GROUND OF INDUCTION. 183 



facts, whicb Kepler had connected by his conception of an elhpse, 

 under the additional conception of bodies acted upon by a central 

 force, and serves therefore as a new bond of connexion for those 

 facts ; a new principle for their classification. 



Moreover, that general description, which is improperly confounded 

 with induction, is nevertheless a necessary preparation for induction ; 

 no less necessary than correct observation of the facts themselves. 

 Without the previous colligation of detached observations by means 

 of one general conception, we could never have obtained any basis for 

 an induction, excejit in the case of phenomena of very limited compass. 

 "VVe should not be able to affirm any predicates at all, of a subject in- 

 capable of being observed otherwise than piecemeal : much less could 

 we extend those predicates by induction to other similar subjects. 

 Induction, therefore, always presupposes, not only that the necessary 

 observations are made with the necessaiy accuracy, but also that the 

 results of these obsen'ations are, so far as practicable, connected 

 together by general descriptions, enabling the mind to represent to 

 itself as wholes whatever phenomena are capable of being so rep- 

 resented. 



To suppose, however, that nothing more is required from the concep- 

 tion than that it shall sei-\e to connect the obsei-vations, would be to 

 substitute hypothesis for theory and imagination for proof The 

 connecting link must be some character which really exists in the facts 

 themselves, and which would manifest itself therein if the conditions 

 could be realized which our organs of sense require. 



What more may be usefully said on the subject of Colligation, or of 

 the correlative expression invented by Mr. Wliewell, the Explication 

 of Conceptions, and generally on the subject of ideas and mental 

 representations as connected with the study of facts, will find a more 

 appropriate place in the Fourth Book, on the Operations Subsidiary 

 to Induction: to which the reader must refer for the removal of any 

 difficulty which the present discussion may have left. 



CHAPTER III. 



OF THE GROUND OF INDUCTION. 



§ 1. Induction properly so called, as distinguished from those mental 

 operations, sometimes though improperly designated by the name, 

 which I have attempted in the preceding chapter to characterize, may, 

 then, be summarily defined as Generalization fi-om Experience. It 

 consists in inferring from some individual instances in which a phe- 

 nomenon is obsei-ved to occur, that it occurs in all instances of a 

 certain class ; namely, in all which resemble the former, in what are 

 regarded as the material circumstances. 



In what Way the material circumstances are to be distinguished fi-om 

 those which are immaterial, or why some of the circumstances are 

 material and others not so, we are not yet ready to point out. We 

 must first observe, that there is a principle implied in the very state- 

 ment of what Induction is ; an assumption with regard to the course 



