306 



INDUCTION. 



in this resolution of the law of a com- 

 plex effect, the laws of which it is 

 compounded are not the only elements. 

 It is resolved into the laws of the 

 •eparate causes, together with the 

 fact of their co-existence. The one 

 is as essential an ingredient as the 

 other ; whether the object be to dis- 

 cover the law of the effect, or only to 

 explain it. To deduce the laws of 

 the heavenly motions, we require not 

 only to know the law of a rectilineal 

 and that of a gravitative force, but 

 the existence of both these forces in 

 the celestial regions, and even their 

 relative amount. The complex laws 

 of causation are thus resolved into 

 two distinct kinds of elements : the 

 one, simpler laws of causation, the 

 other (in the aptly selected expression 

 of Dr. Chalmers) collocations ; the 

 collocations consisting in the existence 

 of certain agents or powers, in certain 

 circumstances of place and time. We 

 shall hereafter have occasion to return 

 to this distinction, and to dwell on it 

 at such length as dispenses with the 

 necessity of further insisting on it 

 here. The first mode, then, of the 

 explanation of Laws of Causation, is 

 when the law of an effect is resolved 

 into the various tendencies of which 

 it is the result, together with the laws 

 of those tendencies. 



§ 3. A second case is when, be- 

 tween what seemed the cause and 

 what was supposed to be its effect, 

 further observation detects an inter- 

 mediate link ; a fact caused by the 

 antecedent, and in its turn causing 

 the consequent ; so that the cause at 

 first assigned is but the remote cause, 

 operating through the intermediate 

 phenomenon. A seemed the cause of 

 C, but it subsequently appeared that 

 A was only the cause of B, and that 

 it is B which was the cause of C. 

 For example : mankind were aware 

 that the act of touching an outward 

 object caused a sensation. It was 

 subsequently discovered, that after 

 we have touched the object, and be- 

 fore we experience the sensation, some 



change takes place in a kind of thread 

 called a nerve, which extends from our 

 outward organs to the brain. Touch - 

 mg the object, therefore, is only the re- 

 mote causeof oursensation ; that is, not 

 the cause, properly speaking, but the 

 cause of the cause ; — the real cause of 

 the sensation is the change in the 

 state of the nerve. Future experience 

 may not only give us more knowledge 

 than we now have of the particular 

 nature of this change, but may also 

 interpolate another link : between the 

 contact (for example) of the object 

 with our outward organs, and the 

 production of the change of state in 

 the nerve, there may take place some 

 electric phenomenon, or some pheno- 

 menon of a nature not resembling the 

 effects of any known agency. Hitherto, 

 however, no such intermediate link 

 has been discovered ; and the touch 

 of the object must be considered, pro- 

 visionally, as the proximate cause of 

 the affection of the nerve. The se- 

 quence, therefore, of a sensation of 

 touch on contact with an object is 

 ascertained not to be an ultimate law ; 

 it is resolved, as the phrase is, into 

 two other laws, — the law that contact 

 with an object produces an affection 

 of the nerve, and the law that an 

 affection of the nerve produces sensa- 

 tion. 



To take another example : the more 

 powerful acids corrode or blacken or- 

 ganic compounds. This is a case of 

 causation, but of remote causation ; 

 and is said to be explained when it is 

 shown that there is an intermediate 

 link, namely, the separation of some 

 of the chemical elements of the organic 

 structure from the rest, and their en- 

 tering into combination with the acid. 

 The acid causes this separation of the 

 elements, and the separation of the 

 elements causes the disorganisation, 

 and often the charring of the structure. , 

 So, again, chlorine extracts colouring 

 matters (whence its efficacy in bleach- 

 ing) and purifies the air from infec- 

 tion. This law is resolved into the 

 two following laws. Chlorine has a 

 powerful affinity for bases of all kinds, 



