On Saturday, August 9, 2014 2:48:48 PM UTC+10, Brent wrote: > > On 8/8/2014 8:34 PM, Pierz wrote: > > In "The Conscious Mind", Chalmers bases his claim that materialism has > failed to provide an explanation for consciousness on a distinction between > 'logical' and 'natural' supervenience, where logical supervenience simply > means that if A supervenes on B, then B logically and necessarily entails > A. > > Because we can logically conceive of a (philosophical) zombie, then it > seems that consciousness cannot *logically* supervene on the physical. > > > This kind of argument is very weak. "Logically" anything can be true that > doesn't entail "x and not-x", i.e. direct contradiction. When a > philosopher slips in "can logically conceive", it is the "conceive" that > does all the work. No one could "logically conceive" of particles that were > two places at once, or became correlated by future instead of past > interactions - until quantum mechanics was invented. It's at base an > argument from incredulity. >
I agree - partially. The devil is in the detail. Chalmers asks whether one can "logically conceive" of a universe in which mathematicians disprove (something like) the fact that there are infinite primes. He claims such a world is not logically conceivable, but only one in which mathematicians are wrong. But this illustrates the problem. The more complex a scenario becomes, the more difficult it is to say whether it is logically possible. For example, I can conceive of a people living in a world with four extended spatial dimensions, but it may well be that such a scenario is logically impossible, due to the fact that no self-consistent set of physical laws can describe it. But who can be sure? Perhaps everything logically conceivable happens. Some physicists such as Tegmark would seem to believe so. However I'm not sure that your objection has it the right way round. Usually it's the philosophers arguing for the logical possibility of something against objectors who finds it inconceivable for mistaken reasons such as "common sense". So the argument from incredulity usually goes in the reverse direction to what you're suggesting. With respect to the problem of zombies though, he's pointing out that **within the definitions given** of what matter is, within the current understanding of matter's properties, the philosophical zombie is extremely conceivable, and in fact is exactly what the model could be said to predict. It's just that we happen to know first-hand that prediction to be wrong. > > There is simply nothing in the physical description that entails or even > *suggests* the arising of subjective experiences in any system, > biological or otherwise. This is a well-trodden path of argumentation that > I'm sure we're all familiar with. However, since it does appear that, > empirically, consciousness supervenes on physical processes, then this > supervenience must be "natural" rather than logical. > > > I agree. > > It must arise due to some natural law that demands it does. So far so > good, though what we end up with in Chalmers' book - "property dualism" - > hardly seems like the nourishing meal a phenomenologically inclined > philosopher might have hoped for. Bruno's version of comp seems like more > nourishing fare than the the watery gruel of property dualism, but > Chalmers' formulation of logical supervenience got me thinking again about > the grit in the ointment of comp that I've never quite been able to get > comfortable with. This is only another way of formulating an objection that > I've raised before, but perhaps it encapsulates the issue neatly. We can > really only say we've "explained" something when explicated the > relationships between the higher order explanandum and some ontologically > prior basis, demonstrating how the latter necessarily entails the former. > Alternatively we might postulate some new "brute fact", some hitherto > unknown principle, law or entity which we accept because it does such a > good job of uniting disparate, previously unexplained observations. > > Now the UDA does a good job of making the case that if we accept the > premise of comp (supervenience on computational states), then materialism > can be seen to dissolve into "machine psychology" as Bruno puts it, or to > emerge from arithmetic. But the problem here is that we can no more see > mathematical functions as necessarily entailing subjective experience as we > can see physical entities as doing so. It is perfectly possible to imagine > computations occurring in the complete absence of consciousness, and in > fact nearly everybody imagines precisely this. I would say that it is an > undeniable fact that no mathematical function can be said to* logically > entail *some correlated conscious state. Rather, we must postulate some > kind of law or principle which claims that it is just so that mathematical > functions, or certain classes thereof, co-occur with or are somehow > synonymous with, conscious experiences. In other words, we are still forced > back on a kind of natural supervenience. But the problem here is that, > whereas with matter we may be able to invoke some kind of ontological > 'magic' that "puts the fire into the equations" to quote Hawking, with pure > mathematics it is hard to see how there can be any such natural law that is > distinct from pure logic itself. > > > I think the way to look at it, is to ask how and why evolution invented > consciousness. It's pretty clear that not *all* computation produces > consciousness. So what is it about the computation in human brains that > produces consciousness. I speculate that it's because it's computation > that is about something. It's computation that is representing, reflecting > on and predicting the world. That world is perceived by our sensory > systems and evolution built this representational system on top of the > sensory system. So when we recall something we experience images of it. > When we think about playing some music we experience sounds. It has been > my reservation about Bruno's step 8 that he considers a dream state in > order to avoid the question of it's relation to the world, to being about > something. I think the world, which Bruno calls physics, is necessary as > the object of consciousness. > Yeah and I don't get that and I don't think it's tenable. A computer being fed data from a camera and responding to it doesn't "know" the data is "about" anything. If it were being fed data from a mathematical function being run on another machine would it become unconscious again? "Man, stop feeding me that mathematical data, it makes me black out something shocking!" Data is data. If it's real world data it will tend to manifest certain complex regularities reflecting the mathematical structure of the world, but it's all just patterns. If you're going to stick with this argument you need to be more rigorous about it and not just lazily rely on your intuition. How specifically does the computer distinguish computation about something from computation about ... what? nothing? Why does processing data that is correlated with the physical world make a computer conscious? How could the machine distinguish between simulator data and real data? And if simulator data is OK, what exactly is data that is not OK? Please convince me, but right now I see no reason to take the idea seriously at all. > > > Now when I've put this objection to Bruno in the past in slightly > different words, claiming that it is hard to see any way to reconcile the > language of mathematics with the language of qualia, Bruno has invoked > Gödel to claim that mathematics is more than mere formalism, that it > embodies a transcendent Truth that is beyond that which can be captured in > any mathematical formulation. At least, that is the best summary I can make > of my understanding of his reply. He also claims to have discovered the > 'placeholder' for qualia within the mathematics of Löbian machines: the gap > between statements which the machine knows to be true and those which the > machine knows to be true and can prove to be so. It's a fascinating > argument, but it seems at the very least incomplete. The fact that a > machine making self-referentially correct statements will be able to assert > some (true) things without being able to prove them does not compel me in > any way to believe that such a machine will have a conscious experience of > some particular phenomenal quality. It may be true that correct statements > about qualia are correct statements which can't be proven, but this does > not mean that statements about qualia are statements about unprovable > mathematical propositions. I might claim that Chaitin's constant is > 0.994754987543925216... and it might just happen that I'm right, through > divine inspiration, but Chaitin's constant is not a quale of mine. Bruno > can point to this space in his formalism to say "that's where the qualia > fit", but there is a similar leap of faith involved to actually put them > there as we make when attributing qualia to emergence from neurology. > > Gödel's theorem might show that mathematics is more than mere formalism, > but it does not allow us to make the leap to mathematics being more than > abstract relationships between numbers. There will always be some true, > unprovable statement in any set of axioms, but this statement will still be > about numbers, not about feelings. If we start to say mathematics is more > than that, we are making a metaphysical, and indeed mystical claim, and I > believe we have also expanded mathematics to become something else, > something that we can no longer truly claim to be maths as that is usually > understood. > > Now of course the "gap" between the maths and the qualia (I don't like > the obfuscating and often confused language of Craig's posts, but I think > "Gödel of the gaps" is a pretty good turn of phrase, if indeed he is > pointing to the same thing as me) is actually imported into comp with the > initial assumption of qualia supervening on computational states. That > postulate is of course unexplained, mystifying and, when taken to its > logical end as Bruno has done, mystical. But when all is said and done, > we're still left with it as a "brute fact", if anything more naked than it > was at the beginning of the argument. More naked because it is even less > clear how we are going to get a natural law to bridge the gap between the > putative ontological basis of consciousness and consciousness itself when > that basis is pure mathematics. > > > That doesn't bother me as much. If you look back how we have explained > gravity, electromagnetism, atoms, thermodynamics,all that hard science that > is held up as the paradigm of explanation, you see that at bottom is just > precise, predictive description. John von Neumann said, "The sciences do > not try to explain, they hardly even try to interpret, they mainly make > models. By a model is meant a mathematical construct which, with the > addition of certain verbal interpretations, describes observed phenomena. > The justification of such a mathematical construct is solely and precisely > that it is expected to work." That's why I think that the "hard problem > of consciousness" is hard because people think that when we have a theory > that works we still won't have an explanation - but we will, just as good > and bad explanation as we have for gravity and electromagnetism. > > Deutsch would heartily disagree with von Neumann. He says that explain is exactly what the sciences try to do. But sure, the explanation may at first sound preposterous and there's always something left unexplained by it (the incompletion). Maybe the problem is purely the habitual way we've thought of maths as being in the mind and distinct from nature, so adding what seems to be a kind of natural law to it, the idea that it also has an interior with qualities, seems, well, unnatural. I find this whole area in the category of "hard to think about". > > After all, what is mathematics? If it includes all consciousness, is > inseparable from it, if it encompasses love, pain, the smell of rain, and > everything else it is possible to experience, then we are really talking > about the mind as a whole, and the claim of a reduction to arithmetic > starts to look at the very least misleading. Arithmetic is just the sugar > coating that gives the rationalist a better chance of swallowing the > psychedelic pill. > > > Bruno seems to be able to make arithmetic pretty mystical - calling parts > of it angels and God. :-) > > Brent > "The duty of abstract mathematics, as I see it, is precisely to > expand our capacity for hypothesizing possible ontologies." > --- Norm Levitt > > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. 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