524 INDUCTION. 



the less conspicuous of the two, is called the disturb- 

 ing force, prevails sufficiently over the other force in 

 some one case, to constitute that case what is com- 

 monly called an exception, the same disturbing force 

 probably acts as a modifying cause in many other cases 

 which no one will call exceptions. 



" Thus if it were stated to be a law of nature that 

 all heavy bodies fall to the ground, it would probably 

 be said that the resistance of the atmosphere, which 

 prevents a balloon from falling, constitutes the balloon 

 an exception to that pretended law of nature. But 

 the real law is, that all heavy bodies tend to fall ; and 

 to this there is no exception, not even the sun and 

 moon ; for even they, as every astronomer knows, 

 tend towards the earth, with a force exactly equal to 

 that with which the earth tends towards them. The 

 resistance of the atmosphere might, in the particular 

 case of the balloon, from a misapprehension of what 

 the law of gravitation is, be said to prevail over the 

 law ; but its disturbing effect is quite as real in every 

 other case, since though it does not prevent, it retards 

 the fall of all bodies whatever. The rule, and the 

 so-called exception, do not divide the cases between 

 them ; each of them is a comprehensive rule extend- 

 ing to all cases. To call one of these concurrent 

 principles an exception to the other, is superficial, and 

 contrary to the correct principles of nomenclature and 

 arrangement. An effect of precisely the same kind, and 

 arising from the same cause, ought not to be placed 

 in two different categories, merely as there does or does 

 not exist another cause preponderating over it." 



6. We have now to consider according to what 

 method these complex effects, compounded of the 

 effects of many causes, are to be studied ; how we are 



