Scientific "Materialism" is often synonymous with, and has so far been described, as being a reductive materialism. In recent years, Paul and Patricia Churchland have advocated a radically contrasting position (at least, in regards to certain hypotheses); eliminativist materialism holds that some mental phenomena simply do not exist at all, and that talk of those mental phenomena reflects a totally spurious "folk psychology" and introspection illusion. That is, an eliminative materialist might suggest that a concept like "belief" simply has no basis in fact - the way folk science speaks of demon-caused illnesses. Reductive materialism being at one end of a continuum (our theories will reduce to facts) and eliminative materialism on the other (certain theories will need to be eliminated in light of new facts), Revisionary materialism is somewhere in the middle.