INDUCTIONS IMPEOPERLY SO CALLED. 221 



to affirm any predicates at all, of a subject incapable of being observed 

 otherwise than piecemeal : much less could we extend those predicates by 

 induction to other similar subjects. Induction, therefore, always presup- 

 poses, not only that the necessary observations are made with the necessary 

 accuracy, but also that the results of these observations are, so far as prac- 

 ticable, connected together by general descriptions, enabling the mind to 

 represent to itself as wholes whatever phenomena are capable of being so 

 represented. 



§ 5. Dr. Whewell has replied at some length to the preceding observa- 

 tions, restating his opinions, but without (as far as I can perceive) adding 

 any thing material to his former arguments. Since, however, mine have 

 not had the good fortune to make any impression upon him, I will subjoin 

 a few remarks, tending to show more clearly in what our difference of 

 opinion consists, as well as, in some measure, to account for it. 



^-^Nearly all the definitions of induction, by writers of authority, make it 

 consist in drawing inferences from known cases to imknown ; affirming of 

 a class, a predicate which has been found true of some cases belonging to 

 the class; concluding because some things have a certain property, that 

 other things which resemble them have the same property — or because a 

 thing has manifested a property at a certain time, that it has and will have 



^ that property at other times. 



** It will scarcely be contended that Kepler's operation was an Induction 

 in this sense of the term. The statement, that Mars moves in an elliptical 

 orbit, was no generalization from individual cases to a class of cases. Nei- 

 ther was it an extension to all time, of what had been found true at some 

 particular time. The whole amount of generalization which the case ad- 

 mitted of, was already completed, or might have been so. Long before 

 the elliptic theory was thought of, it had been ascertained that the planets 

 returned periodically to the same appai*ent places ; the series of these 

 places was, or might have been, completely determined, and the apparent 

 course of each planet marked out on the celestial globe in an uninterrupted 

 line. Kepler did not extend an observed truth to other cases than those in 

 which it had been observed : ho did not widen the subject of the proposi- 

 tion which expressed the observed facts. The alteration he made was in 

 the predicate. Instead of saying, the successive places of Mars are so and 

 so, he summed them up in the statement, that the successive places of Mars 

 are points in an ellipse. It is true, this statement, as Dr. Whewell says, 

 was not the sum of the observations merely; it was the sum of the obser- 

 vations seen under a nevo point of view* But it was not the sum of more 

 than the observations, as a real induction is. It took in no cases but those 

 which had been actually observed, or which could have been inferred from 

 the observations before the new point of view presented itself. There was 

 not that transition from known cases to imknown, which constitutes Induc- 

 tion in the original and acknowledged meaning of the term. 



Old definitions, it is true, can not prevail against new knowledge : and if 

 the Keplerian operation, as a logical process, be really identical with what 

 takes place in acknowledged induction, the definition of induction ought to 

 be so widened as to take it in ; since scientific language ought to adapt it- 

 self to the true relations which subsist between the things it is employed 

 to designate. Here then it is that I am at issue with Dr. Whewell. He 



Phil, of Discov., p. 256. 



P 



