Abstract
Beau Branson rounds out the previous two chapters, by exploring the doctrine of inseparable operations ad extra in the writings of St Gregory of Nyssa. This doctrine says that all the activities of the three hypostases of the Trinity, at least insofar as they relate to things outside of (“ad extra”) the Trinity, are not only qualitatively identical but numerically identical. Importantly, Branson focuses his attention on Gregory’s theory of action and the individuation of events that emerges from his theological defense of the doctrine of inseparable operations ad extra. Through a heavy engagement with contemporary metaphysics, Branson shows that Gregory’s philosophy of action is not only coherent, anticipating current trends in the ontology of actions and events, but may provide novel solutions to longstanding problems in this field.