FALLACIES OF SIMPLE INSPECTION. 461 



It rany be said in objection, that tlic error in these cases was in the 

 minor premiss, not the major; an error of fact, not of principle; that 

 it did not consist in snpposing that what is inconceivable cannot be 

 true, but in supposing Antipodes to be inconceivable, when present 

 experience so fully proves that they can be conceived. Even if this 

 objection were allowed, and tlio proposition that what is inconceivfvble 

 cannot be true were suflered to remain unquestioned as a ajreculative 

 ti'utli, it would be a truth upon which no practical consequence could 

 ever bo founded, since, upon tliis showing, it is ini])ossible to affimi' of 

 any proposition, not being a contradiction in terms, that it is inconceiva- 

 ble. Antipodes were really, not fictitiously, inconceivable to our 

 ancestors: they are indeed conceivable to us ; and as the limits of Our 

 power of conception have been so largely extended, by the extension 

 of our experience and the more varied exercise of our imagination, so 

 may posterity find many combinations perfectly conceivable to them 

 which are inconceivable to us. But, as beings of limited experience, 

 we must always and necessarily have limited conceptivc powers ; while 

 it does not by any means follow that the same limitation obtains in the 

 possibilities of nature, nor even in her actual manifestations. 



Rather more than a century and a half ago it was a philosophical 

 maxim, disputed by no one, and which no one deemed to require any 

 proof, that " a thing cannot act where it is not." With this weapon 

 the Cartesians waged a formidable war against the theory of gravita- 

 tion, which, according to them, involving so obvious an absurdity, 

 must be rejected in limine ; the sun could not possibly act upon the 

 earth, not laeing there. It was not surprising that the adherents of the 

 old systems of astronomy should urge this objection against the new ; 

 but the false assumption imposed equally upon Newton hin\self, who 

 in order to turn the edge of the objection, imagined a subtle ether 

 which filled up the space between the sun and the earth, and by its 

 intermediate agency was the proximate cause of the phenomena of 

 gravitation. " 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 



aflect other matter ^cithout mutual contact That gravity should be 



innate, inherent, and essential to matter, so that one body may a(-t on 

 another, at a distance, through a vacuum, without the mediation of 

 anythiiig else, by and througli 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 philosophical mattei's has a competent faculty 

 of thinking, can ever fall into it." This passage should be hung >ip 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 injustice, to reverse 

 the concluding observation, and consider the seeing any absurdity at 

 all in a thing so simple and natural, to be vyhat really marks the ab- 

 sence of " a competent faculty of thinking." No one now feels any 

 difficulty in conceiving gravity to Ix;, as much as any other pi-ojierty 

 is, "innate, inherent, 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 



* I quote this passage from Playfair's celebrated Dissertation on the Progress of Mathemat- 

 ical and Physical Science. 



