() INDUCTION. 



another, or that all of them may be resolved into some 

 more general mode of production not hitherto recog- 

 nised. But when the modes of production are reduced 

 to one, we cannot, in point of simplification, go any 

 further. This one may not, after all, be the ultimate 

 mode ; there may be other links to be discovered 

 between the supposed cause and the effect ; but we 

 can only further resolve the known law, by introducing 

 some other law hitherto unknown; which will not 

 diminish the number of ultimate laws. 



In what cases, accordingly, has science been most 

 successful in explaining phenomena, by resolving their 

 complex laws into laws of greater simplicity and 

 generality? Hitherto chieiiy in cases of the pro- 

 pagation of various phenomena through space: and, 

 first and principally, the most extensive and impor- 

 tant of all facts of that description, the fact of motion. 

 Now this is entirely what might be expected from the 

 principles which I have laid down. Not only is 

 motion one of the most universal of all phenomena, 

 it is also (as might be expected from the former cir- 

 cumstance) one of those which, apparently at least, 

 are produced in the greatest number of ways: but the 

 phenomenon itself is always, to our sensations, the 

 same in every respect but degree. Differences of 

 duration, or of velocity, are evidently differences in 

 degree only; and differences of direction in space, 

 which alone has any semblance of being a distinc- 

 tion in kind, entirely disappear (so far as our sensa- 

 tions are concerned) by a change in our own position ; 

 indeed the very same motion appears to us, according 

 to our position, to take place in every variety of 

 direction, and motions in every different direction to 

 take place in the same. And, again, motion in a 

 straight line and in a curve are no otherwise distinct 



