256 Heredity. 



the second sensation, it furnishes proof that its scientific 

 education has begun. Of course I do not intend to 

 say that the order of nature, according to which the 

 Rhizopod adjusts its actions, is consciously apprehended, 

 but simply that it is the experience of the existence of 

 this order which determines the action. Throughout 

 the whole course of the evolution of one of the higher 

 organisms each variation which served to bring about a 

 closer harmony between the organism and its environ- 

 ment, and was accordingly preserved by natural selec- 

 tion, and added on to the series of hereditary structures 

 and functions, was in its subjective aspect the experi- 

 ence of a new external connection, a new step in the 

 recognition of natural law, an advance in scientific 

 knowledge. Human advancement is of course widely 

 different from the slow progress of the lower forms of 

 life, but it is fundamentally the same. Experience is 

 continually spreading over new fields, and bringing about 

 a more wide and exact recognition of the persistent re- 

 lations of the external world. The scientific laws thus 

 recognized then gradually take the shape of principles 

 or laws of conduct, according to which actions are de- 

 termined in those cases where experience has shown 

 that they apply. Those laws of conduct which have 

 been long recognized gradually assume the shape of 

 habits or intuitions, according to which conduct is al- 

 most unconsciously regulated, and the habit finally be- 

 comes established as one of the hereditary characteris- , 

 tics of the race. 



We are apt to confine our attention to the subjective 

 side of human advancement, and to neglect the struct- 

 ural side, and at the same time to neglect the subjective 

 side of the evolution of the lower forms of life, and to 

 confine our attention to the structural side, but of 



