INDUCTIONS IMPROPERLY SO CALLED. 



199 



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 can scarcely be contended that 

 Kepler's operation was an Induction 

 in this sense of the term. The state- 

 ment that Mars moves in an ellipti- 

 cal orbit was no generalisation from 

 individual cases to a class of cases. 

 Neither was it an extension to all 

 time of what had been found true at 

 some particular time. The whole 

 amount of generalisation which the 

 case admitted of was already com- 

 pleted, 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 apparent places ; the series of 

 these places was, or might have been, 

 completely determined, and the ap- 

 parent course of each planet marked 

 out on the celestial globe in an unin- 

 terrupted line. Kepler did not ex- 

 tend an observed truth to other cases 

 than those in which it had been ob- 

 served : he did not widen the subject 

 of the proposition 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 succes- 

 sive 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 observations seen under a 

 new 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 actu- 

 ally 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 unknown which 

 constitutes Induction in the original 



* Phil, of Discov., p. 256. 



and acknowledged meaning of the 

 term. 



Old definitions, it is true, cannot 

 prevail against new knowledge : and 

 if the Keplerian operation, as a logi- 

 cal process, be really identical with 

 what takes place in acknowledged in- 

 duction, the definition of induction 

 ought to be so widened as to take it 

 in ; since scientific language ought to 

 adapt itself to the true relations which 

 subsist between the things it is em- 

 ployed to designate. Here then it is 

 that I am at issue with Dr. Whewell. 

 He does think the operations identi- 

 cal. He allows of no logical process 

 in any case of induction other than 

 what there was in Kepler's case, 

 namely, guessing until a guess is found 

 which tallies with the facts ; and ac- 

 cordingly, as we shall see hereafter, 

 he rejects all canons of induction, be- 

 cause it is not by means of them that 

 we guess. Dr. Whewell's theory of 

 the logic of science would be very per- 

 fect if it did not pass over altogether 

 the question of Proof. But in my ap- 

 prehension there is such a thing as 

 proof, and inductions differ altogether 

 from descriptions in their relation to 

 that element. Induction is proof ; 

 it is inferring something imol»erved 

 from something observed : it requires, 

 therefore, an appropriate test of proof ; 

 and to provide that test is the special 

 purpose of inductive logic. When, 

 on the contrary, we merely collate 

 known observations, and, in Dr. Whe- 

 well's phraseology, connect them by 

 means of a new conception ; if the 

 conception does serve to connect the 

 observations, we have all we want. 

 As the proposition in which it is em- 

 bodied pretends to no other truth than 

 what it may share with many other 

 modes of representing the same facts, 

 to be consistent with the facts is all 

 it requires : it neither needs nor ad- 

 mits of proof ; though it may serve 

 to prove other things, inasmuch as, 

 by placing the facts in mental con- 

 nection with other facts not previously 

 seen to resemble them, it assimilates' 

 the case to another class of phenomena, 



