 Those who believe in the ‘extreme realist’ notion of possible worlds may respond by thinking of Clover as having a four-legged part in our world, and a three-legged part at some other world. This is Yagisawa’s (2010) view (cf. Lewis 1986, 210–220). Yagisawa thinks of concrete entities—everyday things such as cats, trees and macbooks—as extended across possible worlds (as well as across times and places), in virtue of having stages (or parts) which exist at those worlds (and times and places). Ordinary entities thus comprise spatial, temporal and modal stages, all of which are equally real. Metaphysically, modal stages (and the worlds at which they exist) are on a par with temporal and spatial stages (and the times and places at which they exist). (This view is the modal analogue of the ‘perdurance’ account of identity over time, according to which an object persists through time by having ‘temporal parts’ that are located at different times.) Thus, when we say that Clover has four legs in our world but only three in some other world, we are saying that she has a four-legged modal stage and a distinct three-legged modal stage. Clover herself is neither four-legged nor three-legged. (However, there is a sense in which Clover herself—the entity comprising many modal stages—has awfully many legs, even though she actually has only four.)