10 INDUCTION. 



fluid, is not that the attempt itself is unphilosophical, 

 but that the existence of the fluid, and the fact of its 

 vibratory motion, are not proved ; but are assumed, on 

 no other ground than the facility they are supposed to 

 afford of explaining the phenomena. And these con- 

 siderations lead us to the important question of the 

 proper use of scientific hypotheses ; a subject the 

 connexion of which with that of the explanation of 

 the phenomena of nature, and of the necessary limits 

 to that explanation, needs not be pointed out. 



4. An hypothesis is any supposition which we 

 make (either without actual evidence, or upon evi- 

 dence avowedly insufficient,) in order to endeavour to 

 deduce from it conclusions in accordance with facts 

 which are known to be real ; under the idea that if the 

 conclusions to which the hypothesis leads are known 

 truths, the hypothesis itself either must be, or at least 

 is likely to be, true. If the hypothesis relates to the 

 cause, or mode of production of a phenomenon, it 

 will serve, if admitted, to explain such facts as are 

 found capable of being deduced from it. And this 

 explanation is the purpose of many, if not most, 

 hypotheses. Since explaining in the scientific sense 

 means resolving an uniformity which is not a law of 

 causation, into the laws of causation from which it 

 results, or a complex law of causation into simpler 

 and more general ones from which it is capable of 

 being deductively inferred ; if there do not exist any 

 known laws which fulfil this requirement, we may 

 feign or imagine some which would fulfil it ; and this 

 is making an hypothesis. 



An hypothesis being a mere supposition, there are 

 no other limits to hypotheses than those of the human 

 imagination; we may, if we please, imagine, by way 



