Though the numerous resembling instances that give rise to the idea of power have no influence on each other, and can never produce in the object any new quality that could be the model for that idea, our observation of this resemblance produces a new impression in our mind, and that is the idea’s 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 the latter in a stronger light on account of that determination. [Feeling a ‘determination’ to form a certain idea is just feeling oneself being made to form the idea. Most of Hume’s uses of ‘determine’ etc. have been rendered here by ‘make’ etc., but in the present section ‘determination’ is allowed to stand.] This determination is the only effect of the resemblance, and so it must be the power or efficacy the idea of which is derived from the resemblance. The numerous 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 except in our mind, which observes them and collects their ideas. So necessity is the effect of this observation, and is nothing but an internal impression of the mind—a determination to carry our thoughts from one object to another. If we don’t view it in this way 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.