THE BIRTH-TIME OF THE WORLD 1 



By J. JOLY, Sc.D., F.R.S. 



Professor of Geology and Mineralogy, Trinity College, Dublin 



Long ago Lucretius wrote : " For lack of power to solve the 

 question troubles the mind with doubts, whether there was 

 ever a birth-time of the world and whether likewise there is 

 to be any end." "And if" (he says in answer) "there was no 

 birth-time of earth and heaven and they have been from ever- 

 lasting, why before the Theban war and the destruction of 

 Troy have not other poets as well sung other themes ? 

 Whither have so many deeds of men so often passed away, 

 why live they nowhere embodied in lasting records of fame ? 

 The truth methinks is that the sum has but a recent date, 

 and the nature of the world is new and has but lately had 

 its commencement." 2 



Thus spake Lucretius nearly 2,000 years ago. Since then 

 we have attained another standpoint and found very different 

 limitations. To Lucretius the world commenced with man, and 

 the answer he would give to his questions was in accord with 

 his philosophy : he would date the birth-time of the world from 

 the time when poets first sung upon the earth. Modern 

 Science has swept utterly away this beautiful imagining, along 

 with the theory that the earth dated its beginning with the 

 advent of man. We can, indeed, find no beginning of the 

 world. We trace back events and come to barriers which 

 close our vista— barriers which, for all we know, may for ever 

 close it. They stand like the gates of ivory and of horn ; 

 portals from which only dreams proceed ; and Science cannot 

 as yet say of this or that dream if it proceeds from the gate of 

 horn or from that of ivory. 



In short, of the earth's origin we have no certain knowledge ; 



1 A lecture delivered before the Royal Dublin Society, February 6, 1914. 



2 H. A. J. Munro, De Rerum Natura (Cambridge, 1886). 



37 



