222 OPERATIONS SUBSIDIARY TO INDUCTION. 



4. If this be a correct account of the instrumen- 

 tality of general conceptions in the comparison which 

 necessarily precedes Induction, we shall easily be able 

 to translate into our own language what Mr. Whewell 

 means by saying that conceptions, to be subservient 

 to Induction, must be " clear" and " appropriate. 



If the conception corresponds to a real agreement 

 among the phenomena ; if the comparison which we 

 have made of a set of objects has led us to class them 

 according to real resemblances and differences; the 

 conception which does this may not indeed be clear, 

 but it cannot fail to be appropriate, for some purpose 

 or other. The question of appropriateness is relative 

 to the particular object we have in view. As soon as, 

 by our comparison, we have ascertained some agree- 

 ment, something which can be predicated in common 

 of a number of objects; we have obtained a basis on 

 which an inductive process is capable of being founded. 

 But the agreements, or the ulterior consequences 

 to which those agreements lead, may be of very 

 different degrees of importance. If, for instance, we 

 only compare animals according to their colour, and 

 class those together which are coloured alike, we 

 form the general conceptions of a white animal, a 

 black animal, &c., which are conceptions legitimately 

 formed; and if an induction were to be attempted 

 concerning the causes of the colours of animals, this 

 comparison would be the proper and necessary prepa- 

 ration for such an induction, but would not help us 

 towards a knowledge of the laws of any other of the 

 properties of animals : while if, with Cuvier, we com- 

 pare and class them according to the structure of the 

 skeleton, or, with Blainville, according to the nature 

 of their outward integuments, the agreements and 

 differences which are observable in these respects are 



