338 INDUCTION. 



known cases to unknown, which constitutes Induction in the 

 original and acknowledged meaning of the term. 



Old definitions, it is true, cannot prevail against new 

 knowledge : and if the Keplerian operation, as a logical pro- 

 cess, be really identical with what takes place in acknow- 

 ledged induction, 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 employed to designate. Here then it is that I 

 am at issue with Dr. Whewell. He does think the operations 

 identical. He allows of no logical process in any case of in- 

 duction, other than what there was in Kepler's case, namely, 

 guessing until a guess is found which tallies with the facts ; 

 and accordingly, as we shall see hereafter, he rejects all canons 

 of induction, because it is not by means of them that we guess. 

 Dr. Whewell's theory of the logic of science would be very 

 perfect if it did not pass over altogether the question of 

 Proof But in my apprehension 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 unobserved 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. 

 Whewell's phraseology, connect them by means of a new con- 

 ception ; if the conception does serve to connect the observa- 

 tions, we have all we want. As the proposition in which it 

 is embodied 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 admits of proof ; though it may serve to prove other 

 things, inasmuch as, by placing the facts in mental connexion 

 with other facts, not previously seen to resemble them, it assi- 

 milates the case to another class of phenomena, concerning 

 which real Inductions have already been made. Thus Kep- 

 ler's so-called law brought the orbit of Mars into the class 

 ellipse, and by doing so, proved all the properties of an ellipse 



