 Panpsychism might be regarded as a fourth type of property dualism in that it regards all the constituents of reality as having some psychic, or at least proto-psychic, properties distinct from whatever physical properties they may have (Nagel 1979). Indeed neutral monism might be consistently combined with some version of panprotopsychism (Chalmers 1996) according to which the proto-mental aspects of micro-constituents can give rise under suitable conditions of combination to full blown consciousness. (See the entry on  panpsychism.)