2009/9/3 Flammarion <peterdjones.domain.name.hidden>:
>
>
>
> On 3 Sep, 01:26, David Nyman <david.ny....domain.name.hidden> wrote:
>> 2009/9/2 Flammarion <peterdjo....domain.name.hidden>:
>>
>>
>>
>> >> and is thus not any particular physical
>> >> object. A specific physical implementation is a token of that
>> >> computational type, and is indeed a physical object, albeit one whose
>> >> physical details can be of any variety so long as they continue to
>> >> instantiate the relevant computational invariance. Hence it is hard
>> >> to see how a specific (invariant) example of an experiential state
>> >> could be justified as being token-identical with all the different
>> >> physical implementations of a computation.
>>
>> > I was right.
>>
>> > A mental type can be associated with a computational
>> > type.
>>
>> > Any token of a mental type can be associated with a token
>> > of the corresponding computational type.
>>
>> But what difference is that supposed to make? The type association is
>> implicit in what I was saying. All you've said above is that it makes
>> no difference whether one talks in terms of the mental type or the
>> associated computational type because their equivalence is a posit of
>> CTM. And whether it is plausible that the physical tokens so picked
>> out possess the causal efficacy presupposed by CTM is precisely what I
>> was questioning.
>
>
> question it then. what's the problem?
>
>> >> But even on this basis it still doesn't seem possible to establish any
>> >> consistent identity between the physical variety of the tokens thus
>> >> distinguished and a putatively unique experiential state.
>>
>> > The variety of the physical implementations is reduced by grouping
>> > them
>> > as equivalent computational types. Computation is abstract.
>> > Abstraction is
>> > ignoring irrelevant details. Ignoring irrelevant details establishes a
>> > many-to-one relationship : many possible implementations of one mental
>> > state.
>>
>> Again, that's not an argument - you're just reciting the *assumptions*
>> of CTM, not arguing for their plausibility.
>
> you're not arguing against its plausibility
>
>> The justification of the
>> supposed irrelevance of particular physical details is that they are
>> required to be ignored for the supposed efficacy of the type-token
>> relation to be plausible. That doesn't make it so.
>
> why not? we already know they can be ignored to establish
> computational
> equivalence.
>
>> >> On the
>> >> contrary, any unbiased a priori prediction would be of experiential
>> >> variance on the basis of physical variance.
>>
>> > Yes. The substance of the CTM claim is that physical
>> > differences do not make a mental difference unless they
>> > make a computational difference. That is to say, switching from
>> > one token of a type of computation to another cannot make
>> > a difference in mentation. That is not to be expected on an
>> > "unbiased" basis, just because it is a substantive claim.
>>
>> Yes it's precisely the claim whose plausibility I've been questioning.
>
> You haven't said anything specific about what is wrong with it at all.
>
>> > The variety of the physical implementations is reduced by grouping
>> > them
>> > as equivalent computational types. Computation is abstract.
>> > Abstraction is
>> > ignoring irrelevant details. Ignoring irrelevant details establishes a
>> > many-to-one relationship : many possible implementations of one mental
>> > state.
>>
>> Yes thanks, this is indeed the hypothesis. But simply recapitulating
>> the assumptions isn't exactly an uncommitted assessment of their
>> plausibility is it?
>
>
> Saying it is not necessarily correct is not a critique
>
>>That can only immunise it from criticism. There
>> is no whiff in CTM of why it should be considered plausible on
>> physical grounds alone.
>
>
>> Hence counter arguments can legitimately
>> question the consistency of its claims as a physical theory in the
>> absence of its type-token presuppositions.
>
> If you mean you can criticise the CTM as offering nothing specific
> to resolve the HP, you are correct. But I *thought* we were
> discussing the MG/Olympia style of argument, which purportedly
> still applies even if you restrict yourself to cognition and forget
> about experience/qualia.
> Are we?
>
>> Look, let me turn this round. You've said before that you're not a
>> diehard partisan of CTM. What in your view would be persuasive
>> grounds for doubting it?
>
> I'll explain below. But the claim I am interested in is that CTM
> somehow disproves materalism (Maudlin, BTW takes it the other way
> around--
> materialism disproves CTM). I have heard not a word in support of
> *that* claim.
>
>
> ust an Artificial Intellence be a Computer ?
>
> An AI is not necessarily a computer. Not everything is a computer or
> computer-emulable. It just needs to be artificial and intelligent!
Then it's no more *CTM*. (C means Computational)
> The
> extra ingredient a conscious system has need not be anything other
> than the physics (chemistry, biology) of its hardware -- there is no
> forced choice between ghosts and machines.
>
> A physical system can never be exactly emulated with different
> hardware -- the difference has to show up somewhere. It can be hidden
> by only dealing with a subset of a systems abilities relevant to the
> job in hand; a brass key can open a door as well as an iron key, but
> brass cannot be substituted for iron where magnetism is relevant.
> Physical differences can also be evaded by taking an abstract view of
> their functioning; two digital circuits might be considered equivalent
> at the "ones and zeros" level of description even though they
> physically work at different voltages.
>
> Thus computer-emulability is not a property of physical systems as
> such. Even if all physical laws are computable, that does not mean
> that any physical systems can be fully simulated. The reason is that
> the level of simulation matters. A simulated plane does not actually
> fly; a simulated game of chess really is chess. There seems to be a
> distinction between things like chess, which can survive being
> simulated at a higher level of abstraction, and planes, which can't.
> Moreover, it seems that chess-like things are in minority, and that
> they can be turned into an abstract programme and adequately simulated
> because they are already abstract.
>
> Consciousness. might depend on specific properties of hardware, of
> matter.
Then it is no more CTM. Specific hardware properties are *totally irrelevant*.
> This does not imply parochialism, the attitude that denies
> consciousness to poor Mr Data just because he is made out of silicon,
> not protoplasm. We know our own brains are conscious; most of us
> intuit that rocks and dumb Chinese Rooms are not; all other cases are
> debatable.
>
> Of course all current research in AI is based on computation in one
> way or another. If the Searlian idea that consciousness is rooted in
> physics, strongly emergent, and non-computable is correct, then
> current AI can only achieve consciousness accidentally. A Searlian
> research project would understand how brains generate consciousness in
> the first place -- the aptly-named Hard Problem -- before moving onto
> possible artificial reproductions, which would have to have the right
> kind of physics and internal causal activity -- although not
> necessarily the same kind as humans.
>
> "When I say that the brain is a biological organ and consciousness
> a biological process, I do not, of course, say or imply that it would
> be impossible to produce an artificial brain out of nonbiological
> materials that could also cause and sustain consciousness...There is
> no reason, in principle, why we could not similarly make an artificial
> brain that causes consciousness. The point that needs to be empnasized
> is that any such artificial brain would have to duplicate the actual
> causes of human and animal brains to produce inner, qualitative,
> subjective states of consciousness. Just producing similar output
> behavior would not by itself be enough."
>
> [Searle, MLS, p. 53]
>
> "Is the Brain A Machine?"
> John Searle thinks so .
>
> The brain is indeed a machine, an organic machine; and its
> processes, such as neuron firings, are organic machine processes.
>
> The Mystery of Consciousness. page 17: Is he right ? To give a
> typically philosophical answer, that depends on what you mean by
> 'machine'. If 'machine' means an artificial construct, then the answer
> is obviously 'no'. However. Searle also thinks the the body is a
> machine, by which he seems to mean that it has been understand in
> scientific terms, we can explain biology by in terms of to chemistry
> and chemistry in terms of physics. Is the brain a machine by this
> definition ? It is being granted that the job of he brain is to
> implement a conscious mind, just as the job of the stomach is to
> digest, the problem then is that although our 'mechanical'
> understanding of the stomach does allow us to understand digestion we
> do not, according to Searle himself, understand how the brain produces
> consciousness. He does think that the problem of consciousness is
> scientifically explicable, so yet another definition of 'machine' is
> needed, namely 'scientifically explained or scientifically explicable'
> -- with the brain being explicable rather than explained. The problem
> with this stretch-to-fit approach to the meaning of the word 'machine'
> is that every time the definition of brain is broadened, the claim is
> weakened, made less impactful.
>
> PDJ 03/02/03
> The Chinese Room
> The Chinese Room and Consciousness
> According to the proponents of Artificial Intelligence, a system is
> intelligent if it can convince a human interlocutor that it is. This
> is the famous Turing Test. It focuses on external behaviour and is
> mute about how that behaviour is produced. A rival idea is that of the
> Chinese Room, due to John Searle. Searle places himself in the room,
> manually executing a computer algorithm that implements intelligent-
> seeming behaviour, in this case getting questions written in Chinese
> and mechanically producing answers, without himself understanding
> Chinese. He thereby focuses attention on how the supposedly
> intelligent behaviour is produced. Although Searle's original idea was
> aimed at semantics, my variation is going to focus on consciousness.
> Likewise, although Searle's original specification has him
> implementing complex rules, I am going to take it that the Chinese
> Room is implemented as a conceptually simple system --for instance, a
> Giant Look-Up Table -- in line with the theorem of Computer Science
> which has it that any computer can be emulated by a Turing Machine.
>
> If you think a Chinese Room implemented with a simplistic, "dumb"
> algorithm can still be conscious, you are probably a behaviourist; you
> only care about that external stimuli get translated into the
> appropriate responses, not how this happens, let alone what it feels
> like to the system in question.
>
> If you think this dumb Chinese Room is not conscious, but a smart one
> would be, you need to explain why. There are two explanatory routes:
> one that says consciousness is inessential, and another that says that
> hardware counts as well as software.
>
> Any smart AI can be implemented as a dumb TM, so the more complex
> inner workings which supposedly implement consciousness , could be
> added or subtracted without making any detectable difference. Given
> the assumption that the computational differences are what matter,
> this would to add up to epiphenomenalism, the view that consciousness
> exists but is a bystander that doesn't cause anything, since there is
> not any computational difference between the simple implementation and
> the complex one.
>
> On the other hand, if it is assumed that epiphenomenalism if false,
> then it follows that implementational differences must matter, since
> the difference between the complex and the dumb systems is not in
> their computational properties. That in turn means computationalism is
> false. The Chinese Room argument then succeeds, but only as
> interpreted fairly strictly as an argument about the ability of
> algorithms to implement consciousness. Any actual computational
> systems, or artificial intelligence construct, will be more than just
> an algorithm; it will be the concrete implementation of an algorithm.
> Since it is the implementation that makes the difference between a
> fully successful AI and a "zombie" (functional enough to pass a Turing
> test, but lacking real consciousness), and since every AI would have
> some sort of implementation, the possibility of an actual systems
> being conscious is far from ruled out. The CR argument only shows that
> it is not conscious purely by virtue of implementing an algorithm. It
> is a succesful argument up to that point, the point that why AI may be
> possible, it will not be pruely due to running the right algorithm.
> While the success of an AI programme is not ruled out, it is not
> guaranteed either. It is not clear which implementations are the right
> ones. A system running the right algorithm on the wrong hardware may
> well be able to pass a Turing Test, but if the hardware is relevant to
> consciousness as well, a system with the wrong hardware will be an
> artificial zombie. It will be cognitively competent, but lacking in
> genuine phenomenal consciousness. (This is in line with the way robots
> and the like are often portrayed in science fiction. A further wrinkle
> is that an exact computational emulation of a real person -- a real
> person who believes in qualia anyway -- would assert its possession of
> qualia while quite possibly not possessing any qualia to boast about).
>
> Thus the success of the CR argument against a software-only approach
> to AI has the implication that the TT is not adequate to detect the
> success of a strong AI (artificial consciousness) project. (Of course,
> all this rests on beahviourism being false; if behaviourism is true
> there is no problem with a TT, since it is a test of behaviour). We
> need to peek inside the box; in order to know whether an AI device has
> full phenomenal, consciousness, we would need a successful theory
> linking consciousness to physics. Such a theory would be nothing less
> than an answer to the Hard Problem. So a further implication of the
> partial success of Searlian arguments is that we cannot bypass the
> problem of explaining consciousness by some research programme of
> building AIs. The HP is logically prior. Except for beahviourists.
>
> Peter D Jones 8/6/05
> Syntax and Semantics. The Circularity Argument as an Alternative
> Chinese Room
>
> The CR concludes that syntax, an abstract set of rules is insufficient
> for semantics. This conclusions is also needed as a premise for
> Searle's syllogistic argument
>
> 1. Syntax is not sufficient for semantics.
> 2. Computer programs are entirely defined by their formal, or
> syntactical, structure.
> 3. Minds have mental contents; specifically, they have semantic
> contents.
> 4. Therefore, No computer program by itself is sufficient to give a
> system a mind. Programs, in short, are not minds, and they are not by
> themselves sufficient for having minds.
>
> Premise 01 is the most contentious of the four. The Chinese Room
> Argument, which Searle puts forward to support itm is highly
> contentious. We will put forward a different argument to support it.
>
> An objection to the CR argument goes: "But there must be some kind of
> information processing structure that implements meaning in our heads.
> Surely that could be turned into rules for the operator of the Chinese
> Room".
>
> A response, the Circularity Argument goes: a system of syntactic
> process can only transform one symbol-string into another; it does not
> have the power to relate the symbols to anything outside the system.
> It is a circualr, closed system. However, to be meaningful a symbol
> must stand for something other than itself. (The Symbol must be
> Grounded). Therefore it must fail to have any real semantics.
>
> It is plausible that any given term can be given an abstract
> definition that doesn't depend on direct experience. A dictionary is
> collection of such definitions. It is much less plausible that every
> term can be defined that way. Such a system would be circular in the
> same way as:
>
> "present: gift"
>
> "gift: present"
>
> ...but on a larger scale.
>
> A dictionary relates words to each other on a static way. It does not
> directly have the power to relate words to anything outside itseld. We
> can understand dictionary definitons because we have already grapsed
> the meanings of some words. A better analogy for the Symbol Grounding
> problem is that of trying to learn an entirely unknown langauge for a
> dictionary. (I have switched from talking about syntacital
> manipluation processes to static dicitonaries; Searles arguments that
> syntax cannot lead to semantics have been critices for dealing with
> "syntax" considered as abstract rules, whereas the computational
> processes they are aimend are concrete, physcial and dynamic. The
> Circularity argument does not have that problem. Both abstract syntax
> and symbol-manipulation processed can be considered as circular).
>
> If the Circularity Argument, is correct, the practice of giving
> abstract definitions, like "equine quadruped" only works because
> somewhere in the chain of definitions are words that have been defined
> directly; direct reference has been merely deferred, not avoided
> altogether.
>
> The objection continues: "But the information processing structure in
> our heads has a concrete connection to the real world: so do AI's
> (although those of the Chinese Room are minimal). Call this is the
> Portability Assumption.
>
> But they are not the same concrete connections. The portability of
> abstract rules is guaranteed by the fact that they are abstract. But
> concrete causal connections are not-abstract. They are unlikely to be
> portable -- how can you explain colour to an alien whose senses do not
> include anything like vision?
>
> Copying the syntactic rules from one hardware platform to another will
> not copy the semantics. Therefore,semantics is more than syntax.
>
> If the Portability Assumption is correct, an AI (particularly a
> robotic one) could be expected to have some semantics, but there is no
> reason it should have human semantics. As Wittgenstein said: "if a
> lion could talk, we could not understand it".
>
> Peter D Jones 13/11/05
> The Chinese Room and Computability
> I casually remarked that mental behaviour 'may not be computable'.
> This will shock some AI proponents, for whom the Church-Turing thesis
> proves that everything is computable. More precisely, everything that
> is mathematically computable is computable by a relatively dumb
> computer, a Turing that something can be simulated doesn't mean the
> simulation has all the relevant properties of the original: flight
> simulators don't take off. Thirdly the mathematical sense of
> 'computable' doesn't fit well with the idea of computer-simulating
> fundamental physics. A real number is said to be mathematically
> computable if the algorithm that churns it out keeps on churning out
> extra digits of accuracy..indefinitely. Since such a algorithm will
> never finish churning out a single real number physical value, it is
> difficult to see how it could simulate an entire universe. Yes, I am
> assuming the universe is fundamentally made of real numbers. If it is,
> for instance finite, fundamental physics might be more readily
> computable, but the computability of physics still depends very much
> on physics and not just on computer science).
> The Systems Response and Emergence
> By far the most common response to the CR argument is that, while the
> room's operator, Searle himself, does not understand Chinese, the room
> as a whole does. According to one form of the objection, individual
> neurons do not understand Chinese either; but this is not a fair
> comparison. If you were to take a very simple brain and gradually add
> more neurons to it, the increase in information-processing capacity
> would keep in line with an increase in causal activity. However, the
> equivalent procedure of gradually beefing up a CR would bascially
> consist of adding more and more rules to the rule book while the
> single "neuron", the single causally active constituent, the operator
> of the room did all the work. It is hard to attribute understanding to
> a passive rulebook, and hard to attribute it to an operator performing
> simple rote actions. It is also hard to see how the whole can be more
> than the sum of the parts. It is very much a characteristic of a
> computer, or other mechanism, that there is no mysterious emegence
> going on; the behavour of the whole is always explicable in term sof
> the behaviour of the parts. There is no mystery, by contrast, in more
> neurons being able to do more work. Searle doesn't think you can put
> two dumbs together and get a smart. That is no barrier to putting 100
> billion dumbs together to get a smart. Or to putting two almost-smarts
> together to get a smart.
> The Chinese Room and Speed
> Of course, if we burden the room's operator with more and more rules,
> he will go slower and slower. Dennett thinks a slow chinese room would
> not count as conscious at all. Nature, he notes, requires conscious
> beings to react within a certain timescale in order to survive. That
> is true, but it does not suggest any absolute speed requirement.
> Nature accomodates the tortoise and the mayfly alike. The idea that a
> uselessly slow consciousness would not be actually be a concsiousness
> at all is also rather idiosyncratic. We generally credit a useless
> vestigal limb with being a loimb, at least.
>
> Anyway, Dennett's speed objection is designed to lead into one of his
> favourite ideas: the need for massive parallelism. One Searle might
> lack conscious semantics, but a million might do the trick. Or so he
> says. But what would parallelism bring us except speed?
> The Chinese Room and complexity.
> The Dennettians make two claims; that zombies are impossible, and that
> the problem with the Chinese room is that it is too simple. We will
> show that both claims cannot be true.
>
> What kind of complexity does the Chinese Room lack? By hypothesis it
> can pass a Turing test: it has that much complexity in the sense of
> outward performance. There is another way of thinking about
> complexity: complexity of implementation. . So would the Chinese Room
> be more convincing if it had a more complex algorithm? The problem
> here is that there is a well-founded principle of computer science
> according to which a computer programme of any complexity can emulated
> by a particular type of essentially simple machine called a Turing
> Machine. As it happens, the Chinese Room scenario matches a Turing
> Machine pretty well. A Turing Machine has a simple active element, the
> read-write head and a complex instruction table. In the Chinese Room
> the sole active element is the operator, performing instruction by
> rote; any further complexity is in the rulebooks. Since there is no
> stated limit to the "hardware" of the Chinese Room -- the size of the
> rulebook, the speed of the operator -- the CR could be modified to
> implement more complex algorithms without changing any of the
> essential features.
>
> Of course differences in implementation could make all sorts of non-
> computational differences. Dennett might think no amount of
> computation will make a flight simulator fly. He might think that the
> Chinese Room lack sensor and effectuators to interact with its
> environment, and that such interactions are needed to solve the symbol-
> grounding problem. He might think that implementational complexity,
> hardware over software is what makes the difference between real
> consciousness and zombiehood. And Searle might well agree with him on
> all those points: he may not be a computationalist, but he is a
> naturalist. The dichotomy is this: Denett's appeal to complexity is
> either based on software, in which case it is implausible, being
> undermined by Turing equivalence; or it is based in hardware, in which
> case it is no disproof of Searle. Rather, Searle's argument can be
> seen as a successful disproof of computationalism(ie the only-software-
> matters approach) and Dennett's theory of consciousness is a proposal
> for a non-computationalistic, hardware-based, robotic approach of the
> kind Searle favours.
>
> Some Denettians think a particular kind of hardware issue matters:
> parallelism. The Chinese room is "too simple" in that it is a serial
> processor. Parallel processors cannot in fact computer anything --
> cannot solve any problem -- that single processors can't. So parallel
> processing is a difference in implementation, not computation. What
> parallel-processing hardware can do that serial hardware cannot is
> perform opertations simultaneously. Whatever "extra factor" is added
> by genuine simultaneity is not computational. Presumably that means it
> would not show up in a Turing test -- it would be indetectable from
> the outside. So the extra factor added by simultaneity is something
> that works just like phenomenality. It is indescernable from the
> outside, and it is capable of going missing while external
> functionality is preserved. (We could switch a parallel processor off
> during a TT and replace it with a computationally equivalent serial
> one. According to the parallel processing claim, any genuine
> cosnciousness would vanish, although the external examiner preforming
> the TT would be none the wiser). In short, simulateneity implies
> zombies.
> The Chinese Room and Abstraction
> Consider the argument that computer programmes are too abstract to
> cause consciousness. Consider the counter-argument that a running
> computer programme is a physical process and therefore not abstract at
> all.
>
> 1. Computationalism in general associates that consciousness with a
> specific comptuer programme, programme C let's say.
> 2. Let us combine that with the further claim that programme C
> causes cosnciousness, somehow leveraging the physical causality of the
> hardware it is running on.
> 3. A corrolary of that is that running programme C will always
> cause the same effect.
> 4. Running a programme on hardware is a physical process with
> physical effects.
> 5. It is in the nature of causality that the same kind of cause
> produces the same kind of effects-- that is, causaliy attaches to
> types not tokens.
> 6. Running a programme on hardware will cause physical effects, and
> these will be determined by the kind of physical hardware. (Valve
> computers will generate heat, cogwheel computers will generate noise,
> etc).
> 7. Therefore, running programme C on different kinds of hardware
> will not produce a uniform effect as required by 1.
> 8. Programmes do not have a physical typology: they are not natural
> kinds. In that sense they are abstract. (Arguably, that is not as
> abstract as the square root of two, since they still have physical
> tokens. There may be more than one kind or level of abstraction).
> 9. Conclusion: even running programmes are not apt to cause
> consciousness. They are still too abstract.
>
> Computational Zombies
> This argument explores the consequenes of two assumptions:
>
> 1. We agree that Searle is right in his claim that software alone
> is not able to bring about genuine intelligence,
> 2. But continue to insist that AI research should nonetheless be
> pursued with computers.
>
> In other words, we expect the success or failure of our AI to be
> dependent on the choice of software in combination with the choice of
> hardware.
>
> The external behaviour of a computational system -- software and
> hardware taken together -- is basically detemined by the software it
> is running; that is to say, while running a programme on different
> hardware will make some kind of external differences, they tend to be
> irrelevant and uninteresting differences such as the amount of heat
> and noise generated. Behaviourstic tests like the Turing Test are
> specifically designed to filter out such differences (so that the
> examiner's prejudices about what kind of system could be conscious are
> excluded). The questions and responses in a TT are just the inputs and
> outputs of the software.
>
> Abandoning the software-only approach for a combined software-and-
> hardware approach has a peculiar consequence: that it is entirely
> possible that out of two identically programmed systems running on
> different hardware, one will be genuinely intelligent (or have genuine
> consciousness, or genuine semantic comprehension, etc) and the other
> will not. Yet, as we have seen above, these differences will be --
> must be -- indiscernable in a Turing Test. Thus, if hardware is
> involved in the implementation of AI in computers, the Turing Test
> must be unreliable. There is a high probability that it will give
> "false positives", telling us that unconscious AIs are actually
> conscious -- a probability that rises with the number of different
> systems tested.
>
> To expand on the last point: suppose you get a positive TT result for
> one system, A. Then suppose you duplicate the software onto a whole
> bunch of different hardware platforms, B, C, D....
>
> (Obviously, they are all assumed to be capable of running the software
> in the first place). They must give the same results to the TT for A,
> since they all run the same software, and since the software
> determines the responses to a TT, as we established above, they must
> give positive results. But eventually you will hit the wrong hardware
> -- it would be too unlikely to always hit on the right hardware by
> sheer chance, like throwing an endless series of heads. When you do
> hit the wrong hardware, you get a false positive. (Actually you don't
> know you got a true positive with A in the first place...)
>
> Thus, some AIs would be "zombies" in a restricted sense of "zombie".
> Whereas a zombie is normally thought of a physical duplicate lacking
> consciousness, these are software duplicates lacking appropriate
> hardware.
>
> This peculiar sitation comes about because of the separability of
> software and hardware in a computational approach, and the further
> separation of relevant and irrelvant behaviour in the Turing Test.
> (The separability of software simply means the ability to run the same
> software on differenet hardware). Physical systems in general -- non
> computers, not susceptible to separate descriptions of hardware and
> software -- do not have that separability. Their total behaviour is
> determined by their total physical makeup. A kind of Articial
> Intelligence that was basically non-computational would not be subject
> to the Compuational Zombie problem. Searle is therefore correct to
> maintain, as he does, that AI is broadly possible.
> Neuron-silicon replacement scenarios
> Chalmers claims that replacing neurons with silicon will preserve
> qualia so long as it preserves function -- by which he means not just
> outward, behavioural function but also the internal organisation that
> produces it. Obviously, he has to make that stipulation because it is
> possible to think of cases, such as Searle's Chinese Room, where
> outward behaviour is generated by a very simplistic mechanism, such as
> a lookup table. In fact, if one takes the idea that consciousness
> supervenes on the functional to the extreme, it becomes practically
> tautologous. The most fine-grained possible functional description
> just is a physical description (assuming physics does not deliver
> intrinsic properties, only structural/behavioural ones) , and the
> mental supervenes in some sense on the physical, so consciousness can
> hardly fail to supervene on an ultimately fine-grained functional
> simulation. So the interesting question is what happens between these
> two extremes at, say, the neuronal level.
>
> One could imagine a variation of the thought-experiment where one's
> brain is first replaced at the fine-grained level, and the replaced
> again with a coarser-grained version, and so, on, finishing in a Giant
> Look Up Table. Since hardly anyone thinks a GLUT would have phenomenal
> properties, phenomenality would presumably fade out. So there is no
> rigid rule that phenomenality is preserved where functionality is
> preserved.
>
> It is natural suppose that one's functional dispositions are in line
> with one's qualia. One claims to see red because one is actually
> seeing red. But an intuition that is founded on naturalness cannot be
> readily carried across to the very unnaturual situation of having
> one's brain gradually replaced.
>
> What is it like to have one's qualia fade away ? If one had ever been
> a qualiaphile, one would continue to claim to have qualia, without
> actually doing so. That is, one would be under an increasing series of
> delusions. It is not difficult to imagine thought-experiments where
> the victim's true beliefs are changed into false ones. For instance,
> the Mad Scientist could transport the victim from their bedroom to a
> "Truman Show" replica while they slept. Thus the victim's belief that
> they were still in their own bedroom would be falsified. Since beliefs
> refer to states-of-afairs outside the head, you don't even need to
> change anything about someone's psychology to change the truth of
> their beliefs. So there is no great problem with the idea that
> rummaging in someone's head does change their beliefs -- any such
> process must change beliefs relating to what is physically inside the
> victims head. Since the victim is funtionally identical, they must
> carry on believing they have neural tissue in their head, even after
> it has all been replaced. It doesn't follow from this that replacing a
> brain with silicon must destroy qualia, but there is definitely a
> precedent for having false beliefs about one's own qualia after one's
> brain has been tampered with.
>
> A GLUT of Turings
> An old programmer's trick is to store "potted" results rather than
> calculating them afresh each time. This saves tiem at the expense of
> using up memory. Earlier, we used the idea of a "Giant Look-Up Table"
> to implement, in an essentially dumb way, the whole of an extremely
> coplicated system, such as a human brain.
>
> Can a (Giant) Look-Up Table emulate any Turing Machine (and therefore,
> any computer, and therefore, if computationalism is true, any brain).
>
> The usual objection to LUT's is that they are stateless. But that is
> easy get round. Add a timestamp as an additional input.
>
> Or includde with the fresh input each time a record of all previous
> conversations it has had, with the total table size limiting the
> "lifespan" of the machine
>
> The feedback of the old conversation gives the machine a state memory,
> very straightforwardly is voluminously encoded
>
> What is the LUT for a sorting algorithm?
>
> It is a table which matches lists of unsorted numbers against sorted
> numbers. it doesn't even need to be stateful. And, yes, if it is
> finite it will only sort lists of up to some size limit. But then any
> algorithm has to run for a finite length of time, and will not be able
> to sort some lists in the time allowed. So time limits are just being
> traded for space limits.
>
> If you want to pass a Turing test with a glut, you only need a coarse-
> grained (but still huge) GLUT, that matches verbal resonses to verbal
> inputs. (A GLUT that always produced the same response to the same
> query would be quickly detected as a machine, so it would need the
> statefullness trick, making it even larger...). However, it is
> counterinutitive that such a GLUT would simulate thought since nothing
> goes on between stimulus and response. Well, it is counterintuitive
> that any GLUT would think or feel anything. Daryl McCullough and Dave
> Chalmers chew the issue over in this extract from a Newsgroup
> discussion.
> Computationalism
> Computationalism is the claim that the human mind is essentially a
> computer. It can be picturesquely expressed in the "yes, doctor"
> hypothesis -- the idea that, faced with a terminal disease, you would
> consent to having your consciousness downloaded to a computer.
>
> There are two ambiguities in "computationalism" -- consciousness vs.
> cognition, process vs programme -- leading to a total of four possible
> meanings.
>
> Most people would not say "yes doctor" to a process that recorded
> their brain on a tape a left it in a filing cabinet. Yet, that is all
> you can get out of the timeless world of Plato's heaven (programme vs
> process).
>
> That intuition is, I think, rather stronger than the intuition that
> Maudlin's argument relies on: that consciousness supervenes only on
> brain activity, not on counterfactuals.
>
> But the other ambiguity in computationalism offers another way out. If
> only cognition supervenes on computational (and hence counterfactual)
> activity, then consciousness could supervene on non-counterfactual
> activity -- i.e they could both supervene on physical processes, but
> in different ways.
> Aritifical intelligence and emotion
> AI enthusiasts are much taken with the analogy between the brain's
> (electro) chemical activity and the electrical nature of most current
> computers. But brains are not entirely electrical. Neurons sit in a
> bath of chemicals which effects their behaviour, too. Adrenaline, sex
> hormones, recreational drugs all affect the brain. Why are AI
> proponents so unconcerned about brain chemistry? Is it because they
> are so enamoured with the electrical analogy? Or because they just
> aren't that interested in emotion?
> Platonic computationalism -- are computers numbers?
> Any computer programme (in a particular computer) is a long sequence
> of 1's and 0's, and therefore, a long number. According to Platonism,
> numbers exist immaterially in "Plato's Heaven". If programmes are
> numbers, does that mean Plato's heaven is populated with computer
> programmes?
>
> The problem, as we shall see is the "in a a particular computer"
> clause.
>
> As Bruno Marchal states the claim in a more formal language:
>
> "Of course I can [identify programmes with numbers ]. This is a key
> point, and it is not obvious. But I can, and the main reason is Church
> Thesis (CT). Fix any universal machine, then, by CT, all partial
> computable function can be arranged in a recursively enumerable list
> F1, F2, F3, F4, F5, etc. "
>
> Of course you can count or enumerate machines or algorithms, i.e.
> attach unique numerical labels to them. The problem is in your "Fix
> any universal machine". Given a string of 1's and 0s wihouta universal
> machine, and you have no idea of which algorithm (non-universal
> machine) it is. Two things are only identical if they have all*their
> properties in common (Leibniz's law). But none of the propeties of the
> "machine" are detectable in the number itself.
>
> (You can also count the even numbers off against the odd numbers , but
> that hardly means that even numbers are identical to odd numbers!)
>
> "In computer science, a fixed universal machine plays the role of a
> coordinate system in geometry. That's all. With Church Thesis, we
> don't even have to name the particular universal machine, it could be
> a universal cellular automaton (like the game of life), or Python,
> Robinson Aritmetic, Matiyasevich Diophantine universal polynomial,
> Java, ... rational complex unitary matrices, universal recursive group
> or ring, billiard ball, whatever."
>
> Ye-e-es. But if all this is taking place in Platonia, the only thing
> it can be is a number. But that number can't be associated with a
> computaiton by another machine, or you get infinite regress.
> Is the computationalist claim trivial -- are all systems computers?
> It can be argued that any physical theory involving real numbers poses
> problems (and all major theories do, at the time of writing). Known
> physics is held to be computable, but that statement needs to be
> qualified in various ways. A number thinking particularly of a real
> number, one with an infinite number of digits -- is said to be
> computable if a Turing machine will continue to spit out digits
> endlessly. In other words, there is no question of getting to the
> "last digit". But this sits uncomfortably with the idea of simulating
> physics in real time (or any plausible kind of time). Known physical
> laws (including those of quantum mechanics) are very much infused with
> real numbers and continua.
>
> "So ordinary computational descriptions do not have a cardinality
> of states and state space trajectories hat is sufficient for them to
> map onto ordinary mathematical descriptions of natural systems. Thus,
> from the point of view of strict mathematical description, the thesis
> that everything is a computing system in this second sense cannot be
> supported"
>
> Moreover, the universe seems to be able decide on their values on a
> moment-by-moment basis. As Richard Feynman put it: "It always bothers
> me that, according to the laws as we understand them today, it takes a
> computing machine an infinite number of logical operations to figure
> out what goes on in no matter how tiny a region of space, and no
> matter how tiny a region of time. How can all that be going on in that
> tiny space? Why should it take an infinite amount of logic to figure
> out what one tiny piece of space/time is going to do?
>
> However, he went on to say:
>
> So I have often made the hypotheses that ultimately physics will not
> require a mathematical statement, that in the end the machinery will
> be revealed, and the laws will turn out to be simple, like the chequer
> board with all its apparent complexities. But this speculation is of
> the same nature as those other people make I like it, I dont like it,
> and it is not good to be prejudiced about these things".
> Is no physical system a computer, except in the eye of the beholder
> Comsider the claim that "computation" may not correctly be ascribed to
> the physics per se. Maybe it can be ascribed as an heuristic device as
> physical explanation has an algorithmic component as Wolfram suggests.
>
> Whether everything physical is computational or whether specific
> physical systems are computational are two quite different questions.
> As far as I can see, a NAND's gate being a NAND gate is just as
> objective as a square thing's being square.
>
> Are the computations themselves part of the purely physical story of
> what is going on inside a compter?
>
> Seen mathematically, they have to be part of the physical story. They
> are not some non-physical aura hanging over it. A computer doing
> something semantic like word-processing needs external interpretation
> in the way anything semantic does: there is nothing intrinsic and
> objective about a mark that makes it a sign standing for something.
> But that is down to semantics, not computation. Whilst we don't expect
> the sign "dog" to be understood universally, we regard mathematics as
> a universal language, so we put things like
>
> | || ||| ||||
>
>
> on space probes, expecting them to be understood. But an entity that
> can understand a basic numeric sequence could understand a basic
> mathematical function. So taking our best guesses about
> intersubjective comprehensibility to stand for objectivity,
> mathematical computation is objective.
> Is hypercomoutation a testable hypothesis? We can decide between non-
> computable physics (CM) and computable physics (QM). What the question
> hinges on is the different kinds and levels of proof used in emprical
> science and maths/logic.
> Is Reality real ? Nick Bostrom's Simulation Argument
> The Simulation Argument seeks to show that it is not just possible
> that we are living inside a simulation, but likely.
>
> 1 You cannot simulate a world of X complexity inside a world of X
> complexity.(quart-into-a-pint-pot-problem).
>
> 02 Therefore, if we are in a simulation the 'real' world outside the
> simulation is much more complex and quite possibly completely
> different to the simulated world.
>
> 3 In which case, we cannot make sound inferences from the world we are
> appear to be in to alleged real world in which the simulation is
> running
>
> 04 Therefore we cannot appeal to an argumentative apparatus of advanced
> races, simulations etc, since all those concepts are derived from the
> world as we see it -- which, by hypothesis is a mere simulation.
>
> 05 Therefore, the simulation argument pulls the metaphysical rug from
> under its epistemological feet.
>
> The counterargument does not show that we are not living in a
> simulation, but if we are , we have no way of knowing whether it is
> likely or not. Even if it seems likely that we will go on to create
> (sub) simulations, that does not mean we are living in a simulation
> that is likely for the same reasons, since our simulation might be
> rare and peculiar. In particular, it might have the peculiarity that
> sub-simulations are easy to create in it. For all we know our
> simulators had extreme difficulty in creating our universe. In this
> case, the fact that it is easy to create sub simulations within our
> (supposed) simulation, does not mean it is easy to creae simulations
> per se.
> Computational counterfactuals, and the Computational-Platonic Argument
> for Immaterial Minds
> For one, there is the argument that: A computer programme is just a
> long number, a string of 1's and 0's.
> (All) numbers exist Platonically (according to Platonism)
> Therefore, all programmes exist Platonically.
>
> A mind is special kind of programme (According to computaionalism)
> All programmes exist Platonically (previous argument)
> Therefore, all possible minds exist Platonically
> Therefore, a physical universe is unnecessary -- our minds exist
> already in the Platonic realm
>
> The argument has a number of problems even allowing the assumptions of
> Platonism, and computationalism.
>
> A programme is not the same thing as a process.
>
> Computationalism refers to real, physical processes running on
> material computers. Proponents of the argument need to show that the
> causality and dynamism are inessential (that there is no relevant
> difference between process and programme) before you can have
> consciousness implemented Platonically.
>
> To exist Platonically is to exist eternally and necessarily. There is
> no time or change in Plato's heave. Therefore, to "gain entry", a
> computational mind will have to be translated from a running process
> into something static and acausal.
>
> One route is to replace the process with a programme. let's call this
> the Programme approach.. After all, the programme does specify all the
> possible counterfactual behaviour, and it is basically a string of 1's
> and 0's, and therefore a suitable occupant of Plato's heaven. But a
> specification of counterfactual behaviour is not actual counterfactual
> behaviour. The information is the same, but they are not the same
> thing.
>
> No-one would believe that a brain-scan, however detailed, is
> conscious, so not computationalist, however ardent, is required to
> believe that a progamme on a disk, gathering dust on a shelf, is
> sentient, however good a piece of AI code it may be!
>
> Another route is "record" the actual behaviour, under some
> circumstances of a process, into a stream of data (ultimately, a
> string of numbers, and therefore something already in Plato's heaven).
> Let's call this the Movie approach. This route loses the conditional
> structure, the counterfactuals that are vital to computer programmes
> and therefore to computationalism.
>
> Computer programmes contain conditional (if-then) statements. A given
> run of the programme will in general not explore every branch. yet the
> unexplored branches are part of the programme. A branch of an if-then
> statement that is not executed on a particular run of a programme will
> constitute a counterfactual, a situation that could have happened but
> didn't. Without counterfactuals you cannot tell which programme
> (algorithm) a process is implementing because two algorithms could
> have the same execution path but different unexecuted branches.
>
> Since a "recording" is not computation as such, the computationalist
> need not attribute mentality to it -- it need not have a mind of its
> own, any more than the characters in a movie.
>
> (Another way of looking at this is via the Turing Test; a mere
> recording would never pass a TT since it has no condiitonal/
> counterfactual behaviour and therfore cannot answer unexpected
> questions).
>
> A third approach is make a movie of all possible computational
> histories, and not just one. Let's call thsi the Many-Movie approach.
>
> In this case a computation would have to be associated with all
> related branches in order to bring all the counterfactuals (or rather
> conditionals) into a single computation.
>
> (IOW treating branches individually would fall back into the problems
> of the Movie approach)
>
> If a computation is associated with all branches, consciousness will
> also be according to computationalism. That will bring on a White
> Rabbit problem with a vengeance.
>
> However, it is not that computation cannot be associated with
> counterfactuals in single-universe theories -- in the form of
> unrealised possibilities, dispositions and so on. If consciousness
> supervenes on computation , then it supervenes on such counterfactuals
> too; this amounts to the response to Maudlin's argument in wihch the
> physicalist abandons the claim that consciousness supervenes on
> activity.
>
> Of ocurse, unactualised possibilities in a single universe are never
> going to lead to any White Rabbits!
> Turing and Other Machines
> Turing machines are the classical model of computation, but it is
> doubtful whether they are the best model for human (or other organic)
> intelligence. Turing machines take a fixed input, take as much time as
> necessary to calculate a result, and produce a perfect result (in some
> cases, they will carry on refining a result forever). Biological
> survival is all about coming up with good-enough answers to a tight
> timescale. Mistaking a shadow for a sabre-tooth tiger is a msitake,
> but it is more accpetable than standing stock still calculating the
> perfect interpretation of your visual information, only to ge eaten.
> This doesn't put natural cognition beyone the bounds of computation,
> but it does mean that the Turing Machine is not the ideal model.
> Biological systems are more like real time systems, which have to
> "keep up" with external events, at the expense of doing some things
> imprefectly.
> Quantum and Classical Computers
> (Regarding David Deutsch's FoR)
> To simulate a general quantum system with a classical computer you
> need a number of bits that scales exponentially with the number of
> qubits in the system. For a universal quantum computer the number of
> qubits needed to simulate a system scales linearly with the number of
> qubits in the system. So simulating quantum systems classically is
> intractable, simulating quantum systems with a universal quantum
> computer is tractable.
> Time and Causality in Physics and Computation
> The sum total of all the positions of particles of matter specififies
> a (classical) physical state, but not how the state evolves. Thus it
> seems that the universe cannot be built out of 0-width (in temporal
> terms) slices alone. Physics needs to appeal to something else.
>
> There is one dualistic and two monistic solutions to this.
>
> The dualistic solution is that the universe consists (separately) of
> states+the laws of universe. It is like a computer, where the data
> (state) evolves according to the programme (laws).
>
> One of the monistic solutions is to put more information into states.
> Physics has an age old "cheat" of "instantaneous velocities". This
> gives more information about how the state will evolve. But the state
> is no longer 0-width, it is infinitessimal.
>
> Another example of states-without-laws is Julian Barbour's Platonia.
> Full Newtonian mechanics cannot be recovered from his "Machian"
> approach, but he thinks that what is lost (universes with overall
> rotation and movement) is no loss.
>
> The other dualistic solution is the opposite of the second: laws-
> without-states. For instance, Stephen Hawking's No Boundary Conditions
> proposal
>
> Maudlin's Argument and Counterfactuals
> We have already mentioned a parallel with computation. There is also
> relevance to Tim Maudlin's claim that computationalism is incompatible
> with physicalism. His argument hinges on serparating the activity of a
> comptuaitonal system from its causal dispositions. Consciousness, says
> Maudlin supervened on activity alone. Parts of an AI mechansim that
> are not triggered into activity can be disabled without changing
> consciousness. However, such disabling changes the computation being
> performed, because programmes contain if-then statements only one
> branch of which can be executed at a time. The other branch is a
> "counterfactual", as situation that could have happened but didn't.
> Nonetheless, these counterfactuals are part of the algorithm. If
> changing the algorithm doesn't change the conscious state (because it
> only supervenes on the active parts of the process, not the unrealised
> counterfactuals), consciousness does not supervene on computation.
>
> However, If causal dispositions are inextricably part of a physical
> state, you can't separate activity from counterfactuals. Maudlin's
> argument would then have to rely on disabling counterfactuals of a
> specifically computational sort.
>
> We earlier stated that the dualistic solution is like the separation
> between programme and data in a (conventional) computer programme.
> However, AI-type programmes are typified by the fact that there is not
> a barrier between code and programme -- AI software is self-modifying,
> so it is its own data. Just as it is not physically necessary that
> there is a clear distinction between states and laws (and thus a
> separability of physical counterfactuals), so it isn't necessarily the
> case that there is a clear distinciton between programme and data, and
> thus a separability of computational counterfactuals. PDJ 19/8/06
> Chalmers on GLUTS
> Daryl McCullough writes:
>
> I made the split to satisfy *you*, Dave. In our discussion about
> the table lookup program, your main argument against the table lookup
> being conscious was the "lack of richness" of its thinking process.
> And this lack of richness was revealed by the fact that it took zero
> time to "think" about its inputs before it made its outputs. So I have
> patched up this discrepancy by allowing "silent" transitions where
> there is thinking, but no inputs. However, as I thought my example
> showed, this silent, internal thinking can be perfectly trivial; as
> simple as counting. It is therefore not clear to me in what sense
> there can be more "richness" in some FSA's than there is in a table
> lookup.
>
> Dave Chalmers writes:
>
> I made it abundantly clear that the problem with the lookup table
> is not the mere lack of silent transitions -- see my response to your
> message about the brain that beeps upon every step. Rather, the
> objection is that (a) a lot of conscious experience goes on between
> any two statements I make in a conversation; and (b) it's very
> implausible that a single state-transition could be responsible for
> all that conscious experience.
>
> Like the beeping brain, ordinary FSAs with null inputs and outputs
> aren't vulnerable to this argument, as in those cases the richness of
> such conscious experience need not result from a single state-
> transition, but from a combination of many.
>
> DM:
>
> If you allow a "null input" to be a possible input, then the
> humongous table lookup program becomes functionally equivalent to a
> human brain. To see this, note that the states of the table lookup
> program are essentially sequences of inputs [i_1,i_2,i_3,...,i_n]. We
> use the mapping M([]) = the initial state, M([i_1,i_2, ..., i_n,i_{n
> +1}]) = I(M([i_1,i_2, ..., i_n]),i_{n+1}). The output for state
> [i_1,i_2, ..., i_n] is whatever the lookup table has for that sequence
> of inputs, which is correct by the assumption that the table lookup
> program gets the behavior right.
>
> DC:
>
> You made essentially this argument before, and I responded in a
> message of Feb 28. Here's the relevant material:
>
> Your complaint about clocks, that they don't support
> counterfactuals, is I think, easily corrected: for example, consider a
> machine M with a state determined by a pair: the time, and the list of
> all inputs ever made (with the times they were made). If
> "implementation" simply means the existence of a mapping from the
> physical system to the FSA, then it seems that such a system M would
> simultaneously implement *every* FSA. Counterfactuals would be
> covered, too.
>
> This is an interesting example, which also came up in an e-mail
> discussion recently. One trouble with the way you've phrased it is
> that it doesn't support outputs (our FSAs have outputs as well as
> inputs, potentially throughout their operation); but this can be fixed
> by the usual "humongous lookup table" method. So what's to stop us
> saying that a humongous lookup table doesn't implement any FSA to
> which it's I/O equivalent? (You can think of the table as the
> "unrolled" FSA, with new branches being created for each input. To map
> FSA states to (big disjunctions of) table states, simply take the
> image of any FSA state under the unrolling process.) This is a tricky
> question. Perhaps the best answer is that it really doesn't have the
> right state-transitional structure, as it can be in a given state
> without producing the right output and transiting into the appropriate
> next state, namely when it's at the end of the table. Of course this
> won't work for the implementation of halting FSAs (i.e. ones that must
> halt eventually, for any inputs, but one could argue that the FSA
> which describes a human at a given time isn't a halting FSA (the human
> itself might be halting, but that's because of extraneous influences
> on the FSA). Your example above doesn't have the problem at the end of
> the table; it just goes on building up its inputs forever, but at cost
> of being able to produce the right outputs.
>
> Not that I don't think lookup-tables pose some problems for
> functionalism -- see my long response to Calvin Ostrum. But in any
> case this is far from Putnam's pan-implementationalism.
>
> DM:
>
> The conclusion, whether you have silent transitions or not, is
> that functional equivalence doesn't impose any significant constraints
> on a system above and beyond those imposed by behavioral equivalence.
>
> DC:
>
> Even if your argument above were valid, this certainly wouldn't
> follow -- the requirement that a system contains a humongous lookup
> table is certainly a significant constraint! I also note that you've
> made no response to my observation that your original example, even
> with the silent transitions, is vastly constrained, about as
> constrained as we'd expect an implementation to be.
>
> >
>
--
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Received on Thu Sep 03 2009 - 10:41:56 PDT