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Can Quantum Gravity Explain Free Will?

May 6, 2013

A few months back I shared videos from the CERN physicist Dr. Russell Stannard, who did not seem to feel free will or consciousness could be explained by quantum physics.  However, not all physicists agree with him, so I want to share another side of the story.

Before we get started, you may be wondering what quantum physics has to do with free will and consciousness.  Well, quantum physics describes the world as a superposition of possibilities governed by these wave functions.  All these different things are possible, but we can calculate that some outcomes are more likely to happen than others.  If you’re controlling your thoughts and mind within your brain, somehow “you” are involved in making the quantum wave function collapse, leading to certain outcomes as to opposed to others.

I’d like to introduce you to the renowned physicist Dr. Roger Penrose of Oxford.   He is a mathematical physicist famous for his contributions to general relativity and cosmology.

In his 1989 book The Emperor’s New Mind, Penrose offers a proposal to modify the laws of physics so that we can better explain consciousness.  He says that we must bridge classical mechanics and quantum mechanics with what he calls “correct quantum gravity”.  In later works he’s argued that consciousness may be the result of quantum gravity effects within the brain’s microtubules.  An interesting idea, but has anyone actually got in there and done the physics, modeling the neurons to see if the idea is plausible?

MIT physicist Dr. Max Tegmark responded in a paper in the Physical Review E, working through the calculations and reported the following.

Based on a calculation of neural decoherence rates, we argue that that the degrees of freedom of the human brain that relate to cognitive processes should be thought of as a classical rather than quantum system, i.e., that there is nothing fundamentally wrong with the current classical approach to neural network simulations. We find that the decoherence timescales (∼ 10^−13 − 10^−20 seconds) are typically much shorter than the relevant dynamical timescales (∼ 10^−3 − 10^−1 seconds), both for regular neuron firing and for kink-like polarization excitations in microtubules. This conclusion disagrees with suggestions by Penrose and others that the brain acts as a quantum computer, and that quantum coherence is related to consciousness in a fundamental way.

– MIT physicist Max Tegmark, The Importance of Quantum Decoherence In Brain Processes

What does all that mean, in English?  Basically he’s saying that considering all the noise within the system, the conclusion is that it’s very unlikely the brain is doing quantum computations.  For instance, say you went to build a computer that did its calculations on individual atoms.  To do that, you’d need to use quantum physics, but here’s the problem.  Unless you can keep the insides of that computer at pretty much absolute zero, random vibrations, heat, and other “noise” will destroy the information that’s being used to do your calculation.  Memory would always be corrupted with random garbage.  You’d ask the computer to calculate 10 times 5 and you’d get random answers.  Random noise would jiggle all the atoms and the calculation method would fail.

The noise destroys the information in a way that’s similar to an old radio getting noise as you’re trying to listen to your favorite station.  If something obscures or destroys your radio signal, you just hear fuzz.  Thoughts require information to hold onto itself within the brain, but it doesn’t seem that “thought” information is being stored down at a quantum level, which deals with matter at nanometer scales.  It’s too noisy and chaotic down there and the physics just doesn’t seem to work out.

To say that we can model all the brain’s processes with classical physics means that all that quantum weirdness doesn’t apply at the scales we’re dealing with.  Like if you’re in the lab doing an electrical experiment with wires, resistors, and batteries, you can always use Ohms law to calculate the currents.  There’s no “free will” in the circuit.  Electrical currents don’t just randomly jump around and do whatever.  Tegmark is saying the same applies to our brain.  It’s deterministic.  No free will.  And if you try to bring in quantum physics to give us “freedom”, there’s no way that could work because all the information is destroyed at those small scales.  You’d “will” to move your arm but the information you “injected” into the system is immediately destroyed by random noise.  Your brain would have to be at absolute zero, made of completely different stuff in order for that to work.

So, I tend to agree with Dr. Tegmark.  I don’t think it works out, but Penrose is a fascinating man to listen to.  I really enjoyed this next interview with Robert Kuhn.

If you follow my blog carefully, you’ll hear him discussing the same sorts of things I’ve been talking about on here for quite a while.  Most physical processes in the universe do not create consciousness.  In fact, we’re not conscious of most of the activity going on within our own brains!  Consciousness, that subjective feeling of seeing colors, tasting things, hearing sounds, perceiving the flow of time, the feeling that you’re within a body, etc, all happens within the outer “bark” of your brain, a thin layer of neurons on the outside of the brain.  This is called the neocortex.  So the question is why are those neurons special?  What are they doing?

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