354 INDUCTION. 



true even of merely experimental inquiry, the conversion of experimental 

 into deductive truths could still less have been effected without large 

 temporary assistance from hypotheses. The process of tracing regularity 

 in any complicated, and at first sight confused, set of appearances, is neces- 

 sarily tentative; we begin by making any supposition, even a false one, to 

 see what consequences will follow from it ; and by observing how these 

 differ from the real phenomena, we learn what corrections to make in our 

 assumption. The simplest supposition which accords with the more obvi- 

 ous facts is the best to begin with ; because its consequences are the most 

 easily traced. This rude hypothesis is then rudely corrected, and the op- 

 eration repeated ; and the comparison of the consequences deducible from 

 the corrected hypothesis, with the observed facts, suggests still further 

 correction, until the deductive results are at last made to tally with the phe- 

 nomena. " 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 consequences ca- 

 pable 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 veiy 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 

 statements 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 extemporizes, from a few of the particulars, a first rude the- 

 ory 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 

 provisional 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 mathematicians, we arrive, by means of hy- 

 potheses, at conclusions not hypothetical.f 



* Comte, Philosophie Positive, ii. , 434-437. 



t 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 dis- 

 ease must originate in some definite part or other of the organism, boldly assumed that cer- 

 tain 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 gen- 

 erally admitted, erroneous ; but he was justified in making it, since by deducing the conse- 

 quences of the supposition, and comparing them with the facts of those maladies, he might be 

 certain of disproving his hypothesis if it was ill founded, and might expect that the compari- 

 son would materially aid him in framing another more (Conformable to the phenomena. 



The doctrine now universally received that the earth is a natural magnet, was originally an 

 hypothesis of the celebrated Gilbert. 



Another hypothesis, to the legitimacy of which no objection can lie, and which is well cal- 

 culated to light the path of scientific inquiry, is that suggested by several recent writers, that 

 the brain is a voltaic pile, and that each of its pulsations is a discharge of electricity through 

 the system. It has been remarked that the sensation felt by the hand from the beating of a 

 brain, bears a strong resemblance to a voltaic shock. And the hypothesis, if followed to its 

 consequences, might afford a plausible explanation of many physiological facts, while there is 

 nothing to discourage the hope that we may in time sufficiently understand the conditions of 

 voltaic phenomena to render the truth of the hypothesis amenable to observation and experi- 

 ment. ' • • - 



The attempt to localize, in different regions of the brain, the physical organs of our different 



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