I argue that Schaffer fails to provide a non-question-begging argument for priority monism. Despite his suggestion to the contrary, Humean pluralists need not, and plausibly do not, endorse his tiling constraint on metaphysically basic objects. Moreover, the distinction between supervenience—of the sort at issue in Humean doctrine—and metaphysical necessitation—of the sort at issue in Schaffer’s tiling constraint—points toward an alternative treatment of the phenomena initially inspiring Schafferian monism. There is an important possibility, one that Humeans can or should embrace, that (...) Schaffer overlooks when drawing his monistic conclusion. (shrink)