EXCEPTIONAL PHENOMENA. 309 



It ought to be clearly understood that in no case is a 

 law of nature really thwarted or prevented from being 

 fulfilled. The effects of a law may be disguised and 

 hidden from our view in some instances in others the 

 law itself may be rendered inapplicable altogether but 

 if a law is applicable it must be carried out. Every 

 law of nature must therefore be stated with the utmost 

 generality of all the instances really coming under it. 

 Babbage proposed to distinguish between universal prin- 

 ciples, which do not admit of a single exception, such 

 as that every number ending in 5 is divisible by five, 

 and general principles which are more frequently obeyed 

 than violated, as that 'men will be governed by what 

 they believe to be their interest 3 / But in a scientific 

 point of view general principles must be universal as 

 regards some distinct class of objects, or they are not 

 principles at all. If a law to which exceptions exist is 

 stated without allusion to those exceptions, the state- 

 ment is erroneous. I have no right to say that 'All 

 liquids expand by heat/ if I know that water below 

 4 C. does not ; 1 ought to say, ' All liquids, except water 

 below 4 C., expand by heat;' and every new exception 

 discovered will falsify the statement until inserted in it. 

 To speak of some laws as being generally true, meaning 

 not universally but in the majority of cases, is a hurt- 

 ful abuse of the word, but is quite usual. General should 

 mean that which is true of a whole genus or class, and 

 every true statement must be true of some assigned or 

 assignable class. 



Imaginary or False Exceptions. 



When a supposed exception to a law of nature is 

 brought to our notice, the first inquiry ought properly 



a Babbage, 'The Exposition of 1851,' p. i. 



