5 ms·

Moreover, it must be confessed that perception and that which depends upon it are inexplicable on mechanical grounds, that is to say, by means of figures and mo

by ugh 15y ago

Moreover, it must be confessed that perception and that which depends upon it are inexplicable on mechanical grounds, that is to say, by means of figures and motions. And supposing there were a machine, so constructed as to think, feel, and have perception, it might be conceived as increased in size, while keeping the same proportions, so that one might go into it as into a mill. That being so, we should, on examining its interior, find only parts which work one upon another, and never anything by which to explain a perception. That seems like too big of a leap. Why can't "parts which work one upon another" not create perception? Is this assumption justified? (I really hope the justification is not "because mills that perceive are self-evidently absurd". If it is then my next question is: Why?) If that assumption doesn't stand the rest of the argument falls flat. I would like to hear a bit more about why compound parts can't create perception. The brain certainly looks like it consists of compound parts. We obviously cannot (yet) explain consciousness so it is possible that it is impossible to create consciousness with compound parts, we just don't know. In that light Leibniz's argument seems unconvincing, at least as far as I can understand it.

ryanklee 15y ago
I believe that parent's point is precisely that it is indeed unconvincing and so we should in turn be mindful that our own idea that the brain is a computer will, it is possible, given further technological advances, come to strike us as just as unconvincing as Leibniz' argument. Metaphors of the brain follow along with the state of the arts of technologies. For the ancient Greeks, the human composition (they didn't talk yet of brains and consciousness) was the city-state; for early modern natural philosophers, the mill and the like; during the industrial revolution, machines; and now, with us, computers and computation. It is unlikely that our current analogy is any more or less true than previous ones, that is to say, they may be illuminating in some way and not entirely useless in our thinking about brains and consciousness, but as it goes, they are not and cannot be true because the conjectures cannot even in the end be shown to be wrong. Consciousness and the brain may not be in the end inexplicable, but I very much doubt that we will find that the brain and consciousness are something else other than the brain and consciousness, like, for instance, a mill or a computer. It would be the most surprising thing of all were we to find out that evolution produced a kind of technology before in fact that technology as a human tool was ever produced -- but that is a different argument and I'm not even sure what I mean by it.
- ckuehne 15y ago
  Your reasoning is wrong. There is a crucial difference between believing that a computer can simulate a brain and believing that a windmill can do so. That is, that a computer can, in principle, simulate mills as well as city-states and all the other objects you listed. "It would be the most surprising thing of all were we to find out that evolution produced a kind of technology before in fact that technology as a human tool was ever produced" Evolution has produced technologies long before humans invented them. For example, bats and whales use sonar, humans use lenses, plants use photosynthesis. In fact, one could argue evolution does not much else than to invent technologies.
  - ryanklee 15y ago
    "There is a crucial difference between believing that a computer can simulate a brain and believing that a windmill can do so." That depends entirely on what you think a brain is, and it just so happens that a prevalent view these days is that a brain is a computer, and so of course it follows very easily that a computer can simulate a brain. But once that assumption is gotten rid of, it doesn't follow so easily at all. People are ignoring a good lot of scientific method when they propose that were a computer to every simulate a brain the veracity of that simulation could ever be verified. The only data that could ever be provided would be a very limited set, namely, to the external behaviors. What would essentially be needed in the simulation, that is the production of consciousness, could never empirically tested. Consciousness as an object isn't even a scientific entity, it's something that can only be corroborated internal to the agent that has it. It isn't analyzable into parts and it isn't able to be abstracted out of its environment, and so cannot be turned into a scientific object. The brain, on the other hand, we might suppose is an object fitted to empirical methods, but what people really want to get at is consciousness, and the brain without that is probably not the problem most people have in mind. So one could simulate the brain but only on a very restricted very of what a brain is. On the other hand, on second thought I do agree with you that evolution produces technologies and even maybe that that's all evolution has ever done. I'm afraid I'll have to think about that point more if I am to respond to it specifically, though I think it's tangential to the rest of the argument I am trying to make above (which is admittedly sketchy).
pygy_ 15y ago
> We obviously cannot (yet) explain consciousness so it is possible that it is impossible to create consciousness with compound parts, we just don't know. Giulio Tononi's Integrated Information Theory of Consciousness addresses this very notion, and it seems to fit neuroscientific observations quite well. --- Consciousness as Integrated Information: a Provisional Manifesto [1] --Giulio Tononi Abstract: The integrated information theory (IIT) starts from phenomenology and makes use of thought experiments to claim that consciousness is integrated information. Speciﬁcally: (i) the quantity of consciousness corresponds to the amount of integrated information generated by a complex of elements; (ii) the quality of experience is speciﬁed by the set of informational relationships generated within that complex. Integrated information (phi) is deﬁned as the amount of information generated by a complex of elements, above and beyond the information generated by its parts. Qualia space (Q) is a space where each axis represents a possible state of the complex, each point is a probability distribution of its states, and arrows between points represent the informational relationships among its elements generated by causal mechanisms (connections). Together, the set of informational relationships within a complex constitute a shape in Q that completely and univocally speciﬁes a particular experience. Several observations concerning the neural substrate of consciousness fall naturally into place within the IIT framework. Among them are the association of consciousness with certain neural systems rather than with others; the fact that neural processes underlying consciousness can inﬂuence or be inﬂuenced by neural processes that remain unconscious; the reduction of consciousness during dreamless sleep and generalized seizures; and the distinct role of different cortical architectures in affecting the quality of experience. Equating consciousness with integrated information carries several implications for our view of nature. --- Theoretical approaches to the diagnosis of altered states of consciousness [2] --Melanie Boly, Marcello Massimini and Giulio Tononi Fig. 1. legend: Information and integration are fundamental properties of conscious experience. (A) Information: the photodiode thought experiment. IITC states that consciousness is highly informative, because each conscious experience is implicitly discriminated by ruling out an inﬁnite number of other available alternatives. According to the theory, the more alternatives you can rule out, the more informative is your conscious experience, and the higher your level of consciousness. This concept is illustrated when comparing a photodiode, simple light-sensitive device to anyone of us (here Galileo Galilei, for the sake of the example), facing a blank screen. According to the theory, the key difference between us and the photodiode relies in the fact that when specifying ‘‘dark,’’ the photodiode discriminates between only two alternatives, while we discriminate it from a large repertoire of other available percepts. This difference affects the meaning of the discrimination performed, and the amount of information generated. (B) Integration: the camera thought experiment. By multiplying the number of photodiodes, like in the case of a camera, one can considerably increase the amount of information generated. The difference between us and the camera is that the information generated by each photodiode is not communicated to the whole system, that is, the information the systems generates is not integrated. This is reﬂected by the fact that if one would separate the camera in two parts with an inﬁnitely thin line, this would not impair its function, nor diminish the amount of information generated. If the same procedure is applied to the brain, this will result in a split in two independent consciousnesses, similarly to what is observed in split-brain patients. Integration of information allows to perform a single discrimination at the scale of the whole system, in order to generate a uniﬁed perception. --- A perturbational approach for evaluating the brain’s capacity for consciousness [3] --Marcello Massimini, , Melanie Boly , Adenauer Casali , Mario Rosanova and Giulio Tononi Abstract: How do we evaluate a brain’s capacity to sustain conscious experience if the subject does not manifest purposeful behaviour and does not respond to questions and commands? What should we measure in this case? An emerging idea in theoretical neuroscience is that what really matters for consciousness in the brain is not activity levels, access to sensory inputs or neural synchronization per se, but rather the ability of different areas of the thalamocortical system to interact causally with each other to form an integrated whole. In particular, the information integration theory of consciousness (IITC) argues that consciousness is integrated information and that the brain should be able to generate consciousness to the extent that it has a large repertoire of available states (information), yet it cannot be decomposed into a collection of causally independent subsystems (integration). To evaluate the ability to integrate information among distributed cortical regions, it may not be sufﬁcient to observe the brain in action. Instead, it is useful to employ a perturbational approach and examine to what extent different regions of the thalamocortical system can interact causally (integration) and produce speciﬁc responses (information). Thanks to a recently developed technique, transcranial magnetic stimulation and highdensity electroencephalography (TMS/hd-EEG), one can record the immediate reaction of the entire thalamocortical system to controlled perturbations of different cortical areas. In this chapter, using sleep as a model of unconsciousness, we show that TMS/hd-EEG can detect clear-cut changes in the ability of the thalamocortical system to integrate information when the level of consciousness ﬂuctuates across the sleep–wake cycle. Based on these results, we discuss the potential applications of this novel technique to evaluate objectively the brain’s capacity for consciousness at the bedside of brain-injured patients. --- [1] http://clm.utexas.edu/~compjc/papers/Tononi2008a.pdf http://clm.utexas.edu/~compjc/papers/Tononi2008a.pdf Very theoretical/mathematical [2] http://www.coma.ulg.ac.be/papers/vs/boly_PBR_coma_science_2009.pdf http://www.coma.ulg.ac.be/papers/vs/boly_PBR_coma_science_20... A more gentle introduction [3] http://www.coma.ulg.ac.be/papers/vs/massimini_PBR_coma_science_2009.pdf http://www.coma.ulg.ac.be/papers/vs/massimini_PBR_coma_scien...

by ugh 15y ago

ryanklee 15y ago

I believe that parent's point is precisely that it is indeed unconvincing and so we should in turn be mindful that our own idea that the brain is a computer will, it is possible, given further technological advances, come to strike us as just as unconvincing as Leibniz' argument. Metaphors of the brain follow along with the state of the arts of technologies. For the ancient Greeks, the human composition (they didn't talk yet of brains and consciousness) was the city-state; for early modern natural philosophers, the mill and the like; during the industrial revolution, machines; and now, with us, computers and computation. It is unlikely that our current analogy is any more or less true than previous ones, that is to say, they may be illuminating in some way and not entirely useless in our thinking about brains and consciousness, but as it goes, they are not and cannot be true because the conjectures cannot even in the end be shown to be wrong. Consciousness and the brain may not be in the end inexplicable, but I very much doubt that we will find that the brain and consciousness are something else other than the brain and consciousness, like, for instance, a mill or a computer. It would be the most surprising thing of all were we to find out that evolution produced a kind of technology before in fact that technology as a human tool was ever produced -- but that is a different argument and I'm not even sure what I mean by it.

ckuehne 15y ago
Your reasoning is wrong. There is a crucial difference between believing that a computer can simulate a brain and believing that a windmill can do so. That is, that a computer can, in principle, simulate mills as well as city-states and all the other objects you listed. "It would be the most surprising thing of all were we to find out that evolution produced a kind of technology before in fact that technology as a human tool was ever produced" Evolution has produced technologies long before humans invented them. For example, bats and whales use sonar, humans use lenses, plants use photosynthesis. In fact, one could argue evolution does not much else than to invent technologies.
- ryanklee 15y ago
  "There is a crucial difference between believing that a computer can simulate a brain and believing that a windmill can do so." That depends entirely on what you think a brain is, and it just so happens that a prevalent view these days is that a brain is a computer, and so of course it follows very easily that a computer can simulate a brain. But once that assumption is gotten rid of, it doesn't follow so easily at all. People are ignoring a good lot of scientific method when they propose that were a computer to every simulate a brain the veracity of that simulation could ever be verified. The only data that could ever be provided would be a very limited set, namely, to the external behaviors. What would essentially be needed in the simulation, that is the production of consciousness, could never empirically tested. Consciousness as an object isn't even a scientific entity, it's something that can only be corroborated internal to the agent that has it. It isn't analyzable into parts and it isn't able to be abstracted out of its environment, and so cannot be turned into a scientific object. The brain, on the other hand, we might suppose is an object fitted to empirical methods, but what people really want to get at is consciousness, and the brain without that is probably not the problem most people have in mind. So one could simulate the brain but only on a very restricted very of what a brain is. On the other hand, on second thought I do agree with you that evolution produces technologies and even maybe that that's all evolution has ever done. I'm afraid I'll have to think about that point more if I am to respond to it specifically, though I think it's tangential to the rest of the argument I am trying to make above (which is admittedly sketchy).

pygy_ 15y ago

> We obviously cannot (yet) explain consciousness so it is possible that it is impossible to create consciousness with compound parts, we just don't know. Giulio Tononi's Integrated Information Theory of Consciousness addresses this very notion, and it seems to fit neuroscientific observations quite well. --- Consciousness as Integrated Information: a Provisional Manifesto [1] --Giulio Tononi Abstract: The integrated information theory (IIT) starts from phenomenology and makes use of thought experiments to claim that consciousness is integrated information. Speciﬁcally: (i) the quantity of consciousness corresponds to the amount of integrated information generated by a complex of elements; (ii) the quality of experience is speciﬁed by the set of informational relationships generated within that complex. Integrated information (phi) is deﬁned as the amount of information generated by a complex of elements, above and beyond the information generated by its parts. Qualia space (Q) is a space where each axis represents a possible state of the complex, each point is a probability distribution of its states, and arrows between points represent the informational relationships among its elements generated by causal mechanisms (connections). Together, the set of informational relationships within a complex constitute a shape in Q that completely and univocally speciﬁes a particular experience. Several observations concerning the neural substrate of consciousness fall naturally into place within the IIT framework. Among them are the association of consciousness with certain neural systems rather than with others; the fact that neural processes underlying consciousness can inﬂuence or be inﬂuenced by neural processes that remain unconscious; the reduction of consciousness during dreamless sleep and generalized seizures; and the distinct role of different cortical architectures in affecting the quality of experience. Equating consciousness with integrated information carries several implications for our view of nature. --- Theoretical approaches to the diagnosis of altered states of consciousness [2] --Melanie Boly, Marcello Massimini and Giulio Tononi Fig. 1. legend: Information and integration are fundamental properties of conscious experience. (A) Information: the photodiode thought experiment. IITC states that consciousness is highly informative, because each conscious experience is implicitly discriminated by ruling out an inﬁnite number of other available alternatives. According to the theory, the more alternatives you can rule out, the more informative is your conscious experience, and the higher your level of consciousness. This concept is illustrated when comparing a photodiode, simple light-sensitive device to anyone of us (here Galileo Galilei, for the sake of the example), facing a blank screen. According to the theory, the key difference between us and the photodiode relies in the fact that when specifying ‘‘dark,’’ the photodiode discriminates between only two alternatives, while we discriminate it from a large repertoire of other available percepts. This difference affects the meaning of the discrimination performed, and the amount of information generated. (B) Integration: the camera thought experiment. By multiplying the number of photodiodes, like in the case of a camera, one can considerably increase the amount of information generated. The difference between us and the camera is that the information generated by each photodiode is not communicated to the whole system, that is, the information the systems generates is not integrated. This is reﬂected by the fact that if one would separate the camera in two parts with an inﬁnitely thin line, this would not impair its function, nor diminish the amount of information generated. If the same procedure is applied to the brain, this will result in a split in two independent consciousnesses, similarly to what is observed in split-brain patients. Integration of information allows to perform a single discrimination at the scale of the whole system, in order to generate a uniﬁed perception. --- A perturbational approach for evaluating the brain’s capacity for consciousness [3] --Marcello Massimini, , Melanie Boly , Adenauer Casali , Mario Rosanova and Giulio Tononi Abstract: How do we evaluate a brain’s capacity to sustain conscious experience if the subject does not manifest purposeful behaviour and does not respond to questions and commands? What should we measure in this case? An emerging idea in theoretical neuroscience is that what really matters for consciousness in the brain is not activity levels, access to sensory inputs or neural synchronization per se, but rather the ability of different areas of the thalamocortical system to interact causally with each other to form an integrated whole. In particular, the information integration theory of consciousness (IITC) argues that consciousness is integrated information and that the brain should be able to generate consciousness to the extent that it has a large repertoire of available states (information), yet it cannot be decomposed into a collection of causally independent subsystems (integration). To evaluate the ability to integrate information among distributed cortical regions, it may not be sufﬁcient to observe the brain in action. Instead, it is useful to employ a perturbational approach and examine to what extent different regions of the thalamocortical system can interact causally (integration) and produce speciﬁc responses (information). Thanks to a recently developed technique, transcranial magnetic stimulation and highdensity electroencephalography (TMS/hd-EEG), one can record the immediate reaction of the entire thalamocortical system to controlled perturbations of different cortical areas. In this chapter, using sleep as a model of unconsciousness, we show that TMS/hd-EEG can detect clear-cut changes in the ability of the thalamocortical system to integrate information when the level of consciousness ﬂuctuates across the sleep–wake cycle. Based on these results, we discuss the potential applications of this novel technique to evaluate objectively the brain’s capacity for consciousness at the bedside of brain-injured patients. --- [1] http://clm.utexas.edu/~compjc/papers/Tononi2008a.pdf http://clm.utexas.edu/~compjc/papers/Tononi2008a.pdf Very theoretical/mathematical [2] http://www.coma.ulg.ac.be/papers/vs/boly_PBR_coma_science_2009.pdf http://www.coma.ulg.ac.be/papers/vs/boly_PBR_coma_science_20... A more gentle introduction [3] http://www.coma.ulg.ac.be/papers/vs/massimini_PBR_coma_science_2009.pdf http://www.coma.ulg.ac.be/papers/vs/massimini_PBR_coma_scien...