500 



FALLACIES. 



sible foundation in the appearances 

 themselves, was doubtless greatly re- 

 commended to adoption by its con- 

 formity to this prejudice. 



§ 7. From the fundamental error of 

 the scientific inquirers of antiquity 

 we pass, by a natural association, to a 

 scarcely less fundamental one of their 

 great rival and successor, Bacon. It 

 has excited the surprise of philoso- 

 phers that the detailed sjrstem of in- 

 ductive logic which this extraordinary 

 man laboured to construct has been 

 turned to so little direct use by subse- 

 quent inquirers, having neither con- 

 tinued, except in a few of its gene- 

 ralities, to be recognised as a theory, 

 nor having conducted in practice to 

 any great scientific results. But this, 

 though not unfrequently remarked, 

 has scarcely received any plausible 

 explanation ; and some indeed have 

 preferred to assert that all rules of 

 induction are useless, rather than sup- 

 pose that Bacon's rules are grounded 

 on an insufficient analysis of the in- 

 ductive process. Such, however, will 

 be seen to be the fact, as soon as it is 

 considered that Bacon entirely over- 

 looked Plurality of Causes, All his 

 rules tacitly imply the assumption, 

 so contrary to all we now know of 

 nature, that a phenomenon cannot 

 have more than one cause. 



When he is inquiring into what he 

 terms the forma caZidi aut frigidi, 

 gravis aut levis, sicci aut humidi^ and 

 the like, he never for an instant 

 doubts that there is some one thing, 

 some invariable condition or set of 

 conditions, which is present in all 

 cases of heat or cold, or whatever 

 other phenomenon he is considering ; 

 the only difficulty being to find what 

 it is, which accordingly he tries to do 

 by a process of elimination, rejecting 

 or excluding, by negative instances, 

 whatever is not the forma or cause, in 

 order to arrive at what is. But that 

 this forma or cause is one thing, and 

 that it is the same in all hot objects, 

 he has no more doubt of than another 

 person has that there is always some 



■ 



state 



cause or other. In the present 

 of knowledge it could not be neces- 

 sary, even if we had not already 

 treated so fully of the question, to 

 point out how widely this supposition 

 is at variance with the truth. It is 

 particularly unfortunate for Bacon 

 that, falling into this error, he should 

 have fixed almost exclusively upon a 

 class of inquiries in which it was 

 especially fatal ; namely, inquiries 

 into the causes of the sensible qua- 

 lities of objects. For his assump- 

 tion, groundless in every case, is false 

 in a peculiar degree with respect to 

 those sensible qualities. In regard to 

 scarcely any of them has it been 

 found possible to trace any unity of 

 cause, any set of conditions invari- 

 ably accompanying the quality. The 

 conjunctions of such qualities with 

 one another constitute the variety of 

 Kinds in which, as already remarked, 

 it has not been found possible to trace 

 any law. Bacon was seeking for what 

 did not exist. The phenomenon of 

 which he sought for the one cause 

 has oftenest no cause at all, and when 

 it has, depends (as far as hitherto 

 ascertained) on an unassignable va- 

 riety of distinct causes. 



And on this rook every •ne must 

 split who represents to himself as the 

 first and fundamental problem of 

 science to ascertain what is the cause 

 of a given effect, rather than what 

 are the effects of a given cause. It 

 was shown, in an early stage of our 

 inquiry into the nature of Induction,* 

 how much more ample are the re- 

 sources which science commands for 

 the latter than for the former inquiry, 

 since it is upon the latter only that 

 we can throw any direct light by 

 means of experiment ; the power of 

 artificially producing an effect im- 

 plying a previous knowledge of a;t 

 least one of its causes. If we dis- 

 cover the causes of effects, it is gene- 

 rally by having previously discovered 

 the effects of causes ; the greatest 

 skill in devising crucial instances for 



* Svipra, book iii. ch. vii. § 4. 



/ 



