How cartesian dualism might be true – updated

The following is a thought-experiment from David Chalmers (check out his webpage; the link is on the blogroll):

We could have been characters in a huge computer simulation. It is a familiar idea that the whole world might be simulated on a computer, and things would seem exactly the same to us (and indeed, who is to say that we are not).

I imagine, though, a different sort of simulation, of the kind common in the fields of artificial intelligence and artifiicial life, where we have (1) a simulated environment and (2) simulated beings which are “moving” through this environment, according to a program that models these beings’ thought processes and their decisions. Imagine a very complex project like this (like the vivarium, say), perhaps with genetic algorithms which get more and more complex and sophisticated, until eventually very sophisticated, rational beings evolve.

When they speculate about the world, they will find that the environment possess certain regularities, and this will lead them to laws of “physics” about their external world. This will lead them to speculate about whether they too, at the bottom line, are subject to the same laws. This might seem plausible…but of course it will not be the case! Their “mental” life obeys a completely different set of laws, and further these laws are off limits for direct observation. Their mental life takes place not within their world at all, but within in a computer in a compltely different universe! When it comes to observing the “laws” of their behaviour, they will reach some dead end in looking for causal mechanisms. Unlike our world, such mechanisms are simply not “locally supported” by simple physical laws. I’m not quite sure what would happen next.

If they tried to “look inside their heads” (assuming they have at least vaguely coherent senses)… They’d just find an empty box. They’d ask “how can I do all this complex processing”. The answer would have to be, well, I’m just kind of non-material mind. Of course, there would be a breakdown in the usual kind of physical causation around the “heads” of such a being, unlike our world.

Moral: Cartesian Dualism isn’t quite so outlandish and conceptually problematic as tends to be supposed.

Huenemann: now consider a modification on this scenario. Suppose that, when the virtual beings look inside their heads, they don’t find an empty box. Suppose they find little virtual neurons and chemicals and stuff, like what we find in our heads. And suppose they find that all their behavior actually can be explained by the laws they think apply in their world, and the operation of their neurons. Suppose, in short, they arrive at a materialistic understanding of their own behavior — given the “laws of nature” which seem to apply to their virtual world.

We know that their explanations are wrong and incomplete. They don’t know the truth — which is that they are in a computer-generated world. But what would it be rational for them to believe? It seems they should be materialists, and the dualists among them wouldn’t really have any evidence at all to support their view.

It seems to me that this describes the situation for dualists in our world. Yes, there is a way to make dualism true — but the way is to deny any measurable causal efficacy for consciousness. It is an idle wheel in explanations of behavior. True, the whole material mechanism of the brain might be a device which somehow “mirrors” or “captures only a part of” the whole, dualistic truth (as in the updated scenario), but there isn’t any need for that hypothesis in order to explain what we observe.


3 thoughts on “How cartesian dualism might be true – updated

  1. Rolfe Schmidt

    I’d say it is entirely rational for the simulated people to believe in materialism in their scenario, and I’d say they are right. They are observing the material of their universe, and the beings running the simulation are irrelevant unless they interact with the program. So they have discovered the truth about their universe.

    The question of whether the material they observe is really part of some simulation is metaphysical and beyond their science. If they dig down into their brain and find some components of cognition that cannot be explained by the microphysical, then they have just discovered a new aspect of their material world. Of course, it consciousness doesn’t interact with the material world in any way, then you have dualism. But I don’t think that’s what Descartes had in mind.


  2. Huenemann Post author

    Have they discovered the truth about their universe? Of course, in a sense they have, since they have a wonderfully complete theory explaining their own behavior, and the world around them. But they are missing out on a very big truth: namely, that they exist in a simulation. Moreover, the laws they discover to hold in their world may have no relation at all to the physical laws holding in the real (i.e., nonsimulated) world.

    What might all this mean? I suppose that it’s conceivable that materialism is, strictly speaking, false, and the laws underwriting our own consciousness are simply out of this world! But the fact remains that, so far, we have no evidence “internal to our world” for thinking this possibility is actual.


  3. Rolfe Schmidt

    But their world has physical laws, the simulated beings have real experiences of the simulated physics. They have an independent consciousness of the universe that is accessible to their senses. They may discover bugs or other features in the program that the designers did not intend, and this will just be part of their physics. If their consciousness interacts with their universe in any way, then that part of consciousness will be a part of their physics.

    Of course they don’t know metaphysical truths. But they can still know a lot — even more than their designers.

    Now here’s a problem I have with these simulated universes: I think it is very unlikely that a simulation would proceed serially in time. Physical simulations often start with a rough approximation across spacetime that gets progressively refined. If the simulation did run serially in time, then time would be something that is shared between the simulated and ‘real’ universe. But unless we’re far wrong about our physics, space and time are not separable. So space would also somehow reflect the physics of the simulators universe.

    But if the simulation isn’t run ‘forward in time’, when do conscious experiences happen? How could they have any effect on the universe? Wouldn’t they just be an odd side-effect of the simulation?

    But if the simulation is not run serially in time



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