EXTENSION OF LAWS TO ADJACENT CASES. 81 



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 

 though during five thousand years they have not amounted to 

 a perceptible quantity, will in one day become overwhelming. 

 Since this cause has not been recognised during such an 

 interval of time, by observers stationed on our earth, it must, 

 if it exist, be either some agent whose effects develop them- 

 selves gradually and very slowly, or one which existed in 

 regions beyond our observation, and is now on the point of 

 arriving in our part of the universe. Now all causes which we 

 have experience of, act according to laws incompatible with 

 the supposition that their effects, after accumulating so slowly 

 as to be imperceptible for five thousand years, should start into 

 immensity in a single day. No mathematical law of propor- 

 tion between an effect and the quantity or relations of its 

 cause, could produce such contradictory results. The sudden 

 development of an effect of which there was no previous trace, 

 always arises from the coming together of several distinct 

 causes, not previously conjoined ; but if such sudden conjunc- 

 tion is destined to take place, the causes, or their causes, must 

 have existed during the entire five thousand years ; and 

 their not having once come together during that period, 

 shows how rare that particular combination is. We have, 

 therefore, the warrant of a rigid induction for considering it 

 probable, in a degree undistinguishable from certainty, that 

 the known conditions requisite for the sun's rising will exist 

 to-morrow. 



VOL. II. 6 



