EMPIRICAL LAWS. 43 



and of coexistence. Some are laws of succession 

 or of coexistence between different effects of the 

 same cause: of these we had abundant examples 

 in the last chapter. Some are laws of succession 

 between effects and their remote causes ; resolvable 

 into the laws which connect each with the interme- 

 diate link. Thirdly, when causes act together and 

 compound their effects, the laws of those causes 

 generate the fundamental law of the effect, namely, 

 that it depends upon the coexistence of those causes. 

 And, finally, the order of succession or of coexistence 

 which obtains among effects, necessarily depends upon 

 their causes. If they are effects of the same cause, it 

 depends upon the laws of that cause ; if of different 

 causes, it depends upon the laws of those causes 

 severally, and upon the circumstances which deter- 

 mine their coexistence. If we inquire further when 

 and how the causes will coexist, that, again, depends 

 upon their causes : and we may thus trace back the 

 phenomena higher and higher, until the different 

 series of effects meet in a point, and the whole is 

 shown to have depended ultimately upon some com- 

 mon cause ; or until, instead of converging to one 

 point, they terminate in different points, and the 

 order of the effects is proved to have arisen from the 

 original collocation of some of the primeval causes, or 

 natural agents. For example, the order of succession 

 and of coexistence among the heavenly motions, 

 which is expressed by Kepler's laws, is derived from 

 the coexistence of two primeval causes, the sun, and 

 the original impulse or projectile force impressed upon 

 each planet*. Kepler's laws are resolved into the 



* Or (according to Laplace's theory) the sun, and the sun's 

 rotation. 



