My rebuttal to Chalmers' "The Conscious Mind"

I've just read part II of David Chalmers' book "The Conscious Mind" and thought I'd jot down my rebuttals to all 5 of his arguments as to why consciousness cannot be explained as an emergent property of a physical system.

First of all, let me state for the record that my own belief is that consciousness is an emergent property of physical systems, and that this occurs on many levels. For example, I believe that NASA, the US, and the Earth are all conscious. So I don't think that consciousness is something that's unique to animals. I am also working on a theory to explain consciousness and seem to be making good progress.

The only reason I wrote the last paragraph is to underscore that one working hypothesis for consciousness is that it's an emergent property of particular kinds of system and that this hypothesis has not been disproven as far as I know (except perhaps by Chalmers, but it's based on circular reasoning and thus not a proof). For the rest of this post, I will call this un-disproven hypotheses "H".

In Part II of his book, Chalmers lays out 5 reasons why he thinks consciousness cannot be an emergent property of physical systems. For each reason I will state the title, a synopsis of his reasoning, and then my rebuttal.

Argument 1. The logical possibility of zombies

In this section Chalmers states that it is possible to have an exact physical replica of himself (presumably down to the subatomic level) that, unlike himself, experiences nothing. He calls this his "zombie twin". However, if H is correct, then such a thing would be impossible, since any system with the same physical structure would experience the same. In other words, if H is true and Chalmers is conscious, then his identical twin would also be conscious. Chalmers then states the the burden of proof that a zombie is impossible lies on those who believe it's impossible. However, that's not true, since the possibility that H is true does not imply that it's true; just that it's a possibility. Chalmers though is trying to prove that H is false, which means that the burden is on him!

Argument 2. The inverted spectrum

In this section Chalmers says that if two physically identical systems can experience different things given the same stimulus (for example, having a different experience when stimulated by the wavelength of red light), then this shows that there are properties of consciousness that are not determined purely by the physical aspects of a system. However, if H is true, then two identical systems would always experience the same spectrum. Chalmers provides no proof that an inverted spectrum is possible with two physically identical systems, but uses examples from famous reductionists who have "conceded" that such a thing is possible if, say, the animals have different underlying neurophysiological properties or if one was based on silicon instead of carbon. However, in both cases the physical systems are different, so they prove nothing. 

Argument 3. From epistemic asymmetry

In this section Chalmers states that because the existence of consciousness is so surprising and non-obvious, there must be something special about it. This is a weak argument at best. A simple counter-argument is that the problem is tough and so it's taking us a long time to figure it out; the answer might be self-evident to higher intelligences.

Argument 4. The knowledge argument

In this section Chalmers says that a human (called Mary) who had never been exposed to light of a particular wavelength (red) should be able to experience it by knowing everything there is to know about light and the brain. However, if H is true, our experience of red light is probably due to (or perhaps simply is) a particular pattern of neural activity. The only way for Mary to experience red would be for her to activate that particular pattern in her brain. But the part of Mary's brain that knows about her brain and the physical aspects of the color red don't have the ability to directly stimulate the part of her brain that is activated when her eyes detect red light. So there's nothing mystical going on here, it's simply that some parts of her brain can't directly stimulate other parts of her brain.

Argument 5. From the absence of analysis

In this section Chalmers says that his opponents need to be able to show an alternative explanation of consciousness if they want to successfully defend against arguments 1..4. Well, I just rebutted 1..4 without any need to prove H; I just needed to assume that H was potentially true. Argument 5 suffers from the same weakness as argument 3; just because no-one's proved H so far doesn't mean that it's false, it could just mean that it's a tough problem.

Summary

I started by assuming that H, the hypothesis that "consciousness is an emergent property of some kinds of physical system", could potentially be true. This is a hypothesis that many people, including myself, believe is true and are trying to prove. I then showed that none of Chalmers' 5 arguments proves that H is false. Therefore Chalmers' argument that he has disproven that consciousness could be an emergent property of a physical system is invalid.

I welcome any feedback on my analysis.

Comments

[Barnaby Dawson]

Absolutely right in your rebuttals here.

[Graham Glass]

Thanks Barnaby!!

[Baby Squid, Born Like Stars]

Graham, look at this photo collection

http://www.bukisa.com/articles/156861_animals-that-live-by-the-hundredsthousandsmillions

There is data that jellyfish gather in formations of special order, direction, and spacing - how beautiful

http://bldgblog.blogspot.com/2007/04/of-jellyfish-loops-site-constraints-and.html

Also baby squid apparently can turn red or any color it sees without having a prior "experience" with it.

Tatiana

[A.]

Hello Mr Glass. I am just curious about something: Did you read Chalmers' sections about supervenience, reductionism and two-dimensional semantics? Those are very important if you want to get a full grasp of the rest of Chalmers' arguments. And I don't mean to be rude when I say that it seems as if you merely skimmed through them.

Let's look at your first rebuttal, for example. Now, Chalmers' argument from philosophical zombies look something like this:

Premise 1: If there are conceivable worlds where there are philosophical zombies, then there are also genuine possible worlds where there are philosophical zombies.
Premise 2: If there are genuine possible worlds where there are philosophical zombies, then mental properties do not strongly supervene on any neuro-physical properties of the brain.
Premise 3: If mental properties do not strongly supervene on any neuro-physical properties of the brain, then mental properties are not reducible to any such properties.
Premise 4: There are conceivable worlds where there are philosophical zombies.
Conclusion: Mental properties are not reducible to any neuro-physical properties of the brain. (From 1-4)

This argument is clearly valid, but is it sound? Well, Chalmers defends the first premise by way of his two-dimensional approach to semantics. Sections on this can be found in the book, but he has written many other papers on it as well. As I see it, his arguments on this point are rather convincing.

The second premise is generally accepted. To understand why, you might want to check out what exactly is meant by the term "reductionism" as well as "weak supervenience" and "strong supervenience." The third premise is also generally accepted. If one set of properties is reducible to another, then this entails that they are both strongly supervenient on one another (In order to get a really clear idea about what supervenience is, I recommend that you check out Jaegwon Kim's article "concepts of supervenience" and some of the discussions it has spawned). Now, if premise 4 is also correct, then the conclusion necessarily follows.

/ A.

PS: By the way, I'm sorry if my English is bad. It is not my mother tongue.

[Graham Glass]

Hi A.,

Thanks for your feedback!

As I stated in my rebuttal, I have a problem with Premise 1. If H (the hypothesis that consciousness is an emergent property of a mind with the physical structure of a human brain) is correct, then premise 1 is incorrect, and so his conclusion is also incorrect.

If his goal is to show that H is false, he cannot use a premise that assumes that H is false in the first place!

Cheers,
Graham

[Graham Glass]

Hi A,

Just to clarify my last post; if H is correct, then there is no conceivable world in which a philosophical zombie can exist.

Cheers,
Graham

[Henry]

Hello Graham

I don't agree with your views. The reason is this: If there are possible worlds that are exactly like ours in terms of their natural laws, but in which an exact physical duplicate of me is without consciousness, then that means that natural laws and physical properties are not enough to explain why something has a consciousness. In other words, something must be added to the picture of consciousness for it to make any sense. This certain something, Chalmers thinks, is consciousness itself which then must be viewed as something not reducible to natural laws and physical properties. I don't think you can escape these conclusions by simply saying that consciousness *happens* to be reducible to natural laws and physical properties (that is to say, in our world).

[Graham Glass]

Hi Henry,

Thanks for your comment.

I already addressed your point in the section "1. The logical possibility of zombies".

Cheers,
Graham