harnad@mind.UUCP (Stevan Harnad) (01/22/87)
MINSKY%OZ.AI.MIT.EDU@XX.LCS.MIT.EDU wrote in mod.ai (AIList Digest V5 #11): > unless a person IS in the grip of some "theoretical > position" - that is, some system of ideas, however inconsistent, they > can't "know" what anything "means" I agree, of course. I thought it was obvious that I was referring to a theoretical position on the mind/body problem, not on the conventions of language and folk physics that are needed in order to discourse intelligibly at all. There is of course no atheoretical talk. As to atheoretical "knowledge," that's another matter. I don't think a dog shares any of my theories, but we both know when we feel a toothache (though he can't identify or describe it, nor does he have a theory of nerve impulses, etc.). But we both share the same (atheoretical) experience, and that's C-1. Now it's a THEORY that comes in and says: "You can't have that C-1 without C-2." I happen to have a rival theory on that. But never mind, let's just talk about the atheoretical experience I, my rival and the dog share... > My point was that > you can't think about, talk about, or remember anything that leaves no > temporary trace in some part of your mind. In other words, I agree > that you can't have C-2 without C-1 - but you can't have, think, say, > or remember that you have C-1 without C-2! So, assuming that I know > EXACTLY what he means, I understand PERFECTLY that that meaning is > vacuous. Fine. But until you've accounted for the C-1, your interpretation of your processes as C-2 (rather than P-2, where P is just an unconscious physical process that does the very same thing, physically and objectively) has not been supported. It's hanging by a skyhook, and the label "C" of ANY order is unwarranted. I'll try another pass at it: I'll attempt to show how ducking or denying the primacy of the C-1 problem gets one into infinite regress or question-begging: There's something it's like to have the experience of feeling a toothache. The experience may be an illusion. You may have no tooth-injury, you may even have no tooth. You may be feeling referred pain from your elbow. You may be hysterical, delerious, hallucinating. You may be having a flashback to a year ago, a minute ago, 30 milliseconds ago, when the physical and neural causes actually occurred. But if at T-1 in real time you are feeling that pain (let's make T-1 a smeared interval of Delta-T-1, which satisfies both our introspective phenomenology AND the theory that there can be no punctate, absolutely instantaneous experience), where does C-2 come into it? Recall that C-2 is an experience that takes C-1 as its object, in the same way C-1 takes its own phenomenal contents as object. To be feeling-a-tooth-ache (C-1) is to have a certain direct experience; we all know what that's like. To introspect on, reflect on, remember, think about or describe feeling-a-toothache (all instances of C-2) is to have ANOTHER direct experience -- say, remembering-feeling-a-toothache, or contemplating-feeling-a-toothache. The subtle point is that this 2nd-order experience always has TWO aspects: (1) It takes a 1st order experience (real or imagined) as object, and is for that reason 2nd-order, and (2) it is ITSELF an experience, which is of course 1st-order (call that C-1'). The intuition is that there is something it is like to be aware of feeling pain (C-1), and there's ALSO something it's like to be aware of being-aware-of-feeling-pain. Because a C-1 is the object of the latter experience, the experience is 2nd order (C-2); but because it's still an EXPERIENCE -- i.e., there's something it's LIKE to feel that way -- every C-2 is always also a C-1' (which can in turn become the object of a C-3, which is then also a C-1'', etc.). I'm no phenomenologist, nor an advocate of doing phenomenology as we just did above. I'm also painfully aware that the foregoing can hardly be described as "atheoretical." It would seem that only direct experience at the C-1-level can be called atheoretical; certainly formulating a distinction between 1st and higher-order experience is a theoretical enterprise, although I believe that the raw phenomenology bears me out, if anyone has the patience to introspect it through. But the point I'm making is simple: It's EASY to tell a story in which certain physical processes play the role of the contents of our experience -- toothaches, memories of toothaches, responses to toothaches, etc. All this is fine, but hopelessly 2nd-order. What it leaves out is why there should be any EXPERIENCE for them to be contents OF! Why can't all these processes just be unconscious processes -- doing the same objective job as our conscious ones, but with no qualitative experience involved? This is the question that Marvin keeps ignoring, restating instead his conviction that it's taken care of (by some magical property of "memory traces," as far as I can make out), and that my phenomenology is naive in suggesting that there's still a problem, and that he hasn't even addressed it in his proposal. But if you pull out the C-1 underpinnings, then all those processes that Marvin interprets as C-2 are hanging by a sky-hook. You no longer have conscious toothaches and conscious memories of toothaches, you merely have tooth-damage, and causal sequelae of tooth-damage, including symbolic code, storage, retrieval, response, etc.. But where's the EXPERIENCE? Why should I believe any of that is CONSCIOUS? There's the C-2 interpretation, of course, but that's all it is: an interpretation. I can intepret a thermostat (and, with some effort, even a rock) that way. What justifies the interpretation? Without a viable C-1 story, there can be no justification. And my conjecture is that there can be no viable C-1 story. So back to methodological epiphenomenalism, and forget about C of any order. [Admonition to the ambitious: If you want to try to tell a C-1 story, don't get too fancy. All the relevant constraints are there if you can just answer the following question: When the dog's tooth is injured, and it does the various things it does to remedy this -- inflamation reaction, release of white blood cells, avoidance of chewing on that side, seeking soft foods, giving signs of distress to his owner, etc. etc. -- why do the processes that give rise to all these sequelae ALSO need to give rise to any pain (or any conscious experience at all) rather than doing the very same tissue-healing and protective-behavioral job completely unconsciously? Why is the dog not a turing-indistinguishable automaton that behaves EXACTLY AS IF it felt pain, etc, but in reality does not? That's another variant of the mind/body problem, and it's what you're up against when you're trying to justify interpreting physical processes as conscious ones. Anything short of a convincing answer to this amounts to mere hand-waving on behalf of the conscious interpretation of your proposed processes.] -- Stevan Harnad (609) - 921 7771 {allegra, bellcore, seismo, rutgers, packard} !princeton!mind!harnad harnad%mind@princeton.csnet
harnad@mind.UUCP (Stevan Harnad) (01/23/87)
Ken Laws <Laws@SRI-STRIPE.ARPA> wrote on mod.ai: > Given that the dog >>is<< conscious, > the evolutionary or teleological role of the pain stimulus seems > straightforward. It is a way for bodily tissues to get the attention > of the reasoning centers. Unfortunately, this is no reply at all. It is completely steeped in the anthropomorphic interpretation to begin with, whereas the burden is to JUSTIFY that interpretation: Why do tissues need to get the "attention" of reasoning centers? Why can't this happen by brute cuasality, like everything else, simple or complicated? Nor is the problem of explaining the evolutionary function of consciousness any easier to solve than justifying a conscious interpretation of machine processes. For every natural-selectional scenario -- every nondualistic one, that is, i.e., one that doesn't give consciousness an independent, nonphysical causal force -- is faced with the problem that the scenario is turing-indistinguishable from the exact same ecological conditions, with the organisms only behaving AS IF they were conscious, while in reality being insentient automata. The very same survival/advantage story would apply to them (just as the very same internal mechanistic story would apply to a conscious device and a turing-indistinguishable as-if surrogate). No, evolution won't help. (And "teleology" of course begs the question.) Consciousness is just as much of an epiphenomenal fellow-traveller in the Darwinian picture as in the cognitive one. (And saying "it" was a chance mutation is again to beg the what/why question.) > Why (or, more importantly, how) the dog is conscious in the first place, > and hence >>experiences<< the pain, is the problem you are pointing out. That's right. And the two questions are intimately related. For when one is attempting to justify a conscious interpretation of HOW a device is working, one has to answer WHY the conscious interpretation is justified, and why the device can't do exactly the same thing (objectively speaking, i.e., behaviorally, functionally, physically) without the conscious interpretation. > an analogy between the brain and a corporation, > ...the natural tendency of everyone to view the CEO as the > center of corporate conscious was evidence for emergent consciousness > in any sufficiently complex hierarchical system. I'm afraid that this is mere analogy. Everyone knows that there's no AT&T to stick a pin into, and to correspondingly feel pain. You can do that to the CEO, but we already know (modulo the TTT) that he's conscious. You can speak figuratively, and even functionally, of a corporation as if it were conscious, but that still doesn't make it so. > my previous argument that Searle's Chinese Room > understands Chinese even though neither the occupant nor his printed > instructions do. Your argument is of course the familiar "Systems Reply." Unfortunately, it is open to (likewise familiar) rebuttals -- rebuttals I consider decisive, but that's another story. To telescope the intuitive sense of the rebuttals: Do you believe rooms or corporations feel pain, as we do? > I believe that consciousness is a quantitative > phenomenon, so the difference between my consciousness and that of > one of my neurons is simply one of degree. I am not willing to ascribe > consciousness to the atoms in the neuron, though, so there is a bottom > end to the scale. There are serious problems with the quantitative view of consciousness. No doubt my alertness, my sensory capacity and my knowledge admit of degrees. I may feel more pain or less pain, more or less often, under more or fewer conditions. But THAT I feel pain, or experience anything at all, seems an all-or-none matter, and that's what's at issue in the mind/body problem. It also seems arbitrary to be "willing" to ascribe consciousness to neurons and not to atoms. Sure, neurons are alive. And they may even be conscious. (So might atoms, for that matter.) But the issue here is: what justifies interpreting something/someone as conscious? The Total Turing Test has been proposed as our only criterion. What criterion are you using with neurons? And even if single cells are conscious -- do feel pain, etc. -- what evidence is there that this is RELEVANT to their collective function in a superordinate organism? Organs can be replaced by synthetic substances with the relevant functional properties without disturbing the consciousness of the superordinate organism. It's a matter of time before this can be done with the nervous system. It can already be done with minor parts of the nervous system. Why doesn't replacing conscious nerve cells with synthetic molecules matter? (To reply that synthetic substances with the same functional properties must be conscious under these conditions is to beg the question.) [If I sound like I'm calling an awful lot of gambits "question-begging," it's because the mind/body problem is devilishly subtle, and the temptation to capitulate by slipping consciousness back into one's premises is always there. I'm just trying to make these potential pitfalls conscious... There have been postings in this discussion to which I have given up on replying because they've fallen so deeply into these pits.] > What fraction of a neuron (or of its functionality) > is required for consciousness is below the resolving power of my > instruments, but I suggest that memory (influenced by external > conditions) or learning is required. I will even grant a bit of > consciousness to a flip-flop :-). > The consciousness only exists in situ, however: a > bit of memory is only part of an entity's consciousness if it is used > to interpret the entity's environment. What instruments are you using? I know only the TTT. You (like Minsky and others) are placing a lot of faith in "memory" and "learning." But we already have systems that have remember and learn, and the whole point of this discussion concerns whether and why this is sufficient to justify interpreting them as conscious. To reply that it's again a matter of degree is again to obfuscate. [The only "natural" threshold is the TTT, and that's not just a cognitive increment in learning/memory, but complete functional robotics. And of course even that is merely a functional goal for the theorist and an intuitive sop for the amateur (who is doing informal turing testing). The philosopher knows that it's no solution to the other-minds problem.] What you say about flip-flops of course again prejudges or begs the question. > Fortunately, I don't have my heart set on creating conscious systems. > I will settle for creating intelligent ones, or even systems that are > just a little less unintelligent than the current crop. If I'm right, this is the ONLY way to converge on a system that passes the TTT (and therefore might be conscious). The modeling must be ambitious, taking on increasingly life-size chunks of organisms' performance capacity (a more concrete and specific concept than "intelligence"). But attempting to model conscious phenomenology, or interpreting toy performance and its underlying function as if it were doing so, can only retard and mask progress. Methodological Epiphenomenalism. -- Stevan Harnad (609) - 921 7771 {allegra, bellcore, seismo, rutgers, packard} !princeton!mind!harnad harnad%mind@princeton.csnet
colonel@sunybcs.UUCP (01/26/87)
> ... It is a way for bodily tissues to get the attention > of the reasoning centers. Instead of just setting some "damaged > tooth" bit, the injured nerve grabs the brain by the lapels and says > "I'm going to make life miserable for you until you solve my problem." This metaphor seems to suggest that consciousness wars with itself. I would prefer to say that the body grabs the brain by the handles, like a hedge clipper or a geiger counter. In other words, just treat the mind as a tool, without any personality of its own. After all, it's the body that is real; the mind is only an abstraction. By the way, it's well known that if the brain has a twist in it, it needs only one handle. Ask any topologist! -- Col. G. L. Sicherman UU: ...{rocksvax|decvax}!sunybcs!colonel CS: colonel@buffalo-cs BI: colonel@sunybcs, csdsiche@ubvms
mmt@dciem.UUCP (Martin Taylor) (01/27/87)
> To telescope the intuitive sense >of the rebuttals: Do you believe rooms or corporations feel pain, as >we do? That final comma is crucial. Of course they do not feel pain as we do, but they might feel pain, as we do. On what grounds do you require proof that something has consciousness, rather than proof that it has not? Can there be grounds other than prejudice (i.e. prior judgment that consciousness in non-humans is overwhelmingly unlikely?). As I understand the Total Turing Test, the objective is to find whether soemthing can be distinguished from human, but this again prejudges the issue. I don't think one CAN use the TTT to assess whether another entity is conscious. As I have tried to say in a posting that may or may not get to mod.ai, Okham's razor demands that we describe the world using the simplest possible hypotheses, INCLUDING the boundary conditions, which involve our prior conceptions. It seems to me simpler to ascribe consciousness to an entity that resembles me in many ways than not to ascribe consciousness to that entity. Humans have very many points of resemblance; comatose humans fewer. Silicon-based entities have few overt points of resemblance, so their behaviour has to be convincingly like mine before I will grant them a consciousness like mine. I don't really care whether their behaviour is like yours, if you don't have consciousness, and as Steve Harnad has so often said, mine is the only consciousness I can be sure of. The problem splits in two ways: (1) Define consciousness so that it does not involve a reference to me, or (2) Find a way of describing behaviour that is simpler than ascribing consciousness to me alone. Only if you can fulfil one of these conditions can there be a sensible argument about the consciousness of some entity other than ME. -- Martin Taylor {allegra,linus,ihnp4,floyd,ubc-vision}!utzoo!dciem!mmt {uw-beaver,qucis,watmath}!utcsri!dciem!mmt
rjf@ukc.UUCP (01/28/87)
In article <2093@sunybcs.UUCP> colonel@sunybcs.UUCP (Col. G. L. Sicherman) writes: [...] >After all, it's the body that is real; the mind is only an abstraction. So abstractions ain't real, huh? Does that mean I'm only imagining all this high level programming? Don't worry about it - maybe this is all just your imagination. -- Robin Faichney ("My employers don't know anything about this.") UUCP: ...mcvax!ukc!rjf Post: RJ Faichney, Computing Laboratory, JANET: rjf@uk.ac.ukc The University, Canterbury, Phone: 0227 66822 Ext 7681 Kent. CT2 7NF
harnad@mind.UUCP (01/30/87)
mmt@dciem.UUCP (Martin Taylor) of D.C.I.E.M., Toronto, Canada, writes: > Of course [rooms and corporations] do not feel pain as we do, > but they might feel pain, as we do. The solution is not in the punctuation, I'm afraid. Pain is just an example standing in for whether the candidate experiences anything AT ALL. It doesn't matter WHAT a candidate feels, but THAT it feels, for it to be conscious. > On what grounds do you require proof that something has consciousness, > rather than proof that it has not? Can there be grounds other than > prejudice (i.e. prior judgment that consciousness in non-humans is > overwhelmingly unlikely?). First, none of this has anything to do with proof. We're trying to make empirical inferences here, not mathematical deductions. Second, even as empirical evidence, the Total Turing Test (TTT) is not evidential in the usual way, because of the mind/body problem (private vs. public events; objective vs. subjective inferences). Third, the natural null hypothesis seems to be that an object is NOT conscious, pending evidence to the contrary, just as the natural null hypothesis is that an object is, say, not alive, radioactive or massless until shown otherwise. -- Yes, the grounds for the null hypothesis are that the presence of consciousness is more likely than its absence; the alternative is animism. But no, the complement to the set of probably-conscious entities is not "non-human," because animals are (at least to me) just about as likely to be conscious as other humans are (although one's intuitions get weaker down the phylogenetic scale); the complement is "inanimate." All of these are quite natural and readily defensible default assumptions rather than prejudices. > [i] Occam's razor demands that we describe the world using the simplest > possible hypotheses. > [ii] It seems to me simpler to ascribe consciousness to an entity that > resembles me in many ways than not to ascribe consciousness to that > entity. > [iii] I don't think one CAN use the TTT to assess whether another > entity is conscious. > [iv] Silicon-based entities have few overt points of resemblance, > so their behaviour has to be convincingly like mine before I will > grant them a consciousness like mine. {i} Why do you think animism is simpler than its alternative? {ii} Everything resembles everything else in an infinite number of ways; the problem is sorting out which of the similarities is relevant. {iii} The Total Turing Test (a variant of my own devise, not to be confused with the classical turing test -- see prior chapters in these discussions) is the only relevant criterion that has so far been proposed and defended. Similarities of appearance are obvious nonstarters, including the "appearance" of the nervous system to untutored inspection. Similarities of "function," on the other hand, are moot, pending the empirical outcome of the investigation of what functions will successfully generate what performances (the TTT). {iv} [iv] seems to be in contradiction with [iii]. > The problem splits in two ways: (1) Define consciousness so that it does > not involve a reference to me, or (2) Find a way of describing behaviour > that is simpler than ascribing consciousness to me alone. Only if you > can fulfil one of these conditions can there be a sensible argument > about the consciousness of some entity other than ME. It never ceases to amaze me how many people think this problem is one that is to be solved by "definition." To redefine consciousness as something non-subjective is not to solve the problem but to beg the question. [The TTT, by the way, I proposed as logically the strongest (objective) evidence for inferring consciousness in entities other than oneself; it also seems to be the only methodologically defensible evidence; it's what all other (objective) evidence must ultimately be validated against; moreover, it's already what we use in contending with the other-minds problem intuitively every day. Yet the TTT remains more fallible than conventional inferential hypotheses (let alone proof) because it is really only a pragmatic conjecture rather than a "solution." It's only good up to turing-indistinguishability, which is good enough for the rest of objective empirical science, but not good enough to handle the problem of subjectivity -- otherwise known as the mind/body problem.] -- Stevan Harnad (609) - 921 7771 {allegra, bellcore, seismo, rutgers, packard} !princeton!mind!harnad harnad%mind@princeton.csnet
mmt@dciem.UUCP (Martin Taylor) (02/03/87)
>> = Martin Taylor (me) > = Steven Harnad > >> Of course [rooms and corporations] do not feel pain as we do, >> but they might feel pain, as we do. > >The solution is not in the punctuation, I'm afraid. Pain is just an >example standing in for whether the candidate experiences anything AT >ALL. It doesn't matter WHAT a candidate feels, but THAT it feels, for >it to be conscious. Understood. Nevertheless, the punctuation IS important, for although it is most unlikely they feel as we do, it is less unlikely that they feel. > >> [i] Occam's razor demands that we describe the world using the simplest >> possible hypotheses. >> [ii] It seems to me simpler to ascribe consciousness to an entity that >> resembles me in many ways than not to ascribe consciousness to that >> entity. >> [iii] I don't think one CAN use the TTT to assess whether another >> entity is conscious. >> [iv] Silicon-based entities have few overt points of resemblance, >> so their behaviour has to be convincingly like mine before I will >> grant them a consciousness like mine. > >{i} Why do you think animism is simpler than its alternative? Because of [ii]. >{ii} Everything resembles everything else in an infinite number of >ways; the problem is sorting out which of the similarities is relevant. Absolutely. Watanabe's Theorem of the Ugly Duckling applies. The distinctions (and similarities) we deem important are no more or less real than the infinity of ones that we ignore. Nevertheless, we DO see some things as more alike than other things, because we see some similarities (and some differences) as more important than others. In the matter of consciousness, I KNOW (no counterargument possible) that I am conscious, Ken Laws knows he is conscious, Steve Harnad knows he is conscious. I don't know this of Ken or Steve, but their output on a computer terminal is enough like mine for me to presume by that similarity that they are human. By Occam's razor, in the absence of evidence to the contrary, I am forced to believe that most humans work the way I do. Therefore it is simpler to presume that Ken and Steve experience consciousness than that they work according to one set of natural laws, and I, alone of all the world, conform to another. >{iii} The Total Turing Test (a variant of my own devise, not to be >confused with the classical turing test -- see prior chapters in these >discussions) is the only relevant criterion that has so far been >proposed and defended. Similarities of appearance are obvious >nonstarters, including the "appearance" of the nervous system to >untutored inspection. Similarities of "function," on the other hand, >are moot, pending the empirical outcome of the investigation of what >functions will successfully generate what performances (the TTT). All the TTT does, unless I have it very wrong, is provide a large set of similarities which, taken together, force the conclusion that the tested entity is LIKE ME, in the sense of [i] and [ii]. >{iv} [iv] seems to be in contradiction with [iii]. Not at all. What I meant was that the biological mechanisms of natural life follow (by Occam's razor) the same rules in me as in dogs or fish, and that I therefore need less information about their function than I would for a silicon entity before I would treat one as conscious. One of the paradoxes of AI has been that as soon as a mechanism is described, the behaviour suddenly becomes "not intelligent." The same is true, with more force, for consciousness. In my theory about another entity that looks and behaves like me, Occam's razor says I should presume consciousness as a component of their functioning. If I have been told the principles by which an entity functions, and those principles are adequate to describe the behaviour I observe, Occam's razor (in its original form "Entities should not needlessly be multiplied") says that I should NOT introduce the additional concept of consciousness. For the time being, all silicon entities function by principles that are well enough understood that the extra concept of consciousness is not required. Maybe this will change. > >> The problem splits in two ways: (1) Define consciousness so that it does >> not involve a reference to me, or (2) Find a way of describing behaviour >> that is simpler than ascribing consciousness to me alone. Only if you >> can fulfil one of these conditions can there be a sensible argument >> about the consciousness of some entity other than ME. > >It never ceases to amaze me how many people think this problem is one >that is to be solved by "definition." To redefine consciousness as >something non-subjective is not to solve the problem but to beg the >question. > I don't see how you can determine whether something is conscious without defining what consciousness is. Usually it is done by self-reference. "I experience, therefore I am conscious." Does he/she/it experience? But never is it prescribed what experience means. Hence I do maintain that the first problem is that of definition. But I never suggested that the problem is solved by definition. Definition merely makes the subject less slippery, so that someone who claims an answer can't be refuted by another who says "that wasn't what I meant at all." The second part of my split attempts to avoid the conclusion from similarity that beings like me function like me. If a simpler description of the world can be found, then I no longer should ascribe consciousness to others, whether human or not. Now, I believe that better descriptions CAN be found for beings as different from me as fish or bacteria or computers. I do not therefore deny or affirm that they have experiences. (In fact, despite Harnad, I rather like Ken Law's (?) proposition that there is a graded quality of experience, rather than an all-or-none choice). What I do argue is that I have better grounds for not treating these entities as conscious than I do for more human-like entities. Harnad says that we are not looking for a mathematical proof, which is true. But most of his postings demand that we show the NEED for assuming consciousness in an entity, which is empirically the same thing as proving them to be conscious. -- Martin Taylor {allegra,linus,ihnp4,floyd,ubc-vision}!utzoo!dciem!mmt {uw-beaver,qucis,watmath}!utcsri!dciem!mmt
harnad@mind.UUCP (02/03/87)
mmt@dciem.UUCP (Martin Taylor) writes: > we DO see some things as more alike than other things, because > we see some similarities (and some differences) as more important > than others. The scientific version of the other-minds problem -- the one we deal with in the lab and at the theoretical bench, as opposed to the informal version of the other-minds problem we practice with one another every day -- requires us to investigate what causal devices have minds, and, in particular, what functional properties of those causal devices are responsible for their having minds. In other words (unless you know the answer to the theoretical problems of cognitive science and neurosience a priori) it is an EMPIRICAL question what the relevant underlying functional and structural similarities are. The only defensible prior criterion of similarity we have cannot be functional or structural, since we don't know anything about that yet; it can only be the frail, fallible, underdetermined one we use already in everyday life, namely, behavioral similarity. Every other similarity is, in this state of ignorance, arbitrary, a mere similarity of superficial appearance. (And that INCLUDES the similarity of the nervous system, because we do not yet have the vaguest idea what the relevant properties there are either.) Will this state of affairs ever change? (Will we ever find similarities other than behavioral ones on the basis of which we can infer consciousness?) I argue that it will not change. For any other correlate of consciousness must be VALIDATED against the behavioral criterion. Hence the relevant functional similarities we eventually discover will always have to be grounded in the behavioral ones. Their predictive power will always be derivative. And finally, since the behavioral-indistinguishability criterion is itself abundantly fallible -- incommensurably moreso than ordinary scientific inferences and their inductive risks -- our whole objective structure will be hanging on a skyhook, so to speak, always turing indistinguishable from state of affairs in which everything behaves exactly the same way, but the similarities are all deceiving, and consciousness is not present at all. The devices merely behave exactly as if it were. Throughout the response, by the way, Taylor freely interchanges the formal scientific problem of modeling mind -- inferring its substrates, and hence trying to judge what functional conditions are validly inferred to be conscious (what the relevant similarities are) -- with the informal problem of judging who else in our everyday world is conscious. Similarities of superficial appearance may be good enough when you're just trying to get by in the world, and you don't have the burden of inferring causal substrate, but it won't do any good with the hard cases you have to judge in the lab. And in the end, even real-world judgments are grounded in behavioral similarity (indistinguishability) rather than something else. > it is simpler to presume that Ken and Steve experience > consciousness than that they work according to one set of > natural laws, and I, alone of all the world, conform to another. Here's an example of conflating the informal and the empirical problems. Informally, we just want to make sure we're interacting with thinking/feeling people, not insentient robots. In the lab, we have to find out what the "natural laws" are that generate the former and not the latter. (Your criterion for ascribing consciousness to Ken and me, by the way, was a turing criterion...) > All the TTT does, unless I have it very wrong, is provide a large set of > similarities which, taken together, force the conclusion that the tested > entity is LIKE ME The Total Turing Test simply requires that the performance capacity of a candidate that I infer to have a mind be indistinguishable from the performance capacity of a real person. That's behavioral similarity only. When a device passes that test, we are entitled to infer that its functional substrate is also relevantly similar to our own. But that inference is secondary and derivative, depending for its validation entirely on the behavioral similarities. > If a simpler description of the world can be found, then I no > longer should ascribe consciousness to others, whether human or not. I can't imagine a description sufficiently simple to make solipsism convincing. Hence even the informal other-minds problem is not settled by "Occam's Razor." Parsimony is a constraint on empirical inference, not on our everyday, intuitive and practical judgements, which are often not only uneconomical, but irrational, and irresistible. > What I do argue is that I have better grounds for not treating > these [animals and machines] as conscious than I do for more > human-like entities. That may be good enough for everyday practical and perhaps ethical judgments. (I happen to think that it's extremely wrong to treat animals inhumanely.) I agree that our intuitions about the minds of animals are marginally weaker than about the minds of other people, and that these intuitions get rapidly weaker still as we go down the phylogenetic scale. I also haven't much more doubt that present-day artificial devices lack minds than that stones lack minds. But none of this helps in the lab, or in the principled attempt to say what functions DO give rise to minds, and how. > Harnad says that we are not looking for a mathematical proof, which is > true. But most of his postings demand that we show the NEED for assuming > consciousness in an entity, which is empirically the same thing as > proving them to be conscious. No. I argue for methodological epiphenomenalism for three reasons only: (1) Wrestling with an insoluble problem is futile. (2) Gussying up trivial performance models with conscious interpretations gives the appearance of having accomplished more than one has; it is self-deceptive and distracts from the real goal, which is a performance goal. (3) Focusing on trying to capture subjective phenomenology rather than objective performance leads to subjectively gratifying analogy, metaphor and hermeneutics instead of to objectively stronger performance models. Hence when I challenge a triumphant mentalist interpretation of a process, function or performance and ask why it wouldn't function exactly the same way without the consciousness, I am simply trying to show up theoretical vacuity for what it is. I promise to stop asking that question when someone designs a device that passes the TTT, because then there's nothing objective left to do, and an orgy of interpretation can no longer do any harm. -- Stevan Harnad (609) - 921 7771 {allegra, bellcore, seismo, rutgers, packard} !princeton!mind!harnad harnad%mind@princeton.csnet