LOGIC 287 



accidentally. Thus a Jew is a man who believes himself 

 bound to keep a Sabbath, and this is " essential/' but 

 he may be lame or have had his hair cut short, cha- 

 racters which are but " accidental " ones. So it is that, 

 in logic, there are certain names which can only be 

 asserted, or predicated, of things, according to the mode in 

 which the mind regards them. They are therefore 

 called predicables, and there are five of them (i) genus ; 

 (2) difference ; (3) species; (4) property; and (5) acci- 

 dent. 



The predicable " genus " is applied to any larger 

 group which includes other groups within it, to every 

 one of which it applies, and each one of which is, in 

 logic, termed a " species." Thus in the first of the 

 above examples " Jew " is a genus which includes the 

 minor groups or species " certain men of Middlesex," 

 " certain men of Essex," <fcc. to each of which, that 

 which the name of the genus denotes, is applicable. 

 The term " Jews of Middlesex," again, is also a genus, 

 including within it subordinate groups or species, such 

 as " reformed Jews " and " unreformed Jews," while 

 " European " may also be a genus, whereof Jew, 

 Englishman, Russian, &c., are species, 



Thus genus and species in logic are very different 

 from genus and species as these terms are used by 

 zoologists and botanists.* 



In those sciences one set of groups is always genera, 

 and others are always species, and none can be both 

 genus and species. But in logic, groups are not always 

 one or the other, but may be either, according to the 

 direction taken by thought, as we see " Jew " may be a 

 getms, with respect to "men of Middlesex," " Essex," 



* See ante, p. 190, 



