558 INDUCTION. 



indeed, been a matter of great interest at a time when 

 the idea of explaining celestial facts by terrestrial 

 laws, was looked upon as the confounding of an 

 indefeasible distinction. When, however, the celes- 

 tial motions were accurately ascertained, and the 

 deductive processes performed from which it appeared 

 that their laws and those of terrestrial gravity corre- 

 sponded, those celestial observations became a set of 

 instances which exactty eliminated the circumstance 

 of proximity to the earth ; and proved that in the 

 original case, that of terrestrial objects, it was not the 

 earth, as such, that caused the motion or the pressure, 

 but the circumstance common to that case with the 

 celestial instances, namely, the presence of some great 

 body within certain limits of distance. 



6. There are,, then, three modes of explaining 

 laws of causation, or, which is the same thing, 

 resolving them into other laws. First, when the law 

 of an effect of combined causes is resolved into the 

 separate laws of the causes, together with the fact of 

 their combination. Secondly, when the law which 

 connects any two links, not proximate, in a chain of 

 causation, is resolved into the laws which connect each 

 with the intermediate links. Both of these are cases 

 of resolving one law into two or more ; in the third, 

 two or more are resolved into one : when, after the 

 law has been shown to hold good in several different 

 classes of cases, we decide that what is true in each 

 of these classes of cases, is true under some more 

 general supposition, consisting of what all those 

 classes of cases have in common. We may here 

 remark that this last operation involves none of the 

 uncertainties attendant upon induction by the Method 

 of Agreement, since we need not suppose the result 



