28 SCIENCE AND IMMORTALITY 



Thus we see that Lucretius explained the first 

 forms of matter much as Chfford explained the first 

 living molecule, saying they were " produced by 

 a coincidence and preserved by natural selection." 



But Lucretius realises that something more is 

 still wanted — not merely free-will of sorts to cause 

 collision, and not merely natural selection of the 

 combinations so produced, but also preferential 

 affinities between atoms, which he denotes by the 

 term concilium. 



Finally, Lucretius adumbrated the law of con- 

 servation of energy. " Nor was the store of 

 matter ever more dense or ever separated by larger 

 intervals than now ; for nothing is either added 

 to it or lost from it. Wherefore, in whatsoever 

 motion the bodies of the first-beginnings now 

 move, in the same way they moved in time gone 

 by, and in like manner they will always be borne 

 along hereafter. . . . No force can alter the sum 

 of things ; for there is no Beyond into which either 

 any kind of matter can escape out of the universe, 

 or out of which a new force can arise and burst in 

 and change all the nature of things and disturb its 

 motions." 



Such, then, in brief, was the Atomic Theory of 

 Epicurus and Lucretius. Such, then, were the 

 first theories of matter. They were crude, wild, 

 and empiric, yet not without both scientific and 



