Page 1 | 30 Causal Exclusion and Physical Causal Completeness Dwayne MOORE 1 This is the final draft. The published version can be found in dialectica at: https://onlinelibrary-wiley-com.cyber.usask.ca/doi/full/10.1111/1746-8361.12281 ABSTRACT Nonreductive physicalists endorse the principle of mental causation, according to which some events have mental causes: Sid climbs the hill because he wants to. Nonreductive physicalists also endorse the principle of physical causal completeness, according to which physical events have sufficient physical causes: Sid climbs the hill because a complex neural process in his brain triggered his climbing. 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 Sid’s behaviour. In this paper I demonstrate how numerous nonreductive physicalists have responded to the causal exclusion problem by weakening the principle of physical causal completeness in numerous ways. The result: either numerous 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. onreductive physicalists endorse the principle of mental causation, according to which some events have mental causes: Sid climbs the hill because he wants to. Nonreductive physicalists also endorse the principle of physical causal completeness, according to which physical events have sufficient physical causes: Sid climbs the hill because a complex neural process in his brain triggered his climbing. 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 Sid’s behaviour. In this paper I demonstrate how numerous nonreductive physicalists have responded to the causal exclusion problem by weakening the principle of physical causal completeness in various ways. The result: either numerous 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 relaxing the principle of physical causal completeness. This paper has eight parts. I outline the causal exclusion problem, paying attention to four necessary conditions for satisfying a robustly defined principle of physical causal completeness (§1). Namely, the principle of robust physical causal completeness stipulates that all physical 1 Department of Philosophy, University of Saskatchewan, Saskatoon, Canada; Email: dwayne.moore@usask.ca N