344 



iNDtJCTION. 



have recognised two kinds of empi- 

 rical laws : those known to be laws 

 of causation but presumed to be re- 

 solvable into simpler laws, and those 

 not known to be laws of causation at 

 all. Both these kinds of laws agree 

 in the demand which they make for 

 being explained by deduction, and 

 agree in being the appropriate means 

 of verifying such deduction, since they 

 represent the experience with which 

 the result of the deduction must be 

 compared. They agree, further, in 

 this, that, until explained and con- 

 nected with the ultimate laws from 

 which they result, they have not at- 

 tained the highest degree of certainty 

 of which laws are susceptible. It has 

 been shown on a former occasion that 

 laws of causation which are deriva- 

 tive and compounded of simpler laws 

 are not only, as the nature of the case 

 implies, less general, but even less 

 certain, than the simpler laws from 

 which they result, not in the same 

 degree to be relied on as universally 

 true. The inferiority of evidence, 

 however, which attaches to this class 

 of laws is trifling compared with that 

 which is inherent in uniformities 

 not known to be laws of causation 

 at all. So long as these are unre- 

 solved, we cannot tell on how many 

 collocations, as well as laws, their 

 truth may be dependent ; we can 

 never, therefore, extend them with 

 any confidence to cases in which we 

 have not assured ourselves by trial 

 that the necessary collocation of causes, 

 whatever it may be, exists. It is to 

 this class of laws alone that the pro- 

 perty, which philosophers usually con- 

 sider as characteristic of empirical 

 laws, belongs in all its strictness — 

 the property of being unfit to be re- 

 lied on beyond the limits of time, 

 place, and circumstance, in which the 

 observations have been made. These 

 are empirical laws in a more emphatic 

 sense ; and when I employ that term 

 (except where the context manifestly 

 indicates the reverse) I shall generally 

 mean to designate those uniformities 

 only, whether of succession or of co- 



existence» which are Hot known to be 

 laws of causation. 



CHAPTER XVIL 



OF CHANCE AND ITS ELIMINATION. 



§ I. CoNSiDEKiNG then as empiri- 

 cal laws only those observed uniformi- 

 ties respecting which the question 

 whether they are laws of causation 

 must remain undecided until they can 

 be explained deductively, or until 

 some means are found of applying the 

 Method of Difference to the case ; it 

 has been shown in the preceding 

 chapter, that until an uniformity can, 

 in one or the other of these modes, be 

 taken out of the class of empirical 

 laws, and brought either into that of 

 laws of causation or of the demon- 

 strated results of laws of causation, it 

 cannot with any assurance be pro- 

 nounced true beyond the local and 

 other limits within which it has been 

 found so by actual observation. It 

 remains to consider how we are to 

 assure ourselves of its truth even with- 

 in those limits ; after what quantity 

 of experience a generalisation which 

 rests solely on the Method of Agree- 

 ment can be considered sufficiently 

 established, even as an empirical law. 

 In a former chapter, when treating of 

 the Methods of Direct Induction, we 

 expressly reserved this question,* and 

 the time has now come for endeavour- 

 ing to solve it. 



We found that the Method of Ag- 

 reement has the defect of not prov- 

 ing causation, and can therefore only 

 be em^ployed for the ascertainment of 

 empirical laws. But we also found 

 that besides this deficiency, it labours 

 under a characteristic imperfection, 

 tending to render uncertain even such 

 conclusions as it is in itself adapted 

 to prove. This imperfection arises 

 from Plurality of Causes. Although 

 two or more cases in which the phe- 

 nomenon a has been met with may 



* Supra, book iii. cli. x. § 2, 



