Determinism and free will

[JimC]

I’ve been reading “Freedom evolves” by Daniel Dennett, a discussion of the nature of free will. Leaving that to one side for the moment, I want to assert the position that the Universe cannot be strictly deterministic, because of a combination of uncertainty at the quantum level, and the fact that many (all though not all) physical processes are chaotic.
The key feature of chaos is the extreme sensitivity of chaotic systems to initial conditions. As a system (such as a double-jointed pendulum) evolves over time, it never settles into a regular, periodic motion, although some parameters of its motion can be at least set limits by the nature of whatever strange attractor is operating. If you make a tiny change in the initial conditions (such as the initial energy provided), then by time t, there will be a large and essentially unpredictable change in whatever physical parameters of the system you care to measure.
But wait, you say. Perhaps we cannot predict the outcome, but if nature is deterministic in the Laplacian sense, then an entity with perfect knowledge of the initial conditions, and as much computing power as we care to provide, would be able to perfectly predict the state of the system at time t. However, this is where quantum uncertainty has its effects. Perfect knowledge of the initial state amounts to knowing both the position and momentum of every particle of the physical body in question. Heisenberg’s uncertainty principle tells us that we simply cannot have such perfect knowledge. Given that chaotic systems evolve along different pathways even given infinitesimal differences in initial conditions, it seems to me that the determinism envisaged by Laplace is simply impossible.

[Brian Peacock]

I think some people, perhaps even many, confuse a stochastic universe for a deterministic one because their intuitions about cause-and-effect seem a reliable means of understanding the world around them. Similarly, people sometimes confuse a stochastic universe for a mechanistic one, or even a mechanical one; a clockwork universe if you will, one which plays out according to some larger pre-determined plan, schedule or recipe. This is essentially teleological thinking, but again it seems to chime with a certain understanding of cause-and-effect giving the impression that the collapsed wave function of our lives is all that could, would or should ever be. Where this is the case, fatalism is not far behind. The predictive power of scientific laws and theories can give the impression that there lies behind every phenomenon a simple equation or set of rules which can both describe and predict the specifics down to the smallest of detail, but hold this view is to misunderstand the nature and scope of science endeavour which, for example, may be able to tell us when, where, and how clouds form but can tell us very little about what particular shape each individual cloud will be. A stochastic universe renders all our knowledge a kind of 'best guess' given what we think we know about a system, but if determinism is at play it is probably to be found in the fundamentals of the universe, the net energy of the system, the fundamental forces and the fundamental things they interact with and which interact with them - and we are a long way from identifying, let alone determining and quantifying all those variables.

Dennett's book is a cracking good read though, regardless of one's philosophical leanings.

[pErvinalia]

Bookmarking for later. Good to see an intelligent topic on ratz for a change.

[JimC]

Dennett is at pains to say that, even if the physical universe is deterministic, this does not imply, as many previous thinkers have asserted, that free will cannot exist. He develops his argument around an evolutionary framework, and I think gives a convincing argument that free will, or at least a fully satisfying ersatz version exists in a naturalistic universe, without recourse to any deus ex machina. My initial post outlines my reasons for thinking that the physical universe is not truly deterministic, but I am not asserting that as the prime reason for the existence of some form of free will.

[pErvinalia]

From memory Dennett has a ridiculous conception of free will. When I get time later I'll try to reacquaint myself with it.

[JimC]

Right or wrong, it has the twin virtues of eschewing any idea of "soul" or religious base to free will, while simultaneously (to me at least) resonating with my intuition about my own decision making.

[rainbow]

Heisenberg’s uncertainty principle tells us that we simply cannot have such perfect knowledge.

Ordinary mortals, yes.

Who would you back in a fight: Heisenberg, or Chuck Norris?

[JimC]

Chuck would never see Heisenberg's left hook coming...

[Brian Peacock]

..but at least he'd be aware of its momentum. :chuck:

For those who are interested: Who's Afraid Of Determinism?
Chris Taylor and Daniel Dennett.

[pErvinalia]

Dennett is a compatibilist. It's a seriously wishy washy concept, and as much of a fan of Dennett that I am, compatibilism is silly.

They define free will as freedom to act according to one's motives without arbitrary hindrance from other individuals or institutions.

Basically, we can't align our folk psychology intuitions of having free will with determinism, so we'll just redefine free will to be something else (something which doesn't even relate to the concept of free will).

[pErvinalia]

I’ve been reading “Freedom evolves” by Daniel Dennett, a discussion of the nature of free will. Leaving that to one side for the moment, I want to assert the position that the Universe cannot be strictly deterministic, because of a combination of uncertainty at the quantum level, and the fact that many (all though not all) physical processes are chaotic.
The key feature of chaos is the extreme sensitivity of chaotic systems to initial conditions. As a system (such as a double-jointed pendulum) evolves over time, it never settles into a regular, periodic motion, although some parameters of its motion can be at least set limits by the nature of whatever strange attractor is operating. If you make a tiny change in the initial conditions (such as the initial energy provided), then by time t, there will be a large and essentially unpredictable change in whatever physical parameters of the system you care to measure.

We've discussed this before, Jim. I think you are mistaken in the concepts. Being unable to predict something isn't necessarily counter to determinism. It can also be a lack of computational power. That's what Chaos is, as far as I understand it. Chaos is about compounding margins of error. Not non-determinism.

Regarding QM, uncertainty resolves when the wave function collapses, as far as I know. So there is no uncertainty at the macro level (which is the level at which we interact with the universe).

[Brian Peacock]

Indeed. Free will is so bound to Christian apologetics as to generally be worth almost nothing in both the semantic and semiotic senses. One invariable has to ask, "So what do you mean by free will?" and after that things might get interesting, or more often than not plain stoopid.

But the difficulties for free will and determinism do not speak against compatablism in themselves do they, particularly when compatablism defines the term quite clearly for its own purposes. So what's the beef here?

[JimC]

Dennett is a compatibilist. It's a seriously wishy washy concept, and as much of a fan of Dennett that I am, compatibilism is silly.

They define free will as freedom to act according to one's motives without arbitrary hindrance from other individuals or institutions.

Basically, we can't align our folk psychology intuitions of having free will with determinism, so we'll just redefine free will to be something else (something which doesn't even relate to the concept of free will).

Trouble is, the incompatiblists are, IMO, even weirder. They either demand a totally deterministic universe, as in Laplace, and say that any free will we think we have is an illusion, to be stoically ignored, or they go for the reverse, and insist that free will exists by virtue of some supernatural agency which trumps the deterministic but merely physical universe.

Dennett's position is at least compatible with current evolutionary thinking.

[pErvinalia]

Indeed. Free will is so bound to Christian apologetics as to generally be worth almost nothing in both the semantic and semiotic senses. One invariable has to ask, "So what do you mean by free will?" and after that things might get interesting, or more often than not plain stoopid.

But the difficulties for free will and determinism do not speak against compatablism in themselves do they, particularly when compatablism defines the term quite clearly for its own purposes. So what's the beef here?

Well free will in compatibilism isn't anything like the commonly held idea of free will - that is, able to choose a course of action that is independent of everything that has gone before it (i.e. non-determinism).

[pErvinalia]

Dennett is a compatibilist. It's a seriously wishy washy concept, and as much of a fan of Dennett that I am, compatibilism is silly.

They define free will as freedom to act according to one's motives without arbitrary hindrance from other individuals or institutions.

Basically, we can't align our folk psychology intuitions of having free will with determinism, so we'll just redefine free will to be something else (something which doesn't even relate to the concept of free will).

Trouble is, the incompatiblists are, IMO, even weirder. They either demand a totally deterministic universe, as in Laplace, and say that any free will we think we have is an illusion, to be stoically ignored, or they go for the reverse, and insist that free will exists by virtue of some supernatural agency which trumps the deterministic but merely physical universe.

The latter is clearly anathema to us atheists, but the former is why Dennett's compatibilism is even more strange. He holds that consciousness is an illusion. To me, that's a much larger leap into the bizarre than claiming that our folk belief in free will is an illusion. Not least because the two (free will and consciousness) are intimately linked I would have thought.

Dennett's position is at least compatible with current evolutionary thinking.

So is the "free will is an illusion" position.

I don't really know why Dennett adopts compatibilism, particularly given his p-zombie thought experiments. Would Dennett argue that a p-zombie has free will? Surely he couldn't, unless he thinks a machine that passes the Turing-test, say, has free will. So why is possible in his illusory consciousness view of the world for a p-zombie to be indistinguishable from a human, yet not have free will like he claims that we have?