 It has been argued by Kim (1992, 1993) that multiply realized mental kinds of the latter kind can in principle be locally reduced to their realizing states. Mental kinds are analogous to mineral kinds such as jade, which can be locally reduced to nephrite or jadeite depending on the sample. Importantly, a sample that does not consist of either nephrite or jadeite is simply not jade. Nevertheless, there is an important disanalogy between mental kinds and locally reduced kinds like jade. If you want a sample of jade, then it must be composed of either jadeite or nephrite. In other words, if J (jade) is realized by the disjunction P (Jadeite) or Q (Nephrite), then it is metaphysically necessary that the properties a thing has qua J are either properties it has qua P or properties it has qua Q. So, something with all the other qualitative properties of jade in another possible world, but which lacked the essential properties (i.e. of jadeite or nephrite) would simply not be an instance of jade.