140 HUMANISM vm 



joy to the evolutionist and a profit to the doctor, but to 

 the patient the useless and dangerous relic of a damnosa 

 hereditas. And all this degeneration has taken place 

 under the action of Natural Selection. 



Not but what there has also been much progression, 

 and that in the aggregate its amount has far exceeded 

 that of degeneration. That is just the reason why we 

 speak of the history of life as an evolution. Life has 

 been on the whole progressive ; but progress and retro 

 gression have both been effected under the same law of 

 Natural Selection. How, then, can the credit of that 

 result be ascribed to Natural Selection ? Natural Selection 

 is equally ready to bring about degeneration or to leave 

 things unchanged. How, then, can it be that which 

 determines which of the three possible (and actual) cases 

 shall be realised ? Let us grant that Natural Selection is 

 a permanent condition of life, from which no beings can 

 at any time escape. But for that very reason it cannot 

 be the principle of differentiation which decides which of 

 the alternative courses the evolution of life will in fact 

 pursue. It cannot be Natural Selection that causes one 

 species to remain stationary, another to degenerate, a third 

 to develop into a higher form. The constant pressure 

 which it exercises on organisms does not in the least 

 explain the actual course of evolution any more than 

 the constant pressure of the atmosphere determines the 

 direction in which we walk. The cause of the particular 

 changes which have led to the existing forms of life cannot 

 be found in an unchanging law of all life ; it must be 

 sought in forces whose intermittent action has made an 

 instrument of Natural Selection. 



It is clear, then, that to explain the changes which 

 have resulted in the existing forms of life some variable 

 factor has to be added to Natural Selection. And as to 

 the nature of that factor Darwinism, qua Darwinism, tells 

 us nothing. There may have been one or more of them, 

 they may have been of all sorts. They may have been 

 nothing more recondite than climatic changes or geo 

 graphical isolation, to mention two of Darwin s favourite 



