Tuesday, 9 October 2007

Free will is against the laws of physics

Without indulging in Cartesian metaphysics which posits the mind and body are in two separate worlds; the body in the material, the mind in the meta-physical, and assuming that we are all constituted purely of sub-atomic particles (quarks, leptons) i.e. a materialist conception, is free will even a possibility? I don't think it is.

Take Newtonian mechanics where the universe is entirely predictable if we had enough information (spin, velocity, mass, vector etc.). If we had all this information Newtonian mechanics can predict the behaviour of every particle in the universe therefore showing us the future. As each particle is inherently predictable, so are their reactions when they interact. This is as deterministic as a system gets and there can be no free will. How can one's will be free when it is merely the result of sub-atomic interactions that are always knowable. To truly possess free will, one would have to break Newtons immutable laws.

Sadly, this nice predictable view of the world did not last with the discovery of quantum mechanics. At the quantum level it is impossible to ascertain the crucial variables of the sub-atomic particles (position,velocity) together. Furthermore in the quantum world you can never be certain about anything, merely assign probabilities determined by a wave function associated with each particle.

there are features of the universe, like the position and velocity of a particle, that cannot be known with complete precision. Such uncertain aspects of the microscopic world become ever more severe, as the distance and time scales on which they are considered become ever smaller. Particles and fields undulate and jump between all possible values consistent with the quantum uncertainty. This implies that the microscopic realm is a rolling frenzy, awash in a violent sea of quantum fluctuations.

This is seen by many as saving free will, since we cannot know predict anything with certainty - only assign a probability. Huxley famously argued after discovering his Action potential that quantum uncertainty lives between the subatomic interactions that occur cell membranes which is where free will or god 'lives'. And on the more extreme side are biologists like Bruce Lipton and psycholgists like S.D Hart who fundamentally mis-interpret quantum uncertainity.

The premise of this train of thought is that free will is anything which physics cannot predict with absolute certainty. However, this is a vacuous, hollow definition of free will. How are random quantum fluctuations actually free? They're completely capricious and totally random. They are no more free than a ball is on a roulette wheel to land on any random number.

Levels of determinism

There seem to me differing levels of determinism in philosophy and science in regards to human activity. There are significantly 'blurry' abstractions like psychology that show how an abuser is likely to abuse or how phobias are learned from parents. These then restrict the possible behaviour that a person can do. How free is a child that was bullied by his farther, not free to bully other kids? Then it gets progressively clearer, there's sociobiology or genetic-determinism or evolutionary-psychology, our behaviour is a result of our genes with some environmental conditioning. A socio-biologist would postulate that gene X results in a higher probability of behaviour Y. Then it progresses to the most clear - particle physics which seeks casual certainty** - our behaviour is determined by subatomic particles interacting which we have no control over, whatsoever. They are the cause our behaviour is the effect; if we were to break from this cycle of cause and effect it would would break the laws of physics.

Predictability epistemology

There's the famous 'three body problem' in physics, we can describe the behaviour of one body in isolation, or a pair of bodies interacting, but put together three and the equations become unimaginably complex a fortiori for a human brain made up of trillions of particles. I'm not denying we cannot possibly know the future with absolute causal certainty, we can only use abstractions (psychology, socio-biology etc.) but this fact cannot lead to the conclusion that we have free will. Our epistemological shortcomings have no bearing on the question.

A good example of this problem and how it can lead to predictable outcomes is the tossing of a coin. Tossed once, classical mechanics has no way of predicting the outcome the variables are just unimaginably complicated. However, tossed 100 times the laws of probability can give us a probability of either heads or tales as 0.5. The probability result of 0.5 is an abstraction of mechanical interactions that we cannot possibly fathom.

In conclusion, our behaviour is the reaction of subatomic particles in the quantum world, how can we truly have free will? We are merely the result of these interactions and cannot change that. Heisenberg's Uncertainty Principle does not save free will, merely observing yourself does not change anything *


*If you do think that you misunderstandthe importance of Planck’s constant (ћ). If ћ were a big value then indeed we could not predict anything because quantum effects would apply to bigger macroscopic objects. But because ћ is tiny (1.05 x 10-27) quantum mechanics only ruins predictive ability at the tiny microscopic subatomic level. It is simply incorrect to argue it does at the macroscopic level. And since human brains are made up of billions of cells and resulting human behaviour is a combination of cells, it qualifies as a macroscopic object. Furthermore, as I argued above exotic quantum effects are no freer than a roulette ball on a wheel.

** Quantum uncertainity obviously applies here.

arXiv:quant-ph/9711064v1 p7 on the applicability of quantum effects to Hodgkin-Huxley equation.

Here - Using a non Copenhagen interpretation, but rather Von Nuemann's the act of conscious observation collapses the wave function and chooses from a range of alternative possibilities. Rather than this being completely random as in Copenhagen, it's chosen by the brain. Free will? I don't see why it needs to be an actual concious observer. Our constiution doens't make us special, we're made of the same stuff as the rest of the universe.

Here - Quantum effects occur between synaptic nodes as wave function spreads across the gaps between synapses. Therefore the formulation of a thought, which is a firing of snypases has an element of choosing between possible outcomes and collapsing the wave function. However, doesn't withstand the critique that our epistemological shortcomings don't have bearing on the matter of free will. Throws determinism out but does not make a case of free will.

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