1. The fact that previously the decisive categories were not yet familiar. For us, the concepts δύναμις, ἐνέργεια, ἐντελέχεια are so worn out that one is not at all capable of seeing what was at stake in the fundamental meaning of these concepts. We must work to insert ourselves around into the time when the concepts δύναμις and ἐνέργεια were cultivated.
2. Here, it is really not a question of defining movement in some sense, but of making beings as moved visible in their being-there and holding fast to them. If one says that the principal considerations that modern physics has employed are much more determinate, it must be said that the definition of movement (movement as uniform speed): c = s/t, itself already presupposes everything that Aristotle said about movement. No later consideration comes into this discussion at all. What was set up in modern physics (Galileo, Copernicus) in a genuinely fundamental way is the question of the system-of-relations of movement, not the question of movement itself, but rather movement itself with a view to the system-of-relations from which it is to be measureable. More precisely, it is the question of whether there is an absolute system-of-relations or only a relative one. Here movement is already presupposed, not discussed, and is taken in an entirely determinate sense: change of place, change of position—φορά. However, it is here a question of a κοινόν of beings, for Aristotle, insofar as it is φύσει, and lives such that movement includes all that falls within the region of change: taking κίνησις as μεταβολή. Propulsion across space is but an entirely determinate change: constant change of place. This concept of movement is fixed already in the basic formula of movement: s = c · t, c = s/t. Speed itself is not discussed. Aristotle already knew the phenomenon of speed, when he discussed time and the faster and the slower of movement, and he shows that, indeed, a movement can be faster and slower, but not time. Precisely, the fundamental determinations that are not discussed proceeded from Aristotle. They make it possible to see ahead in the direction of a genuine consideration of being: change as a mode of being of being-there itself.
“The consideration of the beings of specific regions is subsequent to that of the κοινά.”30 It is not thereby said that characters such as κίνησις, τόπος, χρόνος, the ἀρχαί, were also already present at first. Precisely these ἀρχαί, that from which a being is seen, are concealed, dissimulated. The δεῖ μὴ λανθάνειν τί ἐστι κίνησις,31 only has sense because it is, in fact, concealed. This fact of the matter is grounded in that the consideration of the world and of beings is maintained in a certain universality. In the natural pre-scientific consideration, there is already a καθόλου, by whose guidance I orient myself toward the world. In Book 1, Chapter 1, Aristotle refers to the fact that children address all men as father and all women as mother.32 What is immediately familiar to the child is father and mother. Because they are so, they are taken by the child in an average
30. Phys. Γ 1, 200 b 24 sq.
31. Phys. Γ 1, 200 b 13 sq.
32. Phys. Α 1, 184 b 3 sqq.