 Such a possibilist theory is faced with a problem of ontological indeterminacy. For there is more than one possible world in which Conan Doyle’s Holmes stories are fact, and in which there is a witty, cocaine-addicted detective called “Holmes” who lives at 221B Baker St., has a friend called “Watson”, and does the things recorded of him in the Holmes stories. Not all of these Holmes-candidates are the same; while they all match each other in terms of what the stories say about Holmes, they may be very different in other crucial ways—they may have had very different childhoods, including different parents, and so on. (Indeed, when characters are underdescribed in a story, a single possible world may contain many individuals who fit exactly what the story says about the character.) We can now ask: which of these different witty, cocaine-addicted detectives is Holmes? (cf. Kaplan 1973: 505–6; Kripke 1972 [1980: 156–8]). There seems to be no principled way of deciding.