466 



OPERATIONS SUBSIDIARY TO INDUCTION. 



gach a way as shall give us the 

 greatest command over our know- 

 ledge already acquired, and lead most 

 directly to the acquisition of more. 

 The general problem of Classification, 

 in reference to these purposes, may 

 be stated as follows : To provide that 

 things shall be thought of in such 

 groups, and those groups in such an 

 order, as will best conduce to the re- 

 membrance and to the ascertainment 

 of their laws. 



Classification thus considered dif- 

 fers from classification in the wider 

 sense, in having reference to real 

 objects exclusively, and not to all 

 that are imaginable ; its object being 

 the due co-ordination in our minds of 

 those things only, with the properties 

 of which we have actually occasion to 

 make ourselves acquainted. But, on 

 the other hand, it embraces all really 

 existing objects. We cannot consti- 

 tute any one class properly, except in 

 reference to a general division of the 

 whole of nature ; we cannot deter- 

 mine the group in which any one ob- 

 ject can most conveniently be placed, 

 without taking into consideration all 

 the varieties of existing objects, all, 

 at least, which have any degree of 

 aflfinity with it. No one family of 

 plants or animals could have been 

 rationally constituted, except as part 

 of a systematic arrangement of all 

 plants or animals ; nor could such a 

 general arrangement have been pro- 

 perly made without first determining 

 the exact place of plants and animals 

 in a general division of nature. 



§ 2. There is no property of ob- 

 jects which may not be taken, if we 

 please, as the foundation for a classi- 

 fication or mental grouping of those 

 objects ; and in our first attempts we 

 are likely to select for that purpose 

 properties which are simple, easily 

 conceived, and perceptible on a first 

 view, without any previous process of 

 thought. Thus Tournefort's arrange- 

 ment of plants was founded on the 

 shape and divisions of the corolla ; 

 and that which is commonly called 



the Linnseaji (though Linnaeus 

 suggested another and more scientific 

 arrangement) was grounded chiefly 

 on the number of the stamens and 

 pistils. 



But these classifications, which are 

 at first recommended by the facility 

 they afford of ascertaining to what 

 class any individual belongs, are sel- 

 dom much adapted to the ends of 

 that Classification which is the suli- 

 ject of our present remarks. The 

 Linnsean arrangement answers the 

 purpose of making us think together 

 of all those kinds of plants which 

 possess the same number of staniens 

 and pistils ; but to think of them in 

 that manner is of little use, since we 

 seldom have anything to affirm in 

 common of the plants which have a 

 given number of stamens and pistils. 

 If plants of the class Pentandria, 

 order Monogynia, agreed in any other 

 properties, the habit of thinking and 

 speaking of the plants under a com- 

 mon designation would conduce to 

 our remembering those common pro- 

 perties so far as they were ascertained, 

 and would dispose us to be on the 

 look-out for such of them as were not 

 yet known. But since this is not 

 the case, the only purpose of thought 

 which the Linnaean classification 

 serves is that of causing us to re- 

 member, better than we should other- 

 wise have done, the exact number of 

 stamens and pistils of every species 

 of plants. Now, as this property is 

 of little importance or interest, he 

 remembering it with any particular 

 accuracy is of no moment. And 

 inasmuch as, by habitually thinking 

 of plants in those groups, we are pre- 

 vented from habitually thinking of 

 them in groups which have a greater 

 number of properties in common, the 

 effect of such a classification, when 

 systematically adhered to, upon our 

 habits of thought, must be regarded 

 as mischievous. 



The ends of scientific classification 

 are best answered when the objects 

 are formed into groups respecting 

 which a greater number of genera] 



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also 



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