100 Epitome of the Progress of Natural Science. 



and acknowledged nothing but atoms, and a vacuum to move in. 

 Figure and motion, and the arrangement of his atoms, produced, 

 according to this philosopher, all the properties of bodies, colour, 

 consistence, heat, cold, &c. 



Democritus of Abdera,* a disciple of Leucippus, was a com- 

 parative anatomist, for he endeavoured to deduce the habits of 

 animals from the differences he had observed in their organiza- 

 tion. On the conquest of Asia-Minor by Xerxes,f the principal 

 philosophers of these various sects, who had brought forward, in 

 turns, all the metaphysical views known to ourselves, established 

 themselves at Athens, in central Greece ; when Anaxagoras, the 

 father of the Socratic school, finally taught the reasonable doc- 

 trine, that mind and matter were separate principles, and cul- 

 tivated more extensively the deduction of the rationale of things 

 from practical observation. 



Socrates was the true reformer of Grecian philosophy : he 

 sought to reduce physics to common sense and observation, and 

 metaphysics to logical reasoning. He endeavoured to overthrow 

 the miserable sophistry that had sprung out of the Eleatic school, 

 and it is to him we owe the elaboration of the thought of Anax- 

 agoras, that an intelligent principle has arranged the world. If 

 the universe, he reasoned, be the work of an intelligent mind, it 

 must be so disposed as to concur to an intelligent end. From this 

 great thought results the important natural truth which geology 

 establishes, that organized beings are connected by necessary re- 

 lations, and that a perfect organized body must contain in itself, all 

 the conditions proper to the performance of the part assigned to it. 

 Socrates declared his regret, at not being sufficiently conversant 

 with natural history, to demonstrate this truth as extensively as 

 it might be done. This great and virtuous man was a cotempo- 

 rary of Pericles, Alcibiades, Xenophon, and Hippocrates, and died 

 a victim to the intolerance of his enemies, and the splendour of 

 his character, B. C. 399. 



Plato, the youngest of the disciples of Socrates, after the death 

 of his master, went to Egypt, and studied under the priests. He 

 afterwards received instruction in the Pythagorean schools, es- 

 tablished in Lower Italy : having before his travels in Egypt, ex- 

 ercised himself in dialectics, with Euclid — who had been himself 

 a pupil of Socrates — he now, fraught with knowledge, returned 

 ♦ Flourished B. C. 400. + B. C. 480. 



