2 CORRELATION OF PHYSICAL FORCES. 



such a time there is no power of testing, by a sufficient range 

 of experience, the truth of the theory ; it is accepted solely 

 or mainly upon authority : there being no means of con- 

 tradiction, its reception is, in the first instance, attended with 

 some degree of doubt, but as the time in which it can fairly 

 be investigated far exceeds that of any lives then in being, 

 and as neither the individual nor the public mind will long 

 tolerate a state of abeyance, a theory shortly becomes, for 

 want of a better, admitted as an established truth : it is 

 handed from father to son, and gradually takes its place in 

 education. Succeeding generations, whose minds are thus 

 formed to an established view, are much less likely to aban- 

 don it. They have adopted it, in the first instance, upon 

 authority to them unquestionable, and subsequently to yield 

 up their faith would involve a laborious remodelling of ideas, 

 a task which the public as a body will and can rarely under- 

 take, the frequent occurrence of which is indeed inconsistent 

 with the very existence of man in a social state, as it would 

 induce an anarchy of thought a perpetuity of mental revolu- 

 tions. 



This necessity has its good; but the prejudicial effect 

 upon the advance of science is, that by this means theories 

 the most immature frequently become the most permanent ; 

 for no theory can be more immature, none is likely to be so 

 incorrect, as that which is formed at the first flush of a new 

 discovery; and though time exalts the authority of those 

 from whom it emanated, time can never give to the illustrious 

 dead the means of analysing and correcting erroneous views 

 which subsequent discoveries confer. 



Take, for instance, the Ptolemaic System, which we may 

 almost literally explain by the expression of Shakspeare : 

 ' He that is giddy thinks the world turns round.' We now 

 see the error of this system, because we have all an imme- 

 diate opportunity of refuting it ; but this identical error was 

 received as a truth for centuries, because, when first pro- 

 mulgated, the means of refuting it were not at hand; and 

 when the means of its refutation became attainable, mankind 

 had been so educated to the supposed truth, that they rejected 

 the proof of its fallacy. 



