14 Introduction . 
which appears with as much Certainty , and of which we arc able to form as clear and diftintt Notions as of any of thofc before mentioned , and that is Mo * tion ; although indeed it is not in the fame Kcfpedt nocellary and efiential to it , becaufc we can have a clear Idea of Matter without it . By Motion , I mean a Power of being moved by any external Caufe from one Place to another . About this likewife have been railed a great many fophirticul Cavils , by fuch who pretend to too much Cunning to be impofed upon by fuch deceitful Informers as their Senfes ; but thefe Alfo may be feen very handfomcly cxpofed by Mr Kelly in the above - mentioned place . 
With equal Certainty alio we find an abfolute capacity in Matter to put it felf into Motion , or any ways to alter the preient State of its Exiftence , lets by the Force of fomc external Caufe . Por though we find every Body fufeeptible of Motion from the Impulfes of external Agents , yet there is no manner ot Confequence from the Idea of Body , to a Power of putting it felf into Motion , but quite the contrary . Let any one confider the next Stone he meets with , firmly compacted and at reft , and fee if he Can pofiibly conceive in it a Power of ever being otherwife , and not be forced to conclude that it muft neceflarily for ever remain fo , unlefs put out of that State by the Means of fomc external Power . 
But yet notwithilanding the Impoffibility of ceiving a power of Self - motion to be inherent in ter , according to the molt fimplc anil mod natural Idea we can have of it \ yet we ore evidently ced by our Senfes , that its Omnipotent Creator hath endued it widi a Power or Tendency of Motion towards fomc determinate Point or Center , which Power we commonly call Gravity . Although like - wife as to this Property there docs not «ppcar any 
neceflary