(I think we’ve corrupted KF’s thread long enough.)
The entire problem of mind/matter dualism is rooted in a single error of thought: the reification of an abstract descriptive model of experience into an causal agency independent of the mind that conceives it and the mental experience it is extrapolated from. It is similar to the same error of thought that mistakes “forces” and “physical laws” and “energy” as independently existing causal agencies, when in fact they are abstract models of various mental experiences.
All experience and all thought about experience takes place in mind, regardless of whether or not it is caused by something external to mind. Therefore, “an external, physical world” is a mental abstraction about mental experiences. Insisting that the content of the abstraction is “real” is entirely irrelevant.
Since all we have to work from and with is mental experience and mental thoughts about mental experiences, mind is not only primary ontologically and epistemologically; it is ontologically and epistemologically exhaustive. Even if some non-mental, independent “secondary” aspect of our existential framework exists, we have no access to it nor any ability to use it. If some sort of independent physicality exists, it is therefore 100% ontologically and epistemologically irrelevent. The “external physical world” abstraction still lies within the ontological and epistemological framework of mind and it is all we can ever have access to or use.
In fact, once one understand this error of thought, the self-evidently true irrelevant nature of any supposed external world comes clearly into focus.
This error of thought has entrenched the idea of an external world as “real” so deeply into general psychology that it has contaminated thousands of years of thought. It has generated “the hard problem of consciousness” out of nothing but error. It has led to adoption of 3rd-layer abstractions about mental experience as having primacy over mental experience itself from which they are generated (much like insisting that one’s grandchild is one’s own father). It has generated an entirely false dependency on the “reality” of that abstract world in many philosophical lines of thought.
One such bizarre perspective it has generated is this: that if the external physical world doesn’t in fact exist (even though it is 100% irrelevant because it is 100% outside of our access), then mental experience – the ONLY kind of experience we actually have – is deemed “delusional,” when in fact “delusion” can factually only ever be a comparison between kinds of mental experiences and can never include any comparison to any supposed “external physical reality.” The idea that unless an actual external world exists we are doomed to delusion is entirely due to an error of thought. The delusion or reality value of anything can only ever be a comparison of kinds of mental experiences.
It gets worse. Non-materialists (people that are not materialists) insist that epistemological validity requires that some sort of external world exists independent of mind that can cause universal or near universal mental states in observers . It seems no one has figured out that if one insists that non-mental, independent external commodities can cause mental states, thoughts and experiences, they have just given up free will and have become an “in principle” materialist, consigning themselves to existence as caused automatons.
How would we determine what is an externally-caused mental state, thought or experience concerning free will and what is an independent free choice? Answer: as long as something external can cause mental states, there’s no way to know. As with materialism, even rationality is lost.