It appears, then, that to whatever side we turn, the same difficulties follow us, and that we cannot advance one step towards the establishing the simplicity and immateriality of the soul, without preparing the way for a dangerous and irrecoverable atheism. 'Tis the same case, if, instead of calling thought a modification of the soul, we should give it the more ancient, and yet more modish name of an _action_. By an action we mean much the same thing as what is commonly called an abstract mode; that is, something which, properly speaking, is neither distinguishable, nor separable from its substance, and is only conceived by a distinction of reason, or an abstraction. But nothing is gained 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 applied to any perception, as derived 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 show 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 enclosed 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 produced 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 confessed, 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_, unaccompanied with any meaning, instead of that of modification, makes no addition to our knowledge, nor is of any advantage to the doctrine of the immateriality of the soul.