| For it will 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 twelve-month 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 it is from this resemblance, that the ideas of necessity, of power, and of efficacy, are derived. |
| These ideas, therefore, represent not anything, 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. |
| Though the several resembling instances, which give rise to the idea of power, have no influence on each other, and can never produce any new quality in the object, which can be the model of that idea, yet the observation of this resemblance produces a new impression in the mind, which is its real model. |
| For after we have observed the resemblance in a sufficient number of instances, we immediately feel a determination of the mind to pass from one object to its usual attendant, and to conceive it in a stronger light upon account of that relation. |
| This determination is the only effect of the resemblance; and therefore must be the same with power or efficacy, whose idea is derived from the resemblance. |
| The several instances of resembling conjunctions lead us into the notion of power and necessity. |
| These instances are in themselves totally distinct from each other, and have no union but in the mind, which observes them, and collects their ideas. |
| Necessity, then, is the effect of this observation, and is nothing but an internal impression of. |
| the mind, or a determination to carry our thoughts from one object to another. |
| Without considering it in this view, we can never arrive at the most distant notion of it, or be able to attribute it either to external or internal objects, to spirit or body, to causes or effects. |
| The necessary connexion betwixt causes and effects is the foundation of our inference from one to the other. |
| The foundation of our inference is the transition arising from the accustomed union. |
| These are, therefore, the same. |
| The idea of necessity arises from some impression. |