.II . THE PROGRESS OF SCIENCE 127 



earth from its earliest to its present state, it 

 forms part of the general doctrine of evolution. 

 An interesting contrast between the geology of 

 the present day and that of half a century ago, is 

 presented by the complete emancipation of the 

 modern geologist from the controlling and per- 

 verting influence of theology, all-powerful at the 

 earlier date. As the geologist of my young days 

 wrote, he had one eye upon fact, and the other on 

 .Genesis ; at present, he wisely keeps both eyes on 

 fact, and ignores the pentateuchal mythology 

 altogether. The publication of the " Principles of 

 Geology " brought upon its illustrious author a 

 period of social ostracism; the instruction given 

 to our children is based upon those principles. 

 Whewell had the courage to attack Lyell's funda- 

 mental assumption (which surely is a dictate of 

 common sense) that we ought to exhaust known 

 causes before seeking for the explanation of geo- 

 logical phenomena in causes of which we have no 

 experience. But geology has advanced to its 

 present state by working from Lyell's l axiom ; 

 and, to this day, the record of the stratified rocks 

 affords no proof that the intensity or the rapidity 

 of action of the causes of change has ever varied 

 between wider limits than those between which 



1 Perhaps I ought rather to say Buffon's axiom. For that 

 great naturalist and writer embodied the principles of sound 

 geology in a pithy phrase of the Thtoric de la, Terre : " Pour 

 juger de ce qui est arrive, et memo de ce qui arrivera, nous 

 n'avous qu'a examiner ce qui arrive." 



