Then why do injuries to the brain directly impact the parts of selfhood we hold most sacred, like feelings memories and attitudes?
What I'm getting at is I could use your reasoning to posit insane things that you would heartily disagree with, using your reasoning without twisting or bending it. Because your reasoning is baseless, or rather it rests on its own conclusion.
Even to just stick to the realm you're suggesting - why would anything about us need to be immaterial to have concepts like justice? I don't see the necessity of an unprovable, nebulous, unnecessary immaterial reality to explain anything.