 Leibniz’s Law of the Indiscernibility of Identicals, according to which, if “two” things are identical, then they share all their properties, can be used to argue for various claims of nonidentity. If you know, for example, that Charles is a philosophy major and that Yoko is not, then you can safely infer that Charles is not identical to Yoko. Essentialist claims have played a role in some prominent Leibniz Law arguments for nonidentity theses. A certain brand of mind-body dualism may be argued for in the following way: \(X\) is essentially a thinking thing; \(X\)’s body is not essentially a thinking thing; so \(X\) is not (identical to) \(X\)’s body. A similar argument can be given for the conclusion that a statue is not identical with the lump of material (wax, clay, marble, or what have you) that constitutes it. Consider a human-shaped statue—call it ‘Goliath’—and the lump of wax that composes it—call it ‘Lump\(_1\)’. Goliath, we may imagine, is throughout its entire existence composed of Lump\(_1\) while Lump\(_1\) throughout its entire existence composes Goliath. In this case, Goliath and Lump\(_1\) are spatiotemporally colocated, which is just to say that they occupy the exact same spatial region at any given time whenever either of them exists. This being the case, they share most of their properties: Goliath weighs 17 kilograms and so does Lump\(_1\); Goliath has a white surface and so does Lump\(_1\); and so on. In fact, it may seem curious that we are writing as though there are two things at all. Why not say simply that Goliath and Lump\(_1\) are identical? Well, it at least seems that a pretty straightforward argument—one that relies on essentialist claims—establishes their nonidentity: