CHAPTER I. 



[ OF MOTION, FORCE, AND PRESSURE. 



Section I. Of undisturbed motion, 



2YI, Axiom. Like causes produce like 

 effects, or, in similar circumstances, similar 

 consequences ensue. 



Scholium 1. This axiom has always been essentially 

 concerned in every improvement of natural philosophy, but 

 it has been more and more employed, ever since the revi- 

 val of letters, under the name Induction. It is the most 

 general and the most important law of nature ; it is the 

 foundation of all analogical reasoning, and it is collected 

 from constant experience, by an indispensable and un- 

 avoidable propensity of the human mind. 



Scholium 2. It does not appear that we can have any 

 other accurate conception of causation, or of the con- 

 nexion of a cause with its effect, than a strong impression 

 of the observation, from uniform experience, that the one 

 has constantly followed the other. We do not know the 

 intimate nature of the connexion by which gravity causes 

 a stone to fall, or how the string of a bow urges the arrow 

 forwards; nor is there any original absurdity in supposing 

 it possible, that the stone might have remained suspended 

 in the air, or that the bowstring might have passed through 

 the arrow as hght passes through glass. But it is obvious 



