Genetic Determination: the Factors 37 



guiding indications for the problem of determination in 

 the sphere of evolution. The evolution series becomes in 

 its hereditary character more and more indeterminate, more 

 and more indefinite, in respect to what will be produced 

 by the union of the heredity impulse with the conditions 

 of development of the successive generations of individ- 

 uals. There is a general direction of progress, secured 

 by the natural selection of variations in the direction of 

 the plasticity which increasing accommodation requires; 

 but the utility of this shows itself in the decay of special 

 congenital functions and the increased freedom of the 

 organism in working out a career for itself. Thus there 

 is secured a blanket utility, as it were, a general character, 

 through the operation of natural selection, which pro- 

 gressively supersedes and annuls many special utilities 

 with their corresponding adaptations, while, at the same 

 time, other special functions having special utilities are 

 given time to reach maturity by variation and selection. 



§ 2. Genetic Determination : the Factors 



The truth of this position regarding the direction of 

 evolution appears from the detailed explanations by which 

 the two leading positions of this work are supported in 

 the following pages. 



Of these two positions the first is that of Organic 

 Selection, explained and applied with considerable rep- 

 etition below. This position is the general one that 

 it is the individual accommodations which set the direc- 

 tion of evolution, that is, which determine it; for if 

 we grant that all mature characters are the result of 

 hereditary impulse plus accommodation, then only those 



