But 'tis evident, in the first place, that the repetition of like objects in like relations of succession and contiguity, _discovers_ nothing new in any one of them; since we can draw no inference from it, nor make it a subject either of our demonstrative or probable reasonings; as has been already proved.[16] Nay, suppose we could draw an inference, 'twould be of no consequence in the present case; since no kind of reasoning can give rise to a new idea, such as this of power is; but wherever we reason, we must antecedently be possessed of clear ideas, which may be the objects of our reasoning. The conception always precedes the understanding; and where the one is obscure, the other is uncertain; where the one fails, the other must fail also. Secondly, 'tis certain that this repetition of similar objects in similar situations, _produces_ nothing new either in these objects, or in any external body. For 'twill readily be allowed, that the several instances we have of the conjunction of resembling causes and effects, are in themselves entirely independent, and that the communication of motion, which I see result at present from the shock of two billiard balls, is totally distinct from that which I saw result from such an impulse a twelvemonth ago. These impulses have no influence on each other. They are entirely divided by time and place; and the one might have existed and communicated motion, though the other never had been in being. There is, then, nothing new either discovered or produced in any objects by their constant conjunction, and by the uninterrupted resemblance of their relations of succession and contiguity. But 'tis from this resemblance, that the ideas of necessity, of power, and of efficacy, are derived. These ideas therefore represent not any thing, that does or can belong to the objects, which are constantly conjoined. This is an argument, which, in every view we can examine it, will be found perfectly unanswerable. Similar instances are still the first source of our idea of power or necessity; at the same time that they have no influence by their similarity either on each other, or on any external object. We must therefore turn ourselves to some other quarter to seek the origin of that idea.