Mind–body dualism point into the traditionally viewed closed system, where a scientifically described physically probable/improbable event could be philosophically described as an action of a non-physical entity on physical reality. He states, however, that none of the arguments in his book will rely on this. It should also be noted that, while some interpretations of quantum mechanics consider wave function collapse to be indeterminate, in others this event is defined and deterministic. The argument from physics is closely related to the argument from causal interaction. Many physicists and consciousness researchers have argued that any action of a nonphysical mind on the brain
Non-physical entity many minds each person can have, which is not an issue for physicalism which can simply declare one-mind-per-person almost by definition; and whether non-physical entities such as minds and souls are simple or compound, and if the latter, what "stuff" the compounds are made from. Describing in philosophical terms what a non-physical entity actually is (or would be) can prove problematic. A convenient example of what constitutes a non-physical entity is a ghost. Gilbert Ryle once labelled Cartesian Dualism as positing the "ghost in the machine". However, it is hard to define in philosophical terms what it is, precisely, about