122 MODERN IDEAS OF EVOLUTION 



diately after the above paragraph, he informs us that 

 , the &quot; spirit &quot; and &quot; mind &quot; of man are but forces which 

 (are inseparably connected with the material substance 

 of our bodies. Just as the motive power of our flesh 

 is involved in the muscular form-element, so is the 

 thinking force of our spirit involved in the form- 

 element of the brain. In a note appended to the 

 passage he says that monism conceives nature as 

 one whole, and nowhere recognises any but mechani- 

 jcal causes. These assumptions as to man and nature 

 pervade the whole book, and of course greatly simplify 

 the task of the writer, as he does not^eajjire to account 

 for the primary_origin of nature, or for anything in 

 man except his^physical frame, and even this he can 

 regard as a thing altogether mechanical. 



It is plain that we might here enter our dissent 



from Haeckel s method, for he requires us to assume 



many things which he cannot prove, before we can 



proceed a single step in the evolution of man. What 



^evidence is there, for example, of the possibility of 



the development of the rational and moral nature of 



man from the intelligence and instinct of the lower 



animals, or of the necessary dependence of the 



phenomena of mind on the structure of brain-cells ? 



*The evidence, as far as it goes, seems to tend the 



Bother way. What proof is there of the spontaneous 



evolution of living forms from inorganic matter? 



^Experiment so far negatives the possibility of this. 



Even if we give Haeckel, to begin with, a single living 



