168 NAMES AND PROPOSITIONS. 



Aristotelian logicians, were considered as genera or 

 species. Differences which extended 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 usual meanings of that vague expres- 

 sion 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 referrable, is called its species. 

 Conformably to this, Sir Isaac Newton would be said 

 to be of the species man. There are indeed nume- 

 rous sub-classes included in the class man, to which 

 Sir Isaac Newton also belongs ; as, for example, 

 Christian, and Englishman, and Mathematician. But 

 these, though distinct classes, are not, in our sense of 

 the term, distinct 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 con- 

 nected with it through some law of cause and effect. 

 We should never think of inquiring what properties, 

 unconnected with Christianity, are common to all 

 Christians and peculiar to them ; while in regard to 

 all Men, physiologists are perpetually carrying on 

 such an inquiry ; nor is the answer ever likely to be 



