Well, it’s because of the uncertainty of whether or not we have it.
a) Historically, generally, free will is a given.
b) Challenges to having it or not have raged for centuries.
c) Popular opinion in 21st century says “we don’t have free will because”
d) Yet, there’s not enough evidence we don’t have free will but more of a hope that technology will be able to recreate it.
e) Even though “no free will” is popular now, our societies, court systems, literature, etc has been built around this concept of free will.
f) functionally, there’s little/no difference whether we have free will or if we have a state machine that resembles free will.
g) pragmatically speaking in either case, free will can be considered a reality so that our courts can keep functioning, etc.
I’ll give an analogy:
There’s no such thing as gravity.
It’s not a thing: It’s a fluctuation in spacetime.
Einstein said so.
So, should we call Gravity a fictitious force and let it go?
Well we do.
we don’t. We speak of it as if it’s real, and some researchers even search for Gravitons, even though Einstein was pretty clear, “Um, no, like cetrifuge, gravity is a fictitious force”
Why? Because we’re NOT 100% certain it’s a fictitious force. Einstein was. People working in fields that deal in relativistic physics do.
Other branches of physics don’t.
So, gravity “might as well be real”
free will “might as well be real”.
I can say without hesitation: We have free will.
I can say without hesitation: Gravity is a force.
It seems as-if it’s holding contradictory positions to say “yes/no/maybe” at the same time, but it’s not contradictory because what’s true on one level can be false on another level and i don’t know on another level.
Depends on what feature we’re zooming into at the time.
That’s my argument.