§1.1.30μὲν οὖν ὁδὸς κατὰ πάντων ἡ αὐτὴ καὶ περὶ φιλοσοφίαν καὶ περὶ τέχνην ὁποιανοῦν καὶ μάθημα·
Thus, then, the method is the same for all, both in philosophy and in any art or science whatsoever.
δεῖ γὰρ τὰ ὑπάρχοντα καὶ οἷς ὑπάρχει περὶ ἑκάτερον ἀθρεῖν, καὶ τούτων ὡς πλείστων εὐπορεῖν, καὶ ταῦτα διὰ τῶν τριῶν ὅρων σκοπεῖν, ἀνασκευάζοντα μὲν ὡδί, κατασκευάζοντα δὲ ὡδί, κατὰ μὲν ἀλήθειαν ἐκ τῶν κατʼ ἀλήθειαν διαγεγραμμένων ὑπάρχειν, εἰς δὲ τοὺς διαλεκτικοὺς συλλογισμοὺς ἐκ τῶν κατὰ δόξαν προτάσεων.
For we must observe the attributes and the subjects to which they belong concerning each subject, and be provided with as many of these as possible, and examine them through the three terms, refuting in this way and establishing in that way; according to truth, from those attributes which are delineated as belonging in truth, but for dialectical syllogisms, from premises according to opinion.
αἱ δʼ ἀρχαὶ τῶν συλλογισμῶν καθόλου μὲν εἴρηνται, ὃν τρόπον τʼ ἔχουσι καὶ ὃν τρόπον δεῖ θηρεύειν αὐτάς, ὅπως μὴ βλέπωμεν εἰς ἅπαντα τὰ λεγόμενα, μηδ᾿ εἰς ταὐτὰ κατασκευάζοντες καὶ ἀνασκευάζοντες, μηδὲ κατασκευάζοντές τε κατὰ παντός ἢ τινὸς καὶ ἀνασκευάζοντες ἀπὸ πάντων ἢ τινῶν, ἀλλʼ εἰς ἀλάττω καὶ ὡρισμένα, καθʼ ἕκαστον δὲ ἐκλέγειν τῶν ὄντων, οἷον περὶ ἀγαθοῦ ἢ ἐπιστήμης.
The principles of syllogisms have been stated in general, both how they are and how we must hunt for them, so that we do not look to everything that is said, nor to the same things when establishing and refuting, nor when establishing of all or of some and refuting from all or from some, but rather look to fewer and definite things, and select for each of the things that exist, as for example concerning the good or science.
ἴδιαι δὲ καθʼ ἑκάστην αἱ πλεῖσται.
But the majority of principles are peculiar to each science.
διὸ τὰς μὲν ἀρχὰς τὰς περὶ ἕκαστον ἐμπειρίας ἐστὶ παραδοῦναι, λέγω δʼ οἶον τὴν ἀστρολογικὴν μὲν ἐμπειρίαν τῆς ἀστρολογικῆς ἐπιστήμης (ληφθέντων γὰρ ἱκανῶς τῶν φαινομένων οὕτως εὑρέθησαν αἰ ἀστρολογικαὶ ἀποδείξεις), ὁμοίως δὲ καὶ περὶ ἄλλην ὁποιανοῦν ἔχει τέχνην τε καὶ ἐπιστήμην·
Therefore, it is the task of experience to provide the principles concerning each subject; I mean, for example, that astronomical experience provides the principles of astronomical science (for once the phenomena were sufficiently grasped, the astronomical proofs were thus discovered); and the same holds also concerning any other art and science whatsoever.
ὥστʼ ἐὰν ληφθῇ τὰ ὑπάρχοντα περὶ ἕκαστον, ἡμέτερον ἤδη τὰς ἀποδείξεις ἑτοίμως ἐμφανίζειν.
So that if the attributes belonging to each subject are grasped, it is already our task to show the proofs readily.
εἰ γὰρ μηδὲν κατὰ τὴν ἱστορίαν παραλειφθείη τῶν ἀληθῶς ὑπαρχόντων τοῖς πράγμασιν, ἕξομεν περὶ ἅπόντος οὗ μὲν ἔστιν ἀπόδειξις, ταύτην εὑρεῖν καὶ ἀποδεικνύναι, οὗ δὲ μὴ πέφυκεν ἀπόδειξις, τοῦτο ποιεῖν φανερόν.
For if nothing of what truly belongs to things should be omitted in our inquiry, we shall be able, concerning everything, to find and demonstrate the proof where a proof is possible, and where a proof is not by nature possible, to make this very fact clear.
Καθόλου μὲν οὖν, ὃν δεῖ τρόπον τὰς προτάσεις ἐκλέγειν, εἴρηται σχεδόν· διʼ ἀκριβείας δὲ διεληλύθαμεν ἐν τῇ πραγματείᾳ τῇ περὶ τὴν διαλεκτικήν.
In general, then, how one must select premises has been pretty well stated; but we have gone through this with accuracy in our treatise on dialectic.