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Comment author: Peterdjones 15 April 2011 06:40:08PM *  0 points [-]

Mary still doesn't have to make anything special happen to her brain have knowledge of anything else. She can still understand photosynthesis without photosynthesising.

Comment author: dfranke 15 April 2011 11:43:49PM *  1 point [-]

She can understand the sequence of chemical reactions that comprises the Calvin cycle just as she can understand what neural impulses occur when red light strikes retinal rods, but she can't form the memory of either one occurring within her body.

Comment author: complexmeme 15 April 2011 06:32:06PM *  0 points [-]

the Kolmogorov complexity of a definition of an equivalence relation which tells us that an AND gate implemented in a MOSFET is equivalent to an AND gate implemented in a neuron is equivalent to an AND gate implemented in desert rocks

Isn't that only a problem for those who answer "functions" to question 5? Desert-rocks-AND-gate and MOSFET-AND-gate are functionally-equivalent by definition, but if you're not excluding side-effects it's obvious that they're not computationally equivalent.

Edit: zaph answered algorithms, so your counter-argument doesn't really target him well.

Comment author: dfranke 15 April 2011 06:40:50PM *  1 point [-]

They're computationally equivalent by hypothesis. The thesis of substrate independence is that as far as consciousness is concerned the side effects don't matter and that capturing the essential sameness of the "AND" computation is all that does. If you're having trouble understanding this, I can't blame you in the slightest, because it's that bizarre.

Comment author: Perplexed 15 April 2011 05:45:14PM 0 points [-]

Not really helpful (though I don't see why it deserved a downvote). It is not that I object to the term 'qualia' because I think it is a residue of discredited worldviews. I object to the term because I have never seen a clear enough exposition of the term so that I could understand/appreciate the concept pulling any weight in an argument.

And, as I stated earlier, I particularly object when philosophers offer color qualia as paradigmatic examples of atomic, primitive qualia. Haven't philosophers ever read a science book? Color vision has been well understood for some time. Cones and rods, rods of three kinds, and all that. So color sensation is not primitive.

And moving up a level from neurons to mind, I cannot imagine how anyone might suggest that there is a higher-level "experience" of the color green which is so similar to an experience of smell-of-mothballs or an experience of A-major-chord so that all three are instances of the same thing - qualia.

Comment author: dfranke 15 April 2011 05:54:17PM 0 points [-]

Yes, I agree that this kind of atomism is silly, and by implication that things like Drescher's gensym analogy are even sillier. Nonetheless, the black box needs a label if we want to do something besides point at it and grunt.

Comment author: TheOtherDave 15 April 2011 05:19:10PM 1 point [-]

Incidentally, while agreeing with your main point, I feel I ought to challenge the implications of "more evolved." This has nothing to do with Mary's position on some scale of evolution; she could be "less evolved" and have those neurons, or "more evolved" and lack them.

Comment author: dfranke 15 April 2011 05:22:26PM 2 points [-]

I should have predicted that somebody here was going to call me on that. I accept the correction.

Comment author: Perplexed 15 April 2011 05:09:13PM 0 points [-]

I can describe qualia in general as the way thing seem to us.

I don't believe so. I'll accept that you can describe them as the way things seem to you. Or define them as the way things seem to us. What I am saying is that you cannot convince me that the definition has a definiendum unless you get more specific. Certainly, your intuitions on the significance of that 'seeming' have no argumentative force on anyone else until you offer some explanation why they should know what you are talking about.

Comment author: dfranke 15 April 2011 05:16:08PM *  0 points [-]

Maybe this analogy is helpful: saying "qualia" isn't giving us insight into consciousness any more than saying "phlogiston" is giving us insight into combustion. However, that doesn't mean that qualia don't exist or that any reference to them is nonsensical. Phlogiston exists. However, in our better state of knowledge, we've discarded the term and now we call it "hydrocarbons".

Comment author: Peterdjones 15 April 2011 04:24:16PM 1 point [-]

There are broadly speaking two versions of physicalism: ontological physicalism, according to which everything that exists is material, spatio-temporal, etc; and epistemological physicalism, according to which everything can be explained in physical terms. Physicalism can be challenged by the inexplicability of qualia in two ways. Firstly, qualia might be physically inexplicable because they are not physical things, which contradicts ontological physicalim. Secondly, the phsyical inexplicability of qualia might be down to their having a first-person epistemology, which contradicts epistemological physicalism. Epistemological physicalism requires that eveything be explicable in physical terms, which implies that everything is explicable in objective, descriptive, public, third-person terms. If there are some things which can only be known by acquantance, subjectively, in first person terms, then it is not the case that everything can be explained in physicalese. However, ontological physicalism could still hold.

Comment author: dfranke 15 April 2011 04:38:26PM *  0 points [-]

My conclusion in the Mary's room thought experiment doesn't challenge either of these versions: something new happens when she steps outside, and there's a perfectly good purely physical explanation of what and why. It is nothing more than an artifact of how human brains are built that Mary is unable to make the same physical thing happen, with the same result, without the assistance of either red light or appropriate surgical tools. A slightly more evolved Mary with a few extra neurons leading into her hippocampus would have no such difficulty.

Comment author: Peterdjones 15 April 2011 04:18:01PM 0 points [-]

If we agree that she learns something on stepping outside we have learnt that a version of physicalism is false.

Comment author: dfranke 15 April 2011 04:19:12PM *  3 points [-]

Can you state what that version is? Whatever it is, it's nothing I subscribe to, and I call myself a physicalist.

Comment author: Peterdjones 15 April 2011 04:09:58PM 2 points [-]

It isn't intended to answer your question about neuroscience.It is intended to pose the philosopher's question about the limitations of physicalism. If physicalism is limited, that eventually folds back to your question, since one way of explaining the limitation of physicalism is that there are non-physical things going on.

Comment author: dfranke 15 April 2011 04:13:37PM 0 points [-]

When she steps outside, something physical happens in her brain that has never happened before. Maybe something "non-physical" (huh?) also happens, maybe it doesn't. We have gained no insight.

Comment author: Peterdjones 15 April 2011 03:58:23PM 0 points [-]

No, the premise of the Mary argument is that Mary has all possible book-larnin' or third person knowledge. She is specifically not supposed to be pre-equipped with experiential knowledge, which means her brain is in one of the physical states of a brain that has never seen colour.

No, she is not going to be able to instantiate a red quale through her book learning: that is not what is at issue. What is at issue is why she would need to.

Third person knowledge does not essentially change on translation from book to paper to CD, and for that matter it should not essentially change when loaded into a brain. And in most cases, we think it doesn't. We don't think that the knowledge of photosyhtesis means photsynthesising in your head. You share that the qualiaphobes assumption that there is something special about knowledge of qualia that requires instantiation.

Comment author: dfranke 15 April 2011 04:06:22PM *  1 point [-]

She is specifically not supposed to be pre-equipped with experiential knowledge, which means her brain is in one of the physical states of a brain that has never seen colour.

Well, then when she steps outside, her brain will be put into a physical state that it's never been in before, and as a result she will feel enlightened. This conclusion gives us no insight whatsoever into what exactly goes on during that state-change or why it's so special, which is why I think it's a stupid thought-experiment.

Comment author: Peterdjones 15 April 2011 03:38:08PM 0 points [-]

But if physicalism is correct, one could understand all that in its entirety from a third person POV, just as one can understand photosynthesis without photosynthesising. And of course, Mary is supposed to have that kind of knowledge. But you think that knowledge of how her brain works from the outside is inadequate, and she has to make changes to her brain so she can view them from the inside.

Comment author: dfranke 15 April 2011 03:45:37PM *  1 point [-]

The very premise of "Mary is supposed to have that kind of knowledge" implies that her brain is already in the requisite configuration that the surgery would produce. But if it's not already in that configuration, she's not going to be able to get it into that configuration just by looking at the right sequence of squiggles on paper. All knowledge can be represented by a bunch of 1's and 0's, and Mary can interpret those 1's and 0's as a HOWTO for a surgical procedure. But the knowledge itself consists of a certain configuration of neurons, not 1's and 0's.

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