Determinism Is Self Defeating

[Angrboda]

Why is this important to this discussion? Because determinism is the argument that: 1) any physical system can only have one possible outcome; 2) the universe consists of nothing but physical systems.

No, the notion that any physical system can have only one outcome is pre-destination, not determinism. Determinism is the view that future physical states are determined by past physical states; nothing more. This is why substance dualism is a challenge to determinism because if substance dualism is correct, and the mind is beyond the physical, then future states are determined by past physical states plus whatever contribution the non-physical mind makes to the outcome.

This whole thread is basically a process of begging the question-- "Well, we know that everything is dictated by the rules of physics, including the brain. Therefore, the mind is deterministic." I have a serious problem with this, for three reasons:
1) Nobody has created a physical description of mind, or interacted directly with one. Nobody has measured one, created one, or even provably destroyed one. Nor have you explained in a sensible way why the subjective perspective exists at all in a universe which could function perfectly well without it.

2) You are assuming that because the mind is supervenient on the brain, it cannot offer anything beyond the function of the brain. That's like saying "Casablanca is just a complex interaction of QM particles, and doesn't offer anything beyond the function of a movie projector"-- it doesn't actually explain how something like Casablanca exists, or describe its symbolic importance to the human minds watching it.

3) You ( and by this I mean you and the other physical monists ) keep asking people to furnish evidence that any competitor to the physical monist determinism you take as the default is wrong/incomplete. However, at no point have you actually established the truth of determinism, particularly with regard to mind. Instead, you point to brain function. However, this begs the question-- kind of the point of non-determinism is that mind on some level transcends the pure physical mechanism of the brain. As for evidence, I take as evidence the existence of the subjective perspective, aka sentience, itself. Why should a purely objective physical process manifest as subjective awareness? So far, Dennett has made the most famous attempt at this, but I find it pretty unconvincing.

All valid points, until you get to the bolded part. Here you appear to be making an argument from ignorance, and that is not valid. Another person's inability to furnish a physicalist explanation for subjectivity counts as zero evidence in favor of other explanations.

Until you can adequately explain WHY brain function is experienced as sentience, then I consider that the elephant in the room.

Indeed.