LAW; ITS DEFINITIONS. 99 



they would be less certain, and the least uncer- 

 tainty would render them incapable of any service. 

 No adjustment, however nice, could secure its 

 purpose if the implements employed were of un- 

 certain temper. 



The notion therefore that the uniformity or invari- 

 ableness of the Laws of Nature, cannot be recon- 

 ciled with their subordination to the exercise of 

 Will, is a notion contrary to our own experience. 

 It is a confusion of thought arising very much 

 out of the ambiguity of language. For let it be 

 observed that, of all the senses in which the word 

 Law is used, there is only one in which it is true 

 that laws are immutable or invariable ; and that is 

 the sense in which Law is used to designate an in- 

 dividual Force. Gravitation, for example, is immu- 

 table in this respect — that (so far as we know) it 

 never operates according to any other measure than 

 " directly as the mass, and inversely as the square of 

 the distance." But in all the other senses in which 

 the word Law is used, laws are not immutable ; 

 but, on the contrary, they are the great instru- 

 ments, the unceasing agencies, of change. When 

 therefore, scientific men speak, as they often do 



