I've just booted myself off the silly Telic Thoughts blog where I was having endless arguments with theists and other crackpots. The trigger that allowed me to break away from what was turning into an alarming addiction was that the list owners started deleting my messages in a thread where I had argued (mildly) for neural determinism over free will. "My neurons made me delete your posts", they childishly claimed. Ha-ha. A good excuse to bow out for me.
This is a standard stupid move in discussions of free will vs. determinism -- "if there's no free will, then your postings are meaningless and so are my actions". Yawn. Obviously, the interesting paradox is that we are apparently completely determined, yet we are capable of asserting meanings and have something that appears to be freedom and independence from the web of causality in which we are embedded.
So I don't believe solely in neural determinism, as does someone like Tom Clark whose version of naturalism attempts to collapse all causation to material causation. Everything we do might be caused by our neurons, but causal explanation is not the same thing as material explanation.
I've also been reading Judea Pearl's book on Causality, which contains some interesting thoughts on the nature of causality and causal explanations. According to Pearl, nobody has yet made a very good mathematics theory of causality, a concept which doesn't fit well into physics or statistics (Pearl claims he has one). I haven't worked through the formal theory, but the informal theory seems to be roughly: while the universe is a seamless web of causal connections, when we make a causal explanation we necessarily sever out a subsystem that we are explaining from its environment, and we create a model that allows us to explore the effects of hypothetical interventions to the system.
If you subscribe to pure materialism, the world is a huge web of interdependency. The problem is, you can't do anything with such a theory. For instance, a car is influenced by the road, the fuel you put in it, the chemical composition o fthe atmosphere, and the gravitational pull of Jupiter. If the car won't start, however, only some of these factors will be invoked as causal explanations. But, why? How do we know that the absense of fuel is likely to be a cause of failure to start, while the position of Jupiter is unlikely? (of course, not everyone agrees!) Because we have a model in our heads and can imagine what would happen if there was no fuel vs what would happen if Jupiter was in a different position.
Such causal models are much more useful than, say, a pure physics model which does not permit us to think about interventions.
Where is this nonsense going? Oh yeah, it's Independence Day! Where we celebrate our severing of certain causal connections between the American colonies and Mother England. A pure fiction of course, since physically Engliand was just as causally connected to North America as before. But a fiction with power, a fiction that could rearrange the causal models of the colonists and thus lead to actual changes in the physical causal connections.
Independence is one of those necessary fictions, like free will. And maybe God is too, although the verdict is still out on that one.