 Strong emergentism asserts that when matter is organized in the appropriate way (i.e. in the way that living human bodies are organized), mental properties emerge in a way not fully accountable for by physical laws. Hence, it is a form of emergent materialism. These emergent properties have an independent ontological status and cannot be reduced to, or explained in terms of, the physical substrate from which they emerge. They are dependent on the physical properties from which they emerge, but opinions vary as to the coherence of top – down causation, i.e. the causal effectiveness of such properties. A form of property dualism has been espoused by David Chalmers and the concept has undergone something of a renaissance in recent years, but was already suggested in the 19th century by William James.
