new Sentiment or Impression, viz. a customary Connexion in the Thought or Imagination betwixt one Object and its usual Attendant; and this Sentiment is the Original of that Idea we seek for. For as this Idea arises from a Number of similar Instances, and not from any single Instance; it must arise from that Circumstance, in which the Number of Instances differ from every individual Instance. But this customary Connexion or Transition of the Imagination is the only Circumstance, in which they differ. In every other particular, they are alike. The first Instance we saw of Motion, communicated by the Shock of two Billiard-balls (to return to this obvious Instance) is exactly similar to any one, that may, at present, occur to us; except only, that we could not, at first, infer the one Event from the other; which we are enabled to do at present, after so long a Course of uniform Experience. I know not, if the Reader will readily apprehend this Reasoning. I am afraid, that, should I multiply Words about it, or throw it into a greater Variety of Lights, it would only become more obscure and intricate. In all abstract Reasonings, there is one Point of View, which, if we can happily hit, we shall go farther towards illustrating the Subject, than by all the Eloquence and copious Expression of the World. This weshould
