EXTENSION OF LAWS TO ADJACENT CASES. 329 



in the smallest dogroo durinr^ five thousand years; will exist to-moirow 

 in 6uch 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 efluct 

 resulting from those causes. 



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

 some cause, proximate or remot-c, of ihat cause must exist noW; and 

 must have existed during the whole of the five thousand years. If, 

 therefore, the sun do liot rise to-morrow, it will be bocause 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 recognized during such 

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

 exist, be citlier some agent whose effects develop themselves gradually 

 and very slowly, or one which existed in regions beyond our observa- 

 tion, 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 proportion 

 between an effect and the quantity or relations of its cause, could pro- 

 duce Kuch 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 3 

 such sudden conjunction 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 fin* considering it probable, in a degree undistin- 

 guishable from certainty, that the known conditions requisite for the 

 sun's rising will exist to-morrow. 



§ 3. But this extension of derivative laws, not causative, beyond the 

 limits of observation, can only be to adjacent cases. If instead of to- 

 morrow we had said this day twemy thousand years, the inductions 

 would have been anything but conclusive. That a cause which, in 

 opposition to very powerful causes, produced no perceptible effect 

 during five thousand years, should produce a very considerable one by 

 the end of twenty thousand, has nothing in it which is not in conformity 

 with our experience of causes. We know many agents, the effect of 

 which in a short period does not amount to a perceptible quantity, but 

 by accumulating for a much longer period becomes considerable. 

 Besides, looking at the immense multitude of the licavenly bodies, their 

 vast distances, and the rapidity (jf the motion of such of them as are 

 known to move, it is a supposition not at all contradictory to experi- 

 enc-e that some body may be in motion towards us, or we towards it, 

 within the limits of whose influence we have not come during five thou- 

 sand years, but which in twenty thousand more may be ])roducing 

 effects upon us of the most extraordinary kind. Or the fact which is 

 capable of preventing sunrise may be, not the cumulative effect of one 

 cause, but some new combination of causes; and the chances favorable 

 to that combination, though they have not produced it once in five 

 thousand years, may produce it once in twenty thousand. So that the 

 inductions which authorize us to expect future events, gi'ow weaker 

 Tx 



