INTERMIXTURE OF EFFECTS. 533 



government, such as the enactment or repeal of a 

 particular law. But, where there are so many in- 

 fluences at work, it requires some time for the 

 influence of any new cause upon national phenomena 

 to become apparent; and as the causes operating in 

 so extensive a sphere are not only infinitely numerous, 

 but in a state of perpetual alteration, it is always 

 certain that before the effect of the new cause becomes 

 conspicuous enough to be a subject of induction, so 

 many of the other influencing circumstances will have 

 changed as to vitiate the experiment. 



Two, therefore, of the three possible methods for 

 the study of phenomena resulting from the compo- 

 sition of many causes, being, from the very nature of 

 the case, inefficient and illusory ; there remains only 

 the third, that which considers the causes sepa- 

 rately, and computes the effect from the balance of 

 the different tendencies which produce it: in short, 

 the deductive, or a priori method. The more parti- 

 cular consideration of this intellectual process requires 

 a chapter to itself. 



