How Cartesian Dualism Might Have Been True

by Luke Muehlhauser on January 24, 2011 in Quotes

It’s not, of course, but David Chalmers explains how it could have been true:

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.

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{ 13 comments… read them below or add one }

Ben January 24, 2011 at 7:31 pm

Except that, “other physical things” is not the same definition as “magic things” or “immaterial things.”

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Hansen January 24, 2011 at 7:36 pm

Slightly off-topic, but have you seen the lecture series from Yale University by Shelly Kagan on the subject of “Death”? I’m watching it on iTunes currently and find it very interesting. Among other things he covers dualism vs physicalism including Descartes’ argument. I don’t have a link but if you search for “Shelly Kagan” on iTunes, you should find it easily.

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Sharkey January 24, 2011 at 7:54 pm

I don’t know if I completely accept that reasoning. In this simulation, Chalmers tacitly assumes there is a non-bridgeable separation between the creatures’ “minds” running in one process on the computer, and the simulated “world” where the creatures interact and learn.

However, eventually the “mind” parts have to interact with the “world” part, and vice versa; the “world” informs the “mind” with sensory input, and the “mind” affects the “world” by adjusting a creature’s behaviour. There may be aspects of this abstract mind that will always be difficult to interrogate using the simulated science, but if it interacts with the “world”, it is of the “world”. For example, the creatures may discover enough information about the computer program that runs their world to interact with the external “mind program” that runs their minds.

Tl;dr: Chalmers’ example is only ‘dualism’ by arbitrarily creating a boundary between mind and world that doesn’t necessarily follow from his scenario.

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MarkD January 24, 2011 at 11:03 pm

Per Sharkey, I think there is a disconnect between the notion that the entity programs can have evolved within the simulation:

…genetic algorithms which get more and more complex and sophisticated, until eventually very sophisticated, rational beings evolve…

and that the evolved entities possess an irrational or other-worldly algorithm.

Regardless of the whether the algorithmic mechanisms are local to their in-simulation hardware, they would be a product of the ecology of simulated universe and their cognitive capacities. Even if their cognition was being “remoted” they would at least come upon an interface that would be coherent and local. That interface could be studied at a minimum and all rational thinking (in that world) could be discerned from its outputs.

Casting this all as an argument concerning our own faculties, I think there are many lifetimes of neuroscience to go before we need reconsider dualism.

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g January 25, 2011 at 1:45 am

I don’t really understand the need for Chalmers’s example. Surely no one is saying “Cartesian dualism is absurd a priori and must therefore be rejected”; it’s more like “Cartesian dualism is almost completely incompatible with facts about the world that we have extremely good evidence for and should therefore be rejected”.

Here’s a possibly more interesting version of the thought experiment. The people running the simulation start off with a “low-level” simulation that implements brains using ordinary (simulated) physics, and after billions of years of simulated time, there are plenty of simulated creatures running around with interesting brains. But then the researchers decide they want to see what happens if they put some much cleverer beings into the system. They can’t easily do this just by making them from scratch (they don’t know how), and they can’t easily just make their existing beings smarter or let them get so by evolution (because there are constraints like the one on human head size that make that difficult) — so instead they put a little hack into the simulation that allows creatures with a special marker in their equivalent of DNA to have part of their brains in a separate (still simulated) physical universe with different rules, which effectively gives them some more-direct access to the computational powers of the simulator.

Now just let evolution run for a while longer. Among the creatures with that special genetic marker, higher intelligence, and maybe other new sorts of mental faculty, arise. But if they look inside their heads, they find brains, which after all they’re still using — it’s just that they’ve been augmented. And if they damage those brains, mental damage is likely to result; again, it’s not like they aren’t using their “physical” brains at all. It’s only once they understand the operation of those brains well enough that they’ll figure out that there has to be something more going on.

(Well … it might be that certain distinctive mental abilities *can’t* be impaired by damage to the (physical) brain, or something. They might be able to figure out that there’s something magical going on without such a detailed neuroscience. But it would be much more difficult than for creatures whose whole mental processing was done outside the simulated physical world.)

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Polymeron January 25, 2011 at 2:00 am

g,
Good example. It actually illustrates some inaccuracy in your opening words: “Cartesian dualism is almost completely incompatible with facts about the world that we have extremely good evidence for and should therefore be rejected”. It’s not that Cartesian Dualism is incompatible with the evidence; it’s that it is superfluous, and requires more and more assumptions to justify as our understanding of the universe deepens. Dualism could still be true, but it’s looking more and more like “Dualism-of-the-gaps” ;-)

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woodchuck64 January 25, 2011 at 7:06 am

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.

Dualism seems built into this example by the above decision to create two separate modules: the environment simulation module and the being-thought-process module. To be anything like our universe, there should be only one module, a law-of-physics module that may eventually give rise to computational models of mind through evolution.

Sure, if an intelligent designer decided to put minds into a special category and physics into another, I might be more sympathetic to dualism, but this thought experiment seems to be begging the important questions.

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Mathew January 25, 2011 at 8:35 am

Ummm no. The whole point is that these supposed beings evolved. The example is not at all clear about how the second set of mental laws (say B) somehow just popped into (at what point?) the rational beings that allegedly evolved from the natural laws of the environment (say A).

The only world in which it is possible for a rational being to suspect Cartesian duality is a world in which there is no evolution, where people aren’t born but just pop into existence. In a world where beings arise through evolution, the A and B laws have to have the same underlying physical source.

So yes, Cartesian Dualism is still very outlandish post-Darwin.

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BenSix January 25, 2011 at 9:08 am
Kaelik January 25, 2011 at 12:31 pm

Apparently you have to actually understand computers and programming to understand this example. As these commentators demonstrate.

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Sharkey January 25, 2011 at 12:43 pm

@Kaelik: My background is in computer science, so I’m honestly curious about which aspects of computers and programming lead you to think this example is worthwhile. I don’t see the logic, but Chalmer’s text is pretty brief, and there might be a perspective I’m missing.

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Mathew January 25, 2011 at 12:51 pm

I just read Sharkey’s take on this and in some sense it’s similar to what I’m saying. If you’re going to say that minds are programmed with different laws, you can’t say at the same time that the other set of laws enable “genetic algorithms which get more and more complex and sophisticated, until eventually very sophisticated, rational beings evolve”. Because that would mean that the mental laws are not really programmed but emerge eventually from the natural laws. Which is clearly going against any dualistic description.

Kaelik is really going to need to explain themselves.

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Lox January 31, 2011 at 2:52 am

Dualism seems built into this example by the above decision to create two separate modules: the environment simulation module and the being-thought-process module.To be anything like our universe, there should be only one module, a law-of-physics module that may eventually give rise to computational models of mind through evolution.Sure, if an intelligent designer decided to put minds into a special category and physics into another, I might be more sympathetic to dualism, but this thought experiment seems to be begging the important questions.  

No, not at all! Chalmers is not putting forth an argument for dualism, he merely created an intuitionpump. If you read: “I imagine, though, a different sort of simulation[...]If they tried to “look inside their heads” (assuming they have at least vaguely coherent senses)… They’d just find an empty box. ” and so on. I read it as a highly hypothetical example meant to show a scenario under which there are no conceptual difficulties to formulate dualism. Surely Chalmers had a reason to construct the example, perhaps to meet some objection about dualism being unintelligeble (haven’t read such an objection before though).

I think you are right that if he used it as a proof or argument for dualism, then it would be questionbegging, as he simply constructs a “dualistic” scenario. What he actually did was construct a monistic scenario (since they are all the same “substance”) which leads the rational agents to a dualistic conclusion, as to show what might (might!) explain dualism without resorting to actual dualism.

Your objection, however, seems to be circular, since you claim that his example is invalid because “To be anything like our universe, there should be only one module, a law-of-physics module that may eventually give rise to computational models of mind through evolution” which basicly assumes that such an explanation is not correct because we have another explanaition that contracicts it – Chalmers point is that they would, in the relevant sense, find their situation to be (almost) identical with ours. They, like you, try to explain everything from the laws of physics (their physics) but hit a dead end when trying to explain their own consciousness – like the dualist philosopher, such as my own prof., claim is actually the case.

But I do mostly agree.

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