Aristotle on Metaphysics(2004) - Bibotu.com

274 THE ULTIMATE CAUSE OF CHANGE: GODheaven. But this may not follow. The everlasting nature of uniform change,even if it implies uniformly changing things, does not require that thesethings, taken individually, should be everlasting. For presumably a series ofthings in time, each with a limited life-span, could secure everlastinguniform change, if they forever changed seamlessly into each other.But <strong>Aristotle</strong> argues that the uniform change that provides a measure fortime must be circular motion; for otherwise it would not be perfectlyuniform and could not provide a measure for time. The obvious objectionis motion in a straight line, for why should such motion be any lessuniform than circular motion? His view that circular rather than rectilinearmotion is uniform is based on the view that the universe is spatially finite.For in a spatially finite universe, bodily motion in a straight line in space islimited by the limits of the universe. Hence a body moving in a straightline is evidently not moving in a perfectly uniform way, since it changesdirection and hence comes to a momentary halt at the limits of theuniverse: first one way, then back again, etc. On the other hand, a finiteuniverse allows for uniform motion, if this motion is circular, and if theuniverse is itself circular, and the circular motion is concentric with it.This again shows how <strong>Aristotle</strong>’s abstract argument relies fundamentallyon features of the concrete, actual universe as he conceives it.Finally, a particular feature of the argument is especially important.From the everlastingness and uniformity of time <strong>Aristotle</strong> derives not onlythe everlastingness of the universe, but its everlasting uniformity. This isimportant, for an everlasting universe may, on the contrary, be such thatfor its first period (but an infinite period, if the universe is infinitebackwards in time) it lacks uniformity and is in a state of chaos, and onlyat a particular point in time does it acquire uniformity and order. Thisuniverse is like <strong>Aristotle</strong>’s in being everlasting, but unlike his in that itsuniformity is not everlasting. But he argues not only that the universe iseverlasting, but also that the uniform, ordered universe, the cosmos, iseverlasting. He drives home this point when he criticizes those thinkers,whether naturalists or those who invoke gods, who claim that order wasborn out of chaos, a state in which ‘all things were thrown together’, likeday out of night. As he says: ‘it is not true that for an infinite time therewas chaos and night, rather the same things existed forever, either incircular motion or in some other state’ (XII. 6, 1072 a 7–9; also 1071 b 26–28).This is the conclusion of a complex argument (XII. 6, 1071 b 12f.), whichruns along the following lines. Suppose that for its first period the universelacked uniformity. Then there must be something that explains why, at aparticular point in time, the universe changes from a disorderly to an