From this point Aristotle comes (De C\nlo, IV. I-5) to a kind of deduction of the elements, which is noteworthy. He shows that there must be four of them, in the following way—because he starts from the fundamental conceptions of weight and of lightness, or what we should call attraction and centrifugal force. The corporeal, he says, in its motion is neither light nor heavy, and, indeed, it is not only relative but also absolute. The relatively light and heavy is what, while equal in volume, descends more slowly or quickly. Absolute lightness goes up to the extremity of the heavens, absolute weight down into the middle. These extremes are fire and earth. Between these there are mediums, other than they, which relate to one another like them; and these are air and water, the one of which has weight, and the other lightness, but only relatively. For water is suspended under everything except earth, and air over everything except fire. “Hence,” Aristotle concludes, “there now are these four matters, but they are four in such a way that they have one in common; more particularly, because they arise out of one another, but exist as different.” Yet it is not the ether that Aristotle designates as this common matter. We must in this regard remark that however little these first determinations may be exhaustive, Aristotle is still far further on than the moderns, since he had not the conception of elements which prevails at the present time, according to which the element is made to subsist as simple. But any such simple determination of Being is an abstraction and has no reality, because such existence would be capable of no motion and change; the element must itself have reality, and it thus is, as the union of opposites, resolvable. Aristotle hence makes the elements, as we have already seen with those who went before (Vol. I., pp. 181, 182; 290-293; 336), arise out of one another and pass into one another; and this is entirely opposed to our Physics, which understands by elements an indelible, self-identical simplicity only. Hence men are wonderfully discerning in reproaching us for calling water, air, &c., elements! Nor yet in the expression “neutrality” have the modern physicists been able to grasp a universality conceived of as a unity, such as Aristotle ascribes to the elements; in fact, however, the acid which unites with a base is no longer, as is asserted, present within it as such. But however removed Aristotle may be from understanding simplicity as an abstraction, just as little does he recognize here the arid conception of consisting of parts. Quite the contrary. He strives enough against this, as, for instance, in relation to Anaxagoras (De C\nl. III. 4).