The mind, though causally reducible, is ontologically irreducible to some physical or neurobiological state or property.
In other words, though the neurobiological structure of the brain is causally responsible for the existence of the mind, it could exist in some non-brain physical predicate.
(Davidson 690 – 691) By Davidson’s reasoning, a mental phenomenon, such as the mind, requires some physical predicate on which to supervene.
However, this causal link between the mind and its physical substance, in this case the human brain, does not imply an ontological link.
This phenomenon supports that physical events can have some mental properties which are causally reducible to physical properties while simultaneously ontologically irreducible, and therefore that property dualism is true.
A successful therapy for phantom pain invented by Ramachandran is further evidence of the theory.(Ramachandran and Hirstein) Ramachandran and Hirstein’s anecdote about the soldier whose phantom hand was permanently stuck in a clenched position serves an argument for property dualism.First one must assume that having one’s hand indefinitely clenched will cause a degree of pain and discomfort.When one’s hand is violently amputated by a detonating grenade, it seems as though that limb should no longer be able to communicate with one’s nervous system; the neurons relating to the hand cease receiving input. If pain is felt only from the limb, then that limb must be present for pain to persist.But because pain, evidently, can persist without the limb, pain must be felt somewhere else.[…] It is consistent with the view that mental characteristics are in some sense dependent, or supervenient, on physical characteristics.Dependence or supervenience of this kind does not entail reducibility through law or definition.This definition of property dualism is consistent and compatible with a combination of supervenience physicalism and token physicalism, which together assert similar claims.Descartes frequently used the phenomenon of phantom limbs as part of his argument for substance dualism.This allows for the “multiple realizability” of mental properties in different physical substances conducive to them.However, property dualism does not allow for immaterial minds, but requires that the mind be based on some sort of physical predicate in order to emerge.