PZ has done a characteristically neat job of skewering the argument of some guy who thinks it’s naive to be an atheist, but in doing so he makes the statement (emphasis mine):
The brain, in other words, is a choice-making machine. It is also not deterministic. It takes in a multitude of inputs, including lots of noise, filters them on the basis of deep personal history, and generates interesting internal states and elaborate responses.
Now, I can see why he said that (I think;) it’s important to the point about free will that he’s making, but I think it’s worth pointing out that in a strict sense the brain is deterministic. Obviously you can’t write a computer program that will predict human behaviour or decision-making. You certainly can’t write one to predict whether or not two people will fall in love. But my point – and I think it’s an important one – is that theoretically, such a program could exist. Being made of physical matter means that the brain is theoretically predictable; that matter will always respond to the same situation in the same way, and it’s would be possible to predict, given full information about its current state and sensory input, what decisions it will make. The fact of the matter is that the brain is never in the same state twice, and the necessary calculations to make any prediction would take Vastly longer than just watching to see what someone does, so the question never arises.
What does this mean for free will, which is what the original article claimed a purely physical brain denied us? Well, I don’t know. Truthfully, I don’t even know what free will is supposed to be. It’s a term that religious people tend to throw around when they want to demonstrate that a purely physical reality would be undesirable, and is therefore impossible, but I don’t think I’ve ever heard a satisfactory definition of the term.
Is it the capacity to make choices free from outside interference? If it is, then I don’t see why the fact that thought processes are rooted in the physical, rather than some invisible thought-stuff should lessen our ability to claim that. The fact that my thoughts are, at the most vanishingly basic level, electro-chemical in nature makes them theoretically predictable, it’s true, but being predictable is not the same thing as being constrained. In fact, physical or not, I actually hope my decision making is predictable (to anyone with full knowledge of my decision making apparatus,) because if it isn’t then it’s, pretty much by definition, random – which is not how I like to think of my mighty intellect. In any case, if your thoughts being predicted negates free will, then the presence of an omnipotent, omniscient creator-being presents it with at least as large a problem as the materialist world-view, since it makes the universe just as deterministic, and more than that: planned.
So where does all that leave us? I still don’t know, but it’s a considered not-knowing, which is more than can be said for the vast flocks of believers who “know” they have free will, because someone told them they do, but don’t have any clear idea of what the term even means, much less of the problems inherant with the whole concept.
So, I’ll tell you what: You come up with a meaningful definition of free will that works in a dualistic universe, but not a materialistic one, and we’ll talk again. But until then; until such a time as you can define the terms you throw around so carelessly, don’t call me naive. OK?
5 Comments
Leave a comment
Site Design :
I thought one of the implications of quantum theory is that (at the quantum level) the universe is not deterministic and that fundamentally matter need not always respond to the same situation in the same way (it may even respond in different ways at the same time). Repeatable effects are only probabalistic, even on the macro scale. It’s possible at a party that all the molecules in the hostess’ undergarments might leap one foot simultaneously to the left, it’s just so cosmically unlikely that it’ll (regrettably) never happen in the lifetime of the universe.
So far so nitpicky, but there’s at least one theory that quantum effects are significant in the function of the brain - see http://www.quantumconsciousness.org/ Although admittedly the guy did get taken apart at the 2006 Beyond Belief conference, and his theories about quantum tunnelling sending our thought processes back in time were pretty wacky, but I just wanted to make the point that the brain may have an inherently random element to it after all. (incidentally V.S. Ramachandran’s half of that video is much more entertaining)
Where that leaves the question of free will I can’t say. Whether it’s Freud’s theories of how childhood experience shape our subconscious, or classical determinism, or quantum randomness, or an omniscient god knowing all that we will ever think and do, the knwolegde that our thoughts are our own seems increasingly to be an illusion.
I remember reading the Roger Penrose book that details that quantum conciousness thing him and the other guy on this link came up with. Most of his idea hinges on non-computability or halting problem type arguments in that there are things that cannot be computed so he argues the brain cannot be a conventional computer analogue since even with neural networks (which can be show to be equivalent to a universal Turing machine) cannot solve certain things, the assumption being the brain can solve these things and as such a computer can never simulate a brain no mater how powerful it is. The only proof Penrose offers that we can solve non-computable problems is an obscure example with tiles on an infinite plane which is a self applicability problem alias (can a program determine when applied to itself if it will terminate a standard unsolvable problem) which is only valid if he can solve every one rather than a few select ones since SAP or things like it stipulate solutions to specific problems could be possible but not a general solution that would work for all.
In fact the whole quantum thing seems to be based on a false premise that the brain needs some hand wavy quantum process to be possible in the first place, there doesn’t seem to be anywhere near enough evidence that this is the case or that the brain can magically solve non-computable problems.
Yeah - I don’t buy the “quantum consciousness” thing, myself. There’s no reason to assume it’s necessary for human cognition, except that it seems to offer a handy get-out for the people who want to believe in this “free will” stuff but can’t quite bring themselves to stand wholly opposed to science, since there’s this belief that anything quantum-y is also random or non deterministic.
Of course, most (or all – I’m not going to claim to be one of the two people on Earth who understand it) of quantum mechanics is actually just as deterministic as classical Newtonian physics, just in a different way. You can’t say with accuracy what the position and momentum of a given photon is, but you don’t need to; you can still predict accurately what the interference pattern produced by the famous two-slits experiment will be.
NTM: I’m interested to know what you mean when you say “the knwolegde [sic] that our thoughts are our own seems increasingly to be an illusion.” I’m not disagreeing or being facetious here, I’ve been asking all sorts of people the same sort of thing over the last couple of days; I really don’t know what people are referring to when they talk about free-will, or their thoughts being their own. To me, there doesn’t seem any conflict between my thoughts being a physical process and them also being mine, and being free. I’m not entirely clear, but I suspect that any feeling otherwise is rooted in dualism; remember that in a materialistic world, human decision making is not constrained by it’s physicality, it’s defined by it. Our thought processes are physical processes. There’s no incorporeal homunculus that wants to make certain choices but is unable to because the physical matter won’t allow it. When I come to a decision point it is that physical process that analyses inputs, correlates with existing experience and generates what is hopefully the best output. That process isn’t a constraint; it’s thinking, and it isn’t constrained by an outside agency, so how is it that that denies me free will? I genuinely don’t understand.
The use of the word Quantum to explain something indirectly related is always a red flag even from reasonably respectable scientists like Penrose, it is used to describe an awful lot of pseudo-scientific bollocks.
Like they say extraordinary claims require extraordinary proof and it sounds like Physics trumps their quantum gravity in microtubles idea.