350 INDUCTION. 



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 universality may be more strongly relied upon. 

 For, in the first place, if they are results of causation (which, even 

 in the class of unifomiities 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 necessary collocations pre- 

 vail, and within which no 'causes exist capable of coimteracting the 

 unknown causes upoii 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 invai'iably accompanies some vei-y numerous and com- 

 plex gi-oup of distinguishing properties ; which, if causation be at all 

 concerned in the matter, argues a combination of many causes, and 

 therefore a very gi-eat liability to counteraction; while the compara- 

 tively narrow range of the observations renders it impossible to pre- 

 dict to what extent unknown counteracting causes may be distributed 

 throughout nature. But when a generalization has been found to hold 

 good of a very large proportion of all things whatever, it is already 

 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 affect 

 it; since the greater number of possible combinations must have 

 already existed in some one or other of the instances in which it has 

 been found true. If, therefore, any empiiical law is a result of causa- 

 tion, the more general it is, the more it may be depended upon. And 

 even if it be no result of causation, but an ultimate coexistence, the 

 more general it is, the greater amount of experience it is derived from, 

 and the gi-eater therefore is the probability that if exceptions had 

 existed, some would already have presented themselves. 



For these reasons, it requires much more evidence to establish an 

 exception 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 kind of bird resembling a crow in 

 the properties hitherto considered distinctive of that Kind. But it 

 would require stronger proof to convince us of the existence of a kind 

 of crow having properties at variance with any generally recognized 

 universal property of birds ; and a still higher dcgi-ee if the properties 

 conflict with any recognized universal property of animals. And this 

 is conformable to the mode of judgment recommended by the common 

 sense and general practice of mankind, who are more incredulous as to 

 any novelties in nature, according to the degree of generality of the 

 experience which these novelties seem to contradict. 



§ 9- Still, however, even these greater generalizations, which em- 

 brace comprehensive Kinds, containing under them a gi'eat number 

 and variety of infimce species, are only empirical laws, resting upon 

 induction by simjjle enumeration merely, and not upon any process of 

 elimination, a process wholly inapplicable to the kind of case. Such 

 generalizations, therefore, ought to be grounded upon an examination 

 of all the inJlmcB species comprehended in them, and not oi a portion 

 only. We cannot conclude, merely because a proposition is ti'ue of a 

 number of things resembling one another only in being animals, that 

 it is therefore time of all animals. If, indeed, anything be true of 

 epecies which differ more from one another than either differs from a 



