I wanted to throw in a quick definition of "supervenience" as I'm understanding the term.
Fact 1: I'm writing in an internet forum.
Fact 2: I'm using a computer.
Fact 2 is supervenient upon Fact 1. That is, 2 follows directly from 1; it's logically necessary that I am using a computer if I'm writing in an internet forum.
So physicalists believe that mental activity is supervenient upon brain activity, in the sense that one follows directly from the other. Two identical brains will have identical mental activity.
Whereas property dualists believe the opposite. Identical brains can support entirely different mental activity. I'm wondering what the reason is that property dualism gives for this.
I was thinking it might have something to do with free will. Whereas materialists would tend to assert that free will is an illusion, and that we obey strict laws like we were a chain of dominoes.
But that's what I was wondering if you could offer some perspective on, Tut. What the reasoning is that leads a property dualist to say that identical brains could produce distinct mental activity.
Also, what do you mean when you say 'over and above'? Physicalists reject PD because it's like a mind-over-matter attitude on awareness? I don't quite get what you mean, that's just my best interpretation. Mind explaining some more?
Here's a clickable version of the link I posted earlier. Pryor brings up supervenience only to show that property dualism is opposed to the idea.
Philosophy 156: Supervenience