68 REASONING. 



tation of all bodies towards one another, on the faith of a 

 general proposition, the reverse of which seemed to them to 

 he inconceivable the proposition that a body cannot act where 

 it is not. All the cumbrous machinery of imaginary vortices, 

 assumed without the smallest particle of evidence, appeared to 

 these philosophers a more rational mode of explaining the 

 heavenly motions, than one which involved what seemed to 

 them so great an absurdity.* And they no doubt found it as 

 impossible to conceive that a body should act upon the earth 

 at the distance of the sun or moon, as we find it to conceive 

 an end to space or time, or two straight lines inclosing a space. 

 Newton himself had not been able to realize the conception, 

 or we should not have had his hypothesis of a subtle ether, the 

 occult cause of gravitation ; and his writings prove, that 

 though he deemed the particular nature of the intermediate 

 agency a matter of conjecture, the necessity of some such 

 agency appeared to him indubitable. It would seem that even 

 now the majority of scientific men have not completely got 

 over this very difficulty ; for though they have at last learnt 

 to conceive the sun attracting the earth without any intervening 

 fluid, they cannot yet conceive the sun illuminating the earth 

 without some such medium. 



If, then, it be so natural to the human mind, even in a 

 high state of culture, to be incapable of conceiving, and on 

 that ground to believe impossible, what is afterwards not only 

 found to be conceivable but proved to be true ; what wonder 



* It would be difficult to name a man more remarkable at once for the great- 

 ness and the wide range of his mental accomplishments, than Leibnitz. Yet this 

 eminent man gave as a reason for rejecting Newton's scheme of the solar system, 

 that God could not make a body revolve round a distant centre, unless either by 

 some impelling mechanism, or by miracle : " Toutce qui n'est pas explicable" 

 says he in a letter to the Abbe" Conti, "par la nature des creatures, est mira- 

 culeux. II ne suffit pas de dire : Dieu a fait une telle loi de nature ; done la 

 chose est naturelle. II faut que la loi soit executable par les natures des 

 CTe'atures. Si Dieu donnait cette loi, par exemple, a un corps libre, de tourner 

 a 1'entour d'un certain centre, il faudrait ou qu'il y joignit d'autres corps qui 

 par leur impulsion Volligeassent de rester toujours dans son orbite circulaire, ou 

 qu'U mil un ange & ses trousses, ou enfin il faudrait qu'il y concourut extraordi- 

 nairement ; car naturellement il s'ecartera par la tangente." Works of Leibnitz, 

 ed. Dutens, iii. 446. 



