These are more numerous than the seven planets; for though each planet is set in but a single sphere, each planet's complex course results from the combined simple motions of more spheres than one. In spite of these more or less intimate relations, the spheres of heaven are separate existences, self-moved, like animals; and, like animals, possess activity, life, and soul. But the motion and life of the heavenly existences are continuous and eternal, and hence these existences--the spheres, and the planets and fixed stars set therein--are all divine; much more divine than man, though man possesses a far larger share of the divine than other animals.[328] Just as the troubled regions which lie below the sphere of the moon are contrasted with the serene heaven which incloses and limits them, so the changing forms of matter which compose our globe and its nearer surroundings are contrasted with the simple unalterable substance of the heavenly spheres. "Of necessity," says Aristotle, "there exists a simple body whose very nature it is to be borne on in circular motion."[329] Elsewhere he says that the men of old "would seem to have assumed that the body which moves forever is likewise divine by nature."[330] This is "an embodied substance different from the compounds here, more divine and prior to them all";[331] a body "of a nature the more precious the farther it is withdrawn from what is here."[332] After reasoning about this body Aristotle says:-- "If what has been laid down be accepted, it is plain from the foregoing why the first of bodies is eternal, and shows neither growth nor decay nor old age nor alteration, and is affected by nothing. The conception seems to testify to the phenomena and the phenomena to the conception.... Therefore, as the first body is something different from earth and fire and air and water, [the ancients] gave the name of ether to the region most on high, naming it from its moving always during all eternity."[333] The place in nature of "the first element," so grandly conceived, is fixed more definitely by Aristotle when he says "that the whole universe in the region of the courses on high is filled with that body."[334] Now, therefore, we have attained the object of our rapid quest; at last we have reached "the element of the stars"; for Aristotle tells us that not only heaven, but all the heavenly bodies as well, consist of the ether, saying:-- "It is most reasonable and consequent, in view of things already said, for us to make each of the stars out of that body in which it has its course, since we have declared the existence of something of which the nature is to be borne in a circle."[335]