308 INDUCTION. 



upon laws but upon a collocation ; and collocations cannot be reduced 

 to any law. 



Now it is the very nature of a derivative law which has not yet been 

 resolved into its elements, in other words, an empirical law, that we 

 do not know whether it results from the different effects of one cause 

 or fi-om effects of different causes. We cannot tell whether it depends 

 wholly upon laws, or partly upon laws and partly upon a collocation. 

 If it depends upon a collocation, it will be true in all the cases in which 

 that particular collocation exists. But since we are entirely ignorant, in 

 case of its depending upon a collocation, what the collocation is, we are 

 not safe in extending the law beyond the limits of time and place in 

 which we have actual experience of its truth. Since within those limits 

 the law has always been found true, we have evidence that the colloca- 

 tions, whatever they are, upon which it depends, do really exist within 

 those limits. But knowing of no rule or principle to which the collo- 

 cations themselves conform, we cannot conclude that because a collo- 

 cation is proved to exist within certain limits of place or time, it will 

 exist beyond those limits. Empirical laws, therefore, can only be held 

 true within the limits of time and place in which they have been found 

 true by observation: and not merely the limits of time and place, but 

 of time, place, and circumstance : for since it is the very meaning of an 

 empirical law that we do not know the ultimate laws of causation upon 

 which it is dependent, we cannot foresee, without actual trial, in what 

 manner or to what extent the introduction of any new circumstance 

 may effect it. 



§ 5. But how are we to know that an uniformity, ascertained by 

 experience, is only an empirical law 1 Since, by the supposition, we 

 have not been able to resolve it into higher laws, how do we know 

 that it is not an ultimate law of causation ] 



I answer, that no generalization amounts to more than an empirical 

 law when the only proof upon which it rests is that of the Method of 

 Agreement. • For it has been seen that by that method alone we never 

 can arrive at causes. All that the Method of Agreement can do is, to 

 ascertain the whole of the circumstances common to all cases in which 

 a phenomenon is produced : and this of course includes not only the 

 cause of the phenomenon, but all phenomena with which it is con- 

 nected by any derivative uniformity, whether as being collateral 

 effects of the same cause, or effects of any other cause which, in all the 

 instances we have been able to obsei^e, coexisted with it. The method 

 affords no means of determining which of these unifoiTtiities are laws of 

 causation, and which are merely derivative laws resulting fi'om those 

 laws of causation and fi-om the collocation of the causes. None of 

 them, therefore, can be received in any other character than that of 

 derivative laws, the derivation of which has not been traced ; in other 

 words, empirical laws : in which light, all results obtained by the 

 Method of Agreement (and therefore almost all the truths obtained by 

 simple observation without experiment) must be considered, until 

 either confirmed by the Method of Difference, or explained deduc- 

 tively, in other words, accounted for a priori. 



These empirical laws may be of greater or of less authority, accord- 

 ing as there is reason to presume that they are resolvable into laws 

 only, or into laws and collocations together. The sequences which we 



