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gjm comments on Zombies Redacted - Less Wrong Discussion

33 Post author: Eliezer_Yudkowsky 02 July 2016 08:16PM

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Comment author: gjm 06 July 2016 04:14:28PM -2 points [-]

To my mind the following

all associations and behavior are the same, only the qualia is different

is incoherent. The associations are part of how seeing something red or green feels. So if turchinB sees something and associates it with blood, then turchinB's subjective experience is not the same as that of turchinA seeing something green.

Now, it looks as if you've retreated a bit from the full "inverted spectrum" scenario and are maybe now just saying that maybe turchinA and turchinB experience different qualia on seeing red, even though their behaviour is the same. That's not so obviously incoherent. Or is it?

Any way of probing turchinB's experience of seeing a tomato has to produce exactly the same result as for turchinA. Any question I might ask turchinB about that experience will produce the same answer. If I hook turchinB up to a polygraph machine while asking the questions, the readings will be the same as turchinA's. If I present turchinB with the tomato and then ask other questions in the hope that the answers will be subtly biased by whatever not-so-conscious influences the tomato may have had -- same results, again.

So whatever differences there are between turchinA's subjective experiences and turchinB's, they have to be absolutely undetectable by turchins A and B: any attempt at describing those experiences will produce the exact same effects; any effect of the experience on their mood will have no detectable consequences; and so on and so forth.

The situation still seems to me the way I described it before. If turchinA's and turchinB's brains run on physics rather than magic, and if their physical states are the same, then everything we can see of their subjective states by asking them questions, or attaching electrodes to them, or having sex with them, or showing them kitten pictures and seeing whether they smile, or any other kind of observation we can make, matches exactly; which means that any differences in their qualia are so subtle that they have no causal influence on turchinA's and turchinB's behaviour, mood, unconscious physiological reactions, etc.

I see no reason to believe in such subtle differences of qualia; I see no reason to think that asking about them is even meaningful; and they seem to me a violation of Ockham's razor. What am I missing? Why should we take this idea more seriously than lizardmen in the White House?

Comment author: turchin 06 July 2016 11:14:55PM 0 points [-]

You say: "The situation still seems to me the way I described it before. If turchinA's and turchinB's brains run on physics rather than magic, and if their physical states are the same, then everything we can see of their subjective states by asking them questions, or attaching electrodes to them, or having sex with them, or showing them kitten pictures and seeing whether they smile, or any other kind of observation we can make, matches exactly; which means that any differences in their qualia are so subtle that they have no causal influence on turchinA's and turchinB's behaviour, mood, unconscious physiological reactions, etc."

I replied to this logic in the another comment to OP here: http://lesswrong.com/r/discussion/lw/nqv/zombies_redacted/dcwi

In short: If we postulate that physicalism is true, than there is no qualia by definition.

But if we use empirism - that is the idea that experiences is more important than theories, than I have to look on my experience for new knowledges, and in them I have qualia. So, my empirical experiences contradict my best theory of reality. And this contradiction is the essence of so called "hard problem".

I think that we need some updated version of physicalism and I have some ideas about how to create them, to get rid of any form of epiphenomenalism, which of course is ugly theory.

Returning to your point: You are arguing that if all associations are the same, the experience must be the same. I don't think that this thesis is proved (It may happen to be true, but we need some instruments to prove it, and I didn't see the yet)

I could imagine my self looking of large red field and looking on large green field, without any associations about them and still having different experiences of their colour.

I also had similar discussions before and we never came to agreement about nature of qualia.

Comment author: gjm 07 July 2016 11:05:00AM -2 points [-]

If we postulate that physicalism is true, then there are no qualia by definition

But I'm not postulating that physicalism is true. (Although it looks to me like it probably is.) I am assuming only that physics gives a correct account of what brains and bodies do. (Or, as I put it before, your brain runs on physics and not on magic.) My understanding is that e.g. David Chalmers does not disagree with this. Of course if some kind of substance dualism is true -- if some of what I think your brain does is actually being done by an immaterial soul that interfaces with your brain at the pineal gland, or something -- then there can be qualia differences without physical differences; that idea has its own problems but they are quite different ones, and the argument against that view has a very different shape.

my empirical experiences contradict my best theory of reality

How?

Your empirical experiences show that there is such a thing as an experience of seeing red. They do not show that this experience isn't built on top of physics. They do not show that your experience of seeing red could be detached from all the physical phenomena involved in actually seeing red things. It's ideas like those that contradict your best theory of reality, and those ideas are not simply a matter of observing your empirical experiences.

(At least, I can't imagine how they could be. But perhaps your empirical experiences are spectacularly unlike mine.)

You are arguing that if all associations are the same, the experience must be the same

No. I am arguing that if the physical causes are the same, and the associations are the same, and everything else we can actually observe is the same, then we cannot have good reason to think that the experience is different; and that, in view of all the evidence favouring physicalism, much the simplest and most plausible conclusion is that in fact the experience is the same when all physical things are the same.

I could imagine my self looking of large red field and looking on large green field, without any associations about them and still having different experiences of their colour.

I agree. (Except that someone who really had no associations with either could hardly actually be your self or mine.) But what's required for zombies or "inverted spectrum" is quite different and goes much further.

We need, let's say, three Turchins. I'll call them R, RG, and G. R and G are versions of real-world-you; R is looking at a field of poppy flowers and G is looking at a field of grass. RG is different in some mysterious way; he is looking at a field of poppy flowers just like R, having the exact same experience as G is having, but also having the exact same behaviour as R. And whatever happens in the physical world, RG's experience is going to continue to match G's and his behaviour is going to continue to match R's.

Now, notice that this scenario as I've stated it is actually extra-specially ridiculous when taken seriously. For instance, suppose you walk with RG into the poppy field and ask about the shape of the plants he's looking at. For his behaviour to be an exact match for G's, he will need to experience seeing grass stalks and leaves while telling you about the poppy plants he sees. This is, for me, firmly in "lizardmen in the White House" territory.

It is to avoid this kind of ridiculousness that people advocating this kind of detachment of qualia from physics always pick on a very simple kind of quale, one with scarcely any "dimensions" to it, namely colour. No one ever talks about how maybe turchinB looks at a square, has the experience of looking at a hexagon, but behaves exactly as if he sees a square (including e.g. counting off its vertices correctly). No one ever talks about how maybe turchinB watches Casablanca, has the experience of watching The Matrix, but behaves exactly as if he is watching Casablanca. No one ever talks about how maybe turchinB eats a really hot Thai curry, has the experience of eating a rather bland lasagne, but behaves exactly as if he is eating a curry. Because the absurdity of those scenarios is plain to see: these are complex experiences, with parts that interrelate, and probing them more closely gives results that are preposterous if we imagine them interchanged. But colour? Well, colour's pretty simple; perhaps seeing red and seeing green could be interchanged. ... But then I say "hold on, actually colour isn't so simple because there are all these other things you associate with different colours, and these physiological things that happen when you see red, etc.", and of course the response is to say: yeah, OK, so let's imagine some kind of stripped-down version of seeing red where somehow all those associations aren't there, and then maybe they could be interchanged.

In other words, if you ignore almost all kinds of experience and focus on one particularly simple one, and then make the further simplification of assuming that all the complications even that simple kind of experience actually has ... why, then you can imagine (or at least you say you can imagine) two different experiences of this kind being interchanged without physical consequence.

I say that what you're trying to imagine is so utterly divorced from reality that thinking you can imagine it tells us nothing about how the world actually is. And that once you're considering things so simple, it becomes much harder to resist the reductionist argument: "We can, in principle, trace the physical consequences of seeing a red thing; we can see neural circuits that get activated, etc.; we can see how this differs from seeing a green thing. Why should we think this bare red-or-green quale, with no further richness to it, no associations or consequences or anything, is anything other than the activation of one or another set of neurons?"

(For more interesting qualia, I can feel the attraction of saying that they surely must be something more than neuron activations -- though I think that's actually a mistake. "How could a mere adjustment of electrical potentials and ion concentrations be so thrilling/moving/terrifying/...?" But for me, at least, that intuition entirely goes away when I consider the stripped-down minimal qualia that seem to be the only ones for which the sort of "inversion" you're talking about seems remotely plausible.)

Comment author: turchin 07 July 2016 03:35:51PM 0 points [-]

I have to reply short as I am working on another long text now.

  1. I still think that sum of your claims about the brain is physicalism in nutshell.
  2. The fact that I see the red colour and the fact that I can't explain in words what is the difference between red feeling and green feeling is the empirical basis of qualia.

Even if we will find that qialia is corresponding to some kind of nuronal state, it will disprove existance of exact zombies and inverted color zombies, but will not help us to answer the reason why 1234 state of neuron is "red". I call this problem "the problem of table of correspondents". It correspondents different states of neurons to different subjective feelings. But it is itself mystical thing as we could ask why 1234 is red, and 4321 is green, and we could imagine many different corresponding tables. Sorry to be a little bit sketchy here.

Comment author: gjm 07 July 2016 04:23:48PM -2 points [-]

(Please feel free to take your time if you have other things to be doing.)

I am, as I think I have already said, a physicalist. If you take everything I have said and lump it together, you doubtless get physicalism. But that doesn't mean that everything I say assumes physicalism, and in particular my main criticism of the "zombie" and "inverted spectrum" scenarios does not presuppose physicalism.

The fact that you can't explain something in words seems like awfully thin evidence on which to base the idea that they might be different in ways that have no physical foundation.

I think the question of just what physical states correspond to what subjective states, and why given physical differences correspond to the subjective-state differences they do, is a very difficult and important problem (conditional on physicalism or something like it, of course; the question doesn't arise if e.g. qualia are actually magical properties of your immaterial soul). I don't think "mystical" is the right word for it, though, and in particular I see no reason in principle why it shouldn't have (what would be for me) a satisfactory answer.

For instance, imagine that after a vast expenditure of effort and ingenuity a team of cognitive scientists, neurologists, etc., comes up with something like this:

  • A detailed neuron-level map of a typical human brain.
  • Higher-level explanations of structures within it at different scales, larger scales corresponding broadly to higher levels of abstraction.
  • Much analysis of how activity in these various structures (generally at the higher levels) corresponds to particular mental phenomena (surprise, sadness, awareness-of-red, multiplying small integers, imagining conversations with a friend, ...).
  • A detailed breakdown of what happens on a typical occasion when the person whose brain it is sees (say) a tomato:
    • Low-level description, right down to the firing of individual neurons.
    • Descriptions at higher levels, each one linked to the descriptions at slightly higher and lower levels that overlap with it and to whatever abstractions are appropriate to the level being described.
    • "So this bit here is something we see whenever he sees something he might eat in a salad. It doesn't fire for meat, though. We think it represents healthy food somehow."
    • "This one fires in that distinctive pattern for anything that makes him think of sex. It's not firing very strongly here, which is probably a good thing. You can see feeding into it some representations of lips and breasts, which are probably related to the colour and shape of the tomato, respectively. Men are weird."
    • "These circuits here, and here, and here all tend to turn on when he sees anything red. The details of their timing and relative strength depends on the brightness of the red and how it's located in his visual field. It doesn't seem to be downstream of anything more sophisticated, but if you compare with what happens when he sees someone bleeding badly you'll notice that that tends to turn this on more strongly and that it feeds into the processes that raise his autonomic arousal levels when he sees red."
    • "This is a part of the language-generating subsystem. It does things whenever he says, or thinks about saying, words like 'red' and 'crimson'. It also operates when he hears or reads those words, but in a slightly different way. The activity you see here tends to occur shortly before that happens -- it looks like his brain is getting ready to talk about the redness it sees, if it needs to."
  • A detailed breakdown of what happens when you ask him about what he's experiencing, including the links from structures like the ones sketched above into structures that are used when introspecting and when describing things.

Of course the above is an outrageous oversimplification, and the thing these people would have to produce would presumably be a vastly complicated computer model with some currently-inconceivable user interface for looking at different parts of it at different levels of abstraction, tracing what happens in the brain at different speeds, etc.

Anyway, if I were shown something like this and could use it to follow the processes by which seeing a tomato turns into saying "What a beautiful rich red colour" (etc., etc., etc.), and likewise for the processes that happen on seeing a green apple and commenting on its colour, and to observe the parallels and differences between these processes -- I would be pretty well satisfied that your "table of correspondents" problem had been adequately solved.

Comment author: turchin 07 July 2016 06:57:17PM 0 points [-]

Hi! It seems like you are reinventing here or suggesting a variant of Mary room thought experiment, https://en.wikipedia.org/wiki/Knowledge_argument

Anyway, for example, the fact is that there are people who are tetrachromatics - they have 4th basic colour. And assuming that i could know everything about their brain, each neuron, each connection, i still don't know how they feel the 4th colour. It is not "correspondent table", because on the right self of the table should be experiences.

You say: "The fact that you can't explain something in words seems like awfully thin evidence on which to base the idea that they might be different in ways that have no physical foundation."

I think that for our discussion is useful to distinguish two main thesis: 1) Do qualia exist? I think: yes, sure. 2) How they are connected to physical? I think: I don't know. All attempts to create such connection results in ugly constructions, like zombies, inverted spectrum, epiphenomenalism, corresponding table - or in denial of existence of qualia.

I also want to remind my point about the post: EY tried to prove that zombies are impossible. The way he do it doesn't work for the thought experiment with inverted spectrum. This approach doesn't work.

I think it is clear the difference between to two types of theses: a theorem is wrong and the prove of the theorem is wrong.

Comment author: gjm 07 July 2016 09:45:07PM -2 points [-]

There may be some things in common between what I describe and the "Mary's room" experiment, but I'm certainly not recreating it -- my position is pretty much the opposite of Jackson's.

I agree that your and my experience of colour are probably importantly different from those of some tetrachromats. (How different depends on how far their 4th cone's peak is from the others.) For that matter, different trichromats have cone response functions that aren't quite the same, so even two people with "normal" colour vision don't have the exact same colour qualia. In fact, they wouldn't have even without that difference, because their past experiences and general psychological makeup aren't identical. I don't see why any of this tells us anything at all about whether qualia are physical or not, though.

I don't understand how your "corresponding table" is an "ugly construction". I mean, if for some reason you actually had to write down such a table then no doubt it would be ugly, but the same is true for all sorts of things we can all agree are real. Is there something about it that you think is a reason not to believe in physicalism?

I don't think Eliezer was exactly trying to prove that zombies are impossible. He was trying to knock down an argument (based on the idea that obviously you can imagine a world just like this one but where the people are zombies) for zombies being possible, and to offer a better set of intuitions suggesting that they probably aren't. And it doesn't seem to me that replacing zombies with inverted qualia in any way refutes Eliezer's argument because (1) his argument was about zombies, not about inverted qualia and (2) for the reasons I've already given above, I think a very similar argument does in fact apply to inverted qualia. It's not as clear-cut as for zombies, but it seems very convincing to me.

Comment author: turchin 07 July 2016 10:40:55PM *  0 points [-]

It seems i start to understand where is the difference between our positions.

Qualia are not about cones in the eye. Because I could see colour dreams. So qualia are somewhere in the brains.

You said: "For that matter, different trichromats have cone response functions that aren't quite the same, so even two people with "normal" colour vision don't have the exact same colour qualia."

(I could also see visual images if I press finger on my eye.)

So the brain use qualia to represent colours in outside world, but qualia are not actual colours.

So qualia themselves are like variables in equation. M represent mass, and F presents force in second law of Newton.

F=Ma.

But "M" is not mass, and "F" is not force, they is just variables. And if we say that now "M" is force, and "F" is mass, we will have the same equation. (It is like an experiment with inverted spectrum, btw)

M=Fa

So, qualia are variables which the brain use to denote external experiences. The same way "F" is letter from latin alphabet, which we use to denote force. The latin alphabet is completely different entity than physical forces. And when we discuss "F" we should always remember what we a speaking about - latin alphabet or force.

EDITED: If we continue this analogy, we could imagine a computer which calculate force. It could tell us everything about results of calculations, but it can’t tell which variables it uses in its internal process.

What we conclude from here:

  • It could be infinitely many different variables which the computer could use. They could be inverted.
  • But it has to use some kind of variables, so it can’t be a zombie. Bingo! We just got new argument against p-zombie.

(The longer version of this new anti p-zombie argument is the following: thinking is impossible without variables and variables must be qualia, because the nature of qualia is that they are simple, different and unbreakable in parts, that is why I also called them “atoms of experience” - but it may need longer elaboration as it is very sketchy)

  1. The programer of the computer chose which variables to use in this particular computer. So he created the table of correspondence in which he stated: "F is force, and M is mass".
Comment author: gjm 07 July 2016 11:16:14PM -2 points [-]

Qualia are not about cones in the eye.

But qualia (at least colour qualia) are often caused by what happens to cones in the eye, and the nature of your colour qualia (even ones that occur in dreams) will depend on how your visual system is wired up, which in turn will depend on the cones in your eyes.

qualia are not actual colours

Of course not. That would be a category error. Qualia are what happens in our brains (or our immaterial souls, or wherever we have experiences) in response to external stimulation, or similar things that arise in other ways (e.g., in dreams).

qualia are variables which the brain uses to denote external experiences

This seems like a dangerous metaphor, because the brain presumably uses kinda-variable-like things at different levels, some of which have no direct connection to experience.

They could be inverted

I think how plausible this is depends on what sort of variables you're thinking of, and is markedly less plausible for the sorts of variables that could actually correspond to qualia.

I mean, you can imagine (lots of oversimplification going on here, but never mind) taking some single neuron and inverting what happens at all its synapses, so that the activation of that neuron has the exact opposite meaning to what it used to be but everything else in the brain carries on just as before. That would be an inversion, of course. But it would be the exact opposite of what's supposed to happen in the "inverted spectrum" thought experiment. There, you have the same physical substrate somehow producing opposite experiences; but here we have the same experiences with part of the physical substrate inverted.

But a single neuron's internal state is not in any way a plausible candidate for what a quale could be. Qualia have to be things we are consciously aware of, and we are not consciously aware of the internal states of our neurons any more than a chess program is making plans by predicting the voltages in its DRAM cells.