502 OPERATIONS SUBSIDIARY TO INDUCTION. 



without any certain standard or guide. The class is steadily fixed, though 

 not precisely limited ; it is given, though not circumscribed ; it is deter- 

 mined, not by a boundary-line without, but by a central point within; not 

 by what it strictly excludes, but by what it eminently includes ; by an ex- 

 ample, not by a precept ; in short, instead of a Definition we have a Type 

 for our director. 



"A Type is an example of any class, for instance a species of a genus, 

 which is considered as eminently possessing the character of the class. All 

 the species which have a greater afiinity with this type-species than with 

 any others, form the genus, and are arranged about it, deviating from it 

 in various directions and different degrees. Thus a genus may consist of 

 several species which approach very near the type, and of which the claim 

 to a place with it is obvious; while there may be other species which 

 straggle farther from this centi'al knot, and which yet are clearly more 

 connected with it than with any other. And even if there should be some 

 species of which the place is dubious, and which appear to be equally 

 bound to two generic types, it is easily seen that this would not destroy 

 the reality of the generic groups, any more than the scattered trees of the 

 intervening plain prevent our speaking intelligibly of the distinct forests 

 of two separate hills. 



" The type-species of every genus, the type-genus of every family, is then, 

 one which possesses all the characters and properties of the genus in a 

 marked and prominent manner. The type of the Rose family has alter- 

 nate stipulate leaves, wants the albumen, has the ovules not erect, has the 

 stigmata simple, and besides these features, which distinguish it from the 

 exceptions or varieties of its class, it has the features which make it promi- 

 nent in its class. It is one of those which possess clearly several leading 

 attributes ; and thus, though we can not say of any one genus that it must 

 be the type of the family, or of any one species that it must be the type of 

 the genus, we are still not wholly to seek; the typo must be connected by 

 many affinities with most of the othei'S of its group; it must be near the 

 centre of the crowd, and not one of the stragglers." 



In this passage (the latter part of which especially I can not help no- 

 ticing as an admirable example of philosophic style) Dr. Whewell has 

 stated very clearly and forcibly, but (I think) without making all necessary 

 distinctions, one of the principles of a Natural Classification. What this 

 principle is, what are its limits, and in what manner he seems to me to 

 have overstepped them, will appear when we have laid down another rule 

 of Natural Arrangement, which appears to me still more fundamental. 



§ 4. The reader is by this time familiar with the general truth (which I 

 restate so often on account of the great confusion in which it is common- 

 ly involved), that there are in nature distinctions of Kind ; distinctions 

 not consisting in a given number of definite properties plus the effects 

 which follow from those properties, but running through the whole nature, 

 through the attributes generally, of the things so distinguished. Our 

 knowledge of the properties of a Kind is never complete. We are always 

 discovering, and expecting to discover, new ones. Where the distinction 

 between two classes of things is not one of Kind, we expect to find their 

 properties alike, except where there is some reason for their being differ- 

 ent. On the contrary, when the distinction is in Kind, we expect to find 

 the properties different unless there be some cause for their being the 

 same. All knowledge of a Kind must be obtained by observation and 



