Philosophy & heology 20, 1–2 99 MODELING THE METAPHYSICS OF THE INCARNATION Anna Marmodoro and Jonathan Hill University of Oxford Abstract What metaphysics can plausibly back up the claim that God became incarnate? In this essay we investigate the main kinds of models of incarnation that have been historically proposed. We highlight the philosophical assumptions in each model, and on this basis offer novel ways of grouping them as metaphysical rather than doctrinal positions. We examine strengths and weaknesses of the models, and argue that ‘composition models’ offer the most promising way forward to account for the pivotal Christian belief that, in Christ, true divinity and true humanity meet in a genuine union. Introduction The doctrine of the incarnation has always been a matter of controversy among both theologians and philosophers. While many have rejected it as either incoherent or literally incredible, a number of philosophical theologians have sought to defend it against these charges and argue for its plausibility. For centuries, one of the key problems that has exercised its defenders is how to give a metaphysical account that backs up the claim expressed in the definition of Chalcedon that Christ is a single person with two natures, one divine and one human. This pivotal claim is underpinned by the soteriological principle that, for salvation to happen, humanity and divinity must have met in a genuine unity. In late ancient and early medieval theology, the belief was not simply that, if Christ is to save, he must be genuinely God, genuinely man, and a single person. That was the view that western theologians such as Anselm of Canterbury developed later. 1 The early theologians did not, typically, think that these constraints