  On the issue of the admissibility of predicates, Quine’s physicalism is more complicated. (This is in keeping with his general idea that we can think of the predicates, rather than the ontology, as “where the metaphysical action is”; 1976, 504). The requirement here is that the difference between a predicate’s being true of a given object and its being false of it should, in all cases, be a physical difference: “nothing happens in the world, not the flutter of an eyelid, not the flicker of a thought, without some redistribution of microphysical states…. physics can settle for nothing less” (1981, 98). If a predicate such as “…is thinking about Fermat’s Last Theorem” picks out genuine events in the world then there is a physical difference between its being true of a person and its not being true of them: a fact of the matter.