394 OPERATIONS SUBSIDIARY TO INDUCTION. 



§ 4. If this be a coirect account of the instrumentality 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 Induc- 

 tion, must be " clear" and " appropriate." 



If the conception corresponds to a real agreement among the phe- 

 nomena ; 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 inay not indeed be clear, but it cannot 

 fail to be appi"opriate, for some purpose or other. The question of ap- 

 propriateness is relative to the particular object we have in view. As 

 soon as, by our comparison, we have ascertained some agreement, some- 

 thing 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 color, 

 and class those together which are colored alike, we form the general 

 conceptions of a white animal, a black animal, &c., which are concep- 

 tions legitimately formed ; and if an induction were to be attempted 

 concerning the causes of the colors of animals, this comparison would 

 be the proper and necessary preparation 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 compare 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 not only of 

 much greater importance in themselves, but are marks of agreements 

 and differences in many other most important particulars of the struc- 

 ture and mode of life of the animals. If, therefore, the study of their 

 structure and habits be our object, the conceptions generated by these 

 last comparisons are far more " appropriate" than those generated by 

 the former. Nothing, other than this, can be meant by the appropri- 

 ateness of a conception. 



When Mr. Whewell says that the ancients, or the schoolmen, or any 

 modern philosophers, missed discovering the real law of a phenomenon 

 because they applied to it an inappropriate instead of an appropriate 

 conception ; he can only mean that in comparing various instances of 

 the phenomenon, to ascertain in what those instances agreed, they 

 missed the important points of agi-eement ; and fastened upon such as 

 were either imaginary, and no agreements at all, or if real agreements, 

 were comparatively trifling, and had no connexion with the phenom- 

 enon, the law of which was sought. 



Aristotle, philosophizing on the subject of motion, remarked that 

 certain motions apparently take place spontaneously ; bodies fall to the 

 ground, flame ascends, bubbles of air rise in water, &c : and these he 

 called natural motions ; while others not only never take place vrithout 

 external incitement, but even when such incitement is applied, tend 

 spontaneously to cease ; which, to distinguish them from the former, 

 he called violent motions. Now, in comparing the so-called natural 

 motions with one another, it appeared to Aristotle that they agreed in 

 one circumstance, namely, that the body which moved (or seemed to 

 move) spontaneously, was moving towards its own place; meaning 



