532 FALLACIES. 



entific speculations, between natural and violent motions, though not with- 

 out a plausible foundation in the appearances themselves, was doubtless 

 greatly recommended to adoption by its conformity 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 phi- 

 losophers that the detailed system of inductive logic, which this extraor- 

 dinary man labored to construct, has been turned to so little direct use by 

 subsequent inquirers, having neither continued, except in a few of its gen- 

 eralities, to be recognized 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 overlooked Plurality of Causes. All his 

 rules tacitly imply the assumption, so contrary to all we now know of na- 

 ture, that a phenomenon can not have more than one cause. 



When he is inquiring into what he terms the forma calidi 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 or- 

 der 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 anoth- 

 er person has that there is always some cause or other. In the present 

 state of knowledge it could not be necessary, 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 qualities of objects. For his assumption, ground- 

 less in every case, is false in a peculiar degree with respect to those sensi- 

 ble qualities. In regard to scarcely any of them has it been found possible 

 to trace any unity of cause, any set of conditions invariably accompanying 

 the quality. The conjunctions of such qualities with one another consti- 

 tute 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 ex- 

 ist. 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 variety of distinct causes. 



And on this rock every one 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 resources 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 



* Supra, book iii., chap, vii., § 4. 



