THE PRINCIPLES OF SCIENCE. 



distinct impression ; the powers of association bring forth 

 the record when the like is felt again. By the higher 

 faculties of judgment and reasoning the mind compares 

 the new with the old, recognises essential identity, even 

 when disguised by diverse circumstances, and expects to 

 find again what was before experienced. It must be the 

 ground of all reasoning and inference that what is true 

 of one thing will be true of its equivalent, and that under 

 carefully ascertained conditions Nature repeats herself. 



Were this indeed a Chaotic Universe, the powers of 

 mind employed in science would be useless to us. Did 

 Chance wholly take the place of order, and did all phe 

 nomena come out, not of one same Infinite Lottery, to 

 use Condorcet s expression, but out of lotteries ever 

 changing in their conditions, there could be no reason to 

 expect the like result in like circumstances. It is possible 

 to conceive a world in which no two things should be 



O 



associated more often, in the long run, than any other 

 two things. The frequent conjunction of any two events 

 would then be purely fortuitous, and if we expected 

 conjunctions to recur continually we should be disap 

 pointed. In such a world we might recognise the same 

 phenomenon as it appeared from time to time, just as we 

 might recognise a marked ball as it was occasionally 

 drawn from a ballot-box ; but the approach of any one 

 phenomenon would be in no way indicated by what had 

 gone before, nor would it be at all a sign of what was to 

 come after. In such a world knowledge would be no 

 more than the memory of past coincidences, and the 

 reasoning powers, if they existed at all, would give no 

 clue to the nature of the present, and no presage of the 

 future. 



Happily the Universe in which we dwell is not the 

 result of chance, and where chance seems to work it is 

 our own deficient faculties which prevent us from recog- 



