On 19 January 2015 at 23:11, meekerdb <meeke...@verizon.net> wrote: On 1/19/2015 1:21 PM, David Nyman wrote: > > On 19 January 2015 at 20:42, meekerdb <meeke...@verizon.net> wrote: > > On 1/19/2015 9:31 AM, David Nyman wrote: >> >> On 19 January 2015 at 14:01, David Nyman <da...@davidnyman.com> wrote: >> >> But if zombies were *logically* impossible, as I believe Dennett for >>> example claims, then it would be analytically true, not a contingent fact. >> >> >> I'd like to amplify here a little in light of my longer response to you >> about comp and the Hard Problem. Dennett's public and oft-repeated position >> is that physics has primacy over (for example) computation or logic. In >> other words, he believes that before something can be deemed computational >> or logical, it must first be physical. My point is that, given this prior >> commitment, he actually has no basis for any claim that zombies are >> *logically* impossible unless they are first *physically* impossible. >> >> >> ?? Everything that exists must be physically possible is compatible with >> everything that exists must also be logically possible and most people >> think that nomologically possible is a subset of logically possible. So >> logically impossible implies physically impossible. I think you're >> confused about Dennett. >> > > I don't think you've taken my point. According to Dennett, at least as > I've always read him, everything that 'exists' must do so physically. This > position (which is an intrinsic part of what he calls his 'third-person > absolutism') has led him to his attempted wholesale substitution of > 'judgements' about consciousness (which can be cashed out physically) for > the supposed 'illusion' of consciousness. On this basis, nothing that is > physically impossible could exist (obviously). Hence, to show that zombies > could not possibly exist Dennett would have to convince us a priori that > they couldn't possibly exist *physically* - i.e. that they violate some > essential principle of physical explanation. > > > An essential principle of a physical explanation (or any explanation) is > that it not be self-contradictory, i.e. logically possible. Hence > logically impossible => physically impossible; at least that's the usual > sense. >
Sure, I agree. But Dennett's never attempted to show that zombies are logically impossible in that absolute sense. What he's actually tried to show is that they're *physically* impossible, as a consequence of his re-definition of 'consciousness' in purely behavioural (hence ultimately physical) terms. More below. > I don't assume that Dennett is right about showing a zombie is logically > impossible; I'm just saying that if he did it would also show it was > physically impossible. > Dennett's aim, based on everything of his I've read, has been to convince us (or, more often, bully us into conceding) that consciousness isn't actually anything other than its behavioural (i.e. ultimately physical) accompaniments. That's actually all he means by the 'logical impossibility' of zombies. If consciousness were conceded to be 'nothing but our judgements', then zombies would indeed be impossible. At least Dennett has been honest enough to admit to the prior commitment (i.e. the aforementioned third-person absolutism) that led him to adopt this extremal conclusion. Maybe you're saying that logically impossible doesn't imply physically > impossible because logic depends are presuppositions and interpretations of > words which always have the possibility of being wrong - which is true, but > are we really asking for certainty? > > My point is that this can't be done. There's nothing about physical > explanation that requires a conscious point of view > > That's assuming that Dennett is wrong. > What aspect of explanation, in terms of physical principles, requires the assumption of a conscious viewpoint? I except, in this regard, certain historical versions of the collapse hypothesis. I also exclude 'the fact that we are conscious', by the way, because that would be to beg the question (i.e. that physics 'causes' consciousness). > and consequently it doesn't harm a zombie's purely 'physical' status to > deny that it has one. > >> However, the fact is (as notoriously argued by Chalmers, for example) >> that we have precisely zero evidence that zombies are physically >> impossible. In point of fact they would appear to be physically >> *inevitable*, given that the system of physical relation appears (very >> convincingly) to be both causally sufficient and causally closed. >> >> Being causally closed would be an argument against libertarian free-will, >> but I don't see why it's an argument against consciousness. >> > > It's an argument against consciousness, as construed as something other > than its physical correlates, because nothing attributable to physical > explanation would ever lead us to believe a priori in the necessity of a > conscious point of view to what we are describing. > > I think you are mixing standards here. The "necessity" you ask for seems > to be logical necessity, which indeed will not be forthcoming from the > physics. > Not really. I simply mean that explanation in physical terms never entails the intervention of 'consciousness', other than in the guise of its putative physical correlates. That's why Dennett has tried so hard to re-define the meaning of the term to one that he trusts can ultimately be reduced, without loss, to physical process. But that's the wrong standard for physical explanation. You can only ask > for nomological explication. As Bruno likes to point out "necessity" is > always relative to some theory. Theories have unexplained parts (called > axioms or premises). Suppose the theory is that certain kinds of physical > processes instantiate consciousness. Of course stated so nakedly that's not > a very good theory. It's like saying some kind of computation instantiates > consciousness. Both need elaboration to see whether they imply anything > unexpected or interesting. > Agreed. We've already been around the block a few times on this topic :-) > But it's not fair to ask the physical theory to show logical necessity > anymore than to ask the computational theory to show physical necessity. > That is the relevance of the causal closure of the physical in this context. > > Consciousness may be one of the things caused. > Then it should be entirely observable, at least in principle. That's Dennett's position, essentially. He's actually gone out of his way to deny that thoughts are any more 'private' than anything else. I think that what you suggest inevitably leads to one or another exclusively 'public' re-definition of the term. David > > > Zombies would appear a priori to be the more obvious progeny of such a > system. Consequently we accept the fact of consciousness (if indeed we do) > as a brute a posteriori datum. > > David > > >> Brent >> >> The conjunction of this inconvenient fact with a prior commitment to >> physical naturalism often seems to result in a kind of cognitive >> dissonance. In Dennett's case this leads to a denial that consciousness can >> be distinguished from our 'judgements' about it (i.e. it is an 'illusion') >> which is superficially at least consistent, though ultimately >> self-defeating. Smolin's unwillingness to deny consciousness, by contrast, >> pushes him into frank inconsistency. >> >> We need something better than either of these positions. >> >> David >> -- >> 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 everything-list+unsubscr...@googlegroups.com. >> To post to this group, send email to everything-list@googlegroups.com. >> Visit this group at http://groups.google.com/group/everything-list. >> For more options, visit https://groups.google.com/d/optout. >> >> >> -- >> 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 everything-list+unsubscr...@googlegroups.com. >> To post to this group, send email to everything-list@googlegroups.com. >> Visit this group at http://groups.google.com/group/everything-list. >> For more options, visit https://groups.google.com/d/optout. >> > > -- > 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 everything-list+unsubscr...@googlegroups.com. > To post to this group, send email to everything-list@googlegroups.com. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/d/optout. > > > -- > 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 everything-list+unsubscr...@googlegroups.com. > To post to this group, send email to everything-list@googlegroups.com. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Everything List" group. 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