132 INDUCTION. 



often realized, that it cannot be considered at all 

 improbable. We have nothing to authorise us in 

 attempting to limit the Kinds of things which exist in 

 nature. The only unlikelihood would be that a new 

 Kind should be discovered in localities which there 

 was previously reason to believe had been thoroughly 

 explored ; and even this improbability depends upon 

 the degree of conspicuousness of the difference between 

 the newly discovered Kind and all others, since new 

 Kinds of minerals, plants, and even animals, previously 

 overlooked or confounded with known species, are 

 still continually detected in the most frequented situa- 

 tions. On this second ground, therefore, as well as 

 on the first, the observed uniformity of coexistence 

 can only hold good as an empirical law, within the 

 limits not only of actual observation, but of an obser- 

 vation as accurate as the nature of the case required. 

 And hence it is that (as remarked in an early chapter 

 of the present Book) we so often give up generaliza- 

 tions of this class at the first summons. If any 

 credible witness stated that he had seen a white crow, 

 under circumstances which made it not incredible 

 that it should have escaped notice previously, we 

 should give full credence to the statement. 



It appears, then, that the uniformities which obtain 

 in the coexistence of phenomena, those which we have 

 reason to consider as ultimate, no less than those 

 which arise from the laws of causes yet undetected 

 are entitled to reception only as empirical laws ; are 

 not to be presumed true except in the limits of time, 

 place, and circumstance, in which the observations 

 were made, or except in cases strictly adjacent. 



8. We have seen in the last chapter that there 

 is a point of generality at which empirical laws become 



