Religions and denominations of the same religion won't even agree on the nature or existence of free will. Why everyone else is so concerned about the same, I don't understand. It's more philosophy than science in most discussions. If acting as if your actions had internal agency offers better chances of survival, that's a good enough fudge for nature.
There's no way we'll be able to do that until we have an agreed-upon definition of free will. Good luck with that. We can't even come up with rigorous definitions of many common, related words: intelligence, thinking/thought, life. Heck, we can't even define pornography!
All of these ultimately boil down to "I know it when I see it". This sort of definition is not good enough for scientific inquiry. For that reason, scientists tend to avoid such questions.
