CHAPTER XVI 



Lamarckian Heredity and Teleology 

 § I . TJie Evidence in favour of Use-inJieritanee 



The evidence for the inheritance of acquired characters, 

 called 'Lamarckian' or 'use-inheritance,' in cases of 

 sexual reproduction, is not very strong. There are no 

 clear and unambiguous cases of transmission of specific 

 modifications. The arguments for such transmission are 

 largely presumptive, based upon the requirements of the 

 theory of evolution. Of such arguments the following 

 seem to be the strongest. 



(i) Incomplete or imperfect instincts — together with 

 complex instincts, which must at some time have been 

 imperfect — cannot be due to natural selection; for their 

 early stages would involve partial correlations of movement 

 of no use to the animal. Selectionists meet this by saying 

 that {a) the organism as a whole must be considered, not 

 the single organs or functions, in the matter of individual 

 survival; {b) a certain degree of intelligence usually 

 accompanies and supplements such instincts ; (r) the in- 

 telligence, together with individual accommodations of all 

 sorts, screens those variations which occur in the direction 

 of the particular function, and secures its evolution under 

 natural selection in accordance with the hypothesis of 

 organic selection; {d) many of the instances cited under 

 this head are not congenital characters at all, but are 



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