Plato's Sophist [31-32]

But here ἐπιστήμη has the quite sharply defined sense of scientific knowledge. Aristotle introduces the analysis of ἐπιστήμη with the remark: δεῖ ἀκριβολογεῖσθαι καὶ μὴ ἀκολουθεῖν ταῖς ὁμοιότησιν (VI, 3, 1139b18f.): "The task is to regard this phenomenon (ἐπιστήμη) itself in the sharpest way and not simply to illustrate it on the basis of something else," i.e., on the basis of that which it is not or is also. The general guiding line Aristotle uses to orient his analysis of the phenomena of ἐπιστήμη, τέχνη, etc. is a double question: 1.) what is the character of the beings which the mode of ἀληθεύειν uncovers, and 2.) does the respective mode of ἀληθεύειν also disclose the ἀρχή of those beings? Thus the guiding line for the analysis of ἐπιστήμη is: 1.) the question of the beings uncovered by ἐπιστήμη, and 2.) the question of the ἀρχή. Why that double question is posed is not, at this point, immediately understandable.

a) The object of ἐπιστήμη: beings that always are (ἀίδιον). Ἐπιστήμη as ἕξις of ἀληθεύειν. The interpretation of Being on the basis of time (ἀίδιον, ἀεὶ, αἰών).

The question of the ἐπιστητόν must be taken up first. ὑπολαμβάνομεν, ὃ ἐπιστάμεθα, μὴ ἐνδέχεσθαι ἄλλως ἔχειν (b20ff.). "We say of that which we know that it cannot be otherwise," it must always be as it is. Aristotle thus begins with the way beings are understood when they are known in the most proper sense of knowledge. In that sense of knowledge, there resides ὃ ἐπιστάμεθα, "that which we know," of which we say: it is so. I am informed about it, I know already. And that implies: it is always so. Ἐπιστήμη thus relates to beings which always are. Only what always is can be known. That which can be otherwise is not known in the strict sense. For if that which can be otherwise, ἕξω τοῦ θεωρεῖν γένηται (b21f.), "comes to stand outside of knowledge," i.e., if I am not actually present to it at the moment, it may change during that interval. I, however, continue in my former view of it. If it has indeed changed, then my view has now become false. In opposition to this, knowing is characterized by the fact that even ἕξω τοῦ θεωρεῖν, outside of my present actual regard, I still always continue to know the beings that I know. For the beings which are the object of knowledge always are. And that means that if they are known, this knowledge, as ἀληθεύειν, always is. To know is hence to have uncovered; to know is to preserve the uncoveredness of what is known. It is a positionality toward the beings of the world which has at its disposal the outward look of beings. Ἐπιστήμη is a ἕξις of ἀληθεύειν (b31). In this the outward look of beings is preserved. The beings known in this way can never be concealed; and they can never become other while in hiddenness, such that then knowledge would no longer be knowledge. Therefore these beings can γενέσθαι ἕξω τοῦ θεωρεῖν, can disappear from what is presently actually perceived and still be known.