Our idea therefore of power, I think, may well have a place amongst other SIMPLE IDEAS, and be considered as one of them; being one of those that make a principal ingredient in our complex ideas of substances, as we shall hereafter have occasion to observe.
4.

The clearest Idea of active Power had from Spirit.
Of passive power all sensible things abundantly furnish us with sensible ideas, whose sensible qualities and beings we find to be in continual flux.

And therefore with reason we look on them as liable still to the same change.

Nor have we of ACTIVE power (which is the more proper signification of the word power) fewer instances.

Since whatever change is observed, the mind must collect a power somewhere able to make that change, as well as a possibility in the thing itself to receive it.