Interactionists hold that minds are non-physical objects that interact with brains. The neural discernment problem for interactionism is that of explaining how non-physical minds produce behavior and cognition by exercising different causal powers over physiologically similar neurons. This paper sharpens the neural discernment problem and proposes two interactionist models of mind-brain interaction that solve it. One model avoids overdetermination while the other respects the causal closure of the physical domain.

The pairing argument aims to demonstrate the impossibility of non-spatial objects (including minds) standing in causal relations. Its chief premises are (roughly) that causation requires pairing relations between causes and effects and that pairing relations require spatial relations. Critics have argued that the first claim suffers from counterexamples involving indeterministic causation. After briefly rehearsing the pairing argument and the objection from indeterministic causation, I offer two ways of revising the pairing argument to meet the objection from indeterministic causation.