THE MECHANICAL SYSTEM AND ITS LIMITS 37 1 



some sense for them before they are developed, if they 

 are to be recognised at once and selected ; and they 

 must be equally sensitive to any increase in the 

 characters. Hence the male characteristics act before 

 they exist ; in other words, sexual selection even in its 

 simplest form is teleological.^ 



The Lamarckian principle, also orthogenesis, rest on 

 teleological foundations. The statement that certain 

 organs have attained their higher development by 

 inheriting the effects of exercise supposes that the 

 organism in question acts consciously, and that there 

 is a special disposition in the animal's body. And when 

 explanations are offered us such as that pressure causes 

 the skin to become thicker in some animals and thinner 

 in others, that is to credit the organism in question with 

 a purposive adaptability and regulate this so as to attain 

 the end that is to be explained. The Lamarckian 

 principle postulates a force in animals, in each case, that 

 strives to attain an end, and exercise and other agencies 

 merely help it to attain it. 



The third auxiliary theory to natural selection, 

 germinal selection, may also be described as a 

 teleological principle. In the first place this hypothesis 

 supposes that the germ has a purposive faculty of self- 

 correction, controlling the advancing and retreating 

 movements of the determinants in most cases. But 

 purposive forces within a determinant must above all 

 things prevent too unequal a nourishment of the various 



1 We have already shown on p. 82 that female choice seeks to attain 

 an end. 



