SECT. 19.] Induction. 210 



18. But then at once there begins to arise some doubt 

 and ambiguity as to what exactly is to be understood by his 

 circumstances. We may know very well what these circum 

 stances are in themselves, and yet be in perplexity as to 

 how many of them we ought to take into account when 

 endeavouring to estimate his fate. We might conceivably, 

 for a beginning, choose to confine our attention to those 

 properties only which he has in common with all animals. 

 If so, and statistics on the subject were attainable, they 

 would presumably be of some such character as this, Ninety- 

 nine animals out of a hundred die within a year. Unusual as 

 such a reference would be, we should, logically speaking, be 

 doing nothing more than taking a wider class than the one 

 we were accustomed to. Similarly we might, if we pleased, 

 take our stand at the class of vertebrates, or at that of 

 mammalia, if zoologists were able to give us the requisite 

 information. Of course we reject these wide classes and 

 prefer a narrower one. If asked why we reject them, the 

 natural answer is that they are so general, and resemble the 

 particular case before us in so few points, that we should be 

 exceedingly likely to go astray in trusting to them. Though 

 accuracy cannot be insured, we may at least avoid any need 

 less exaggeration of the relative number and magnitude of 

 our errors. 



19. The above answer is quite valid ; but whilst cau 

 tioning us against appealing to too wide a class, it seems to 

 suggest that we cannot go wrong in the opposite direction, 

 that is in taking too narrow a class. And yet we do avoid 

 any such extremes. John Smith is not only an Englishman ; 

 he may also be a native of such a part of England, be living 

 in such a Presidency, and so on. An indefinite number of 

 such additional characteristics might be brought out into 

 notice, many of which at any rate have some bearing upon 



