208 



INDUCTION. 



tain force, and have had a certain 

 instantaneous impulse originally im- 

 pressed upon them. After this great 

 discover^', Kepler's three propositions, 

 though still called laws, would hardly, 

 by any person accustomed to use 

 language with precision, be termed 

 laws of nature : that phrase would 

 be reserved for the simpler and more 

 general laws into which Newton is 

 said to have resolved them. 



According to this language, every 

 well-grounded inductive generalisa- 

 tion is either a law of nature or a 

 result of laws of nature, capable, if 

 those laws are known, of being pre- 

 dicted from them. And the problem 

 of Inductive Logic may be summed 

 up in two questions : how to ascertain 

 tihe laws of nature ; and how, after 

 having ascertained them, to follow 

 them into their results. On the other 

 hand, we must not suffer ourselves to 

 imagine that this mode of statement 

 amounts to a real analysis, or to any- 

 thing but a mere verbal transforma- 

 tion of the problem ; for the expression, 

 Laws of Nature, means nothing but 

 the uniformities which exist among 

 natural phenomena (or, in other 

 words, the results of induction) when 

 reduced to their simplest expression. 

 It is, however, something to have ad- 

 vanced so far as to see that the study 

 of nature is the study of laws, not a 

 law ; of uniformities in the plural 

 number ; that the different natural 

 phenomena have their separate rules 

 or modes of taking place, which, 

 though much intermixed and en- 

 tangled with one another, may, to a 

 certain extent, be studied apart ; that 

 (to resTime our former metaphor) the 

 regularity which exists in nature is 

 a web composed of distinct threads, 

 and only to be understood by tracing 

 each of the threads sepai-ately ; for 

 which purpose it is often necessary to 

 unravel some portion of the web, and 

 exhibit the fibres apart The rules 

 of experimental inquiry are the con- 

 trivances for unravelling the web. 



§ 2. In thus attempting to ascertain 



the general order of nature by ascer- 

 taining the particular order of the 

 occurrence of each one of the pheno- 

 mena of nature, the most scientific 

 proceeding can be no more than an 

 improved form of that which was 

 primitively pursued by the human 

 understanding while undirected by 

 science. When mankind first formed 

 the idea of studying phenomena ac- 

 cording to a stricter and surer method 

 than that which they had in the first 

 instance spontaneously adopted, they 

 did not, conformably to the well-meant 

 but impracticable precept of Des- 

 cartes, set out from the supposition 

 that nothing had been already ascer- 

 tained. Many of the uniformities 

 existing among phenomena are so 

 constant, and so open to observation, 

 as to force themselves upon involun- 

 tary recognition. Some facts are 

 so perpetually and familiarly accom- 

 panied by certain others, that man- 

 kind learnt, as children learn, to 

 expect the one where they found the 

 other, long before they knew how to 

 put their expectation into words by 

 asserting, in a proposition, the exist- 

 ence of a connection between those 

 phenomena. No science was needed 

 to teach that food nourishes, that 

 water drowns, or quenches thirst, 

 that the sun gives light and heat, 

 that bodies fall to the ground. The 

 first scientific inquirers assumed these 

 and the like as known truths, and 

 set out from them to discover others 

 which were unknown : nor were they 

 wrong in so doing, subject, however, 

 as they afterwards began to see, to 

 an ulterior revision of these spon- 

 taneous generalisations themselves, 

 when the progress of knowledge 

 T-iointed out limits to them, or showed 

 their truth to be contingent on some 

 circumstance not originally attended 

 to. It will appear, I think, from the 

 subsequent part of our inquiry, that 

 there is no logical fallacy in this 

 mode of proceeding ; but we may see 

 already that any other mode is rigor- 

 ously impracticable : since it is im- 

 possible to frame any scientific method 



