COMPOSITION OF CAUSES. 215 



particular case into tlic gcjioral principle of the Composition of Causes : 

 tlie causes compounded being, in this instance, liompgeneous ; in which 

 case, if in any, their joint elfect might be expected to" be identical with 

 the sum of their separate eflects. If a force equal to one hundred 

 -weight, will raise a certain body along an inclined plane, a force equal 

 to two hundred weight will, we know, raise two bodies exactly similar, 

 and thus the effect is proportienal to the cause. But does not a force 

 equal to two hundred weight, actually contain in itself two forces each 

 equal to one hundred: weight, which, if employed apait, would sepa- 

 rately raise the two bodies in (juestion i The fact, therefore, that 

 wlien exerted jointly they raise both bodies at once, results from the 

 Composition of Causes, and is a mere instance of the general fact that 

 mechanical forces are subject to the law of Composition. And so in 

 every other case which can be supposed. For the doctrine of the 

 proportionality of eflects to their causes cannot of course be applicable 

 to cases in which the augmentation of the cause alters the ki?id of effect; 

 that is, in which the su7-j)lus quantity superadded to the cause does not 

 become compounded with it, but the two together generate an alto- 

 gether' new phenomenon. Su^jpose that the application of a certain 

 quantity of heat to a body merely increases its bulk, that a double 

 quantity melts it, and a triple quantity decomposes it: these three 

 eflects being heterogeneous, no ratio, whether corresponding or not to 

 that of the quantities of heat applied, can be established between them. 

 Thus we see that the supposed axiom of the proportionality of effects 

 to their causes fails at the precise point whei?e the principle of the 

 Composition of Causes also fails ; viz., where the concuiTence of 

 causes is such as to determine a change in the properties of the body 

 generally, and render it subject to new laws, more or less dissimilar 

 to those to which it conformed in its previous state of existence. The 

 recognition, therefore, of any such law of proportionality, is superseded 

 by the more comprehensive principle, in which as much of it as is true 

 is implicitly asserted. 



The. general remarks on causation, which seqmed necessary as an 

 introduction to the theory of the inductive process, may here termi- 

 nate. That process is essentially an inquiry into cases of causation. 

 All the uniformities which exist in the succession of plienomena, and 

 most of those which prevail in their coexistence, are either, as we have 

 seen, themselves laws of causation, or consequences resulting from, 

 and corollaries capable of being deduced from, such laws. If we could 

 determine what causes are correctly assigned to what effects, and what 

 effects to what causes, we should be virtually acquainted with the 

 whole course of nature. All those uniformities which are mere results 

 of causation, might then be explained and accounted for ; and every 

 individual fact or event might be predicted, provided we had the 

 requisite data, that is, the recjuisite knowledge of the circumstances 

 which, in the particular instance, preceded it. 



To ascertain, therefore, what are the laws of causation which exist 

 in nature ; to determine the effects of eveiy cause, and the causes of 

 all effects, is the main business of Induction ; and to point out how this 

 is done is the chief object of Inductive Logic. 



