||Some possibilities (e.g., the possibility that some objects are furry) are qualitative, because they involve properties but not specific objects. Other possibilities (e.g., the possibility that Napoleon is shorter than Bush) are non-qualitative, because they involve specific objects. According to haecceitism, some maximal possibilities--total ways things could be--differ only with respect to the non-qualitative possibilities they include. In terms of possible worlds, haecceitism is the thesis that some possible worlds differ only with respect to the distribution of non-qualitative properties like haecceities (e.g, Socrateity) and "impure properties" (e.g, being five feet from Socrates). Consider, for example, a world qualitatively indiscernible from actuality where you fail to exist or a world where you swap qualitative roles with Obama. Such worlds differ only haecceitistically from actuality and therefore entail haecceitism.