1891 LETTER TO DR. McCLURE 299 



HODESLEA, EASTBOURNE, March 17, 1891. 



DEAR MR. McCLURE I am very much obliged for your 

 letter, which belongs to a different category from most of those 

 which I receive from your side of the hedge that, unfortunately, 

 separates thinking men. 



So far as I know myself, after making due deduction for the 

 ambition of youth and a fiery temper, which ought to (but un- 

 fortunately does not) get cooler with age, my sole motive is to 

 get at the truth in all things. 



I do not care one straw about fame, present or posthumous, 

 and I loathe notoriety, but I do care to have that desire manifest 

 and recognised. 



Your paper deals with a problem which has profoundly in- 

 terested me for years, but which I take to be insoluble. It would 

 need a book for full discussion. But I offer a remark only on 

 two points. 



The doctrine of the conservation of energy tells neither one 

 way nor the other. Energy is the cause of movement of body, 

 i.e. things having mass. States of consciousness have no mass, 

 even if they can be conceded to be movable. Therefore even if 

 they are caused by molecular movements, they would not in any 

 way affect the store of energy. 



Physical causation need not be the only kind of causation, 

 and when Cabanis said that thought was a function of the brain, 

 in the same way as bile secretion is a function of the liver, he 

 blundered philosophically. Bile is a product of the transforma- 

 tion of material energy. But in the mathematical sense of the 

 word " function," thought may be a function of the brain. That 

 is to say, it may arise only when certain physical particles take 

 on a certain order. 



By way of a coarse analogy, consider a parallel-sided piece 

 of glass through which light passes. It forms no picture. Shape 

 it so as to be bi-convex, and a picture appears in its focus. 



Is not the formation of the picture a ' function " of the 

 piece of glass thus shaped? 



So, from your own point of view, suppose a mind-stuff \6yos 

 a noumenal cosmic light such as is shadowed in the fourth 

 gospel. The brain of a dog will convert it into one set of 

 phenomenal pictures, and the brain of a man into another. But 

 in both cases the result is the consequence of the way in which 

 the respective brains perform their " functions." 



Yet one point. 



The actions we call sinful are as much the consequence of 



