EXPLANATION OF LAWS. 



307 



particularly metalllo bases and hydro- 

 gen. Such bases are essential ele- 

 ments of colouring matters and con- 

 tagions compounds, which substances, 

 therefore, are decomposed and de- 

 stroyed by chlorine. 



§ 4. It is of importance to remark, 

 that when a sequence of phenomena 

 is thus resolved into other laws, they 

 are always laws more general than 

 itself. The law that A is followed by 

 C, is less general than either of the 

 laws which connect B with C and A 

 with B. This will appear from very 

 simple considerations. 



All laws of causation are liable to 

 be counteracted or frustrated by the 

 non-fulfilment of some negative con- 

 dition : the tendency, therefore, of B 

 to produce C may be defeated. Now 

 the law that A produces B, is equally 

 fulfilled whether B is followed by C 

 or not ; but the law that A produces 

 C by means of B, is of course only 

 fulfilled when B is really followed by 

 C, and is therefore less general than 

 the law that A produces B. It is 

 also less general than the law that B 

 produces C. For B may have other 

 causes besides A ; and as A produces 

 C only by means of B, while B pro- 

 duces C whether it has itself been 

 produced by A or by anything else, 

 the second law embraces a greater 

 number of instances, covers as it 

 were a greater space of ground, than 

 the first. 



Thus, in our former example, the 

 law that the contact of an object 

 causes a change in the state of the 

 nerve, is more general than the law 

 that contact with an object causes 

 sensation, since, for aught we know, 

 the change in the nerve may equally 

 take place when, from a counteracting 

 cause, as, for instance, strong mental 

 excitement, the sensation does not 

 follow ; as in a battle, where wounds 

 are sometimes received without any 

 consciousness of receiving them. And 

 again, the law that change in the state 

 of a nerve produces sensation, is more 

 general than the law that contact 



with an object produces sensation j 

 since the sensation equally follows . 

 the change in the nerve when not 

 produced by contact with an object, 

 but by some other cause ; aa in th* 

 well-known case when a person who 

 has lost a limb feels the same sensa- 

 tion which he has been accustomed to 

 call a pain in the limb. 



Not only are the laws of more im- 

 mediate sequence, into which the law 

 of a remote sequence is resolved, laws 

 of greater generality than that law is, 

 but (as a consequence of, or rather as 

 implied in, their greater generality) 

 they are more to be relied on ; there 

 are fewer chances of their being ulti- 

 mately found not to be universally 

 true. From the moment when the 

 sequence of A and C is shown not to 

 be immediate, but to depend on an 

 intervening phenomenon, then, how- 

 ever constant and invariable the se- 

 quence of A and C has hitherto been 

 found, possibilities arise of its failure, 

 exceeding those which can effect either 

 of the more immediate sequences. A, 

 B, and B, C. The tendency of A to 

 produce C may be defeated by what- 

 ever is capable of defeating either the 

 tendency of A to produce B, or the 

 tendency of B to produce C ; it is 

 therefore twice as liable to failure as 

 either of those more elementary ten- 

 dencies; and the generalisation that 

 A is always followed by C, is twice 

 as likely to be found erroneous. And 

 so of the converse generalisation, that 

 C is always preceded and caused by 

 A ; which will be erroneous not only 

 if there should happen to be a second 

 immediate mode of production of C 

 itself, but, moreover, if there be a 

 second mode of production of B, the 

 immediate antecedent of C in the 

 sequence. 



The resolution of the one generalisa- 

 tion into the other two not only shows 

 that there are possible limitations of 

 the former, from which its two ele- 

 ments are exempt, but shows also 

 where these are to be looked for. As 

 soon as we know that B intervenes 

 between A and C, we also know that if 



