 may owe its indeterminacy to the semantic indeterminacy of ‘Tibbles’: our linguistic practices do not, on closer look, specify exactly which portion of reality is currently picked out by that name. In particular, they do not specify whether the name picks out something whose current parts include the whisker that is coming loose and, as a consequence, the truth conditions of (65) are not fully determined. But this is not to say that the stuff out there is mereologically indeterminate. Each one of a large variety of slightly distinct chunks of reality has an equal claim to being the referent of the vaguely introduced name ‘Tibbles’, and each such thing has a perfectly precise mereological structure: some of them currently include the lose whisker among their parts, others do not. (Proponents of this view, which also affords a way of dealing with the so-called “problem of the many” of Unger 1980 and Geach 1980, include Hughes 1986, Heller 1990, Lewis 1993a, McGee 1997, and Varzi 2001.) Alternatively, one could hold that the indeterminacy of (65) is due, not to the semantic indeterminacy of ‘Tibbles’, but to that of ‘part’ (as in Donnelly 2014): there is no one parthood relation; rather, several slightly different relations are equally eligible as extension of the parthood predicate, and while some such relations connect the loose wisker to Tibbles, others do not. In this sense, the dashed lines in Figure 9 would be “defects” in the models, not in the reality that they are meant to represent. Either way, it is apparent that, on a de dicto understanding, mereological indeterminacy need not be due to the way the world is (or isn't): it may just be an instance of a more general and widespread phenomenon of indeterminacy that affects our language and our conceptual apparatus at large. As such, it can be accounted for in terms of whatever theory—semantic, pragmatic, or even epistemic—one finds best suited for dealing with the phenomenon in its generality. (See the entry on  vagueness.)  The principles of mereology, understood as a theory of the parthood relation, or of all the relations that qualify as admissible interpretations of the parthood predicate, would hold  regardless.[26]