EXPLANATION OF LAWS. 333 



was supposed to be its effect, further observation detects an intermediate 

 link ; a fact caused by the antecedent, and in its turn causing the conse- 

 quent; so that the cause at first assigned is but the I'emote 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 subsequent- 

 ly discovered that after we have touched the object, and before we ex- 

 perience the sensation, some change takes place in a kind of thread called 

 a nerve, which extends from our outward organs to the brain. Touching 

 the object, therefore, is only the remote cause of our sensation; 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 pro- 

 duction of the change of state in the nerve, there may take place some 

 electric phenomenon, or some phenomenon 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, 

 provisionally, as the proximate cause of the affection of the nerve. The 

 sequence, 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 sensation. 

 To take another example : the more powerful acids corrode or blacken 

 organic 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 organ- 

 ic structure from the rest, and their entering into combination with the 

 acid. The acid causes this separation of the elements, and the separation 

 of the elements causes the disorganization, and often the chari-ing of the 

 structure. So, again, chlorine extracts coloring matters (whence its efficacy 

 in bleaching) and purifies the air from infection. This law is resolved into 

 the two following laws : Chlorine has a powerful affinity for bases of all 

 kinds, particularly metallic bases and hydrogen : such bases are essential 

 elements of coloring matters and contagioiis compounds, which substances, 

 therefore, are decomposed and destroyed 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 fustrated, by the 

 non-fulfillment of some negative condition ; the tendency, therefore, of B 

 to produce C may be defeated. Now the law that A produces B, is equal- 

 ly fulfilled whether B is followed by C or not ; but the law that A pro- 

 duces 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 any thing else, the 



