INTERMIXTURE OF EFFECTS. 



291 



position (for it is no more) grounded 

 solely on the fact that the weight of 

 the water is the sum of the separate 

 weights of th« two ingredients. If 

 there had not been this exception to 

 the entire disappearance in the com- 

 pound of the laws of the separate 

 ingredients; if the combined agents 

 had not, in this one particular of 

 weight, preserved their own laws, and 

 produced a joint result equal to the 

 sum of their separate results, we 

 should never, probably, have had the 

 notion now implied by the words 

 chemical composition ; and, in the 

 facts of water produced from hydro- 

 gen and oxygen, and hydiogen and 

 oxygen produced from water, as the 

 transformation would have been com- 

 plete, we should have seen only a 

 transformation. 



In these cases, where the hetero- 

 pathic effect (as we called it in a 

 former chapter *) is but a transfor- 

 mation of its cause, or, in other words, 

 where the effect and its cause are 

 reciprocally such, and mutually con- 

 vertible into each other, the problem 

 of finding the cause resolves itself 

 into the far easier one of finding an 

 effect, which is the kind of inquiry 

 that admits of being prosecuted by 

 direct experiment. But there are 

 other cases of heteropathic effects to 

 which this mode of investigation is 

 not applicable. Take, for instance, 

 the heteropathic laws of mind, that 

 portion of the phenomena of our men- 

 tal nature which are analogous to 

 chemical rather than to dynamical 

 phenomena ; as when a complex pas- 

 sion is formed by the coalition of 

 several elementary impulses, or a 

 complex emotion by several simple 

 pleasures or pains, of which it is the 

 result without being the aggregate, 

 or in any respect homogeneous with 

 them. The product, in these cases, 

 is generated by its various factors ; 

 but the factors cannot be reproduced 

 from tht product ; just as a youth 

 can grow into an old man, but an old 



* jLutm, chap. tli. 1 1. 



man cannot grow into a youth. We 

 cannot ascertain from what simple 

 feelings any of our complex states of 

 mind are generated, as we ascertain 

 the ingredients of a chemical com- 

 pound, by making it, in its turn, 

 generate them. We can only, there- 

 fore, discover these laws by the slow 

 process of studying the simple feel« 

 ings themselves, and ascertaining 

 synthetically, by experimenting on 

 the various combinations of which 

 they are susceptible, what they, by 

 their mutual action upon one another, 

 are capable of generating. 



§ 5. It might have been supposed 

 that the other, and apparently simpler 

 variety of the mutual interference of 

 causes, where each cause continues to 

 produce its own proper effect accord- 

 ing to the same laws to which it con- 

 forms in its separate state, would 

 have presented fewer diflBculties to 

 the inductive inquirer than that of 

 which we have just finished the con- 

 sideration. It presents, however, so 

 far as direct induction apart from 

 deduction is concerned, infinitely 

 greater diflBculties. When a concur- 

 rence of causes gives rise to a new 

 effect, bearing no relation to the 

 separate effects of those causes, the 

 resulting phenomenon stands forth 

 undisguised, inviting attention to its 

 peculiarity, and presenting no obstacle 

 to our recognising its presence or ab- 

 sence among any number of surround- 

 ing phenomena. It admits, therefore, 

 of being easily brought under the 

 canons of Induction, provided in- 

 stances can be obtained such as those 

 canons require : and the non-occur- 

 rence of such instances, or the want 

 of means to produce them artificially, 

 is the real and only difficulty in such 

 investigations ; a diflBculty not logical, 

 but in some sort physical. It is other- 

 wise with cases of what, in a preceding 

 chapter, has been denominated the 

 Composition of Causes. There, the 

 effects of the separate causes do not 

 terminate and give place to others, 

 thereby ceasing to form any part of 



