136 NAMES AND PROPOSITIONS. 



to those particular properties. The differences, however, are 

 made by nature, in both cases ; while the recognition of those 

 differences as grounds of classification and of naming, is, equally 

 in both cases, the act of man : only in the one case, the ends of 

 language and of classification would be subverted if no notice 

 were taken of the difference, while in the other case, the neces 

 sity of taking notice of it depends on the importance or unim 

 portance of the particular qualities in which the difference 

 happens to consist. 



Now, these classes, distinguished by unknown multitudes 

 of properties, and not solely by a few determinate ones which 

 are parted off from one another by an unfathomable chasm, 

 instead of a mere ordinary ditch with a visible bottom are 

 the only classes which, by the Aristotelian logicians, were 

 considered as genera or species. Differences which extended 

 only to a certain property or properties, and there terminated, 

 they considered as differences only in the accidents of things ; 

 but where any class differed from other things by an infinite 

 series of differences, known and unknown, they considered the 

 distinction as one of kind, and spoke of it as being an essential 

 difference, which is also one of the current meanings of that 

 vague expression at the present day. 



Conceiving the schoolmen to have been justified in drawing 

 a broad line of separation between these two kinds of classes 

 and of class-distinctions, I shall not only retain the division 

 itself, but continue to express it in their language. According 

 to that language, the proximate (or lowest) Kind to which any 

 individual is referable, is called its species. Conformably to 

 this, Sir Isaac Newton would be said to be of the species 

 man. There are indeed numerous sub-classes included in 

 the class man, to which Newton also belongs; for example, 

 Christian, and Englishman, and Mathematician. But these, 

 though distinct classes, are not, in our sense of the term, dis 

 tinct Kinds of men. A Christian, for example, differs from 

 other human beings ; but he differs only in the attribute 

 which the word expresses, namely, belief in Christianity, and 

 whatever else that implies, either as involved in the fact itself, 

 or connected with it through some law of cause and effect. We 



