Causal Exclusion and Physical Causal Completeness

Nonreductive physicalists endorse the principle of mental causation, according to which some events have mental causes. Nonreductive physicalists also endorse the principle of physical causal completeness, according to which physical events have sufficient physical causes. Critics typically level the causal exclusion problem against this nonreductive physicalist model, according to which the physical cause is a sufficient cause of the behavioural effect, so the mental cause is excluded from causally influencing the behaviour. Numerous nonreductive physicalists have responded to the causal exclusion problem by weakening the principle of physical causal completeness in various ways. The result: either various nonreductive physicalist solutions fail on account of the fact that they do not satisfy a robustly defined principle of physical causal completeness, or there is an accelerating trend of solving the causal exclusion problem by suitably weakening the principle of physical causal completeness.