LAW OF CAUSATION. 



237 



He distinctly refused to admit the 

 will of God as a sufficient explanation 

 of anything except miracles ; and in- 

 sisted upon finding something that 

 would account better for the pheno- 

 mena of nature than a mere reference 

 to divine volition.* 



Again, and conversely, the action 

 of mind upon matter (which, we are 

 now told, not only needs no explana- 

 tion itself, but is the explanation of 

 all other effects) has appeared to 

 some thinkers to be itself the grand 

 inconceivability. It was to get over 

 this very difficulty that the Cartesians 

 invented the system of Occasional 

 Causes. They could not conceive that 

 thoughts in a mind could produce 

 movements in a body, or that bodily 

 movements could produce thoughts. 

 They could see no necessary connec- 

 tion, no relation d priori, between a 

 motion and a thought. And as the 

 Cartesians, more than any other school 

 of philosophical speculation before or 

 since, made their own minds the mea- 

 sure of all things, and refused, on 

 principle, to believe that Nature had 

 done what they were unable to see 

 any reason why she must do, they 

 affirmed it to be impossible that a 

 material and a mental fact could be 

 causes one of 'another. They regarded 

 them as mere Occasions on which the 

 real agent, God, thought fit to exert 

 his power as a Cause. When a man 

 wills to move his foot, it is not his 

 will that moves it, but God (they 

 said) moves it on the occasion of his 

 will. God, according to this system, 

 is the only efficient cause, not qua 

 mind, or qud endowed with volition, 

 but qud omnipotent. This hypothe- 

 sis was, as I said, originally suggested 

 by the supposed inconceivability of 

 any real mutual action between Mind 

 and Matter ; but it was afterwards ex- 

 tended to the action of Matter upon 

 Matter, for on a nicer examination 

 they found this inconceivable too, and 

 therefore, according to their logic, im- 

 possible. The deus ex machind was 

 ultimately called in to produce a spark 

 * Vide supra, p. 157, note, 



on the occasion of a flint and steel 

 coming together, or to break an egg 

 on the occasion of its falling on the 

 ground. 



All this, undoubtedly, shows that 

 it is the disposition of mankind in 

 general not to be satisfied with know- 

 ing that one fact is invariably ante- 

 cedent and another consequent, but 

 to look out for something which may 

 seem to explain their being sa But 

 we also see that this demand may be 

 completely satisfied by an agency 

 purely physical, provided it be much 

 more familiar than that which it is 

 invoked to explain. To Thales and 

 Anaximenes it appeared inconceiv- 

 able that the antecedents which we 

 see in nature should produce the con- 

 sequents, but perfectly natural that 

 water or air should produce them. 

 The writers whom I oppose declare 

 this inconceivable, but can conceive 

 that mind, or volition, is per se an 

 efficient cause ; while the Cartesians 

 could not conceive even that, but 

 peremptorily declared that no mode 

 of production of any fact whatever 

 was conceivable, except the direct 

 agency of an omnipotent being. Thus 

 giving additional proof of what finds 

 new ct)nfirmation in every stage of 

 the history of science, that both what 

 persons can, and what they cannot, 

 conceive is very much an affair of 

 accident, and depends altogether on 

 their experience and their habits of 

 thought ; that by cultivating the re- 

 quisite associations of ideas, people 

 may make themselves unable to con- 

 ceive any given thing ; and may make 

 themselves able to conceive most 

 things, however inconceivable these 

 may at first appear : and the same 

 facts in each person's mental his- 

 tory which determine what is or is 

 not conceivable to him, determine 

 also which among the various se- 

 quences in nature will appear to him 

 so natural and plausible as to need 

 no other proof of their existence ; to 

 be evident by their own light, inde- 

 pendent equally of experience and of 

 ezplanatioD, 



