28 THE HISTORY OF CREATIOX. 



place, necessarily exert on one another — solely by the correct 

 estimate of these simple facts, and by skilfully combining 

 them, Darwin has succeeded in finding the true active 

 causes (causag efficientes) of the immensely intricate world 

 of forms in organic nature. 



In any case we are in duty bound to accept this theory 

 till a better one be found, which will undertake to explain 

 the same amount of facts in an equally simple manner. 

 Until now we have been in utter want of such a theory. 

 The fundamental idea that all different animal and vege- 

 table forms must be descended from a few or even from one 

 single, most simple primary form, was indeed not new. This 

 idea was long since distinctly formulated — first by the great 

 Lamarck, at the beginning of our century. But Lamarck 

 in reality only expressed the hypothesis of the Doctrine of 

 Filiation, without establishing it by an explanation of the 

 active causes. And it is just the demonstration of these 

 causes which marks the extraordinary progress which 

 Darwin's theory has made beyond that of Lamarck. In 

 the physiological properties of Inheritance and Adaptation 

 of orofanic matter, Darwin discovered the true cause of the 

 genealogical relationship of organisms. It was not possible 

 for the genius of Lamarck in his day to command that 

 colossal material of biological facts which has been collected 

 by the patient zoological and botanical investigations of the 

 last fifty years, and which has been used by Darwin as an 

 overpowering apparatus of evidence. 



Darwin's theory is therefore not what his opponents fre- 

 quently represent it as being — an unwarranted hypothesis 

 taken up at random. It is not for zoologists or botanists to 

 accept or reject this as an explanatory theory, as they 



