 Another problem with views like the ones sketched above, some argue (Kim 1989, 1998), is that mental and physical causes would thereby overdetermine their effects, since each would be causally sufficient for their production. And, though some theorists argue that overdetermination is widespread and unproblematic (see Loewer 2002, and also Shaffer, 2003, and Sider 2003, for a more general discussion of overdetermination), others contend that there is a special relation between role and realizer that provides an intuitive explanation of how both can be causally efficacious without counting as overdetermining causes. For example, Yablo (1992), suggests that mental and physical properties stand in the relation of determinable and determinate (just as red stands to scarlet), and argues that our conviction that a cause should be commensurate with its effects permits us to take the determinable, rather than the determinate, property to count as causally efficacious in psychological explanation. Bennett (2003) suggests, alternatively, that the realizer properties metaphysically necessitate the role properties in a way that prevents them from satisfying the conditions for overdetermination. Yet another suggestion (Wilson, 1999, 2011, and Shoemaker, 2001) is that the causal powers of mental properties are included among (or are proper subsets of) the causal powers of the physical properties that realize them. (See also Macdonald and Macdonald 1995, Witmer, 2003, Yates, 2012, and Strevens, 2012, for related views.) 