494 INDUCTION. 



mical phenomena ; as when a complex passion 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 the 

 product; just as a youth can grow into an old man, but an old 

 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, 

 therefore, discover these laws by the slow process of studying 

 the simple feelings 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 

 according to the same laws to which it conforms in its separate 

 state, would have presented fewer difficulties 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 diffi 

 culties. When a concurrence 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 absence among any number 

 of surrounding phenomena. It admits therefore of being easily 

 brought under the canons of Induction, provided instances 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 investiga 

 tions ; a difficulty not logical, but in some sort physical. It is 

 otherwise with cases of what, in a preceding chapter, has been 

 denominated the Composition of Causes. There, the effects of 



