Darwin's vietvs on the Descent of Man 151 



must read his life and the introduction to The Descent of Man. From 

 the moment that he was convinced of the truth of the principle of 

 descent that is to say, from his thirtieth year, in 1838 he recognised 

 clearly that man could not be excluded from its range. He recognised 

 as a logical necessity the important conclusion that "man is the co- 

 descendant with other species of some ancient, lower, and extinct 

 form." For many years he gathered notes and arguments in support 

 of this thesis, and for the purpose of showing the probable line of 

 man's ancestry. But in the first edition of The Origin of Species 

 (1859) he restricted himself to the single line, that by this work 

 " light would be thrown on the origin of man and his history." In 

 the fifty years that have elapsed since that time the science of the 

 origin and nature of man has made astonishing progress, and we are 

 now fairly agreed in a monistic conception of nature that regards the 

 whole universe, including man, as a wonderful unity, governed by 

 unalterable and eternal laws. In my philosophical book Die 

 Weltratsel (1899) 1 and in the supplementary volume Die Lebens- 

 wunder (1904) 2 , I have endeavoured to show that this pure 

 monism is securely established, and that the admission of the all- 

 powerful rule of the same principle of evolution throughout the 

 universe compels us to formulate a single supreme law the all-em- 

 bracing " Law of Substance," or the united laws of the constancy of 

 matter and the conservation of energy. We should never have 

 reached this supreme general conception if Charles Darwin a " mo- 

 nistic philosopher" in the true sense of the word had not prepared 

 the way by his theory of descent by natural selection, and crowned 

 the great work of his life by the association of this theory with a 

 naturalistic anthropology. 



1 The Riddle of the Universe, London, 1900. 



2 The Wonders of Life, London, 1904. 



