Of the further details into which Aristotle enters, I shall only give the following. As against atoms and their motion, he remarks (Phys. VI. 10) that the indivisible has no motion and mutation, which is the direct opposite of the proposition of Zeno that only simple indivisible Being and no motion exists. For as Zeno argues from the indivisibility of atoms against motion, Aristotle argues from motion against atoms. “Everything which moves or changes is in the first division of this time partly here and partly there. The atom, as simple indivisible Being, can, however, not have any part of it in both points in space, because it then would be divisible. The indivisible could thus only move if time consisted of the Now; this is, however, impossible, as we proved before.” Because atoms thus neither have change in themselves, nor can this come to them from without through impulse, &c., they are really without truth. The determination of the pure ideality of change is important. Aristotle says of this (Phys. VII. 3), “That which is changed is alone the sensuous and perceptible (αἰσθητόν); and forms and figures, as also capacities, are not changed, they arise and disappear in a thing only, without being themselves changed.” In other words: the content of change is unchangeable; change as such belongs to mere form. “Virtues or vices belong, for example, to habits acquired. Virtue is the perfection (τελείωσις) in which something has reached the end of its nature. Vice, however, is the corruption and non-attainment of this. They are not changes, for they only arise and pass away while another alters.” Or the difference becomes a difference of Being and non-being, _i.e._ a merely sensuous difference. From these conceptions Aristotle now comes nearer to the first real or physical motion (Phys. VIII. 6, 8, 9; De C\nlo, I. 4): The first principle of motion is itself unmoved. An endless motion in a straight line is an empty creation of thought; for motion is necessarily an effort after something. The absolute motion is the circular, because it is without opposition. For because movement has to be considered in regard to the starting-place and the end in view, in the straight movement the directions from A to B and from B to A are opposed, but in motion in a circle they are the same. The idea that heavenly bodies would of themselves have moved in a straight line, but that they accidentally came into the sphere of solar attraction, is an empty reflection which is far from occurring to Aristotle.