They're Made Out Of Meat

This has been called 'the best response to the Chinese Room argument,' which will be covered in our Searle reading. Really it's no response at all. It is more of a mockery of the intuitions that tell some philosophers that there is something special about the human mind.

Links

For those of you who are interested in some additional reading, there is a lot of material available online. David Chalmers has compiled a lot of it here.

Daniel Dennett is a really good writer. Here is a little something he wrote that I think should be accessible.

For those of you keeping score at home, there were three counterarguments in opposition to Jackson's Knowledge Argument (the one about Mary).

Papineau provides two of them:

1. Jackson's epiphenomenalism denies the obvious truth that conscious experience causes physical effects. For example, when I have a headache, I take aspirin.

2. "Ontological danglers" are not found anywhere else in nature, so why should the mind be special? An ontological dangler is something that is causally impotent. It is the end of the line for a causal chain. It is something that is caused, but does not cause anything else. This is the upshot of Jackson's epiphenomenalism.

A Digression: Why be an epiphenomenalist?

If you remember, it makes sorting out the relationship between the mind and the brain a lot easier for someone who maintains that the mind is not a material thing. Otherwise you would have to explain how something nonphysical (the mind) has causal effects on something physical (the body). Daniel Dennett compares this to an explanation of how Casper the Ghost can fly through walls one minute and carry a mop the next. Maybe it works in cartoons, but making consistent science out of it is a problem.

So that's why Jackson decides to take another route and go epiphenomenalist.

3. Churchland's criticism of the Knowledge argument is that Jackson is equivocating two different meanings of knowledge. Equivication is a fallacy, to find out why, read more here. Churchland's contention is that there are two different types of knowledge at play in Jackson's thought experiment. The first kind of know means something like "has mastered the relevant set of neuroscientific propositions." This is what Mary knows when she learns all the facts of a complete visual neurophysics. The second kind of knowledge, what she learns when she sees red for the first time, Churchland calls "having a prelinguistic representation of redness in her mechanisms for noninferential discrimination."

To put this more simply, Churchland claims that physicalism does not depend on Mary's complete knowledge of visual neurophysics entailing that she also has knowledge of what it's like to see red.

Jackson's Reply to Churchland

Jackson says that Churchland is knocking down a strawman, a misrepresentation of the Knowledge Argument.

Here is how Churchland has been describing it:

1. Mary knows everything ther is to know about brain states and their properties.
2. It is not the case that Mary knows everything there is to know about sensations and their properties.
Therefore, by Leibiniz's law (remember the stuff Churchland cites in the text about Clark Kent and Superman being the same, even though Lois doesn't know that they are the same,)
3. Sensations and their properties are not identical with brain states and their properties.

Here is Jackson's formulation of what he is actually saying:

1'. Mary (before her release) knows everything physical there is to know about other people.
2'. Mary (before her release) does not know everything there is to know about other people (because she learns something about them on her release).
Therefore,
3'. There are truths about other people (and herself) which escape the physicalist story.

Jackson: "What is immediately to the point is not the kind, manner, or type of knowledge Mary has, but what she knows. What she knows beforehand is ex hypothesi everything physical there is to know, but is it everything there is to know? That is the crucial question."

The Zombie Argument

It seemed like there was some interest in zombies, so here is a rough and ready version of the zombie argument.

The rough idea is that it I can conceive a molecule-for-molecule physical duplicate of myself that is identical to me not only in its material constitution but also in its behavior and reactions to various stimuli. The only thing that separates Alden from zombie-Alden is a full-night’s sleep, or, to be serious, phenomenal consciousness or qualia. There is nothing that it is like to be zombie-Alden. To make it more perspicuous, here is a formalization of Chalmers’ argument. It is important to note that it’s not necessary that there be a full-blown zombie-Alden; a partial zombie or someone with inverted qualia serves the argument just as well. Let P be the conjunction of all microphysical truths about the universe and Q be a phenomenal truth, either that someone is phenomenally conscious or that someone instantiates a particular phenomenal property.

(1) P&~Q is conceivable

(2) If P&~Q is conceivable, P&~Q is metaphysically possible

(3) If P&~Q is metaphysically possible, materialism is false.
________

(4) Materialism is false (Chalmers, 2005).

Here is an excerpt of someone else explaining the same point, perhaps more clearly.

"The materialist claims that there is an identity between brain states and mental states. Or to put it another way: mental states are nothing other than brain states.

Let's make believe that brain science shows us that the conscious experience of pain is correlated with c-fiber firing. (It doesn't show that, but let's make believe.) What that means is that, whenever my c-fibers fire, I experience pain, and whenever I experience pain, my c-fibers are firing.

Now correlation is different from identity. Let's say that I have a marionette, and whenever I pull the string, its arm raises, and whenever its arm raises, it's because I pulled the string. (Imagine that nothing else, like another person or the wind, could intervene to make the marionette's arm raise except my pulling the string.) This is a case of correlation without identity, because my hand is not identical to the raising of the marionette's arm. They're two separate things, but one causes the other.

The materialist is claiming that there is correlation and identity between brain states and mental states. He's saying that they're equivalent, in the same way that, for example, heat and molecular motion are equivalent. (Make sure you distinguish in your mind heat from the sensation of heat. That's important.) In the same way that it's impossible that heat could be anything other than molecular motion (and vice versa), it is likewise impossible that pain could be anything other than c-fiber firing (and vice versa).

Are you following me so far? The materialist I'm talking about is saying that brain states and mental states are identical. So brain states = x and mental states = x, so brain states = mental states. It's a physical relationship, but it's also a logical relationship. What that means is that, in any possible universe, these two things are the same thing. This is because identity is special. You can't have contingent identity, only necessary identity. This is crucial. Saying "brain states = mental states" is just like saying "A = A." Just like it's never true that A = ~A, so it is never true that brain states = ~(mental states). Got it?

Now here's the counterargument, known as the "Conceivability Argument." It's not exactly the same thing as the Zombie Argument, but it takes the same form, and I think it's easier to understand. It goes like this:

1. It is conceivable that c-fibers fire without pain taking place. (Imagine, for example, a zombie!)



2. From (1), it is logically possible that there could be c-fibers firing without pain.



3. Therefore, c-fibers firing is not identical with pain.

Do you see why the conclusion follows? Identity is a logical relation between two things. An identity relation is true in all possible worlds. But if you can conceive of a world in which you can have one without the other, then the two things can't be identical to one another."

Zefrank has a better, albeit less philosophical, blog than me.

Here is some interesting evidence for Frank Jackson's epiphenomenalism, courtesy of zefrank. Some recent research shows that the neuronal firings responsible for muscle movement happened temporally prior to the conscious awareness of muscle movement, suggesting that the conscious mind may not be causally responsible for our behaviour, even though it feels that way to us.

The next day he continues to discuss evolutionary explanations for why we might have developed consciousness, as something to help us navigate the social world instead of the physical world.

Oh, and his summary of the gravitas of Bush's plan to send more troops to Iraq is pretty good too.

The Problem of Qualia

P: Mary knows all possible physical facts about colour-vision, but has been taught them in a completely black-and-white environment. If all knowledge is physical knowledge, then upon hearing that she had been shown a red tomato for the first time, we would have to say that she had not learned anything new.
P: But clearly, we would want to say that she had learned something new.
--
C: Therefore, not all knowledge is physical knowledge.

- Frank Jackson

"In this argument, the conclusion must be presupposed for the argument to be sound, and therefore, each is either circular or unsound. Specifically, in order to assent to the second premise, a person has to have a pre-existing intuition in favour of the conclusion. If you do not have this intuition, you simply cannot assent to the truth of the second premise, and therefore, you cannot consider the argument sound. If you DO have the intuition, great, but the fact that the argument requires pre-existing agreement with the conclusion for its soundness makes it plainly circular." (This criticism is offered here: http://community.livejournal.com/real_philosophy/371530.html)