THE 'ORIGIN OF SPECIES.' 195 



sufficiently within the bounds of probability to justify the 

 belief in its occurrence on the strength of any attainable, or, 

 indeed, imaginable, evidence ? 



In view of the assertion (often repeated in the early days 

 of the opposition to Darwin) that he had added nothing to 

 Lamarck, it is very interesting to observe that the possibility 

 of a fifth alternative, in addition to the four he has stated, has 

 not dawned upon Dr. Whewell's mind. The suggestion that 

 new species may result from the selective action of external 

 conditions upon the variations from their specific type which 

 individuals present and which we call "spontaneous," because 

 we are ignorant of their causation is as wholly unknown to 

 the historian of scientific ideas as it was to biological spe- 

 cialists before 1858. But that suggestion is the central idea 

 of the ' Origin of Species,' and contains the quintessence of 

 Darwinism. 



Thus, looking back into the past, it seems to me that my 

 own position of critical expectancy was just and reasonable, 

 and must have been taken up, on the same grounds, by many 

 other persons. If Agassiz told me that the forms of life 

 which had successivelv tenanted the globe were the incarna- 

 tions of successive thoughts of the Deity ; and that He had 

 wiped out one set of these embodiments by an appalling 

 geological catastrophe as soon as His ideas took a more 

 advanced shape, I found myself not only unable to admit the 

 accuracy of the deductions from the facts of paleontology, 

 upon which this astounding hypothesis was founded, but I 

 had to confess my want of any means of testing the correctness 

 of his explanation^ them. And besides that, I could by no 

 means see what the explanation explained. Neither did it 

 help me to be told b by an eminent anatomist that species had 

 succeeded one another in time, in virtue of " a continuously 

 operative creational law." That seemed to me to be no more 

 than saying that species had succeeded one another, in the 

 form of a vote-catching resolution, with " law " to please the 



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