Consideration of Weismanris Arguments 179 



4. Finally the last argument of Weismann is that 

 it is incomprehensible how the inheritance of acquired 

 characters could be effected. 142 



In the endeavor to examine these four arguments 

 with the most scrupulous objectivity, we must first divide 

 them into two categories: The fourth is the only one 

 which attacks the principle of inheritance directly; the 

 first, the second, and the third, on the contrary, con- 

 trovert this theory only indirectly, in that they seek to 

 show that many formations are of such a nature or 

 arose under such circumstances that they can be explained 

 only by the theory of natural selection. The conclusion 

 which it is desired to have drawn from this is clear, and 

 is indeed admitted: If natural selection is capable of 

 explaining some formations it will be capable also of 

 explaining all the others; if all formations can be ex- 

 plained by natural selection alone, the inheritance of 

 acquired characters becomes useless for the purpose of 

 explaining the transformation of species; consequently 

 if it is useless it is very probable that it does not exist 

 at all. 



The impartial reader will admit that this manner of 

 reasoning is deceptive. Even if it be proved that natural 

 selection must necessarily have been capable of producing 

 certain formations with the help of fortuitous individual 

 variations, it does not follow that it must also have been 

 capable of producing all other phylogenetic formations, 

 especially if they are different in nature from the former. 

 And even if the proof were forthcoming that it is capable 

 of explaining by itself all phylogenetic formations what- 

 ever, it is evident that even this would not constitute 



142 Weismann : Ibid. P. 61. 



