More on Dust Theory

"Dust Theory" is really no different than the idea that an accurate computer simulation of your brain would be conscious. The exact same reasoning holds. If you say that Dust Theory in this case is incorrect, then I think you're also saying that an accurate computer simulation of your brain would not be conscious either, despite the fact that it would respond to inputs in exactly the same way as your real brain would (a necessary condition of being an "accurate" simulation).

As I mentioned, the state of the dust cloud particles evolves in time according to the laws of physics. There is a causal connection between the state of the dust cloud at time t1 and any subsequent time (t2). Why? Because it's the same cloud of dust with particles drifting around affecting each other, in the same way that the particles of your brain drift around and affect each other.

But, taking the total state of the dust cloud at time t2, you should be able to work back to the state of the cloud t1 (setting aside possible problems due to quantum indeterminancy). Starting at t2 you would follow the causal chain of each particle back and eventually find out where it was at t1. Though, you would need a massive amount of processing power to do this of course, due to the n-body problem. But this is a thought experiment, so assume that we have that processing power.

So, as is true of the dust cloud, a computer simulation of your brain is "accurate" if there exists a mapping of the state of the computer simulation to the state of your brain at a given time. A simulation run on a digital computer is done as arbitrarily small, discrete time slices, so at the end of each time slice you would compare the state of the computer to the state of your brain, and if there was a consistent mapping, then the computer is accurately simulating your consciousness.

In this case, if you agree that the computer simulation is conscious, then where does consciousness exist in the simulation process? We do the calculations for each time slice one processor instruction at a time. There are probably billions of processor instructions executed per time slice. Which processor instructions cause "consciousness" to occur?

Keep in mind that the processor may be interrupted many times to run programs other than the brain simulation. So at any time in the process of calculating the next time slice, the processor might be interrupted and diverted to another program's calculations for an arbitrary length of time. When the computer returns to the simulation it will pick up where it left off, and the integrity and accuracy of the simulation will not be affected.

This is equivalent to the dust cloud *only sometimes* being in a state that maps to the state of your brain. So the dust cloud spends 10 minutes drifting in a configuration that maps to the state of your brain. Then it drifts out of synch and the dust cloud particles no longer map to the state of your brain. A billion years go by with the dust cloud particles out of synch. Finally the dust cloud again drifts into a configuration that maps to the state of your brain for another 10 minutes. And so on. There is a causal connection between the two 10 minute interludes in the same way that there is causal continuity with the computer simulation even when the computer is occasionally diverted to execute other programs due to the demands of preemptive multitasking.

Also note that the speed of the computer has no impact on how the simulated consciousness perceives the passage of time. If the computer takes a year to compute 1 minute of subjective time for the simulated consciousness, that will still only feel like 1 minute for the consciousness being simulated. Conversely, if the computer runs faster than the human brain and it only takes 1 minute to compute 1 year of subjective time for the simulated consciousness, that year will still feel like a year to the simulated consciousness, even though it actually only took 1 minute of "external" time.

So, I think this pretty much shows that the basic idea of Dust Theory is correct, IF you accept that an accurate computer simulation of a brain would also be conscious. If you don't accept that a computer simulation would be conscious, then I have a whole seperate set of arguments I can make on that subject (ha!).

So, this is just step 1 of my multi-step response to Pete and Teed. I also want to address the non-causal-chain case of Dust Theory, and also Teed's Hypothesis of Extended Cognition. But I need to go eat supper.

Again, Hans Moravec covers a lot of this in:

http://www.frc.ri.cmu.edu/~hpm/project.archive/general.articles/1998/SimConEx.98.html