14S HABIT AND INTELLIGENCE. [chap. 



writing, are caused by our voluntary determinations, is 



that we always find that the voluntary determinations are 



followed by the motions. But if any one were to tell me 



that hearing good news is not the cause of joy, or that my 



reading a sound demonstration is not the cause of my 



assenting to it, this would contradict a fact of direct 



cognition, just as much as if he were to assvxre me that 



sugar was bitter or toothache pleasant. 



How we We say that fire causes heat, and that good news causes 



identify joj- ^ire causing heat is a fact of matter ; and this rela- 



physical ^jqjj Qf causc and effect is not within our consciousness, 



and mental ■ r> -i ^ /> -ip /-it 



cansation but is, as I believe, inferred by us Irom the tacts. Grood 

 as cases of jjg^g causing iov is a fact of mind ; and this relation 



the same & J J _ ' _ 



law. of cause and effect is witliin our consciousness, and is, 



I think, self-evidently no mere inference, but a fact 

 of direct cognition. But mankind naturally and spon- 

 taneously regard these as both alike cases of causation ; 

 and I believe that here, as in so many other cases, the 

 spontaneous belief of mankind is right. But how do we 

 come mentally thus to ascribe the same law of causation 

 to these two sets of actions, the physical and the mental, 

 between which there is so little intelligible resemblance ? 

 T think, though the subject is most difficult to analyse, 

 that the connecting link by which we learn to identify 

 causation as cognised within the mind with causation as 

 inferred in the world of matter outside of it, consists in the 

 fact that we have the power, inexplicable as that power is, 

 of making our own will an acting cause in the world of 

 matter. Thus, if I will to think, my thoughts act as 

 desired ; if I will to write, my fingers and my pen act as 

 tlesired ; and though the causal connexion, as already 

 pointed out, is within the sphere of consciousness in the 

 one case and not in the other, yet the effect follows the 

 cause in both cases with equal certainty, and we learn to 

 identify the nature of the causal action in the two cases. 

 In a word, we identify the two facts of mental causation 

 and physical causation in consequence of the fact that a 

 mental determination is capable of becoming a physical 

 cause ; as when the determination of my will causes the 



