FALLACIES OF SIMPLE INSPECTION. 359 



"It is inconceivable," said Newton, in one of his 

 letters to Dr. Bentley*, " that inanimate brute matter 

 should, without the mediation of something else, 

 which is not material, operate upon and affect other 

 matter without mutual contact. . . . That gravity 

 should be innate, inherent, and essential to matter, so 

 that one body may act on another, at a distance, 

 through a vacuum, without the mediation of anything 

 else, by and through which their action and force may 

 be conveyed from one to another, is to me so great 

 an absurdity, that I believe no man, who in philoso- 

 phical matters has a competent faculty of thinking, 

 can ever fall into it." This passage should be hung- 

 up in the cabinet of every man of science who is 

 ever tempted to pronounce a fact impossible because 

 it appears to him inconceivable. In our own day 

 one would be more inclined, though with equal in- 

 justice, to reverse the concluding observation, and 

 consider the seeing any absurdity at all in a thing so 

 simple and natural, to be what really marks the 

 absence of " a competent faculty of thinking." No 

 one now feels any difficulty in conceiving gravity to 

 be, as much as any other property is, " innate, inhe- 

 rent, and essential to matter," nor finds the compre- 

 hension of it facilitated in the smallest degree by the 

 supposition of an ether; nor thinks it at all incredible 

 that the celestial bodies can and do act where they, 

 in actual bodily presence, are not. To us it is not 

 more wonderful that bodies should act upon one an- 

 other " without mutual contact," than that they should 

 do so when in contact: we are familiar with both 

 these facts, and we find them equally inexplicable, but 



* I quote this passage from Playfair's celebrated Dissertation on 

 the Progress of Mathematical and Physical Science. 



