384 



INDUCTION. 



and even animals, previously over- 

 looked or confounded with known 

 species, are still continually detected 

 in the most frequented situations. 

 On this second ground, therefore, as 

 well as on the first, the observed 

 uniformity of co-existence can only 

 hold good as an empirical law, within 

 the limits not only of actual observa- 

 tion, but of an observation as accu- 

 rate as the nature of the case re- 

 quired. And hence it is that (as re- 

 marked in an early chapter of the 

 present Book) we so often give up 

 generalisations of this class at the 

 first summons. If any credible wit- 

 ness 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 unifor- 

 mities which obtain in the co-existence 

 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 

 within the limits of time, place, and 

 circumstance, in which the observa- 

 tions were made, or except in cases 

 strictly adjacent. 



§ 8. We have seen in the last chap- 

 ter that there is a point of generality 

 at which empirical laws become as 

 certain as laws of nature, or rather, 

 at which there is no longer any dis- 

 tinction between empirical laws and 

 laws of nature. As empirical laws 

 approach this point, in other words, as 

 they rise in their degree of generality, 

 they become more certain ; their uni- 

 versality may be more strongly relied 

 on. For, in the first place, if they are 

 results of causation, (which, even in 

 the class of uniformities treated of in 

 the present chapter, we never can be 

 certain that they are not,) the more 

 general they are, the greater is proved 

 to be the space over which the neces- 

 sary collocations prevail, and within 

 which no causes exist capable of 



counteracting the unknown causes on 

 which the empirical law depends. To 

 say that anything is an invariable 

 property of some very limited class of 

 objects, is to say that it invariably 

 accompanies some very numerous and 

 complex group of distinguishing pro- 

 perties ; which, if causation be at all 

 concerned in the matter, argues a com- 

 bination of many causes, and there- 

 fore a great liability to counterac- 

 tion ; while the comparatively narrow 

 range of the observations renders it 

 impossible to predict to what extent 

 unknown counteracting causes may be 

 distributed throughout nature. But 

 when a generalisation has been found 

 to hold good of a very large propor- 

 tion of all things whatever, it is al- 

 ready proved that nearly all the 

 causes which exist in nature have no 

 power over it ; that very few changes 

 in the combination of causes can 

 effect it, since the greater number of 

 possible combinations must have al- 

 ready existed in some one or other of 

 the instances in which it has been 

 found true. If, therefore, any em- 

 pirical law is a result of causation, the 

 more general it is, the more it may be 

 depended on. And even if it be no 

 result of causation, but an ultimate 

 co-existence, the more general it is, 

 the greater amount of experience it is 

 derived from, and the greater there- 

 fore is the probability that if excep- 

 tions had existed, some would already 

 have presented themselves. 



For these reasons, it requires much 

 more evidence to establish an ex- 

 ception to one of the more general 

 empirical laws than to the more 

 special ones. We should not have 

 any difficulty in believing that there 

 might be a new Kind of crow, or a 

 new kind of bird resembling a crow 

 in the properties hitherto considered 

 distinctive of that Kind. But it 

 would require stronger proof to con- 

 vince us of the existence of a Kind of 

 crow having properties at variance 

 with any generally recognised univer- 

 sal property of birds ; and a still 

 higher degree if the properties con- 



