Wait, are you referencing some actual argument I've had here or is that an example of a discussion that I might have? Because my stance has certainly never been that free will is impossible in a causal world.
I think we've had some discussion approaching that at some point.
do you believe you can make decisions?
Depends on what is "you", and that is the crux of the issue. If you hold the belief that "you" is
not limited to a body that follows the laws of physics, then indeed you get the mind-body problem. Granted, this is thoroughly uninteresting.
But it's even worse than that if you consider that if your definition of identity is purely physical then it doesn't really hold any meaning at all. You are just a big lump of interchangeable stuff structured in some particular way and in constant flux. If "you" have free will, then absolutely every other arbitrary lump of stuff also has free will. And thus the concept of free will itself makes little sense, as it applies to everything that exists. I wouldn't expect most people to say of a rock that it has free will, yet it has it exactly as much as a human being.