The first and most necessary part of philosophy is practical principles; for example: don’t lie. The second part is proofs, as of why we shouldn’t lie. The third, which validates the other two, is logical theory, answering such questions as, how do we know that this is a valid proof? What is a logical demonstration? What does it mean when we say something follows something else? What is contradiction? What is truth? What is falsehood? The third part of philosophy is necessary for the sake of the second, and the second for the sake of the first. But the most necessary part, where we should linger, is the first. Of course we do exactly the opposite. We spend our time on the third part, becoming enthusiasts in that, and utterly neglect the first. So we lie through our teeth, but we certainly can demonstrate why one shouldn’t lie.

The first and most necessary division in philosophy is that which has to do with the application of the principles, as, for example, Do not lie. The second deals with the demonstrations, as, for example. How comes it that we ought not to lie? The third confirms and discriminates between these processes, as, for example, How does it come that this is a proof? For what is a proof, what is logical consequence, what contradiction, what truth, what falsehood? Therefore, the third division is necessary because of the second, and the second because of the first; while the most necessary of all, and the one in which we ought to rest, is the first. But we do the opposite; for we spend our time in the third division, and all our zeal is devoted to it, while we utterly neglect the first. Wherefore, we lie, indeed, but are ready with the arguments which prove that one ought not to lie.

The first and most necessary department of philosophy deals with the application of principles; for instance, ‘not to lie’. The second deals with demonstrations; for instance, ‘How comes it that one ought not to lie?’ The third is concerned with establishing and analysing these processes; for instance, ‘How comes it that this is a demonstration? What is demonstration, what is consequence, what is contradiction, what is true, what is false?’ It follows then that the third department is necessary because of the second, and the second because of the first. The first is the most necessary part, and that in which we must rest. But we reverse the order: we occupy ourselves with the third, and make that our whole concern, and the first we completely neglect. Wherefore we lie, but are ready enough with the demonstration that lying is wrong.

The first and most necessary place (part) in philosophy is the use of theorems (precepts), for instance, that we must not lie: the second part is that of demonstrations, for instance, How is it proved that we ought not to lie: the third is that which is confirmatory of these two and explanatory, for example, How is this a demonstration?

For what is demonstration, what is consequence, what is contradiction, what is truth, what is falsehood? The third part (topic) is necessary on account of the second, and the second on account of the first; but the most necessary and that on which we ought to rest is the first. But we do the contrary. For we spend our time on the third topic, and all our earnestness is about it: but we entirely neglect the first. Therefore we lie; but the demonstration that we ought not to lie we have ready to hand.

The first and most necessary point in philosophy is the practice of the maxims, for example, not to lie. The second is the proof of the maxims, as, Whence it comes that one ought not to lie. The third is that which gives confirmation and coherence to these, as, Whence it comes that this is a proof, for what is proof? what is consequence? what is contradiction? what is truth? what is falsehood?

Thus the third point is necessary through the second, and the second through the first. But the most necessary of all, and that where we must rest, is the first. But we do the contrary. For we delay in the third point, and spend all our zeal upon that, while of the first we are utterly careless: we are liars, while we are ready in explaining how it is shown that it is wrong to lie.

The first and most necessary topic in philosophy is the practical application of principles, as, We ought not to lie; the second is that of demonstrations, as, Why it is that we ought not to lie; the third, that which gives strength and logical connection to the other two, as, Why this is a demonstration. For what is demonstration? What is a consequence; what a contradiction; what truth; what falsehood? The third point is then necessary on account of the second; and the second on account of the first. But the most necessary, and that whereon we ought to rest, is the first. But we do just the contrary. For we spend all our time on the third point, and employ all our diligence about that, and entirely neglect the first. Therefore, at the same time that we lie, we are very ready to show how it is demonstrated that lying is wrong.

The first and most necessary topic in philosophy is that of the use of moral theorems, such as, “We ought not to lie;” the second is that of demonstrations, such as, “What is the origin of our obligation not to lie;” the third gives strength and articulation to the other two, such as, “What is the origin of this is a demonstration.” For what is demonstration? What is consequence? What contradiction? What truth? What falsehood? The third topic, then, is necessary on the account of the second, and the second on the account of the first. But the most necessary, and that whereon we ought to rest, is the first. But we act just on the contrary. For we spend all our time on the third topic, and employ all our diligence about that, and entirely neglect the first. Therefore, at the same time that we lie, we are immediately prepared to show how it is demonstrated that lying is not right.

Ὁ πρῶτος καὶ ἀναγκαιότατος τόπος ἐστὶν ἐν φιλοσοφίᾳ ὁ τῆς χρήσεως τῶν θεωρημάτων, οἷον τὸ μὴ ψεύδεσθαι: ὁ δεύτερος ὁ τῶν ἀποδείξεων, οἷον πόθεν ὅτι οὐ δεῖ ψεύδεσθαι: τρίτος ὁ αὐτῶν τούτων βεβαιωτικὸς καὶ διαρθρωτικός, οἷον πόθεν ὅτι τοῦτο ἀπόδειξις; τί γάρ ἐστιν ἀπόδειξις, τί ἀκολουθία, τί μάχη, τί ἀληθές, τί ψεῦδος;

οὐκοῦν ὁ μὲν τρίτος τόπος ἀναγκαῖος διὰ τὸν δεύτερον, ὁ δὲ δεύτερος διὰ τὸν πρῶτον: ὁ δὲ ἀναγκαιότατος καὶ ὅπου ἀναπαύεσθαι δεῖ, ὁ πρῶτος. ἡμεῖς δὲ ἔμπαλιν ποιοῦμεν: ἐν γὰρ τῷ τρίτῳ τόπῳ διατρίβομεν καὶ περὶ ἐκεῖνόν ἐστιν ἡμῖν ἡ πᾶσα σπουδή: τοῦ δὲ πρώτου παντελῶς ἀμελοῦμεν. τοιγαροῦν ψευδόμεθα μέν, πῶς δὲ ἀποδείκνυται ὅτι οὐ δεῖ ψεύδεσθαι, πρόχειρον ἔχομεν.