40 INDUCTION. 



inquire further when and how the causes will coexist, that, 

 again, depends on 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 de 

 pended ultimately on some common 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 

 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 hy Kepler s laws, is 

 derived from the coexistence of two primeval causes, the sun, 

 and the original impulse or projectile force belonging to each 

 planet.* Kepler s laws are resolved into the laws of these 

 causes and the fact of their coexistence. 



Derivative laws, therefore, do not depend solely on the 

 ultimate laws into which they are resolvable: they mostly 

 depend on those ultimate laws, and an ultimate fact ; namely, 

 the mode of coexistence of some of the component elements 

 of the universe. The ultimate laws of causation might be 

 the same as at present, and yet the derivative laws completely 

 different, if the causes coexisted in different proportions, 

 or with any difference in those of their relations by which 

 the effects are influenced. If, for example, the sun s attrac 

 tion, and the original projectile force, had existed in some 

 other ratio to one another than they did (and we know of no 

 reason why this should not have been the case), the derivative 

 laws of the heavenly motions might have been quite different 

 from what they are. The proportions which exist happen 

 to be such as to produce regular elliptical motions ; any 

 other proportions would have produced different ellipses, or 

 circular, or parabolic, or hyperbolic motions, but still regular 

 ones ; because the effects of each of the agents accumulate 

 according to an uniform law ; and two regular series of quan 

 tities, when their corresponding terms are added, must pro 

 duce a regular series of some sort, whatever the quantities 

 themselves are. 



* Or (according to Laplace s theory) the sun and the sun s rotation. 



