LAWS OF NATURE. 231 



According to this language, every well-grounded inductive generaliza- 

 tion is either a law of nature, or a result of laws of nature, capable, if those 

 laws are known, of being predicted from them. And the problem of In- 

 ductive Logic may be summed up in two questions : how to ascertain the 

 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 im- 

 agine that this mode of statement amounts to a real analysis, or to any 

 thing but a mere verbal transformation 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 re- 

 duced 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 phe- 

 nomena have their separate rules or modes of taking place, which, though 

 much intermixed and entangled with one another, may, to a certain extent, 

 be studied apart: that (to resume our former raetaphoi') the regularity 

 which exists in nature is a web composed of distinct threads, and only to 

 be understood by tracing each of the threads separately ; for which pur- 

 pose it is often necessary to unravel some portion of the web, and exhibit 

 the fibres apart. The rules of experimental inquiry are the contrivances 

 for unraveling the web. 



§ 2. In thus attempting to ascertain the general order of nature by as- 

 certaining the particular order of the occurrence of each one of the phe- 

 nomena of nature, the most scientific proceeding can be no more than an im- 

 proved form of that which was primitively pursued by the human under- 

 standing, while undirected by science. When mankind first formed the 

 idea of studying phenomena according 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 Descartes, 

 set out from the supposition that nothing had been already ascertained. 

 Many of the uniformities existing among phenomena are so constant, and 

 so open to observation, as to force themselves upon involuntary recognition. 

 Some facts are so perpetually and familiarly accompanied by certain oth- 

 ers, that mankind learned, 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 existence 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 afterward began to see, to an ulterior revision of these spontaneous 

 generalizations themselves, when the progress of knowledge pointed out 

 limits to them, or showed their truth to be contingent on some circum- 

 stance not originally attended to. It will appear, I think, from the subse- 

 quent 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 rigorously im- 

 pi'acticable : since it is impossible to frame any scientific method of induc- 

 tion, or test of the correctness of inductions, unless on the hypothesis that 

 some inductions deserving of reliance have been already made. 



Let us revert, for instance, to one of our former illustrations, and con- 

 sider why it is that, with exactly the same amount of evidence, both nega- 



I 



