Saturday, 29 November 2008

Determinism, quantum silliness and broken steam engines

A while ago, I got entrenched in a conversation with somone over free will and determinism.. At the time, I was rather flumoxxed by the problems that quantum mechanics throws in the face of determinism. I've thought about it rather a lot since then, and this is the product of those thoughts. I don't take any credit for the originality of these thoughts. They've probably been printed thousands of times before. Nevermind.

It seems to me that, at best, a view of the universe based on probabilistic principles could scupper a deterministic argument against free will. But unfortunately, it merely replaces it with a probabilistic argument against free will. At worst, I believe that it could replace it with a different type of determinism.

Put simply, if one assumes that quantum effects scupper determinism, then one has only replaced it with probability. People are no longer automatons that respond mechanically to inputs, instead they roll Schroedinger's dice, and act accordingly with the results. Free will still doesn't exist.

To take this notion further, quantum mechanics is still based on probabilities. If you could know the probabilities of those quantum events, you could still know any possible futures. If you had a really tremendously powerful computer (something of an understatement; keep reading!) you could calculate them all, and in doing, compute the actual future; the only problem is that you wouldn't know exactly which of your possible futures was the actual future until it happened. The best you could do is state with varying degrees of accuracy which of your futures you expect to happen.

Well okay, perhaps that doesn't work. For a start, any such computer almost certainly couldn't be built; it would simply be too huge: one assumes the number of theoretical futures must be really rather huge, if not infinite, given the total number of possible states of the universe arising from those initial quantum states at the time of the Big Bang. Secondly, isn't making predictions about the future without knowing whether they're true what we do all the time? Yet we don't say the universe is deterministic just because we can make predictions about the future. Predictable, maybe.

At any rate, I assume there are all sorts of weird things that prove me completely wrong on this matter. Please do tell me about them!

Another argument the person made was that the brain is not a 'perfect' machine in the same way that, say, a steam engine is. They're are wet and squishy, some bits are arbitrarily broken, other bits may not work exactly as intended. Given some thought, I don't understand how this could make a difference to free will, or determinism.

Supposing that the brain is designed to operate with this taken into account. Well then in that case, we can only consider these 'problems' to be a part of the machine: put simply, they are not problems at all! They are not, for example, faults in the same way that a split seam on a steam tank is a fault in a steam engine. Such a problem could cause the machine to not work as intended. But if the 'faults' of the brain are taken into account by the working of the brain, then the brain still works exactly as intended.

On the other hand, if the 'faults' of the brain are actual faults, they would not be there if we built a 'perfect' brain, then it might seem like there's more of a problem. But again I don't think this follows at all. If there is an overall effect of these problems, it might be a slight loss of efficiency in the brain, in the same way that a tiny leak in a pipe in a steam engine might have a tiny effect on the overall efficiency of the engine. If the faults had a major effect on the brain, then it's not clear how the brain could work at all. A steam engine wouldn't work at all if the boiler had a gaping rupture in its side.

Even if we're generous and say that even if a steam engine riddled with hundreds of holes, leaks, and broken parts might limp on regardless, objections are raised from the biological field. The human body is a finely tuned machine that relies on many hundreds, if not thousands, of internal and external variables to survive. Minimal changes to blood oxygen content, blood alcohol content, temperature and concentrations of various chemicals in the body, to name but a handful, have drastic effects on the body, including death. A brain, the most complex part of a machine of staggering complexity, that is drastically unable to regulate its internal chemistry in a fairly precise way doesn't seem to fit with this picture of biology. And indeed, we see what happens to brains that do not work as intended: epilepsy, narcolepsy, etc.

In addition, all brains are built to the same basic blueprints. If we assume that any intended operation is riddled with unintentional misfires, false starts and leaky boilers, then it's not clear what the purpose of the original blueprint is. If they're there to provide the framework in which these 'mistakes' can help create consciousness, then as per my first point they're not mistakes at all. If, on the other hand, they're actual mistakes that contribute random effects to the workings of the brain, they couldn't contribute too much to the overall effect, because then there's no way to account for the fact that we all basically think and act in the same way. You might as well be putting all the constituent elements that make the brain into a bowl, stirring it up and expecting it to start writing second-rate philosophy blogs.

So I feel like the 'not a perfect machine' argument is rather a non-event. It's either not a problem, or at worst an additional complexity, or instead it could only contribute very little to the operation of the brain. At any rate, it's not free from the problems of determinism. Whether they're intentional quirks or faults, they're determined by all the events leading up to them, and they have an effect on all the events after them.

Well I guess that's it for my first post. I'll add more as I have more ideas, which is approximately once in a blue moon.

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