HYPOTHESES. 



327 



equivocally, the first aupposition." 

 Neither induction nor deduction would 

 »»nable us to understand even the 

 simplest phenomena, "if we did not 

 often commence by anticipating on 

 the results ; by making a provisional 

 uipposition, at first essentially con- 

 jectural, as to some of the very 

 notions which constitute the final 

 object of the inquiry."* Let any 

 one watch the manner in which he 

 kimself unravels a complicated mass 

 cf evidence ; let him observe how, for 

 instance, he elicits the true history 

 of any occurrence from the involved 

 itatements of one or of many wit- 

 nesses : he will find that he does not 

 take all the items of evidence into 

 his mind at once, and attempt to 

 weave them together : ho extem- 

 porises, 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 recon- 

 ciled 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 Approxi- 

 mation of mathematicians, we arrive, 

 by means of hypotheses, at conclu- 

 sions not hypothetical.t 



* 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 Broussaia, 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 aliment-iry canal. 

 The supposition was indeed, as is now 

 generally admitted, erroneous ; but he was 

 justified in making it, since by deducing 

 the consequences of the supposition, and 

 comparing them with the facts of those 

 maladies, he might be certain of disprovint,' 

 his hypothesis if it was ill-founded, and 

 might expect that the comparison would 

 materially aid him in framing anoth^ 

 more conformable to the phenomena. 



The doctrine now universally received 

 that the earth is a natural magnet, was 

 originsQly an hypothesis of the celebrated 

 Gilbert. 



Another hypothesis, to the legitimacy of 



§ 6. It is perfectly consistent with 

 the spirit of the method, to assuni** 

 in this provisional manner not only 

 an hypothesis respecting the law of 

 what we already know to be the 

 cause, but an hypothesis respecting 

 the cause itself. It is allowable, use- 

 ful, and often even necessary, to begin 

 by asking ourselves what cause mai/ 

 have produced the effect, in order 

 that we may know in what direction 

 to look out for evidence to determine 

 whether it actually did. The vortices 

 of Descartes would have been a per- 

 fectly legitimate hypothesis, if it had 

 been pcissible, by any mode of explo- 

 ration which we could entertain the 

 hope of ever possessing, to bring the 

 reality of the vortices, as a fact in 

 nature, conclusively to the test of 

 observation. The vice of the h3rpo- 

 thesis was that it could not lead to 

 any course of investigation capable of 

 converting it from an hypothesis into 

 a proved fact. It might chance to 

 be disproved, either by some want of 

 correspondence with the phenomena 

 it purported to explain, or (as actu- 

 ally happened) by some extraneous 

 fact. "The free passage of comets 

 through the spaces in which these 

 vortices should have been, convinced 

 men that these vortices did not 



which no objection can He, and which ie 

 well calculated to light tlie path of scien- 

 tific 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 fol- 

 lowed to its consequences, might afford a 

 plausible explanation of many physiologi- 

 cal facts, while there is nothing to dis- 

 courage the hope that we may in time 

 suflSciently understand the conditions of 

 voltaic phenomena to render the truth of 

 the hypothesis amenable to observation 

 and experiment. 



The attempt to localise, in different 

 regions of the brain, the physical organs 

 of our different mental faculties and pro- 

 pensities, was, on the part of its original 

 author, a legitimate example of a scientific 

 hyjothesis; and we ought not, therefore, 

 to blame him for the extremely slight 

 grounds on which he often proceeded in 



