Smart's case for the identity theory essentially rests on the claim that: a. The fact that mind-body correlations hold effectively rules out any alternative position on the mind-body problem. b. Mind-brain identities provide the simplest, most ontologically parsimonious explanation of mind-brain correlations. c. Failure to identify mental states with brain states would result in the fundamental physical constituents of the world 'dangling' from the nomological net of physical science. d. There is no logically possible world in which mental states are not identical to brain states.