SECT. 21.] Induction. 221 



from the class man to make it worth our while to attend 

 to them. 



Now and then indeed these characteristics do rise into 

 importance, and whenever this is the case we concentrate 

 our attention upon the class to which they correspond, that 

 is, the class which is marked off by their presence. Thus, 

 for instance, the quality of consumptiveness separates any 

 one off so widely from the majority of his fellow-men in all 

 questions pertaining to mortality, that statistics about the 

 lives of consumptive men differ materially from those which 

 refer to men in general. And we see the result ; if a con 

 sumptive man can effect an insurance at all, he must do it 

 for a much higher premium, calculated upon his special 

 circumstances. In other words, the attribute is sufficiently 

 important to mark off a fresh class or series. So with in 

 surance against accident. It is not indeed attempted to 

 make a special rate of insurance for the members of each 

 separate trade, but the differences of risk to which they are 

 liable oblige us to take such facts to some degree into 

 account. Hence, trades are roughly divided into two or 

 three classes, such as the ordinary, the hazardous, and the 

 extra-hazardous, each having to pay its own rate of premium. 



21. Where one or other of the classes thus corresponds 

 to natural kinds, or involves distinctions of co-ordinate im 

 portance with those of natural kinds, the process is not 

 difficult ; there is almost always some one of these classes 

 which is so universally recognised to be the appropriate one, 

 that most persons are quite unaware of there being any 

 necessity for a process of selection. Except in the cases 

 where a man has a sickly constitution, or follows a dangerous 

 employment, we seldom have occasion to collect statistics for 

 him from any class but that of men in general of his age in 

 the country. 



