MENTAL EVOLITIOX OF MAN 237 



events — namely, the physical processes of the brain 

 and the elements of consciousness — are completely 

 independent but entirely parallel. As one writer has 

 put the case, it is as though we had two clocks whose 

 machinery worked at the same rate and whose relation- 

 ships were such that ^'one clock would give the proper 

 number of strokes when the hands of the other pointed 

 to the hour." But in my opinion this attempted ex- 

 planation of the relation of mind to matter evades the 

 whole question, as it does not account for the depend- 

 ence of the former upon the latter, but merely assumes 

 the existence of a more ultimate and unknown group 

 of causes for a parallelism in the rates of operation of 

 two series of things regarded as disconnected. 



The third conception recommends itself to many on 

 account of its greater simplicity. Formulated as the 

 doctrine of monism, it states that the mind and its 

 material basis are merely different aspects of one and 

 the same thing, and that there is only one series of 

 connected elements which are known to us directly as 

 the current of our thoughts and indirectly as the phys- 

 iological processes going on mainly in the cerebrum. 

 Thus mind is purely subjective, the brain is only me- 

 diately objective. It is because the mental and the 

 material are so intimately related that the monist 

 believes them to be connected as are the lungs and 

 respiration, the hand and grasping, or the eye and the 

 reception of visual impressions from without. 



But whichever one of these explanations we choose 

 to adopt as our own, the basic fact of iirirnary im- 

 portance is that there is an invariable dependence of 

 human thought upon a brain comprising a highly de- 



