320 The Theory of Genetic Modes 



who can doubt the issue of their combat ? Can we say 

 then that the evolution which is determined by such a 

 struggle is sufficiently explained by the statement of the 

 strife between the two, with no allusion whatever to the 

 firearms, or to the smokeless powder, or to the mental 

 equipment that invented these ? And shall we call this 

 an explanation of history ? It would seem, indeed, that 

 we were bringing back ' home to roost ' the charge which 

 Professor Pearson makes against the historians, that they 

 are merely cataloguing facts and that his is, for all that, 

 a very incomplete catalogue ! 



The case may indeed serve to give point to two of the 

 main principles which it is the object of this work to set 

 forth. First, if evolution is to take any account of facts, 

 the psychological facts with the laws of their operation 

 are not to be ignored. And if psychophysical evolution 

 is to be the type which the true theory of evolution recog- 

 nizes, then the correlations and dependencies of the two 

 series of facts must be in all cases most carefully made 

 out. Why, for example, select the craving for food, and 

 not that for social companionship ; why that of sex, and 

 not that of religion ? Professor Pearson speaks of biologi- 

 cal principles as giving natural history, as though biology 

 were in possession of a monopoly of nature. Surely the 

 mind is a natural possession ; and to say that imitation is 

 a factor in social progress is as truly to recognize a nat- 

 ural history factor, as to say that struggle for existence is. 

 The working of the mind in effecting an invention is 

 every whit as natural a process as is the origin of varia- 

 tions by sexual reproduction. And second, it will not do 

 to force the yoke of one science in this ruthless way upon 

 the neck of another. Professor Pearson himself holds that 



