§2.4Ἔτι τὸ μεταλαμβάνειν εἰς τὸ γνωριμώτερον ὄνομα, οἷον ἀντὶ τοῦ ἀκριβοῦς ἐν ὑπολήψει τὸ σαφὲς καὶ ἀντὶ τῆς πολυπραγμοσύνης τὴν φιλοπραγμοσύνην· γνωριμωτέρου γὰρ γινομένου τοῦ ῥηθέντος εὐεπιχειρητοτέρα ἡ θέσις.
Furthermore, one should substitute a more familiar word; for example, "clarity" instead of "accuracy in conception," and "activity" instead of "busyness." For if what has been said becomes more familiar, the thesis becomes easier to attack.
Ἔστι δὲ καὶ οὗτος ὁ τόπος πρὸς ἄμφω κοινός, καὶ πρὸς τὸ κατασκευάζειν καὶ ἀνασκευάζειν.
This topic is also common to both, namely establishing and refuting.
Πρὸς δὲ τὸ δεῖξαι τἀναντία τῷ αὐτῷ ὑπάρχοντα σκοπεῖν ἐπὶ τοῦ γένους, οἷον ἐὰν βουλώμεθα δεῖξαι ὅτι ἔστι περὶ αἴσθησιν ὀρθότης καὶ ἁμαρτία, τὸ δ᾿ αἰσθάνεσθαι κρίνειν ἐστί, κρίνειν δ᾿ ἔστιν ὀρθῶς καὶ μὴ ὀρθῶς, καὶ περὶ αἴσθησιν ἂν εἴη ὀρθότης καὶ ἁμαρτία.
In order to show that contraries belong to the same thing, one should look at the genus. For example, if we wish to show that correctness and error exist regarding perception—and perceiving is judging, and judging can be done correctly or incorrectly—then correctness and error would also exist regarding perception.
Νῦν μὲν οὖν ἐκ τοῦ γένους περὶ τὸ εἶδος ἡ ἀπόδειξις· τὸ γὰρ κρίνειν γένος τοῦ αἰσθάνεσθαι· ὁ γὰρ αἰσθανόμενος κρίνει πως.
In this case, the proof proceeds from the genus to the species; for judging is the genus of perceiving, since whoever perceives judges in some way.
Πάλιν δ᾿ ἐκ τοῦ εἴδους τῷ γένει· ὅσα γὰρ τῷ εἴδει ὑπάρχει, καὶ τῷ γένει, οἷον εἰ ἔστιν ἐπιστήμη φαύλη καὶ σπουδαία, καὶ διάθεσις φαύλη καὶ σπουδαία· ἡ γὰρ διάθεσις τῆς ἐπιστήμης γένος.
Conversely, [one should argue] from the species to the genus; for whatever belongs to the species also belongs to the genus; for example, if there is a bad and a good science, there is also a bad and a good disposition, for disposition is the genus of science.
Ὁ μὲν οὖν πρότερος τόπος ψευδής ἐστι πρὸς τὸ κατασκευάσαι, ὁ δὲ δεύτερος ἀληθής.
Now, the former topic is fallacious for establishing, but the second is valid.
Οὐ γὰρ ἀναγκαῖον, ὅσα τῷ γένει ὑπάρχει, καὶ τῷ εἴδει ὑπάρχειν· ζῷον μὲν γάρ ἐστι πτηνὸν καὶ τετράπουν, ἄνθρωπος δ᾿ οὔ.
For it is not necessary that whatever belongs to the genus also belongs to the species; for an animal is winged and four-footed, but a man is not.
Ὅσα δὲ τῷ εἴδει ὑπάρχει, ἀναγκαῖον καὶ τῷ γένει· εἰ γάρ ἐστιν ἄνθρωπος σπουδαῖος, καὶ ζῷόν ἐστι σπουδαῖον.
But whatever belongs to the species must also belong to the genus; for if a man is good, an animal is also good.
Πρὸς δὲ τὸ ἀνασκευάζειν ὁ μὲν πρότερος ἀληθής, ὁ δὲ ὕστερος ψευδής· ὅσα γὰρ τῷ γένει οὐχ ὑπάρχει, οὐδὲ τῷ εἴδει· ὅσα δὲ τῷ εἴδει μὴ ὑπάρχει, οὐκ ἀναγκαῖον τῷ γένει μὴ ὑπάρχειν.
On the other hand, for refuting, the former topic is valid, but the latter is fallacious; for whatever does not belong to the genus does not belong to the species either, but it is not necessary that whatever does not belong to the species does not belong to the genus.
Ἐπεὶ δ᾿ ἀναγκαῖον, ὧν τὸ γένος κατηγορεῖται, καὶ τῶν εἰδῶν τι κατηγορεῖσθαι, καὶ ὅσα ἔχει τὸ γένος ἢ παρωνύμως ἀπὸ τοῦ γένους λέγεται, καὶ τῶν εἰδῶν τι ἀναγκαῖον ἔχειν ἢ παρωνύμως ἀπό τινος τῶν εἰδῶν λέγεσθαι, οἷον εἴ τινος ἐπιστήμη κατηγορεῖται, καὶ γραμματικὴ ἢ μουσικὴ ἢ τῶν ἄλλων τις ἐπιστημῶν κατηγορηθήσεται, καὶ εἴ τις ἔχει ἐπιστήμην ἢ παρωνύμως ἀπὸ τῆς ἐπιστήμης λέγεται, καὶ γραμματικὴν ἕξει ἢ μουσικὴν ἤ τινα τῶν ἄλλων ἐπιστημῶν ἢ παρωνύμως ἀπό τινος αὐτῶν ῥηθήσεται, οἷον γραμματικὸς ἢ μουσικός. Ἐὰν οὖν τι τεθῇ λεγόμενον ἀπὸ τοῦ γένους ὁπωσοῦν, οἷον τὴν ψυχὴν κινεῖσθαι, σκοπεῖν εἰ κατά τι τῶν εἰδῶν τῶν τῆς κινήσεως ἐνδέχεται τὴν ψυχὴν κινεῖσθαι, οἷον αὔξεσθαι ἢ φθείρεσθαι ἢ γίνεσθαι ἢ ὅσα ἄλλα κινήσεως εἴδη.
And since it is necessary that, of whatever things the genus is predicated, one of the species must also be predicated, and whatever things possess the genus or are spoken of paronymously from the genus, must also necessarily possess one of the species or be spoken of paronymously from one of the species (for example, if "science" is predicated of something, then "grammar" or "music" or one of the other sciences will also be predicated, and if someone possesses science or is spoken of paronymously from science, he will also possess grammar or music or one of the other sciences, or will be spoken of paronymously from one of them, as "grammarian" or "musician"); therefore, if anything is posited as spoken of from the genus in any way whatsoever (for example, that the soul moves), one should look whether it is possible for the soul to move according to any of the species of movement, such as growing, perishing, coming to be, or any of the other species of movement.
Εἰ γὰρ κατὰ μηδέν, δῆλον ὅτι οὐ κινεῖται.
For if it does not move in any of these ways, it is clear that it does not move.
Οὗτος δ᾿ ὁ τόπος κοινὸς πρὸς ἄμφω, πρός τε τὸ ἀνασκευάζειν καὶ κατασκευάζειν· εἰ γὰρ κατά τι τῶν εἰδῶν κινεῖται, δῆλον ὅτι κινεῖται, καὶ εἰ κατὰ μηδὲν τῶν εἰδῶν κινεῖται, δῆλον ὅτι οὐ κινεῖται.
This topic is common to both, namely refuting and establishing; for if it moves according to any of the species, it is clear that it moves, and if it moves according to none of the species, it is clear that it does not move.
Μὴ εὐποροῦντι δὲ ἐπιχειρήματος πρὸς τὴν θέσιν, σκοπεῖν ἐκ τῶν ὁρισμῶν ἢ τῶν ὄντων τοῦ προκειμένου πράγματος ἢ τῶν δοκούντων, καὶ μὴ ἀφ᾿ ἑνὸς ἀλλ᾿ ἀπὸ πλειόνων.
If one is at a loss for an argument against the thesis, one should look at the definitions, or the actual properties, or the accepted opinions of the subject before us, and not from one instance only but from many.
Ῥᾷον γὰρ ὁρισαμένοις ἐπιχειρεῖν ἔσται· πρὸς γὰρ τοὺς ὁρισμοὺς ῥᾷον ἡ ἐπιχείρησις.
For it will be easier to argue for those who have defined the terms; for the argument against definitions is easier.
Σκοπεῖν δὲ ἐπὶ τοῦ προκειμένου, τίνος ὄντος τὸ προκείμενόν ἐστιν, ἢ τί ἐστιν ἐξ ἀνάγκης εἰ τὸ προκείμενόν ἐστι, κατασκευάζειν μὲν βουλομένῳ, τίνος ὄντος τὸ προκείμενον ἔσται (ἐὰν γὰρ ἐκεῖνο δειχθῇ ὑπάρχον, καὶ τὸ προκείμενον δεδειγμένον ἔσται), ἀνασκευάζειν δὲ βουλομένῳ, τί ἐστιν εἰ τὸ προκείμενόν ἐστιν· ἐὰν γὰρ δείξωμεν τὸ ἀκόλουθον τῷ προκειμένῳ μὴ ὄν, ἀνῃρηκότες ἐσόμεθα τὸ προκείμενον.
One should also look, in the case of the subject before us, what it is whose existence entails the existence of the subject, or what must necessarily exist if the subject exists. If one wishes to establish, one should look at what it is whose existence will entail the existence of the subject (for if that is shown to belong, the subject will also have been shown); but if one wishes to refute, one should look at what exists if the subject exists; for if we show that the consequence of the subject does not exist, we shall have demolished the subject.
Ἔτι ἐπὶ τὸν χρόνον ἐπιβλέπειν, εἴ που διαφωνεῖ, οἷον εἰ τὸ τρεφόμενον ἔφησεν ἐξ ἀνάγκης αὔξεσθαι· τρέφεται μὲν γὰρ ἀεὶ τὰ ζῷα, αὔξεται δ᾿ οὐκ ἀεί.
Furthermore, one should look at the time, to see if there is any discrepancy anywhere; for example, if he said that what is nourished necessarily grows; for animals are always nourished, but they do not always grow.
Ὁμοίως δὲ καὶ εἰ τὸ ἐπίστασθαι ἔφησε μεμνῆσθαι· τὸ μὲν γὰρ τοῦ παρεληλυθότος χρόνου ἐστί, τὸ δὲ καὶ τοῦ παρόντος καὶ τοῦ μέλλοντος.
Similarly also if he said that to know is to remember; for the latter is of past time, whereas the former is of both the present and the future.
Ἐπίστασθαι μὲν γὰρ λεγόμεθα τὰ παρόντα καὶ τὰ μέλλοντα, οἷον ὅτι ἔσται ἔκλειψις, μνημονεύειν δ᾿ οὐκ ἐνδέχεται ἀλλ᾿ ἢ τὸ παρεληλυθός.
For we are said to know present and future things, as for instance that an eclipse will occur, but it is not possible to remember anything except the past.