section_path: Western philosophy/Incompatibilism/Agent/substance-causal theories
section_name: substance-causal theories
paragraph_text: substance-causal theories
  
  Agent/substance-causal accounts of incompatibilist free will rely upon substance dualism in their description of mind. The agent is assumed power to intervene in the physical world. Agent (substance)-causal accounts have been suggested by both George Berkeley and Thomas Reid. It is required that what the agent causes is not causally determined by prior events. It is also required that the agent's causing of that event is not causally determined by prior events. A number of problems have been identified with this view. Firstly, it is difficult to establish the reason for any given choice by the agent, which suggests they may be random or determined by luck (without an underlying basis for the free will decision). Secondly, it has been questioned whether physical events can be caused by an external substance or mind – a common problem associated with interactionalist dualism.