Mr.Samsa wrote:I have to agree with Loren's comments above - you seem to be defining free will as 'unpredictability'. Whilst it's true that free will necessarily entails an element of unpredictability, it's not necessarily true that unpredictability entails free will.

Could you elaborate on that? What would be the additional properties of free will apart from unpredictability?

Mr.Samsa wrote:I have to disagree with your statements about humans and animals being unpredictable though (in the sense that they are entirely unpredictable). If you simply mean that there will always be some error variance in an otherwise highly predictable system, then I'd agree but you don't seem to be suggesting this.

I´ve given a rather precise meaning in my post noting that "there are truly unpredictable events in nature (though the probabilities with which they occur can be predicted)." If we can not predict something with certainty but only give a probabioity distribution for possible behaviours it is unpredictable in the sense above.

Mr.Samsa wrote:Mice don't turn either way with a 50% probability - the probability of the direction they choose is determined partially by genetic factors but also environmental history.

What I gave was an abstract example, which did assume there was no environmental history. Can you give a reference for genetic factors? It was to illustrate the point that there are situations in which maximizing the variance in a behaviour is the optimal strategy, another one would be a game of rock/paper/scisors where the optimal strategy is picking each of them with a constant probability of one third. The definition of unpredictable used does not imply equiprobability.

Mr.Samsa wrote:That's why when we put mice in a T-maze we can reliably predict their movements between 95-100% of the time as we can control the variables that determine their choices (the same applies to humans in similar situations as well).

They don´t - and that´s the crucial bit - determine the choices. They merely make particular choices more likely than others.

Mr.Samsa wrote:So the question is not whether animals/humans are unpredictable or predictable, the only question is whether the slight error variance we get in behavioral experiments is enough to warrant positing a model of free will to explain it or whether should we assume this is a result of confounding/unknown variables until evidence for free will appears.

You are proposing here that we do have the option of assuming some hidden variables that would make a stochastic system, which neuronal systems are by the grace of the physics they employ deterministic. And the simple reply to this is that no we can not. My point was not about our ability to predict something at our current state of knowledge, but about the property of a system. No matter how precise our knowledge gets the system remains stochastic and thus we can only predict probabilities.

Loren Michael wrote:The universe is complex enough that even if it were strictly, classically deterministic it would still be impossible to make accurate predictions beyond extremely narrow confines.

This is besides the point. The point is that even given perfect knowledge of the universe, knowing everything there is to know, it would still be unpredictable.

Comte de St.-Germain wrote:What you have described is why I - in my few comments about Free Will - have always maintained a 'psychological determinism'. This immediately cuts off the nonsense about quantum mechanics, because determinism is emergent at higher levels.

No it isn´t. The maths there is rather simple - the only way to go from a stochastic system to a deterministic one is to introduce an infinity. There are macroscopic properties of a gas that are deterministic, provided that there are infinitely many gas molecules. Evolution is deterministic, provided population sizes are infinite. Large scale systems can be approximately deterministic, but unless infinite they aren´t deterministic. And large scale systems that are also non-linear may not even be approximately deterministic - as small deviations are amplified.