FALLACIES OF SIMPLE INSPECTION. 367 



state, and therefore the most likely to prevail in 

 nature, which is one of the fallacies or natural preju- 

 dices we have already examined. 



So again of the First Law of Motion ; that a body 

 once moving will, if left to itself, continue to move 

 uniformly in a straight line. An attempt is made to 

 prove this law by saying, that if not the body must 

 deviate either to the right or to the left, and that there 

 is no reason why it should do one more than the 

 other. But who could know, antecedently to experi- 

 ence, whether there was a reason or not ?J Might it 

 not be the nature of bodies, or of some particular 

 bodies, to deviate towards the right? or if the suppo- 

 sition is preferred, towards the east, or south? It 

 was long thought that bodies, terrestrial ones at least, 

 had a natural tendency to deflect downwards ; and 

 there is no shadow of anything objectionable in the 

 supposition, except that it is not true. The pretended 

 proof of the law of motion is even more manifestly 

 untenable than that of the law of inertia, for it is 

 flagrantly inconsistent ; it assumes that the continu- 

 ance of motion in the direction first taken is more 

 natural than deviation either to the right or to the left, 

 but denies that one of these can possibly be more 

 natural than the other. All these fancies of the pos- 

 sibility of knowing what is natural or not natural by 

 any other means than experience, are, in truth, entirely 

 futile. The real and only proof of the laws of motion, 

 or of any other law of the universe, is experience ; it 

 is simply that no other suppositions explain or are 

 consistent with the facts of universal nature. 



Geometers have, in all ages, been open to the 

 imputation of endeavouring to prove the most general 

 facts of the outward world by sophistical reasoning, in 

 order to avoid appeals to the senses. Archimedes, 



