Re: Everything Physical is Based on Consciousness

From: Bruno Marchal <>
Date: Fri, 6 May 2005 17:48:42 +0200

Le 06-mai-05, à 17:20, Stathis Papaioannou a écrit :

> This is a wonderfully clear explanation of Bruno's UDA. Perhaps Bruno
> could confirm that it is what he intended.

Quite nice indeed, except one point. See below in Brian's message. It
*is* related to something we have already discussed.

> As for the observer - or more fundamentally, the observer-moment - I
> think you can get away without explicitly defining it. All you need is
> two assumptions:
> Firstly, you have to assume that observer-moments exist. I think it is
> pretty clear that this is the case; you know it and I know it. You may
> not know how to explain it, define it, or even describe it, but you
> definitely know that observer-moments exist if you are a conscious
> being.
> Secondly, you have to assume that this mysterious consciousness thing
> is "Turing emulable". It is not nearly as obvious that this second
> assumption is true, and biological chauvinists may continue to deny it
> no matter what progress AI research may make. At some point, as Bruno
> says, you may have to take "comp" on faith; for example, say "yes
> doctor" to the offer of a durable new electronic brain when yours is
> starting to break down.
> It should now be clear that if both of the above assumptions are true,
> then the UD should generate all the observer-moments as per Bruno and
> Brian. The "observer" is then a derivative entity, made up of certain
> subsets of observer-moments. You know what an observer-moment is
> through direct experience, but you have nowhere been forced to
> explicitly define it. If you want to say that consciousness is
> something utterly mysterious forever, you can say this, and the UDA
> still holds.
> --Stathis Papaioannou
>> From: Brian Scurfield <>
>> To: "'Stephen Paul King'" <>
>> CC:
>> Subject: RE: Everything Physical is Based on Consciousness
>> Date: Fri, 06 May 2005 18:04:45 +1200
>> In reply to Lee Corbin on the Fabric of Reality List
>> ----------------------------------------------------
>> Lee,
>> You gave us some wonderful examples of totally ridiculous Turing
>> Machines
>> that are nevertheless possible (I would at this point ask somebody to
>> take
>> away Charles' keyboard). You have noted that these TMs are
>> improbable; we
>> would not expect them to be instantiated in any great measure
>> throughout the
>> multiverse. They are similar to Harry Potter universes in this
>> respect.
>> Surely, though, the fact that they are improbable is not a blow
>> against
>> Bruno! His argument is concerned with measure and you are playing
>> right into
>> that. Let me try to explain...
>> To make this easier, let's forget about physical reality for a while.
>> Let's
>> consider the Universal Dovetailer (UD). For those not in the know,
>> the UD is
>> a TM that systematically lists and executes all possible TMs. Because
>> there
>> are an infinite number of TMs, the UD cannot wait until all the TMs
>> are
>> listed before it executes them. It also cannot allow any one TM to
>> monopolise the runtime, lest that TM never halts. So it must execute
>> a step
>> of one TM, then a step of another TM and so on, and it must do this
>> while
>> continuing to list the TMs. The first TMs off the list will be the
>> simple
>> ones - those with the shortest bitstrings and these are the first to
>> be
>> kicked off. Complex TMs with very long specifications will not be
>> kicked off
>> until much later. At any point in time in which they are still
>> running,
>> these complex TMs will have received less runtime than any simpler TM
>> that
>> is still running. This is important, as we shall see.

The problem is that from the first person point of view, the arbitrary
introduced by the UD, cannot be taken into account, so that big
programs cannot
be evacuated so easily. This does not mean little programs, or some
programs, does not win in the limit, just that something more must be
Sorry for not explaining more because I have a lot of work to finish
(I'm still not
connected at home, but in this case I'm not sure I will find the time
to go home...).
See you next week.


>> As we have discussed, some (an infinite subset) of the TMs will
>> support
>> observers when they are executed. The observers and their worlds
>> unroll as
>> computational histories.
>> What does an observer observe?
>> It is important to see that the computational histories of different
>> TMs can
>> be identical up to a point and then diverge. So different TMs can
>> produce
>> the same observer history up to a point. The observer moment, then, is
>> "simultaneously" generated by many different TMs. You can't pluck one
>> history and say you are in that history. You are part of many
>> identical
>> histories that are about to diverge. And you can't pluck one TM and
>> say that
>> that is the TM that is instantiating you. Your history is generated
>> by many
>> different TMs. These are very important points. And, I think, the
>> source of
>> much confusion over Bruno's work.
>> What an observer observes depends on all the computational histories
>> their
>> current moment is in and how the histories branch. The question also
>> depends
>> on what we mean by observer, but let's put that aside for now because
>> I
>> don't yet understand this part. Note that observer time has no
>> relation to
>> dovetailer time.
>> Obviously, the computational history of a TM that consistently
>> supports an
>> observer can't be random. It must perform the computations necessary
>> for an
>> observer. Now the history might become random after the n-th step, at
>> which
>> point the observer no longer exists. Or the observer might morph into
>> a
>> completely different observer that has no memory of its former
>> existence (I
>> would argue that the observer is now a new observer). Or fluffy white
>> bunny
>> rabbits might appear. The TM's executing these histories first run an
>> observer and then do something strange. Presumably this makes the TM
>> more
>> complex because the strangeness requires extra bits to specify. These
>> TMs
>> therefore get less runtime than the "unmodified" TM.
>> OK, suppose you're in a set of identical computational histories that
>> are
>> unfolding on many different TMs. Some of those histories are about to
>> go
>> strange. For your existence as an observer to continue, they must go
>> strange
>> in such a way that they still support you as an observer. Given what
>> I have
>> said, do you think you are likely to branch into a strange world or to
>> continue on in your normal world, whatever that may be? The measure
>> of the
>> computational history of the world where you continue on as normal is
>> much
>> larger than the measure of the computational history of the strange
>> branch
>> because the strange TMs receive less runtime (remember, many
>> different TMs
>> instantiate you).
>> So, if you were an observer on the dovetailer, your computational
>> history
>> branches in such a way that some branches are much more probable than
>> others. The world the observer observes will likely not be totally
>> stupid.
>> This is how you play into Bruno's hands!
>> Writing the above has made me realize that I may have not been
>> accurate in
>> some of my earlier statements about Bruno's work. Apologies to Bruno.
>> All I
>> need now is to be convinced that we can give a satisfactory
>> definition of an
>> observer. Oh, and that we are most likely to observe QM.
>> Brian Scurfield
> _________________________________________________________________
> REALESTATE: biggest buy/rent/share listings
Received on Fri May 06 2005 - 12:05:57 PDT

This archive was generated by hypermail 2.3.0 : Fri Feb 16 2018 - 13:20:10 PST