432 ANTIENT METAPHYSICS. Book V. 



And this I hold to be all the fcience that is in modern natural philofo- 

 phy. 



But thefe laws of nature are very far from having the evidence of 

 axioms^ properly fo called ; for» as we do not know the effence of bo- 

 dy, we cannot from thence deduce its properties, that is, we cannot 

 demonftrate them ; and much lefs can we perceive them intuitively ; 

 for we can fee no contradidion in fuppofmg that a ftone fliculd go 

 upwards, as flame does, inftead of falling downwards, fuch as we 

 conceive in fuppofing that a pari is equal to the ivhok. 



Yet, that the ftone falls to the ground, and that bodies are moved 

 in the feveral other ways above mentioned, no body doubts ; but this 

 unlverfal belief does not fatisfy the philofopher, and he itdl inquires, 

 upon what grounds do men believe fo ? The auihor of the Lflkys 

 fays, that It is ciijlom which produces this belief *. but cultom hath 

 nothing to do with belief, or any ot the operations of uitellect ; it re- 

 lates only to praBice \ for, by being in the frequent ule ot domg any 

 thing, we form the habit or difpohtion to do it. And this is common 

 to us with the brutes, who have no belief or opinion of any kind, 

 which is peculiar to the rational or intelledlual nature. We therefore 

 never believe without fome reafon, though perhaps that reafon may 

 not be attended to, and Is only difcoverable upon refledlon. And the 

 reafon. In this cafe, I take to be twofold ; one of which operates 

 upon the vulgar, the other upon the philofopher. The firft is, that, 

 having obferved the fame thing happen often, and not feeing any 

 reafon why It ftiould not happen again, we believe that It will happen 

 in time to come, and that it has happened in time paft. This reafon 

 is only a negative reafon, which has no other foundation than our ig- 

 norance 



"* Volume third of Mr Hume's Eflays, fe^l. 5. 



