pjeby comments on Rationality Quotes: April 2011 - Less Wrong

6 Post author: benelliott 04 April 2011 09:55AM

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Comment author: pjeby 06 April 2011 12:55:09AM *  0 points [-]

I can lift a rock, a Turing machine can't. A Turing machine can only manipulate symbols on a strip of tape, it can't do anything else that's physical.

So... you support euthanasia for quadriplegics, then, or anyone else who can't pick up a rock? Or people who are so crippled they can only communicate by reading and writing braille on a tape, and rely on other human beings to feed them and take care of them?

Your claim that consciousness (whatever we mean when we say that) is possible for Turing machines, rests on the assumption that consciousness is about computation alone, not about computation+some unidentified physical reaction that's absent to pure Turing machines resting in a box on a table.

This "unidentified physical reaction" would also need to not be turing-computable to have any relevance. Otherwise, you're just putting forth another zombie-world argument.

At this point, we have no empirical reason to think that this unidentified mysterious something has any existence at all, outside of a mere intuitive feeling that it "must" be so.

And so, all we have are thought experiments that rest on using slippery word definitions to hide where the questions are being begged, presented as intellectual justification for these vague intuitions... like arguments for why the world must be flat or the sun must go around the earth, because it so strongly looks and feels that way.

(IOW, people try to prove that their intuitions or opinions must have some sort of physical form, because those intuitions "feel real". The error arises from concluding that the physical manifestation must therefore exist "out there" in the world, rather than in their own brains.)

Comment author: ArisKatsaris 06 April 2011 01:12:22AM *  0 points [-]

This "unidentified physical reaction" would also need to not be turing-computable to have any relevance. Otherwise, you're just putting forth another zombie-world argument.

A zombie-world seems extremely improbable to have evolved naturally, (evolved creatures coincidentally speaking about their consciousness without actually being conscious), but I don't see why a zombie-world couldn't be simulated by a programmer who studied how to compute the effects of consciousness, without actually needing to have the phenomenon of consciousness itself.

The same way you don't need to have an actual solar system inside your computer, in order to compute the orbits of the planets -- but it'd be very unlikely to have accidentally computed them correctly if you hadn't studied the actual solar system.

At this point, we have no empirical reason to think that this unidentified mysterious something has any existence at all, outside of a mere intuitive feeling that it "must" be so.

Do you have any empirical reason to think that consciousness is about computation alone? To claim Occam's razor on this is far from obvious, as the only examples of consciousness (or talking about consciousness) currently concern a certain species of evolved primate with a complex brain, and some trillions of neurons, all of which have have chemical and electrical effects, they aren't just doing computations on an abstract mathematical universe sans context.

Unless you assume the whole universe is pure mathematics, so there's no difference between the simulation of a thing and the thing itself. Which means there's no difference between the mathematical model of a thing and the thing itself. Which means the map is the territory. Which means Tegmark IV.

And Tegmark IV is likewise just a possibility, not a proven thing.

Comment author: pjeby 06 April 2011 01:39:53AM 1 point [-]

A zombie-world seems extremely improbable to have evolved naturally, (evolved creatures coincidentally speaking about their consciousness without actually being conscious), but I don't see why a zombie-world couldn't be simulated by a programmer who studied how to compute the effects of consciousness, without actually needing to have the phenomenon of consciousness itself.

This is a "does the tree make a sound if there's no-one there to hear it?" argument.

That is, it assumes that there is a difference between "effects of consciousness" and "consciousness itself" -- in the same way that a connection is implied between "hearing" and "sound".

That is, the argument hinges on the definition of the word whose definition is being questioned, and is an excellent example of intuitions feeling real.

Comment author: ArisKatsaris 06 April 2011 01:51:02AM 1 point [-]

That is, it assumes that there is a difference between "effects of consciousness" and "consciousness itself" -- in the same way that a connection is implied between "hearing" and "sound".

Not quite. What I'm saying is there might be a difference between the computation of a thing and the thing itself. It's basically an argument against the inevitability of Tegmark IV.

A Turing machine can certainly compute everything there is to know about lifting rocks and their effects -- but it still can't lift a rock. Likewise a Turing machine could perhaps compute everything there was to know about consciousness and its effects -- but perhaps it still couldn't actually produce one.

Or at least I've not been convinced that it's a logical impossibility for it to be otherwise; nor that I should consider it my preferred possibility that consciousness is solely computation, nothing else.

Wouldn't the same reasoning mean that all physical processes have to be solely computation? So it's not just "a Turing machine can produce consciousness", but "a Turing machine can produce a new physical universe", and therefore "Yeah, Turing Machines can lift real rocks, though it's real rocks in a subordinate real universe, not in ours".

Comment author: pjeby 06 April 2011 03:35:46PM 2 points [-]

What I'm saying is there might be a difference between the computation of a thing and the thing itself. It's basically an argument against the inevitability of Tegmark IV.

I think you mean, it's the skeleton of an argument you could advance if there turned out to actually be some meaning to the phrase "difference between the computation of a thing and the thing itself".

Or at least I've not been convinced that it's a logical impossibility for it to be otherwise;

Herein lies the error: it's not up to anybody else to convince you it's logically impossible, it's up to you to show that you're even describing something coherent in the first place.

Really, this is another LW-solved philosophical problem; you just have to grok the quantum physics sequence, in addition to the meanings-of-words one: when you understand that physics itself is a machine, it dissolves the question of what "simulation" or "computation" mean in this context. That is, you'll realize that the only reason you can even ask the question is because you're confusing the labels in your mind with real things.

Comment author: Vladimir_M 06 April 2011 03:51:27PM 7 points [-]

Really, this is another LW-solved philosophical problem; you just have to grok the quantum physics sequence, in addition to the meanings-of-words one: when you understand that physics itself is a machine, it dissolves the question of what "simulation" or "computation" mean in this context.

Could you point to the concrete articles that supposedly dissolve this question? I find the question of what "computation" means as still very much open, and the source of a whole lot of confusion. This is best seen when people attempt to define what constitutes "real" computation as opposed to mere table lookups, replays, state machines implemented by random physical processes, etc.

Needless to say, this situation doesn't give one the license to jump into mysticism triumphantly. However, as I noted in a recent thread, I observe an unpleasant tendency on LW to use the notions of "computation," "algorithms," etc. as semantic stop signs, considering how ill-understood they presently are.

Comment author: pjeby 06 April 2011 04:15:17PM 0 points [-]

Could you point to the concrete articles that supposedly dissolve this question? I find the question of what "computation" means as still very much open, and the source of a whole lot of confusion.

Please note that I did not say the sequence explains "computation"; merely that it dissolves the illusion the intuitive notion of a meaningful distinction between a "computation" or "simulation" and "reality".

In particular, an intuitive understanding that people are made of interchangeable particles and nothing else, dissolves the question of "what happens if somebody makes a simulation of you?" in the same way that it dissolves "what happens if there are two copies of you... which one's the real one?"

That is, the intuitive notion that there's something "special" about the "original" or "un-simulated" you is incoherent, because the identity of entities is an unreal concept existing only in human brains' representation of reality, rather than in reality itself.

The QM sequence demonstrates this; it does not, AFAIR, attempt to rigorously define "computation", however.

This is best seen when people attempt to define what constitutes "real" computation as opposed to mere table lookups, replays, state machines implemented by random physical processes, etc.

Those sound like similarly confused notions to me -- i.e., tree-sound-hearing questions, rather than meaningful ones. I would therefore refer such questions to the "usage of words" sequence, especially "How an Algorithm Feels From The Inside" (which was my personal source of intuitions about such confusions).

Comment author: Vladimir_M 06 April 2011 04:22:54PM *  1 point [-]

Please note that I did not say the sequence explains "computation"; merely that it dissolves the illusion the intuitive notion of a meaningful distinction between a "computation" or "simulation" and "reality".

Fair enough, though I can't consider these explanations as settled until the notion of "computation" itself is fully clarified. I haven't read the entire corpus of sequences, though I think I've read most of the articles relevant for these questions, and what I've seen of the attempts there to deal with the question of what precisely constitutes "computation" is, in my opinion, far from satisfactory. Further non-trivial insight is definitely still needed there.

Comment author: pjeby 06 April 2011 04:31:20PM 0 points [-]

Fair enough, though I can't consider these explanations as settled until the notion of "computation" itself is fully clarified.

Personally, I would more look for someone asking that question to show what isn't "computation". That is, the word itself seems rather meaningless, outside of its practical utility (i.e. "have you done that computation yet?"). Trying to pin it down in some absolute sense strikes me as a definitional argument... i.e., one where you should first be asking, "Why do I care what computation is?", and then defining it to suit your purpose, or using an alternate term for greater precision.

Comment author: ArisKatsaris 06 April 2011 06:17:00PM -1 points [-]

You say it has a practical utility, and yet you call it meaningless? If rationality is about winning, how can something with practical utility be meaningless?

Here's what I mean by computation: The handling of concepts and symbolic representations of concepts and mathematical abstractions in such a way that they return a causally derived result. What isn't computation? Pretty much everything else. I don't call gravity a computation, I call it a phenomenon. Because gravity doesn't act on symbolisms and abstractions (like numbers), it acts on real things. A division or a multiplication is a computation, because it acts on numbers. A computation is a map, not a territory, same way that numbers are a map, not a territory.

What I don't know is what you mean by "physics is a machine". For that statement to be meaningful you'd have to explain what would it mean for physics not to be a machine. If you mean that physics is deterministic and causal, then sure. If you mean that physics is a computation, then I'll say no, you've not yet proven to me that the bottom layer of reality is about mathematical concepts playing with themselves.

That's the Tegmark IV hypothesis, and it's NOT a solved issue, not by a long shot.

Comment author: AlephNeil 06 April 2011 08:38:40PM *  0 points [-]

Here's what I think. It's just a "mysterious answer to a mysterious question" but it's the best I can come up with.

From the perspective of a simulated person, they are conscious. A 'perspective' is defined by a mapping of certain properties of the simulated person to abstract, non-uniquely determined 'mental properties'.

Perspectives and mental properties do not exist (that's the whole point - they're subjective!) It's a category mistake to ask: does this thing have a perspective? Things don't "have" perspectives the way they have position or mass. All we can ask is: "From this perspective (which might even be the perspective of a thermostat), how does the world look?"

The difference between a person in a simulation and a 'real person' is that defining the perspective of a real person is slightly 'easier', slightly 'more natural'. But if the simulated and real versions are 'functionally isomorphic' then any perspective we assign to one can be mapped onto the other in a canonical way. (And having pointed these two facts out, we thereby exhaust everything there is to be said about whether simulated people are 'really conscious'.)

ETA: I'm actually really interested to know what the downvoter thinks. I mean, I know these ideas are absurd but I can't see any other way to piece it together. To clarify: what I'm trying to do is take the everyday concept of "what it's likeness" as far as it will go without either (a) committing myself to a bunch of arbitrary extra facts (such as 'the exact moment when a person first becomes conscious' and 'facts of the matter' about whether ants/lizards/mice/etc are conscious) or (b) ditching it in favour of a wholly 'third person' Dennettian notion of consciousness. (If the criticism is simply that I ought to ditch it in favour of Dennett-style consciousness then I have no reply (ultimately I agree!) but you're kind-of missing the point of the exercise.)