Free Will
"Free Will." Two more incoherent words were never penned.
Imagine you are an atomic physicist, and you study atoms, and work out to a great degree of accuracy and precision (within the limits of the Heisenberg uncertainty principle) mathematical models which describe how atoms interact.
Suppose you program your super computer to simulate atoms according to the rules of physics.
Further, suppose you invent a machine, a kind of three dimensional scanner which is capable of recording the positions and velocities and atomic identity and so on of all the atoms and electrons within a cube which is 3 meters on a side, all within a nanosecond or two.
Now suppose you connect this scanner up to the super computer, so that the data the scanner reads -- data which amounts to a snapshot of whatever atoms are inside a 3 meter cube -- is fed into the atomic simulation.
So, you decide to put some things in the scanner and take atomic snapshots and see how the simulation does. What sorts of interesting things could you put in the scanner?
Well, let's say you put a television, and a video camera in the scanner, and batteries to run them. Let's say you put yourself in the scanner, and your wife too. Then you throw the switch and zap, information about all the atoms in the scanner is zapped into the computer simulation.
Now, suppose you rig the simulation to be able to artificially put electric charges onto the simulated TV's antenna, and to artificially monitor the charges on the simulated video camera's outputs, and take these monitored signals and cause them to be converted to real analog electrical signals which are sent to a real TV. Now you, wathing this TV, can see what the simulated video camera is pointed at inside the simulation. Further suppose you connect a real video camera's outputs to the super computer and cause those signals to be inserted into the simulation as charges on the simulated TV's simulated antenna. Now the people inside the simulation can watch the output of the real world video camera on their simulated TV. Communication between the simulated world and the real world is possible.
Do the people in the simulation have free will? You could ask them. They would likely feel as if they do. They could clap their hands, scratch their butt, or pick their nose at will.
At any time, the observer could stop the simulation, back it up to a previously saved check point, and know precisely what would happen next. he would know for instance that at 1 minute 45 seconds into the simulation, the guy in there is going to scratch his butt.
You might object that various quantum effects and so on have a random, unpredictable element to them, which might, in a "butterfly effect" way, cause different outcomes with each run of the simulation.
Well, the simulation would need to simulate this randomness, and this randomness could be drawn from a fixed pool of random data, so that each time the siulation was run, it would behave the same. The randomness could be removed, or at least duplicated exactly. Yet if you asked the simulated human if he had free will, and if he thought he could do whatever he felt like, he would think that he could, or at least, as much as he ever felt like he could, which might not be that much if he happened to be a philosopher.
Unpredictability does not mean that free will exists. A robot responding to random stimuli is unpredictable, but few would say such a robot has free will.
Some would say that the simulation would necessarily fail, because a human is more than the sum of the atoms it is made of, and there must be some sort of magic soul involved which makes consciousness work, and the simulation doesn't take this into account. That may be so, however, there is not a scrap of evidence to suggest such a thing is true, and what we know from neuroscience seems to indicate there is no such magic soul, and the brain acts in ways consistent with a purely material explanation..
Similar to the "what caused God" objection to the first cause argument, supposing a magic soul just moves the problem to a place where it cannot be examined without actually explaining anything.