82 INDUCTION. 



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 twenty thousand 

 years, the inductions would have been anything but conclu- 

 sive. 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 percep- 

 tible quantity, but by accumulating for a much longer period 

 becomes considerable. Besides, looking at the immense multi- 

 tude of the heavenly bodies, their vast distances, and the 

 rapidity of the motion of such of them as are known to move, 

 it is a supposition not at all contradictory to experience 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 thousand years, but which in twenty thousand more may 

 be producing 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 favourable to that combination, 

 though they have not produced it once in five thousand years, 

 may produce it once in twenty thousand. So that the induc- 

 tions which authorize us to expect future events, grow weaker 

 and weaker the further we look into the future, and at length 

 become inappreciable. 



We have considered the probabilities of the sun's rising 

 to-morrow, as derived from the real laws, that is, from the 

 laws of the causes on which that uniformity is dependent Let 

 us now consider how the matter would have stood if the uni- 

 formity had been known only as an empirical law ; if we had 

 not been aware that the sun's light, and the earth's rotation 

 (or the sun's motion), were the causes on which the periodical 

 occurrence of daylight depends. We could have extended this 

 empirical law to cases adjacent in time, though not to so great 

 a distance of time as we can now. Having evidence that the 

 effects had remained unaltered and been punctually conjoined 



