CLASSIFICATION AND TUB TREDICABLES. 85 



uncoTinocteJ with Christianity, are common to all Christians and pe- 

 culiar to them ; while in regard to all Men, physiologists are perpetu- 

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

 completed. Man, therefore, we may be permitted to call a species ; 

 Christian, or Mathematician, we cannot. 



Note here, that it is by no means intended to imply that there may 

 not be different Kind^, or logical species, of man. The various races 

 and temperaments, the two sexes, and even the various ages, may be 

 differences of kind, within our meaning of the term. I say, they may 

 be ; I do not say, they are. For in the progress of jihysiology it may 

 be made out, that the differences which distinguis.i different races, 

 sexes, &c., fi'om one another, follow as consequences, under laws of 

 nature, fi-om some one or a few primai-y differences which can be pre- 

 cisely determined, and which, as the phrase is, account for all the rest. 

 If this be so, these are not distinctions in kind ; no more than Chris- 

 tian, Jew, Mussulman, and Pagan, a difference which also can-ies 

 many consequences along with it. And in this way classes are often 

 mistaken for real kinds, which are afterwards proved not to be so. 

 But if it shall turn out, that the differences are not capable of being 

 accounted for, then man and woman, Caucasian, Mongolian, and Ne- 

 gro, &c., are really different Kinds of human beings, and entitled to 

 be ranked as species by the logician ; though not by the naturalist. 

 For (as already hinted) the word species is used in a very different 

 signification in logic and in natural history. By the naturalist, organ- 

 ized beings are never said to be of different species, if it is supposed 

 that they could possibly have descended fi-om the same stock. That, 

 however, is a sense aitificially given to the word, for the technical pur- 

 poses of a particular science. To the logician, if a negro and a white 

 man differ in the same manner (however less in degi'ee), as a horse 

 and a camel do, that is, if their differences are inexhaustible, and not 

 referrible to any common cause, they are different species, whether 

 they are both descended fi-om Noah or not. But if their differences 

 can all be traced to climate and habits, they are not, in the logician's 

 view, specifically distinct. 



^Vlien the injima s^pecics, or proximate Kind, to which an indi^^dual 

 belongs, ha.s been ascertained, the properties common to that Kind 

 include necessarily the whole of the common properties of every other 

 real Kind to which the individual can be refemble. Let the indi\'id- 

 ual, for example, be Socrates, and the pi-oximate Kind, man. Animal, 

 or living creature, is also a real Kind, and includes Socrates ; but since 

 it likewise includes man, or in other words, since all men are animals, 

 the properties common to animals form a portion of the common prop- 

 erties of the sub-class, man : and if there be any class which includes 

 Socrates without including man, that class is not a real Kind. Let the 

 class, for example, be fat-nosed ; that being a class which includes 

 Socrates, without including all men. To detei-mine whether it is a 

 real Kind, we must ask ourselves this question : Have all flat-nosed 

 animals, in addition to whatever is implied in their flat noses, any 

 common properties, other than those which are common to all animals 

 whatever 1 If they had ; if a flat nose were a mark or index to an in- 

 definite number of other peculiarities, not deducible fi-om the former 

 by any ascertainable law ; then out of the class man we might cut an- 

 other class, flat-nosed man, which, according to our definition, would 



