 For any metaphysical account compatible with physics the question arises, what the truth-makers of causal claims are or what grounds these claims. There are three options: (i) either the truth-makers of causal claims are physical features of the world, (ii) or they supervene on physical features of the world, (iii) or they are non-physical features of the world that do not supervene on physical features of the world. If the truth-makers of causal claims are either physical features or supervene on such features, then the metaphysical account is compatible with the thesis of the completeness of the physical. On the third option, however, the account is incompatible with the completeness of the physical.