The analogy may be carried even farther. If Plato regarded the things of sense as not merely a veil, but an imperfect imitation of the only true realities; so also did Aristotle represent the sublunary elements as copying the disposition and activities of the ethereal spheres. They too have their concentric arrangements—first fire, then air, then water, and lastly earth in the centre; while their perpetual transformation into one another presents an image in time of the spatial rotation which those sublime beings perform. And although we think that Sir A. Grant is quite mistaken in identifying Aristotle’s Supreme Mind with the Idea of Good, there can be no doubt of its having been suggested by that Idea. It is, in fact, the translation of Plato’s abstraction into concrete reality, and the completion of a process which Plato had himself begun. From another point of view we may say that both master and disciple were working, each in his own way, at the solution of a problem which entirely dominates Greek philosophy from Empedocles on—the reconciliation of Parmenides and Heracleitus, Being and Becoming, the eternal and the changeful, the one and the many. Aristotle adopts the superficial, external method of placing the two principles side by side in space; and for a long time the world accepted his solution for the same reason that had commended it to his own acceptance, its apparent agreement with popular tradition and with the facts of experience. It must be confessed, however, that here also he was following the lines laid down by Plato. The _Timaeus_ and the _Laws_ are marked by a similar tendency to substitute astronomy for dialectics, to study the celestial movements with religious veneration, to rebuild on a scientific basis that ancient star-worship which, even among the Greeks, enjoyed a much higher authority and prestige than the humanised mythology of the poets. But for Christianity this star-worship would probably have become the official faith of the Roman world. As it is, Dante’s great poem presents us with a singular compromise between the two creeds. The crystalline spheres are retained, only they have become the abode of glorified spirits instead of being the embodiment of eternal gods. We often hear it said that the Copernican system was rejected as offensive to human pride, because it removed the earth from the centre of the universe. This is a profound mistake. Its offence was to degrade the heavenly bodies by assimilating them to the earth.[254] Among several planets, all revolving round the sun, there could not be any marked qualitative difference. In the theological sense there was no longer any heaven; and with the disappearance of the solid sidereal sphere there was no longer any necessity for a Prime Mover.