A Research Report submitted to the Faculty of Humanities, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Arts, 2017 / Any comprehensive theory of the realist position in metaethics must be equipped with a version of moral ontology. Metaethical theological voluntarism, which purports that supernatural facts, i.e. commands issued by a divine being, determine moral states of affairs, has been accused for a long time of rendering morality ‘arbitrary’. Implicit in this widely-accepted objection is the idea that a moral theory cannot have an arbitrary ontological foundation because then anything could have been right or wrong. This paper gives a detailed analysis of this objection that theological voluntarism is arbitrary and makes the case that a commitment to avoiding arbitrariness imposes constraints on the formulation of a moral theory. In particular, this paper argues that accounting for such a commitment decreases the significance that natural facts play for moral theories that maintain a naturalist account of moral ontology. / XL2018