THE WONDERS OF LIFE 



these remarkable efforts to found a primitive monism, 

 which found so finished an expression in the De rerum 

 natiira of the great poet-philosopher, Lucretius Carus 

 (98-54 B.C.), were shortly thrust out by the spread — 

 through Plato's curious dualism — of the belief in the 

 immortality of the soul and the transcendental world of 

 ideas. 



The Eleatics, Parmenides and Zeno, had foreshadowed 

 in the fifth century the division of philosophy into two 

 branches; but Plato and his pupil Aristotle (in the 

 fourth century b.c.) succeeded in gaining general accept- 

 ance for this dualism and antithesis of physics and meta- 

 physics. Physics devoted itself on the ground of experi- 

 ence to the study of the phenom.ena of things, leaving 

 their real essences (or noumena) that lay behind the 

 phenomena to metaphysics. These inner eSvSences are 

 transcendental and inaccessible to empirical research; 

 they form the metaphysical world of eternal ideas, which 

 is independent of the real world, and has its highest 

 unity in God, as the Absolute. The soul, an eternal idea 

 that dwells for a time in the passing human body, is 

 immortal. This consistent dualism of Plato's system, 

 with its sharp antithesis of this world and the next, of 

 body and soul, of world and God, is its chief character- 

 istic. It became all the more influential when Plato's 

 pupil Aristotle blended it with his empirical metaphysics, 

 based on ample scientific experience, and pointed out the 

 idea in the entelechy, or purposively acting principle, of 

 every being; and especially when Christianity (three 

 hundred years afterwards) found in this dualism a 

 welcome philosophic support of its own transcendental 

 tendency. 



In the course of the thousand vears which historians 

 call the Middle Ages, and which are usually dated from 

 the fall of the Roman Empire (476) to the discovery of 

 America (1492), the superstition of civilized races 



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