HYPOTHESES. 17 



its consequences are the most easily traced. This rude hypo- 

 thesis is then rudely corrected, and the operation repeated ; 

 and the comparison of the consequences deducible from the 

 corrected hypothesis, with the oberved facts, suggests still 

 further correction, until the deductive results are at last made 

 to tally with the phenomena. " Some fact is as yet little 

 understood, or some law is unknown : we frame on the subject 

 an hypothesis as accordant as possible with the whole of the 

 data already possessed ; and the science, being thus enabled to 

 move forward freely, always ends by leading to new conse- 

 quences capable of observation, which either confirm or refute, 

 unequivocally, the first supposition." Neither induction nor 

 deduction would enable us to understand even the simplest 

 phenomena, "if we did not often commence by anticipating 

 on the results ; by making a provisional supposition, at first 

 essentially conjectural, as to some of the very notions which 

 constitute the final object of the inquiry.* Let any one 

 watch the manner in which he himself unravels a complicated 

 mass of evidence ; let him observe how, for instance, he elicits 

 the true history of any occurrence from the involved state- 

 ments of one or of many witnesses : he will find that he does 

 not take all the items of evidence into his mind at once, and 

 attempt to weave them together : he extemporises, from a few 

 of the particulars, a first rude theory of the mode in which the 

 facts took place, and then looks at the other statements one 

 by one, to try whether they can be reconciled with that provi- 

 sional theory, or what alterations or additions it requires to 

 make it square with them. In this way, which has been justly 

 compared to the Methods of Approximation of mathema- 

 ticians, we arrive, by means of hypotheses, at conclusions not 

 hypothetical.f 



* Philosophic Positive, ii. 434-437. 



f As an example of legitimate hypothesis according to the test here laid 

 down, has been justly cited that of Broussais, who, proceeding on the very 

 rational principle that every disease must originate in some definite part or 

 other of the organism, boldly assumed that certain fevers, which not being 

 known to be local were called constitutional, had their origin in the mucous 

 membrane of the alimentary canal. The supposition was indeed, as is now 



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