PRINCIPAL ATTEMPTS AT EXPLANATION 149 



according to whom it is the individuals which by chance 

 are better fitted which survive.) 



(b) On the other hand the acceptance of spontaneous 

 generation, independently of the philosophical impos- 

 sibility, is a serious methodological error. Everything 

 that we observe and every hypothesis must be 

 based on that speaks against spontaneous generation 

 (see above, p. 96). 



(c) The idea which Lamarck has formed regarding 

 the process of the new formation of separate organs, 

 cannot a priori be disproved. Lamarck, however, at 

 the most explains how many birds acquire swimming 

 webs, long necks, climbing claws, etc. ; he does not, 

 however, explain at all how these animals arrived at 

 the general organic type of e Birds ' : since before 

 they acquired swimming webs, etc. i.e. a part of the 

 entire organism adapted to definite services they 

 were already birds. The same applies to the other 

 ' types ' which we term families and classes. They 

 are now sharply separated from each other and, 

 according to palseontological evidence, were always 

 so ; they must therefore be regarded as a ( given ' 

 something not as something which has ( happened ' 

 (geworden). 



Certainly Lamarck, at least according to his words, 

 regards the whole development as due to a plan of the 

 Creator. Therefore we must assume that either from 

 the beginning or from a very early period the said types 

 were established in the primary forms, so that every 

 further development should occur within the limits 



