ABSTRACT
The concept of a causal power includes two root concepts: dispositions to respond to external conditions, and radical agency or spontaneity. The virtus dormativa objection undercuts the use of the concept of "power" in scientific theorizing in a much more serious way. It poses a dilemma that force to pay close attention to the criteria of identity, both numerical and qualitative, of causal powers, whether they are attributes of powerful particulars or individual substances. Proposing events for the ontology of causality renders the link between causal laws and counterfactuals mysterious. A primary powerful particular is a being that is efficacious in a stronger sense: namely, its efficacy is not the result of internal processes within the particular itself. A secondary powerful particular acts by virtue of some process or structure, or both, internal to the being in question. The requirement that a conditional be grounded in an occurrent state of a powerful particular leads to a powers/natures hierarchy.
