BOOK III. 



OF INDUCTION. 



" According to the doctrine now stated, the highest, or rather the only proper object of 

 physics, is to ascertain those estabhshed conjunctions of successive events, which consti- 

 tute the order of the universe; to record the phenomena which it exhibits to our observa- 

 tions, or which it discloses to our experiments ; and to refer these phenomena to their gen- 

 eral laws."— D. Stewart, Elements of the Philosophy of the Human Mind, vol. ii., chap. iv. 

 sect. 1. 



" In such cases the inductive and deductive methods of inquiry may be said to go hand 

 in hand, the one verifying the conclusions deduced by the other; and the combination of 

 experiment and theory, which may thus be brought to bear in such cases, forms an engine 

 of discovery infinitely more powerful than either taken separately. This state of any de- 

 partment of science is perhaps of all others the most interesting, and that which promises 

 the most to research." — Sir J. Herschel, Discourse on the Study of Natural Philosophy. 



CHAPTER I. 



PRELIMINARY OBSERVATIONS ON INDUCTION IN GENERAL. 



§ 1. The portion of the present inquiry upon which we are now 

 about to enter, may be considered as the principal, both from its sur- 

 passing in intricacy all the other branches, and because it relates to a pro- 

 cess which has been shown in the preceding Book to be that in which 

 the Investigation of Nature essentially consists. We have found that 

 all Inference, consequently all Proof, and all discovery of truths not 

 self-evident, consists of inductions, and the interpretation of inductions : 

 that all our knowledge, not intuitive, comes to us exclusively from 

 that source. What Induction is, therefore, and what conditions render 

 it legitimate, cannot but be deemed the main question of the science of 

 logic — the question which includes all others. It is, however, one 

 which professed writers on logic have almost entirely passed over. 

 The generalities of the subject have not been altogether neglected by 

 metaphysicians ; but, for want of sufficient acquaintance with the pro- 

 cesses by which science has actually succeeded in establishing general 

 truths, their analysis of the inductive operation, even when unexcep- 

 tionable as to coiTectness, has not been specific enough to be made 

 the foundation of practical rules, which might be for induction itself 

 what the rules of the syllogism are for the interpretation of induction : 

 while those by whom physical science has been carried to its present 

 high state of improvement — and who, to arrive at a complete theory of 

 the process, needed only to generalize, and adapt to all varieties of 

 problems, the methods which they themselves employed in their ha- 

 bitual pursuits — never until very lately made any serious attempt to 

 philosophize on the subject, nor regarded the mode in which they ar- 

 rived at their conclusions as deserving of study, independently of the 

 conclusions themselves. 



