CLASSIFICATION. 



467 



propositions can be made, and those 

 propositions more important, than 

 could be made respecting any other 

 groups into which the same things 

 could be distributed. The properties, 

 therefore, according to which objects 

 are classified should, if possible, be 

 those which are causes of MEiny other 

 properties ; or, at any rate/which are 

 sure marks of them. Causes are pre- 

 ferable, both as being the surest and 

 most direct of marks, and as being 

 themselves the properties on which it 

 is of most use that our attention 

 should be strongly fixed. But the 

 pi'operty which is the cause of the 

 chief peculiarities of a class is un- 

 fortunately seldom fitted to serve 

 also as the diagnostic of the class. 

 Instead of the cause, we must gene- 

 rally select some of its more promi- 

 nent effects, which may serve as 

 marks of the other effects and of the 

 cause. 



A classification thus formed is pro- 

 perly scientific or philosophical, and 

 is commonly called a Natural, in 

 contradistinction to a Technical or 

 Artificial, classification or arrange- 

 ment. The phrase Natural Classifi- 

 cation seems most peculiarly appro- 

 priate to such arrangements as corre- 

 spond, in the groups which they form, 

 to the spontaneous tendencies of the 

 mind, by placing together the objects 

 most similar in their general aspect ; 

 in opposition to those technical sys- 

 tems which, arranging things ac- 

 cording to their agreement in some 

 circumstance arbitrarily selected, often 

 throw into the same group objects 

 which in the general aggregate of 

 their properties present no resem- 

 blance, and into different and remote 

 groups others which have the closest 

 similarity. It is one of the most 

 valid recommendations of any classi- 

 fication to the character of a scientific 

 one, that it shall be a natural classifi- 

 cation in this sense also ; for the test 

 of its scientific character is the num- 

 ber and importance of the properties 

 which can be asserted in common of 

 all objects included in a group ; and 



properties on which the general aspect 

 of the things depends are, if only on 

 that ground, important as well as, in 

 most cases, numerous. But, though 

 a strong recommendation, this cir- 

 cumstance ia not a sine qud non; 

 since the most obvious properties of 

 things may be of trifling importance 

 compared with others that are not 

 obvious. I have seen it mentioned as 

 a great absurdity in the Linnsean 

 classification, that it places (which, by 

 the way, it does not) the violet by the 

 side of the oak ; it certainly dissevers 

 natural affinities and brings together 

 things quite as unlike as the oak and 

 the violet are. But the difference, 

 apparently so wide, which renders the 

 juxtaposition of those two vegetables 

 so suitable an illustration of a bad 

 arrangement, depends, to the common 

 eye, mainly on mere size and texture ; 

 now if we made it our study to adopt 

 the classification which would involve 

 the least peril of similar rapjyi'oche- 

 merits, we should return to the obsolete 

 division into trees, shrubs, and herbs, 

 which, though of primary importance 

 with regard to mere general aspect, 

 yet (compared even with so petty and 

 unobvious a distinction as that into 

 dicotyledons and monocotyledons) an- 

 swers to so few differences in the 

 other properties of plants, that a 

 classification founded on it (indepen- 

 dently of the indistinctness of the 

 lines of demarcation) would be as 

 completely artificial and technical as 

 the Linnaean. 



Our natural groups, therefore, must 

 often be founded not on the obvious, 

 but on the unobvious properties of 

 things, when these are of greater 

 importance. But in such cases it is 

 essential that there should be some 

 other property or set of properties, 

 more readily recognisable by the ob- 

 server, which co-exist with, and may 

 be received as marks of, the properties 

 which are the real groundwork of the 

 classification. A natural arrange- 

 ment, for example, of animals, must 

 be founded in the main on their 

 internal structure, but (as M. Comte 



