THE 'ORIGIN OF SPECIES.' 



549 



cause we are ignorant of their causation — is as wholly un- 

 known to the historian of scientific ideas as it was to biologi- 

 cal specialists before 18*58. 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 successively 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 correct- 

 ness of his explanation of them. And besides that, I could 

 by no means see what the explanation explained. Neither 

 did it help me to be told by an eminent anatomist that species 

 had succeeded one another in time, in virtue of " a continu- 

 ously 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 man of science, and " creational " to draw the orthodox. 

 So I took refuge in that " thatige Skepsis " which Goethe has 

 so well defined ; and, reversing the apostolic precept to be 

 all things to all men, I usually defended the tenability of the 

 received doctrines, when I had to do with the transmutation- 

 ists ; and stood up for the possibility of transmutation among 

 the orthodox — thereby, no doubt, increasing an already 

 current, but quite undeserved, reputation for needless com- 

 bativeness. 



I remember, in the course of my first interview with Mr. 

 Darwin, expressing my belief in the sharpness of the lines of 

 demarcation between natural groups and in the absence of 

 transitional forms, with all the confidence of youth and im- 



