 Once one becomes aware of Leibniz’s technical notion of an aggregate and of certain aspects of his conception of the part-whole relation, it becomes less clear exactly how the “grounding argument” in texts  [1]  and  [2]  is supposed to work. The intuitive appeal of the argument seems to depend, at least in part, on assuming a straightforward account of the relation between bodies and monads that Leibniz does not actually endorse. Leibniz seems to encourage this oversimplified account of the relation by omitting an explanation of his notion of an aggregate and of his account of the part-whole relation, among other things. This suggests that Leibniz is not trying to provide a fully rigorous argument for the existence of simple substances or a full explanation of the relation between monads and bodies in the Monadologie or the Principes de la Nature et de la Grace. What Leibniz is doing, one might think, is helping his readers attain a preliminary grasp of the relation between bodies and simple substances—to help them recognize that simple substances provide some kind of ontological grounding for the world of bodies. By introducing the view in the form of a simple and intuitive argument Leibniz helps to motivate the radical idea that an infinity of immaterial mind-like simple substances exist. The reader will thus be more likely to take the view seriously enough to consider the further elaborations of the theory that are presented in the remainder of the texts. This is not to deny that Leibniz might have had a fully demonstrative “grounding argument” for the existence of simple substances, or that he wanted the fully demonstrative argument to be consistent with the versions of the argument that are presented in texts  [1]  and  [2].  The point is that Leibniz omits too many essential distinctions and details for even a very discerning reader to be able to reconstruct a demonstrative argument merely on the basis of texts  [1]  or  [2].  On this reading significant portions of the Monadologie and the Principes de la Nature et de la Grace are exoteric in content and form. They serve to introduce some of the central features of Leibniz’s metaphysics while omitting many important details (more details are omitted in the latter text, as we will soon see).