Meta Ontology

Orthodox neural materialists think mental states are neural events or orthodox material properties of neutral events. Orthodox material properties are defining properties of the ''physical''. A ''defining property'' of the physical is a type of property that provides a necessary condition for something's being correctly termed ''physical''. In this paper I give an argument against orthodox neural materialism. If successful, the argument would show at least some properties of some mental states are not orthodox material properties of neural events. Opposing philosophical orthodoxy, I show there are no posteriori identities -- identities that cannot be known of a priori.