 Another type of argument for the conclusion that unless things have non-trivial individual essences there will be ‘bare’ transworld identities: identities that do not supervene on (are not grounded in) other facts, is presented by Graeme Forbes. (Strictly speaking, Forbes is concerned to avoid identities that are not grounded in what he calls ‘intrinsic’ properties.) A sketch of a type of argument used by Forbes is this. (What follows is based on Forbes 1985, Ch. 6; see also Mackie 2006, Ch. 3.) Suppose (as is surely plausible) that an actually existing oak tree could have been different in some respects from the way that it is; suppose also that, even if it has some essential properties (perhaps it is essentially an oak tree, for example), it has no non-trivial individual essence consisting in some set of its intrinsic properties. Then there is the danger that there may be three possible worlds (call them ‘w2’, ‘w3’, and ‘w4’), where in w2 there is an oak tree that is identical with the original tree (w2 representing one way in which the tree could have been different), and in w3 there is an oak tree that is identical with the original tree (w3 representing another way in which the tree could have been different), and in w4 there are two oak trees, one of which is an intrinsic duplicate of the tree as it is in w2, and the other an intrinsic duplicate of the tree as it is in w3. If all of w2, w3, and w4 are possible, then, given that at least one of the trees in w4 is not identical with the original tree (since two things cannot be identical with one thing) there are instances of transworld identity (and transworld distinctness) concerning a tree in one possible world and a tree in another that are not grounded in (do not supervene on) the intrinsic features that those trees possess in those possible worlds. For example, suppose that, of the two trees in w4, the intrinsic duplicate of the w2 tree is not identical with the original tree. Then, obviously, the distinctness (non-identity) between this w4 tree and the tree in w2 is not grounded in the intrinsic features that the trees have in w2 and w4—and nor is the identity between the tree in w2 and the original tree grounded in the intrinsic features that the tree has in w2 and in the actual world.