376 INDUCTION. 



detached from some of the elements with which we 

 had hitherto found them conjoined, and united to 

 others of quite a contrary description. To an inha- 

 bitant of Central Africa, fifty years ago, no fact pro- 

 bably appeared to rest upon more uniform experience 

 than this, that all human beings are black. To 

 Europeans, not many years ago, the proposition, All 

 swans are white, appeared an equally unequivocal 

 instance of uniformity in the course of nature. Fur- 

 ther experience has proved to both that they were 

 mistaken ; but they had to wait fifty centuries for 

 this experience. During that long time, mankind 

 believed in an uniformity of the course of nature 

 where no such uniformity really existed. 



According to the notion which the ancients enter- 

 tained of induction, the foregoing were cases of as 

 legitimate inference as any inductions whatever. In 

 these two instances, in which, the conclusion being 

 false, the ground of inference must have been insuffi- 

 cient, there was, nevertheless, as much ground for it 

 as this conception of induction admitted of. The 

 induction of the ancients has been well described by 

 Bacon, under the name of " Inductio per enumera- 

 tionem simplicem, ubi non reperitur instantia contra- 

 dictoria." It consists in ascribing the character of 

 general truths to all propositions which are true in 

 every instance that we happen to know of. This is 

 the kind of induction, if it deserves the name, which 

 is natural to the mind when unaccustomed to scien- 

 tific methods. The tendency, which some call an 

 instinct, and which others account for by association, 

 to infer the future from the past, the known from the 

 unknown, is simply a habit of expecting that what 

 has been found true once or several times, and never 

 yet found false, will be found true again. Whether 



