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245 we mean much the same thing, as what is commonly call'd an abstract mode; that is, something, which, properly speaking, is neither distinguishable, nor separable from its substance, and is only conceiv'd by a distinction of reason, or an abstraction. But nothing is gain'd by this change of the term of modification, for that of action; nor do we free ourselves from one single difficulty by its means; as will appear from the two following reflections.

First, I observe, that the word, action, according to this explication of it, can never justly be apply'd to any perception, as deriv'd from a mind or thinking substance. Our perceptions are all really different, and separable, and distinguishable from each other, and from every thing else, which we can imagine; and therefore 'tis impossible to conceive, how they can be the action or abstract mode of any substance. The instance of motion, which is commonly made use of to shew after what manner perception depends, as an action, upon its substance, rather confounds than instructs us. Motion to all appearance induces no real nor essential change on the body, but only varies its relation to other objects. But betwixt a person in the morning walking in a garden with company, agreeable to him; and a person in the afternoon inclos'd in a dungeon, and full of terror, despair, and resentment, there seems to be a radical difference, and of quite another kind, than what is produc'd on a body by the change of its situation. As we conclude from the distinction and separability of their ideas, that external objects have a separate existence from each other; so when we make these ideas themselves our objects, we must draw the same conclusion concerning them, according to the precedent reasoning. At least it must be confest, that having no idea of the substance of the soul, 'tis impossible for us to tell how it can admit of such differences, and even contrarieties of perception without any fundamental change; and consequently can never tell in what sense perceptions are actions of that substance. The use, therefore, of the word, action,