422 OPERATIONS SUBSIDIARY TO INDUCTION. 



record shall exactly show what fact it is which has been observed. In 

 other words, there must be an accurate Descriptive Terminology. 



The only things which we can obsei-\e directly being our own sen- 

 sations, or other feelings, a complete descriptive language would be 

 one in which there should be a name for eveiy variety of elementary 

 sensation or feeling. Combinations of sensations or feelings may al- 

 ways be described, if we have a name for each of the elementary 

 feelino- s which compose them ; but brevity of description, as well as 

 clearness (which often depends very much upon brevity,) is greatly 

 promoted by giving distinctive names not to the elements alone, but also 

 to all combinations which are of frequent recuiTence. On this occasion 

 I cannot do better than quote from Mr. Whewell some of the excellent 

 remarks which he has made on this important branch of our subject. 



" The meaning" (says he*) "of [descriptive] technical terms, can 

 be fixed in the first instance only by convention, and can be made 

 intelligible only by presenting to the senses that which the terms are 

 to signify. The knowledge of a color by its name can only be 

 taught through the eye. No description can convey to a hearer A\hat 

 we mean by apple-green or French-gray. It might, perhaps, be sup- 

 posed that, in the first example, the term apple, refemng to so 

 familiar an object, sufficiently suggests the color intended. But it may 

 easily be seen that this is not true ; for apples are of many different 

 hues of green, and it is only by a conventional selection that we can 

 appropriate the term to one special shade. When this appropriation 

 is once made, the term refers to the sensation, and not to the paxts of 

 the terra ; for these enter into the compound merely as a help to the 

 -memory, wliether the suggestion be a natural connexion as in ' apple- 

 green,' or a casual one as in ' French-gray.' In oi'der to derive due 

 advantage from technical terms of this kind, they must be associated 

 imjnediatehj with the perception to which they belong, and not con- 

 nected with it through the vague usages of common language. The 

 memory must retain the sensation ; and the technical word must be 

 understood as directly as the most familiar word, and more distinctly. 

 When we find such terms as tin-white or pinchbeck-broun, the metallic 

 color so denoted ought to start up in our memory without delay or 

 search. 



" This, which it is most important to recollect with respect to the 

 simpler properties of bodies, as color and form, is no less ti'ue with 

 respect to more compound notions. In all cases the terai is fixed to a 

 peculiar meaning by convention ; and the student, in order to use the 

 word, must be completely familiar with the convention, so that he has 

 no need to frame conjectures from the word itself Such conjectures 

 would always be insecure, and often eiToneous. Thus the ierm papi- 

 lionaceous applied to a flower is employed to indicate, not only a re- 

 semblance to a butterfly, but a resemblance arising from five petals of 

 a certain peculiar shape and arrangement ; and even if the resem- 

 blance were much stronger than it is in such cases, yet if it were pro- 

 duced in a different way, as, for example, by one petal, or two only, 

 instead of a 'standard,' two 'wings,' and a ' keel' consisting of two 

 parts more or less united into one, we should no longer be justified in 

 speaking of it as a 'papilionaceous' flov/er." 



• Philosophy of the Inductive Sciences, i., 464-5. 



