Russell Standish wrote:
On Mon, Apr 11, 2005 at 10:41:53PM +1000, Stathis Papaioannou wrote:
> It may be the case that quantum indeterminacy adds a random element which
> contributes to our experience of free will, but you are dismissing the
> other theoretical possibility, which is that our brains are vastly,
> chaotically and perhaps even intractably complex, but nonetheless
> completely deterministic machines. We would then still believe that we had
> "free will" , even though in reality we are all blindly following a
> predetermined script. How could we possibly know that this is not what is
> in fact happening?
> --Stathis Papaioannou
I think this situation is essentially hypothetical. No machine is completely deterministic - computers are designed to be as deterministic as possible, but still suffer bit errors through chance. Human brains, however, strongly appear to be tuned to amplify noise generated at the synaptic level to effect system level. (Fractal structures in brainwave patterns, and the like).
I would like this important point clarified. There is a fundamental difference between a classical, chaotic system and a truly random quantum system. The classical system may look random and for practical purposes may be taken as random, but if (a) we could measure the system's initial conditions to an arbitrary level of precision, (b) we knew the equations governing the behaviour of the system to an arbitrary level of precision, and (c) we had an arbitrarily fast/precise computer (or an arbitrarily long period in which to perform the calculation), we could calculate all future states of the system. With even a relatively simple quantum system, however, such as a single atom of a radioactive isotope, no amount of computing power, precise measurement or knowledge of the laws of physics can help us decide exactly when it will decay.
Now, it seems to me that in the brain both types of "random" event would combine to give a very complex and unpredictable picture indeed: quantum events at the atomic or subatomic scale would be amplified by chaotic interactions at the classical scale. However, I have seen it stated that quantum events would in fact not be significant at the scale of neuronal processes. Which is correct? And does it really make much difference, whether we are talking truly random or intractably pseudo-random?
Now for the age-old corny question of whether free-will is an illusion or not. Mind is an emergent property - it is not to found among the neurons making up the brain, however it is a useful predictive model. This makes it emergent in just the same way as a glider is an emergent property in the Game of Life. Just as the mind is emergent, so is free-will, for the same reason. And just as you can argue (if you want to) that GoL gliders are an illusion, you can argues that mind and free-will is also an illusion - this does not preclude them as a useful modeling concept for the organism. My personal preference is to label these emergent concepts as real (when they're useful that is), but it is a matter of taste. As an aside, I always considered the high school explanation that centrifugal force was fictitious with suspicion.
My own view on free will: I feel as if I have it, but I know that in reality my brain (hence my mind) is either following a deterministic script, or (more likely) following a mostly deterministic script with a few random numbers thrown in. This does not upset me, or make me change my behaviour, any more than the knowledge that my brain is just a computer and my heart is just a pump does.
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