Plato's Sophist [36,37,38]

In this way, it always already makes use of an ἐπαγωγή which it itself does not, properly speaking, carry out. For at the very outset it is sufficiently familiar with the "that out of which." Ἐπιστήμη, hence, as ἀπόδειξις, always presupposes something, and what it presupposes is precisely the ἀρχή. This latter is not properly disclosed by the ἐπιστήμη itself.

Therefore, since ἐπιστήμη cannot itself demonstrate that which it presupposes, the ἀληθεύειν of ἐπιστήμη is deficient. It is ill-provided to exhibit beings as such, inasmuch as it does not disclose the ἀρχή. Therefore ἐπιστήμη is not the βελτίστη ἕξις of ἀληθεύειν. It is rather σοφία that is the highest possibility of the ἐπιστημονικόν.

Nevertheless genuine knowledge is always more than a mere cognizance of results. He who has at his disposal merely the συμπεράσματα (cf. b34), i.e., what emerges at the end, and then speaks further, does not possess knowledge. He has ἐπιστήμη only κατὰ συμβεβηκός (Post. An. I, 2, 71b10), from the outside; he has it only accidentally, and he is and remains unknowing in any proper sense. Knowledge itself entails having the συλλογισμός at one's disposal, being able to run through the foundational nexus upon which a conclusion depends. Thus ἐπιστήμη is an ἀληθεύειν which does not make beings, and specifically the everlasting beings, genuinely available. For ἐπιστήμη, these beings are precisely still hidden in the ἀρχαί

At the outset we emphasized that Aristotle pursues his analysis of the phenomena of ἀληθεύειν in two directions: at first he asks about the beings which are to be disclosed; then he raises the question of whether the respective ἀληθεύειν also discloses the ἀρχή of those beings. The second question is always a criterion for determining whether the ἀληθεύειν is a genuine one or not. This double questioning is at work in the case of τέχνη as well. Τέχνη is an ἀληθεύειν within the λογιστικόν. And just as, in the case of the ἐπιστημονικόν, ἐπιστήμη, though the most immediate ἀληθεύειν, was not the genuine ἀληθεύειν, so also in the case of the λογιστικόν, τέχνη, though the most familiar ἀληθεύειν, proves to be an ungenuine form of it. Insofar as τέχνη belongs to the λογιστικόν, it is a disclosing of those beings ὃ ἐνδέχεται ἄλλως ἔχειν (cf. Nic. Eth. VI, 4, 1140a1), "which can also be otherwise." But to such beings φρόνησις also relates. Therefore within the ἐνδεχόμενον there is a distinction; it can be a ποιητόν or a πρακτόν, i.e., the theme of a ποίησις, a producing, or of a πρᾶξις, an acting.

c) Πρᾶξις and ποίησις as the first ways of carrying out
ἀληθεύειν. Ἐπιστήμη as the autonomous "πρᾶξις" of

Up to now we have not yet been able to see in ἐπιστήμη a phenomenon which is included more or less explicitly in all modes of ἀληθεύειν.

GA 19