Free The Sleepwalkers by Arthur Koestler Page B

purposeful and goal-directed – even the motions of inanimate bodies: a stone will fall to the earth, as a horse will canter to its stable, because that is its "natural place" in the universal hierarchy. We shall have occasion, later on, to marvel at the disastrous effects of this Aristotelian brainwave on the course of European science; at the moment, I merely wish to point out that Aristotle's attitude to Change, though he rejects evolution and progress, is not quite as defeatist as Plato's. 14 Yet Neoplatonism, in its dominant trend, ignores Aristotle's dissent on this essential point, and manages to make the worst of both worlds. It adopts the Aristotelian scheme of the universe, but makes the sub-lunary sphere a Platonic vale of shadows; it follows the Platonic doctrine of the natural world as a dim copy of ideal Forms – which Aristotle rejected – yet follows Aristotle in placing the Prime Mover outside the confines of the world. It follows both in their anxious effort to build a walled-in universe, protected against the Barbarian incursions of Change; a nest of spheres-within-spheres, eternally revolving in themselves, yet remaining in the same place; thus hiding its one shameful secret, that centre of infection, safely isolated in the sub-lunary quarantine.
    In the immortal parable of the Cave, where men stand in their chains backs to the light, perceiving only the play of shadows on the wall, unaware that these are but shadows, unaware of the luminous reality outside the Cave – in this allegory of the human condition, Plato hit an archetypal chord as pregnant with echoes as Pythagoras' Harmony of the Spheres. But when we think of Neoplatonism and Scholasticism as concrete philosophies and precepts of life, we may be tempted to reverse the game, and to paint a picture of the founders of the Academy and the Lyceum as two frightened men standing in the self-same Cave, facing the wall, chained to their places in a catastrophic age, turning their backs on the flame of Greece's heroic era, and throwing grotesque shadows which are to haunt mankind for a thousand years and more.

    VTHE DIVORCE FROM REALITY

    1.
Spheres Within Spheres (Eudoxus)
    IN a closed universe, where the fixed stars offered as yet no specific problems, the challenge to understanding came from the planets; the chief task of cosmology was to devise a system which explained how sun, moon and the remaining five planets moved.
    This task was further narrowed down when Plato's dictum that all heavenly bodies move in perfect circles, became the first Academic dogma in the first institution that bore that solemn name. The task of Academic astronomy was now to prove that the apparently irregular meanderings of the planets were the result of some combination of several simple, circular, uniform motions.
    The first serious attempt was made by Plato's pupil Eudoxus, and improved by the latter's pupil, Calippus. It is an ingenious attempt – Eudoxus was a brilliant mathematician, to whom most of Euclid's fifth book is due. In the earlier geocentric models of the universe, each planet, we remember, was attached to a transparent sphere of its own, and all spheres were turning round the earth. But, since this did not account for the irregularities of their motions, such as standing occasionally still and going backward for a while: their "stations" and "retrogressions", Eudoxus assigned to each planet not one, but several spheres. The planet was attached to a point on the equator of a sphere, which rotates round its axis, A. The two ends of this axis are let into the inner surface of a concentric larger sphere S 2 , which rotates round a different axis, A 2 and carries A around with it. The axis of S 2 is attached to the next larger sphere S 3 , which rotates again round a different axis A 3 : and so on. The planet will thus participate in all the independent rotations of the various spheres which form its "nest"; and by letting each sphere rotate at the