Causation as Composition: Mary Shepherd and the Metaphysics of Causation

At the heart of Mary Shepherd’s philosophical system lies her understanding of efficient causation. But what exactly is Shepherd’s view of efficient causation? Her claims about causation seem puzzling. She suggests, for example, that causes and effects are identical. Furthermore, Shepherd suggests that causes and effects must be synchronous, that in some sense causes and effects must occur at the same time. Finally, Shepherd implies that all the properties of an effect are contained in its causes. But how could these claims be true? McDonough aims to give a coherent, sympathetic account of Shepherd’s understanding of efficient causation. First, he takes the core thesis of Shepherd’s view to be that the relation of efficient causation just is the relation of composition, where the relation of composition itself is understood in terms of identity. Second, he argues that causes and effects are synchronous for Shepherd in two distinct senses, with each sense grounded in a different aspect of her philosophical system. Third, McDonough argues that Shepherd thinks that all properties of an effect are contained in its causes because she embraces a modest view concerning emergent properties. For Shepherd, causal interactions may give rise to new complex properties but not to new simple properties.