EXTENSION OF LAWS TO ADJACENT CASES. 89 



are, the sun giving out light, the earth in a state of 

 rotation and intercepting light. The induction which 

 shows these to be the real causes, and not merely 

 prior effects of a common cause, being complete and 

 irrefragable ; the only circumstances which could 

 defeat the derivative law are such as would destroy 

 or counteract one or other of the combined causes. 

 While the causes exist, and are not counteracted, the 

 effect will continue. If they exist and are not coun- 

 teracted to-morrow, the sun will rise to-morrow. 



Since the causes, namely the sun and the earth, 

 the one in the state of giving out light, the other 

 in a state of rotation, will exist until something 

 destroys them ; all depends upon the probabilities of 

 their destruction, and upon those of their counterac- 

 tion. We know by observation (omitting the inferen- 

 tial proofs of an existence for thousands of ages ante- 

 rior,) that these phenomena have continued for five 

 thousand years. Within that time there has existed 

 no cause sufficient to diminish them appreciably ; nor 

 which has counteracted their effect in any appreciable 

 degree. The chance, therefore, that the sun may not 

 rise to-morrow, amounts to the chance that some 

 cause, which has not manifested itself in the smallest 

 degree during five thousand years, will exist to-morrow 

 in such intensity as to destroy the sun or the earth, 

 the sun's light or the earth's rotation, or to produce 

 an immense disturbance in the effect resulting from 

 those causes. 



Now, if such a cause will exist to-morrow, or at 

 any future time, some cause, proximate or remote, of 

 that cause must exist now ; and must have existed 

 during the whole of the five thousand years. If, 

 therefore, the sun do not rise to-morrow, it will be 

 because some cause has existed, the effects of which, 



