There’s no such thing as free will

I was a freshman in college when I first realized that free will didn’t exist. When I explained the little thought experiment which led me to this conclusion to a friend, it was sort of interesting to see him recoil in a bit of horror as the implications dawned on him. I’m not the first person to think of this, by any means, though I haven’t seen this precise thought experiment outlined anywhere else.

Here’s the thought experiment:

Imagine you are an atomic physicist, and you study atoms, and you 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. You can feed it in data about atoms, let the simulation run, and the simulated atoms interact with each other just as they would in the real world.

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. You arrange to take these monitored simulated signals and cause them to be converted to real analog electrical signals which are sent to a real TV outside the computer. Now you, watching 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 the output of this real camera to be inserted into the simulation as onto the simulated TV’s simulated antenna. Now the simulated people inside the simulation can watch the output of the real world video camera on their simulated TV. By this means, communication between the simulated world and the real world is possible.

Here’s the question:

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 simulation 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.

Daniel Dennett, in his book “Freedom Evolves”, tries to argue that free will exists. I was not able to find in that book an argument which can withstand my little thought experiment. I suspect Dennett would simply say that my hypothetical simulated people have exactly as much free will as we do, but I think that I’ve shown that that amount is zero. Dennett might argue that point, but, I suspect, by redefining free will practically out of

Sam Harris has a good discussion of free will in his book, “The End of Faith”, in footnote 7 of chapter 6. As footnotes go, it’s rather long, as essays about free will go, it’s rather short, esp. compared to Dennett’s rambling tome. Among other things, he talks a little bit about the implications a lack of free will has for our notions of justice. How can you punish someone if there is no such thing as free will? Retributive justice is right out, and rehabilitation and containment seem to be the answer.

~ by scaryreasoner on January 13, 2008.

5 Responses to “There’s no such thing as free will”

  1. I’m still studying determinism, so my position on this is quite tentative. I feel that humans have some amount of free will, but not nearly as much as what most people think. Most of how we react seems based on the influence of the world around us.

    “You are free to do what you want, but you are not free to want what you want.” — Arthur Schopenhauer

  2. The quantum effect, and the “butter fly” effect are two separate effects. The strangeness of Quantum mechanical “randomness” is not that a particle’s position, momentum, etc… are just some what random, it’s that the particle can “simultaneously” (it’s a poor substitute for the word superposition) exist with many possible different positions, momentum, etc… all at the same instant.

  3. You’re right about the butterfly effect and quantum mechanical “randomness,” — e.g. Bose-Einstein condensates, and all that.

    This distinction doesn’t seem to affect my conclusion that free will cannot exist though.

    From what we can tell, quantum uncertainty doesn’t enter into it. E.g. software neural nets, based to some extent on how our brains work, are used every day to do things once thought to require human intelligence — e.g. voice recognition used by the phone companies.

    Likewise, IBM’s Blue Brain project aims to be a biologically accurate simulation of the cortical column, and they seem to be having some success — simulating 55 million neurons and 442 billion synapses of a rat cortex.

  4. […] An essay in Nature about free will May 14, 2009. There’s an essay in Nature by Martin Heisenberg about free will entitled “Is free will an illusion?”. I’ve written what I think about the concept of free will before: There’s no such thing as free will. […]

  5. Free will does not seem to exist. But I doubt that the general public will be able to handle the truth. If people cannot accept evolution, then what would happen if all the sudden scientists announced that free will does not exist?

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