Subset realization, parthood, and causal overdetermination

Defenders of the subset view of realization have claimed that we can resolve well-known worries about mental-physical causal overdetermination by holding that mental properties are subset realized by physical properties, that instances of subset realized properties are parts of physical realizers, and that part-whole overdetermination is unproblematic. I challenge the claim that the overdetermination generated by the subset view can be legitimated by appealing to more mundane part-whole overdetermination. I conclude that the subset view does not provide a unique solution to overdetermination worries.