κινήσεως τι, something we encounter in connection with motion. To motion in general, κίνησις or μεταβολὴ, there belongs κινούμενον κινεῖται: a moving thing is moving, is in motion. The most general character of motion is μεταβολὴ, a turn or change or better a transition from something to something.17 The simplest form of motion, and the one most frequently used by Aristotle in his analysis of motion, of transition, is φορά, transition from one place (τόπος) to another, shift, change of place. This is the motion we are familiar with also as physical motion. In such motion the κινούμενον is the φερόμενον, being carried forward from one place to the other. Another form of motion is, for example, ἀλλοίωσις, becoming different in the sense that one quality changes to another, one particular color to another, and here too there is an advance ἐκ τινος εἰς τι, away from something toward something. But this "away from something toward something" does not have the sense of transition from one place to another. Change of color can occur at the same place. It already becomes clear from this that this remarkable structure of the ἐκ τινος εἰς τι, "away from something toward something," belongs to motion. The comparison with ἀλλοίωσις shows that this "away from something toward something" need not necessarily be taken spatially. We shall call this structure of motion its dimension, taking the concept of dimension in a completely formal sense, in which spatial character is not essential. Dimension expresses a general notion of stretch; extension in the sense of spatial dimension then represents a particular modification of stretch. In the case of the determination of ἐκ τινος εἰς τι we should rid ourselves completely of the spatial idea, something that Aristotle did, too. A completely formal sense of stretching out is intended in "from something to something." It is important to see this, because it was with reference to this determination that the Aristotelian concept of time was misunderstood in the modern period, especially by Bergson; from the outset he took this dimensional character of time in the sense of spatial extension in its reference to motion.
The determination of the συνεχές, being-held-together-within-itself, continuum, continuity, also belongs to stretch. Aristotle calls the dimensional character μέγεθος. This determination μέγεθος, extension or magnitude, also does not have a primarily spatial character, but that of stretch. There is no break implied in the concept and essential nature of "from something to something;" it is, instead, a stretching out that is closed within itself. When we experience motion in a moving thing, we necessarily
17. Cf. Physica, 3.1-3 and 5. [In book 5, see particularly 224a 21—224b 9 and 224b 35ff. The latter begins: "And since every change is from something to something-as the word itself (μεταβολὴ) indicates, implying something 'after' (μετα) something else, that is to say something earlier and something later-that which changes must change in one of four ways." Trans. Hardie and Gaye.]