If they prove we don't have free will and somebody gets upset, they can always say "Hey, it wasn't like we choice in what we studied. It just happened that way."
It might have been predetermined, but there's still an act of choosing, a weighing of possibilities, a judgment between them, and action. And those judging them later will too be able to judge their judgment, their character, and make decisions based on that.
The existence of free will in a strong sense, has, as far as I can tell, no logically valid implications in practical terms, though it does do something profound to our psychologies: it certainly injects fatalism.
"It might have been predetermined, but there's still an act of choosing, a weighing of possibilities, a judgment between them, and action. And those judging them later will too be able to judge their judgment, their character, and make decisions based on that."
And that would all be predetermined too.
Someone came up with this before me: you should believe in free will because if it exists you're right and if not you couldn't have done otherwise anyway. It's like Pascal's Wager, except not stupid and wrong.
I could imagine a race of egghead hyper-rationalists who would feel depressed at the thought of the absence of determinism. They would be horrified at the thought of living in an unpredictable, chaotic universe.
