 The commitment to transworld identity should not be confused with a commitment to realism about possible worlds. Prominent champions of rigidity seem favorably inclined to realism (see Davidson’s 2003 collection of Plantinga’s essays; see also Kripke 1980, p. 16). But there is no reason an instrumentalist about possible worlds like Bas Van Fraassen, say, who regards possible-worlds talk as a useful fiction, cannot appeal to rigidity (as Van Fraassen does: 1984). What matters for the position that a designator for an individual x is a rigid designator, is that in using that designator to entertain the various counterfactual situations or worlds S in which x exists, whether we do the counterfactual entertaining about x by way of apprehending abstracta, say (if worlds are real objects, abstract ones), or by way of pretending (if counterfactual talk is a fictional pretense, say, because worlds are not real) or whatnot, we entertain situations (or pretend to do so) that, were they to obtain, would contain x: so we tacitly commit to “the impossibility that S obtain and x fail to exist” (Plantinga 1974, p. 96). Accordingly, suppose I say to you, “If you’d driven to the park instead of walked, you’d have missed the refreshing breeze.” Here I entertain a nonfactual possibility associated with your driving to the park. Whom, in that entertained possibility, do we think of and speak of, as driving and not walking? The transworld-identity theorist says: you. No one else “gets into the act” as the driver according to the transworld-identity theorist (as Lewis would frame that view, without sympathy: 1986, p. 196).