανερὸν ἐκ τοῦ ὁρισμοῦ· τὸ γὰρ ἐνδέχεσθαι παντὶ ὑπάρχειν οὕτως ἐλέγομεν.
And this is clear from the definition; for we said that to be possible to belong to all is in this way.
ὁμοίως δὲ καὶ εἰ τὸ μὲν Α ἐνδέχεται μηδενὶ τῷ Β, τὸ δὲ Β παντὶ τῷ Γ, ὅτι τὸ ἐνδέχεται μηδενὶ τῷ Γ· τὸ γὰρ καθʼ οὗ τὸ Β ἐνδέχεται, τὸ Α μὴ ἐνδέχεσθαι, τοῦτʼ ἦν τὸ μηδὲν ἀπολείπειν τῶν ὑπὸ τὸ Β ἐνδεχομένων.
Similarly also if A is possible to belong to no B, and B to all Γ, that [it is possible for A to belong] to no Γ; for that A is possible not to belong to that of which B is possible was this: to leave out nothing of the things possible under B.
ὅταν δὲ τὸ παντὶ τῷ Β ἐνδέχηται, τὸ δὲ Β ἐνδέχηται μηδενὶ τῷ Γ, διὰ μὲν τῶν εἰλημμένων προτάσεων οὐδεὶς γίνεται συλλογισμός, ἀντιστραφείσης δὲ τῆς Β Γ κατὰ τὸ ἐνδέχεσθαι γίνεται ὁ αὐτὸς ὅσπερ πρότερον.
But when it is possible for A to belong to all B, and B is possible to belong to no Γ, through the assumed premises indeed no syllogism comes about, but when BΓ is converted according to possibility, the same syllogism as before comes about.
ἐπεὶ γὰρ ἐνδέχεται τὸ Β μηδενὶ τῷ Γ ὑπάρχειν, ἐνδέχεται καὶ παντὶ ὑπάρχειν· τοῦτο δʼ εἴρηται πρότερον.
For since it is possible for B to belong to no Γ, it is also possible to belong to all; and this was said before.
ὥστʼ εἰ τὸ μὲν Β παντὶ τῷ Γ, τὸ δʼ Α παντὶ τῷ Β, πάλιν ὁ αὐτὸς γίνεται συλλογισμός.
So if B belongs to all Γ, and A to all B, again the same syllogism comes about.
ὁμοίως δὲ καὶ εἰ πρὸς ἀμφοτέρας τὰς προτάσεις ἡ ἀπόφασις τεθείη μετὰ τοῦ ἐνδέχεσθαι.
Similarly also if the negation is placed with possibility for both premises.
λέγω δʼ οἷον εἰ τὸ ἐνδέχεται μηδενὶ τῷ Β καὶ τὸ Β μηδενὶ τῷ Γ· διὰ μὲν γὰρ τῶν εἰλημμένων προτάσεων οὐδεὶς γίνεται συλλογισμός, ἀντιστρεφομένων δὲ πάλιν ὁ αὐτὸς ἔσται ὅσπερ καὶ πρότερον.
I mean, for example, if it is possible to belong to no B, and B to no Γ; for through the assumed premises indeed no syllogism comes about, but when they are converted, again there will be the same syllogism as before.
φανερὸν οὖν ὅτι τῆς ἀποφάσεως τιθεμέντης πρὸς τὸ ἔλαττον ἄκρον ἢ πρὸς ἀμφοτέρας τὰς προτάσεις ἢ οὐ γίνεται συλλογισμὸς ἢ γίνεται μὲν ἀλλʼ οὐ τέλειος· ἐκ γὰρ τῆς ἀντιστροφῆς περαίνεται τὸ ἀναγκαῖον.
It is clear, then, that when the negation is placed with the minor extreme or with both premises, either no syllogism comes about, or one comes about but not a perfect one; for the necessity is concluded from the conversion.
Ἐὰν δʼ ἡ μὲν καθόλου τῶν προτάσεων ἡ δʼ ἐν μέρει ληφθῇ, πρὸς μὲν τὸ μεῖζον ἄκρον κειμένης τῆς καθόλου συλλογισμὸς ἔσται τέλειος].
But if one of the premises is taken as universal and the other as particular, when the universal is placed with the major extreme there will be a perfect syllogism.
εἰ γὰρ τὸ παντὶ τῷ Β ἐνδέχεται, τὸ δὲ Β τινὶ τῷ Γ, τὸ Α τινὶ τῷ Γ ἐνδέχεται.
For if it is possible for A to belong to all B, and B to some Γ, it is possible for A to some Γ.
τοῦτο δὲ φανερὸν ἐκ τοῦ ὁρισμοῦ τοῦ ἐνδέχεσθαι.
And this is clear from the definition of being possible.
πάλιν εἰ τὸ ἐνδέχεται μηδενὶ τῷ Β, τὸ δὲ Β τινὶ τῷ Γ ἐνδέχεται ὑπάρχειν, ἀνάγκη τὸ Α ἐνδέχεσθαί τινι τῶν Γ μὴ ὑπάρχειν· . ἀπόδειξις δʼ ἡ αὐτή.
Again, if it is possible to belong to no B, and B is possible to belong to some Γ, it is necessary for A to be possible not to belong to some of the Γ; and the proof is the same.
ἐὰν δὲ στερητικὴ ληφθῇ ἡ ἐν μέρει πρότασις, ἡ δὲ καθάλου καταφατική, τῇ δὲ θέσει ὁμοίως ἔχωσιν (οἷον τὸ μὲν παντὶ τῷ Β ἐνδέχεται, τὸ δὲ Β τινὶ τῷ Γ ἐνδέχεται μὴ ὑπάρχειν), διὰ μὲν τῶν εἰλημμένων προτάσεων οὐ γίνεται φανερός συλλογισμός, ἀντιστραφείσης δὲ τῆς ἐν μέρει καὶ τεθέντος τοῦ Β τινὶ τῷ Γ ἐνδέχεσθαι ὑπάρχειν τὸ αὐτὸ ἔσται συμπέρασμα ὃ καὶ πρότερον, καθάπερ ἐν τοῖς ἐξ ἀρχῆς.
But if the particular premise is taken as privative, and the universal as affirmative, and they are in the same position (for example, if it is possible for A to belong to all B, and B is possible not to belong to some Γ), through the assumed premises indeed a clear syllogism does not come about, but when the particular is converted and B is assumed to be possible to belong to some Γ, there will be the same conclusion as before, just as in the original cases.
Ἐὰν δʼ ἡ πρὸς τὸ μεῖζον ἄκρον ἐν μέρει ληφθῇ, ἡ δὲ πρὸς τὸ ἔλαττον καθόλου, ἐάν τʼ ἀμφότεραι καταφατικαὶ τεθῶσιν ἐάν τε στερητικαὶ ἐάν τε μὴ ὁμοιοσχήμονες, ἐάν τʼ ἀμφότεραι ἀδιόριστοι ἢ κατὰ μέρος, οὐδαμῶς ἔσται συλλογισμός·
But if the premise with the major extreme is taken as particular, and that with the minor as universal, whether both are assumed affirmative or privative or not of similar form, and whether both are indefinite or particular, in no way will there be a syllogism.
οὐδὲν γὰρ κωλύει τὸ Β ὑπερτείνειν τοῦ Α καὶ μὴ κατηγορεῖσθαι ἐπ᾿ ἴσων· ᾧ δʼ ὑπερτείνει τὸ Β τοῦ Α, εἰλήφθω τὸ Γ· τούτῳ γὰρ οὔτε παντὶ οὔτε μηδενὶ οὔτε τινὶ οὔτε μή τινι ἐνδέχεται τὸ Α ὑπάρχειν, εἴπερ ἀντιστρέφουσιν αἱ κατὰ τὸ ἐνδέχεσθαι προτάσεις καὶ τὸ Β πλείοσιν ἐνδέχεται ἢ τὸ ὑπάρχειν.
For nothing prevents B from extending beyond A and not being predicated of equal extent; and let Γ be assumed as that by which B extends beyond A; for to this it is possible for A to belong neither to all nor to none nor to some nor not to some, if indeed premises according to possibility convert and B is possible to belong to more than what belongs.
ἔτι δὲ καὶ ἐκ τῶν ὅρων φανερόν· οὕτω γὰρ ἐχουσῶν τῶν προτάσεων τὸ πρῶτον τῷ ἐσχάτῳ καὶ οὐδενὶ ἐνδέχεται καὶ παντὶ ὑπάρχειν ἀναγκαῖον.
And further it is also clear from the terms; for when the premises are in this way, it is necessary for the first to belong to the last both to none and to all.
ὅροι δὲ κοινοὶ πάντων τοῦ μὲν ὑπάρχειν ἐξ ἀνάγκης ζῷον–λευκόν–ἄνθρωπος, τοῦ δὲ μὴ ἐνδέχεσθαι ζῷον–λευκόν–ἱμάτιον.
And common terms of all for belonging of necessity are "animal–white–human", and for not being possible "animal–white–cloak".
φανερόν οὖν τοῦτον τὸν τρόπον ἐχόντων τῶν ὅρων ὅτι οὐδεὶς γίνεται συλλογισμός.
It is clear, then, when the terms are in this way, that no syllogism comes about.
ἢ γὰρ τοῦ ὑπάρχειν ἢ τοῦ ἐξ ἀνάγκης ἢ τοῦ ἐνδέχεσθαι πᾶς ἐστὶ συλλογισμός.
For every syllogism is either of belonging or of necessity or of possibility.
τοῦ μὲν οὖν ὑπάρχειν καὶ τοῦ ἀναγκαίου φανερὸν ὅτι οὐκ ἔστιν· ὁ μὲν γὰρ καταφατικὸς ἀναιρεῖται τῷ στερητικῷ, ὁ δὲ στερητικός τῷ καταφατικῷ.
That there is none of belonging and of the necessary, then, is clear; for the affirmative is destroyed by the privative, and the privative by the affirmative.
λείπεται δὴ τοῦ ἐνδέχεσθαι εἶναι· τοῦτο δʼ ἀδύνατον· δέδεικται γὰρ ὅτι οὕτως ἐχόντων τῶν ὅρων καὶ παντὶ τῷ ἐσχάτῳ τὸ πρῶτον ἀνάγκη καὶ οὐδενὶ ἐνδέχεται ὑπάρχειν.
It remains, then, for it to be of possibility; but this is impossible; for it has been shown that when the terms are in this way, it is necessary for the first to belong to all of the last and possible to none.
ὥστʼ οὐκ ἂν εἴη τοῦ ἐνδέχεσθαι συλλογισμός· τὸ γὰρ ἀναγκαῖον οὐκ ἦν ἐνδεχόμενον.
So there would not be a syllogism of possibility; for the necessary was not possible.
Φανερὸν δὲ ὅτι καθόλου τῶν ὅρων ὄντων ἐν ταῖς ἐνδεχομέναις προτάσεσιν ἀεὶ γίνεται συλλογισμὸς ἐν τῷ πρώτῳ σχήματι, καὶ κατηγορικῶν καὶ στερητικῶν ὄντων, πλὴν κατηγορικῶν μὲν τέλειος, στερητικῶν δὲ ἀτελής.
And it is clear that when the terms are universal in possible premises, there is always a syllogism in the first figure, both when they are affirmative and privative, except that from affirmative premises it is perfect, but from privative it is imperfect.
δεῖ δὲ τὸ ἐνδέχεσθαι λαμβάνειν μὴ ἐν τοῖς ἀναγκαίοις, ἀλλὰ κατὰ τὸν εἰρημένον διορισμόν.
And we must assume "to be possible" not in necessary things, but according to the said definition.
ἐνίοτε δὲ λανθάνει τὸ τοιοῦτον.
And sometimes such a thing is overlooked.