230 THE COMING OF AGE OF V n 



From this point of view, it appears to me that 

 it would be but a poor way of celebrating the 

 Coming of Age of the " Origin of Species," were I 

 merely to dwell upon the facts, undoubted and re- 

 markable as they are, of its far-reaching influence 

 and of the great following of ardent disciples who 

 are occupied in spreading and developing its 

 doctrines. Mere insanities and inanities have 

 before now swollen to portentous size in the course 

 of twenty years. Let us rather ask this prodigious 

 change in opinion to justify 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 burn- 

 ing that which they worshipped. It is only in 

 this way that we shall acquire the means of 

 judging whether the movement we have witnessed 

 is a mere eddy of fashion, or truly one with the 

 irreversible 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 " ap- 



