 [P]ositing instances of determinate properties offers the best explanation for the causal relations we observe in the world […] Should we also accept that there are instances of determinable properties corresponding to predicates such as ‘is colored’ or ‘is charged’? […] There is a clear concern that it is ontologically profligate to take two properties to be contributing causal powers, a determinable and its determinate, where one, the determinate, would apparently suffice. (2005: 487)