What are the rules of the metaphysical game? And how are the rules, whatever they are, to be justified? Above all, the rules should be fair. They should be rules that we metaphysicians would all accept, and thus should be justifiable to all rational persons engaged in metaphysical inquiry. Borrowing from Rawls’s conception of justice as fairness, I develop a model for determining and justifying the rules of metaphysics as a going concern.