272 EVOLUTION AND MAN S PLACE IN NATURE 



personal effort, and obligation, and responsibility, 

 stands unaffected by acknowledgment of evolution as 

 the leading feature in the history of organic life. This 

 conclusion becomes the turning-point in the discussion, 

 and is henceforth to be kept constantly in view. 



The full effect of the contrast now brought out, will 

 be seen if we mark the severance of the two forms of 

 activity, as these are distinguishable in human ex 

 perience. The physical activity and the mental are 

 different, and are known to us as different. Not only 

 so, they are known to us as separate in source. This 

 places the contrast in a vivid light, even while it 

 remains true that there are secrets of physical activity, 

 obviously those of brain action, which research has 

 failed to disclose. 



In man, body and mind are distinct, while they are 

 constituents of a single life. This appears in the 

 distinctness of the sources of action, and in the differ 

 ence of the laws under which action in each case 

 proceeds. Observe how the evidence stands. We 

 take evidence first on the negative side. The activity 

 of mind is not continuous with activity of bodily 

 sensibilities. Environment produces sensory im 

 pressions ; but it does not produce our thoughts, our 

 plans, our resolutions. These mental actions are not 

 effected by mere continuity of stimulation along the 

 sensory line, as if the result reached were something 

 registered in the brain, or some extended movement 

 generated there, within certain circles of co-ordination. 

 The first and readiest hypothesis from the biological 

 side fails. There is no analogy between the muscular 

 movement which follows sensory impression, and 

 mental activity when it follows that impression. The 



