@Reconstructo,
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"It is six o'clock in the evening, the working day is over. Now I can go for a walk, or I can go to the club; I can also climb up the tower to see the sun set; I can go to the theater; I can visit this friend or that one; indeed, I also can run out of the gate, into the wide world, and never return. All of this is strictly up to me, in this I have complete freedom. But still I shall do none of these things now, but with just as free a will I shall go home to my wife." This is exactly as if water spoke to itself: "I can make high waves (yes! in the sea during a storm), I can rush down hill (yes! in the river bed), I can plunge down foaming and gushing (yes! in the waterfall), I can rise freely as a stream of water into the air (yes! in the fountain), I can, finally, boil away and disappear (yes! at certain temperature); but I am doing none of these things now, and am voluntarily remaining quiet and clear water in the reflecting pond."
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Modern science comes close to confirming the truth of this. The treatment for severe epilepsy is (or was) to sever the connection between the two hemispheres. The patients would then have two unconnected brains. They would have them stare at a dot and then display a picture of a house so that only one eye would see it. If they showed it to the left brain, the person would say it was a house (language in the left brain) if they showed it to the right brain they wouldn't be able to say what it was but could point it out on a piece of paper with the left hand (right brain).
When they told the right brain to get up and walk out of the room, the person would start to, and when asked why they would say "I was going to get a drink" or "I was restless", believing it completely. We have a mechanism that confabulates constantly, making sense of what we are doing, providing the illusion of choice.
Quantum type randomness is not relevant to free will--whether an action is predetermined or random it is still not chosen. The Greeks suggested that our spirit could "swerve" electrons, but we can't.
So, factually speaking, we don't have free will. Pragmatically, we do (usually).
Let's take a fat person.
Someone who goes for complete free will might say "they made all of the choices that led to them being fat, they are to blame".
Someone who goes for determinism might say "They had no choice, they are fat because of what tastes good to us, how habits form, modern sedentary lifestyles, fast food, etc". You could use this position to excuse the person, or you could say that actions reflect character.
I think both views are useful. The deterministic view is what the government should take when deciding how to combat obesity. You can't try to change things by just saying "make better choices".
On the personal level, if you treat people like they have choices, they are more likely to do what they should.
That is to me the take away message from "free will vs determinism" (and the point of philosophy should be to find a take away message...).