80 ANALYSIS OF THIJ FOUR PRINCIPLES. 



These six conditions all relate to reproduction. The first and 

 second are that there must be reproduction, and that it must be 

 sufficient with the aid of adaptation to perpetuate the race. The 

 third and fourth are that the reproduction must result in individuals 

 more or less departing from the average character of the parents, but 

 corresponding with them in their fundamental character. The fifth 

 is that reproduction involves the cooperation of separate individuals 

 and binds the intergenerating group together in a common heredity. 

 The sixth is that divergence of character depends on the prevention 

 of free intergeneration, loosening the bond of common descent be- 

 tween the isolated sections, and so opening the way for the divergent 

 forms that variation and heredity controlled by segregation are per- 

 mitted to produce. The causes preventing free intergeneration, and 

 opening the way for divergence, may lie in the organism or be imposed 

 from without. 



2 Six Conditions on which the Evolution of Habitudinal Types must rest. 



First, the power of influencing associates ; second, success (that 

 is, the number of the socially endowed individuals must be sufficient 

 to keep up the organization) ; third, innovation (that is, tentative 

 diversity in the action of individuals in invention and initiation by 

 means of experiment, comparison, and repetition of the best) ; fourth, 

 tradition (that is, influence by means of example and imitation) ; fifth, 

 free association and communication within the social group; sixth, 

 segregate association setting limits to the sphere of free association 

 and so controlling innovation and tradition. 



3. The Modes of the Four Principles. 



In the classification which I have found most convenient, each of 

 the four principles of segregation is presented under two main forms 

 or modes, besides a third covering the reverse or regressive aspects. 

 I also recognize that the indiscriminate action of any one of the four 

 principles may produce results that should not be overlooked. The 

 indiscriminate principle sometimes producing racial intensification is 

 indiscriminate elimination of all but a few, and the indiscriminate 

 principle sometimes producing habitudinal intensification is indis- 

 criminate failure of all but a few. Under selection we have first 

 the two modes, j, reflexive selection, determined by the direct influ- 

 ence of members of the species upon each other, as in sexual 

 selection and social selection, and k, environal selection, deter- 

 mined by the relations between the environment and the species. 

 But each of these modes may be presented in its regressive aspects 



