SCIENTIFIC USE OF THE IMAGINATION 139 



able epoch say when the physical conditions became such 

 as to permit of the development of life? Let us put the 

 question with the reverence due to a faith and culture in 

 which we all were cradled, and which are the undeniable 

 historic antecedents of our present enlightenment. I say, 

 let us put the question reverently, but let us also put it 

 clearly and definitely. There are the strongest grounds 

 for believing that during a certain period of its history the 

 earth was not, nor was it fit to be, the theatre of life. 

 Whether this was ever a nebulous period, or merely a 

 molten period, does not signify much; and if we revert 

 to the nebulous condition, it is because the probabilities 

 are really on its side. Our question is this: Did creative 

 energy pause until the nebulous matter had condensed, 

 until the earth had been detached, until the solar fire had 

 so far withdrawn from the earth's vicinity as to permit 

 a crust to gather round the planet? Did it wait until the 

 air was isolated; until the seas were formed; until evap- 

 oration, condensation, and the descent of rain had begun; 

 until the eroding forces of the atmosphere had weathered 

 and decomposed the molten rocks so as to form soils; 

 until the sun's rays had become so tempered by distance, 

 and by waste, as to be chemically fit for the decomposi- 

 tions necessary to vegetable life? Having waited through 

 these eons until the proper conditions had set in, did it 

 send the fiat forth, "Let there be Life!"? These ques- 

 tions define a hypothesis not without its difficulties, but 

 the dignity of which in relation to the world's knowledge 

 was demonstrated by the nobleness of the men whom it 

 sustained. 



Modern scientific thought is called upon to decide 

 between this hypothesis and another; and public thought 



