Perhaps there is one chain [of inference] leading from the mental and the physical to a common source. It is conceivable in the abstract that if mental phenomena derive from the properties of matter at all, these may be identical at some level with nonphysical properties from which physical phenomena also derive. ...If there were such properties, they would be discoverable only by explanatory inference from both mental and physical phenomena. ... There would be properties of matter that were not physical from which the mental properties of organic systems were derived. This could still be called panpsychism.