The mind -body problem and necessary a posteriori identit

Materialism or physicalism is commonly understood as the view that certain physical properties, that is, properties from the microphysical level, are the basic constituents of the world. According to this view, all properties are related necessarily to the basic physical properties either by being strictly identical with them or by being dependent on them; in this second sense, the relevant properties are said to supervene on the basic physical properties.;If materialism is the correct picture of the world, then consciousness either supervenes on or is identical with the physical properties. Three most widely discussed philosophers in the current literature who challenge this view are Kripke (1980), Chalmers (1996), and Jackson (1982). All of them argue that the main difficulty for materialism lies in the fact that necessity has a conceptual basis---even if the relevant statements expressing necessary truths are true a posteriori. Whether consciousness supervenes on or is necessarily identical with physical properties, the relevant necessary relation must be somehow determined conceptually, by the way we understand phenomenal concepts. The trouble then is that we cannot make sense of such determination in the case of phenomenal concepts.;I will argue that no satisfactory response to this argument has been given and that whether or not materialism is false, we simply do not understand how materialism could be true. I will, in fact, strengthen Kripke's, Chalmers's, and Jackson's argument by providing additional reasons for thinking that we do not understand how, in particular, mental states could be identical with physical states.