 Unfortunately, none of these three definitions seems to succeed in stating a sufficient condition for physicalism. For one thing, they are all compatible with the existence of a necessarily existing God (recall Section 3.5).  But physicalism is surely incompatible with the existence of any God (see Jackson 1998, 22–23 for an attempt to avoid this objection. See Witmer 1999 and Hawthorne 2002 for other counterexamples to these definitions.) Moreover, even if the definitions were counter-example free, it might well be thought that physicalism requires superdupervenience, that is to say, that physicalism should explain why the relevant global supervenience theses holds (see  3.7,  and Horgan 1993; Melnyk 2003; Wilson 2005).