Any Nihilists here?

[LinuxGal]

Since free will relies on the premise that counterfactuals are at least possible in principle, and we don't have epistemic access to counterfactuals, it will always remain an unscientific concept, unless we can build a time machine to find out what we will, in fact, do, and return to attempt to make the counterfactual real.

You don't need to go through all that trouble to have "epistemic access" to counterfactuals. Counterfactuals are right there, in your mind. Unless, of course, you're talking about concrete possible worlds here, and not just abstact?

Also, there are different flavors of "free will".

Alice and Bob measure a stream a particle-pairs in a singlet state.  Alice sets her polarizer at 37.5 degrees off vertical, and Bob sets his to 77.4 degrees off vertical.  We believe Bob could have set his detector to any orientation but all we know is that he set it to that one.  So free will remains a matter of faith.