XIL] "THE ORIGIN OF SPECIES." 313 



itself; let us inquire whether anything has happened 

 since 1859, which will explain, on rational grounds, 

 why so many are worshipping that which they burned, 

 and burning that which they worshipped. It is only 

 in this way that we shall acquire the means of judg- 

 ing whether the movement we have witnessed is a 

 mere eddy of fashion, or truly one with the irrevers- 

 ible current of intellectual progress, and, like it, safe 

 from retrogressive reaction. 



Every belief is the product of two factors : the 

 first is the state of the mind to which the evidence in 

 favour of that belief is presented ; and the second is 

 the logical cogency of the evidence itself. In both 

 these respects, the history of biological science during 

 the last twenty years appears to me to afford an 

 ample explanation of the change which has taken 

 place ; and a brief consideration of the salient events 

 of that history will enable us to understand why, if 

 the " Origin of Species " appeared now, it would meet 

 with a very different reception from that which 

 greeted it in 1859. 



One-and-twenty years ago, in spite of the work 

 commenced by Hutton and continued with rare skill 

 and patience by Lyell, the dominant view of the past 

 history of the earth was catastrophic. Great and 

 sudden physical revolutions, wholesale creations and 

 extinctions of living beings, were the ordinary machi- 

 nery of the geological epic brought into fashion by 

 the misapplied genius of Cuvier. It was gravely 

 maintained and taught that the end of every geo- 

 logical epoch was signalised by a cataclysm, by which 



