On 7 September 2017 at 10:03, Bruno Marchal <marc...@ulb.ac.be> wrote:
> > On 06 Sep 2017, at 19:45, Brent Meeker wrote: > > > > On 9/6/2017 7:35 AM, Bruno Marchal wrote: > > Some physicists can be immaterialist, but still believe that the > fundamental reality is physical, a bit like Tegmark who remains (despite he > is willing to think differently) open to the idea that the physical reality > is a special mathematical structure among all mathematical structures, for > example. That is problematical for pure mathematical reason: the notion of > all mathematical structures do not make much mathematical sense, but it is > of course problematic also with Mechanism, where the physical reality > becomes the border of the whole "computable mathematics" (which is very > tiny, as it is the tiny sigma_1 part of arithmetic). > > > I think Tegmark has changed his opinion and now only champions all > *computable* universes. > > > Yes. The problem now, is that there are no computable physical universes. > Here he miss the first person indeterminacy in arithmetic. He miss that any > universal machine looking below its substitution level is confronted to its > infinity of implementations in arithmetic. In fact, he remains somehow > physicalist, and does not seem aware of the computationalist mind-body > problem. > ​Yes, it's quite surprising how elusive this absence of universes seems to be in the context of mechanism. Old presuppositions seemingly die very hard. Another elusive point is what Chalmers is getting at with what he calls the Paradox of Phenomenal Judgement​. This is the problem of how what one might call an 'extensional infrastructure' and any corresponding phenomenal reality are seemingly able to 'refer' to each other. It's a big fly in the ointment of physicalist theories of mind like panpsychism, although it seems to be exceedingly difficult to point this out to panpsychists in my experience. For example, if we consider a movie being rendered on an LCD screen, nobody imagines that either the pixels comprising the screen, or the action of the movie tracked or carried by those pixels, either do, or in any way need to, refer to each other. They are, in a sense, mutual epiphenomena. However, my own utterances or judgements - standing in a general way for the 'extensional infrastructure' of my perceptions - and those perceptions themselves, do indeed seem to need to cross-refer. It's this cross-reference that is alluded to in Bp and p. I've been thinking about how this might play out very generally in terms of the coincidence or intersection of action and perception as generalisations of B and p. As you say, we assume at the outset a knower in the guise of the universal or generic machine (i.e. a number playing the role of 'processor' with respect to another number). The computational duals enacted by such machines are then projected to be elaborated to the point where they are tracking or carrying the state changes of an extensional infrastructure equivalent to a brain, at whatever level turns out to be necessary for its stable emergence. When I say 'equivalent to' I mean that this is what will appear, from the phenomenal point-of-view of a knower, to be a brain. Such state changes must, by assumption in some general but relevant sense, be equivalent to what you call beliefs, or what Dennett calls judgements, about perception. As in when I utter something like "I see a red apple", or for that matter "I feel strongly about the current state of American politics". At this point, in order for us to persevere with the schema, we grant that the p, heretofore provisionally referred to as true or real by Bp in these cases, is that selfsame phenomenal reality referred to by 'and p'. In doing this, we also grant retrospective validity, or redemption, to the entire Wittgenstein ladder of logical paraphernalia, emulated in computation, that we had been ascending for just this purpose. The question arises as to the 'substitution level' for all this. All universal machines, and consequently all potential knowers, are formally equivalent. Consequently we cannot know which of an infinity of such machines is immediately associated with any given moment of our phenomenal reality. However, the 'yes doctor' assumption is that at some level the computations that track or carry the formal equivalent of a brain must be substitutable by a suitable digital prosthesis, at least in principle. At the very least, we must assume that an atom-for-atom substitution of a physical brain, as presumably occurs naturally through time, would preserve phenomenal reality without significant error. The question also arises as to the possibility of a tractable 'search function' for anything corresponding to the above states of affairs within the Babel-like infinities of the computational plenum. No such function can be both tractable and extrinsic. We are relying here on filtration by internal self-identification; this is (obviously, I would suggest) not a bug, but a feature. The observed robustness and tightness of constraint on the 'extensional' component thus isolated would also seem to render both Bp and p in a certain sense as 'canonical' of their type. These two considerations in tandem are extremely suggestive of a step-change in explanatory style and stand in stark contrast to the situation with the alphabetic Library of Babel which lacks both of them and is consequently intractable and haphazard in the extreme. David > Bruno > > > > > > Brent > > -- > 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 https://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/d/optout. > > > http://iridia.ulb.ac.be/~marchal/ > > > > -- > 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 https://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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