Historical Relations 97 



A clear conception of natural law has here emerged. We 

 note that the writer is entirely without opposition to the theory 

 of the existence of a separate and ultimate cause of all things, but he 

 refuses to confuse that cause with natural law. He has distin- 

 guished sharply between science on the one hand and religion on 

 the other. How long will his distinction be remembered ? The 

 sequel will show. 



Towards the end of the fifth century B.C. there were several 

 schools of thought in Greece that claimed, to offer an explanation 

 of material phenomena. One of these schools, that of Democritus, 

 was very important for its influence on later thought, Democritus 

 [c. 470-f. 400} was the founder of the atomic theory. He regarded 

 atoms and the void as the only existence. Everything, even the 

 phenomena of life and thought, was to be explained as the result of 

 the action of these atoms moving or otherwise acting in the void. 

 Atoms he held were eternal, being neither created nor destroyed, 

 though the combinations in which they occur constantly change. 

 He considered that atoms were infinite in number. Motion of 

 atoms had always existed. Democritus held that there must by 

 consequence have been an infinite number of worlds in various 

 stages of growth and decay. Everything, in his system, could be ex- 

 plained on purely mechanical grounds without introducing any idea 

 of a Providence or of an intelligent cause working toward an end. 



5. The Revolution in Greek Thought 



The earlier and simpler phase of Greek thought terminates 

 with the fifth century in a thinker of an entirely different type, 

 Socrates (470-399 B.C.). His name is associated with the advent 

 of a great intellectual revolution, perhaps the greatest that the 

 world has seen. With the general trend of Socratic thought, 

 however, we are not concerned, but only with certain special 

 tendencies to which it gave rise. 



The position assumed by Socrates was one of scepticism as to 

 the validity of all human knowledge. The direction of his thought 

 and of those of his followers was thus little determined by physical 

 philosophy, which, in those days, set forth very complete and 

 definite and yet very inadequately based doctrines, such as that of 

 Democritus, as to the general nature of the world. The Greek 

 philosophers before the time of Socrates had largely concentrated 

 on the physis of the sensible Universe and had developed a system 



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