μετρεῖν, to take measure, to determine, is the mode in which Dasein makes something intelligible. Μέτρον, and ἀριθμός belong in the same realm as λόγος, namely the realm of ἀληθεύειν.5 The θαυμαστόν is that which is awry. "Here something is awry." The astonishing, the wondrous, is constituted in relation to an onlooking insofar as the understanding at one's disposal does not suffice for this encountered state of affairs. The understanding is shocked by what shows itself. Wondering originally begins simply with what is plain and obvious, τὰ πρόχειρα (982b13), "what lies right at hand." Subsequently, the consideration gradually widens, so that one is also wondering about greater things, which were at first taken as self-evident: about the πάθη of the moon, what happens to the moon, about the remarkable fact that the moon changes, and similarly about what happens to the sun, and finally about the genesis of beings as a whole, whether they are as they show themselves.
2.) Aristotle now interprets wonder as an original phenomenon of Dasein and thereby shows that in wonder there is operative a tendency toward θεωρεῖν Dasein from the very outset possesses a tendency toward sheer onlooking and understanding. In this connection, Aristotle employs an expression familiar to the philosophy of his time: ἀπορεῖν. Ἄπορος means "without passage," one cannot get through. Πόρος originally referred to the passage through a stream at a shallow place. Ἀπορία is a consideration of the world that does not get through; it does not find a way. The immediately familiar αἰτία, the available means of explication, do not suffice. The mode of running through by explication is blocked. Things are distorted, in their genuine outward look as well as in their immediate appearance. Notice how ἀπορία corresponds perfectly to the meaning of ἀληθεύειν and to the conception of Dasein we are already acquainted with: the beings of the world are at first occluded and Dasein does not get through. In this sense of ἀληθεύειν, whose first form of execution is λόγος, there corresponds:
5. Cf. p. 1 2f.