OK, well first of all let me retract any ad hominem remarks that may
have offended you. Call it a rhetorical flourish! I apologise. There
are clearly some theories which require a profound amount of dedicated
learning to understand - such as QFT. I majored in History and
Philosophy of Science and work as a programmer and a writer. I am not
a mathematician - the furthest I took it was first year uni, and I
couldn't integrate to save myself any more. Therefore if the truth of
an argument lies deep within a difficult mathematical proof, chances
are I won't be able to reach it. Then my ignorance would hardly
constitute a criticism, and so it may be with UDA and my complaint of
obscurity. On the other hand, it seems to me that ideas about the core
nature of reality can and should be presented in the clearest, most
intelligible language possible. I can't solve QFT equations, but I can
grasp the fundamental ideas of the uncertainty principle, non-
locality, wave-particle duality, decoherence and so on. I'm not
arguing for dumbed-down philosophy, but maximal clarity. Having said
that, I'm prepared to put effort in to learn something new if I have
You have misread my tone if you think it indicates bias against your
theory. I have read your paper (at least the UDA part, not the machine
interview) several times, carefully, and presented it to my (informal)
philosophy group, because I certainly find it intriguing. I'll admit
that step 8 is where I struggle - it's not well explained in the paper
yet contains the all the really sweeping and startling assertions. The
argument about passive devices activated by counterfactual changes in
the environment is opaque to me and seems devious - probably defeated
in the details of implementation like Maxwell's demon - but that is
obviously not a rebuttal. I will take a look at the additional
information you've linked to.
I can see that you are actually right in asserting that the UDA's
computations are not random, but I'm not sure that negates the core of
my objection. Actually what the UDA does is produce a bit field
containing every possible arrangement of bits. Is this not correct? I
am open to contradiction on this. If it doesn't, then it means it has
to be incapable of producing certain patterns of bits, but in
principle every possible pattern of bits must be able to be generated.
Now a machine with infinite processing power and infinite state memory
that merely generates random bit sequences would eventually also
generate every possible arrangement of bits. So the UDA and the
ultimate random generator are indistinguishable AFAICS.
I think what you are saying is that somehow this computation produces
more pattern and order than a program which simply generates all
possible arrangements of bits. Why? If I were to select at random some
algorithm from the set of all possible algorithms, it would be pretty
much noise almost all the time. *Proving* it is noise is of course
impossible, because meaning is a function of context. You've selected
out "the program emulating the Heisenberg matrix of the Milky Way",
but among all the other possible procedures will be a zillion more
that perform this operation, but also add in various other quantities
and computations that render the results useless from a physicist's
point of view. There are certainly all kinds of amazing procedures and
unfound discoveries lying deep in the UDA's repertoire of algorithms,
but only when we intelligently derive an equation by some other means
(measurements, theory, revision, testing etc) can we find out which
ones are signal and which ones noise.
>> Fine. But then we can simply dispense with the UD altogether and just
>> gather up its final results,
>This does not make any sense. A non stopping program does not output
OK. I realised after I posted that this was wrong, actually hasty
shorthand for what I was trying to say - didn't have time for an
amendment. By 'results' I mean the machine's state. It seems that for
the UDA to work, we have to assume that the simulation has 'finished',
even though from a 3p perspective it never can. What I mean is, if the
UDA had just started running, it wouldn't have any complex
representations in its trace yet. And since the UDA exists purely
mathematically, platonically, how can it be subject to time at all? It
has no processing limitations, so any notion of time as a factor can
be disregarded. Otherwise you'd have to say that to process an
instruction takes t amount of time, and where would such a constant
come from? The time taken to compute something in the physical world
is a function of the fact that all computation we know of is bound to
the manipulation of physical substrates that are embedded in the
constraints of time, space and energy. Sequentiality in the UDA is
purely conceptual. And because my 1-p moments could be anywhere in
the UD's record of histories, I can't speak about where the UD is up
to in its work 'now', but just have to take it as all somehow 'done',
even though it can 'never' be done. I'm granting this, even though it
is itself problematic. 'Results' was my clumsy shorthand for the UD's
infinite record of states.
If this is a misunderstanding, I'm sure you'll point it out!
Actually I'm not sure why you have to resort to the dovetailing in the
first place. Since you grant your machine infinite computational
resources, why not grant it parallelism? Just to make it a Turing
machine? The Turing machine is just an idea, there's no reason to
think the universe (whatever the hell that is) has to be serial in its
> The existence of the UD is already a theorem of Peano
> Arithmetic.Robinson arithmetic *is* a UD.
Huh? You've inverted ontological priority completely. Any form of
arithmetic is a product of human intelligence. Just because someone
has mentally constructed a mathematics with the structure of the UD
does not instantiate a UD that actually 'runs' and creates the whole
universe! That is a vast mathematical hubris - akin to the way any
person tends to over-apply their dominant metaphors. As a writer it's
very easy to see the universe as a vast story. As a programmer, I see
algorithms everywhere. But I'm not so inflated as to think it's more
than a metaphor. I can invent my own logically consistent set of
axioms right here and now, but I wouldn't presume it was anything more
than a set of mental relations.
Oh, and :
>A proof is only something presented as a proof. You can only say: here
>is the flaw, (in case you have found one). I guess that is what you
>did, or thought you did.
That's kind of pedantic. You know what I'm doing.
Unfortunately I don't have time to continue my response/questions now
- I'm amazed and impressed you can find the time for such detailed
responses to random ignorants such as me! I'm more than prepared to
concede my naivete and have my eyes opened to the revelation of UDA.
On the other hand, the intelligent naive person has some advantages
(hence the emperor's clothes reference). Whether I'm the child in the
story or merely ignorant is the question. I remain open the
discovering the latter.
On Sep 26, 3:20 am, Bruno Marchal <marc...@ulb.ac.be> wrote:
> On 25 Sep 2011, at 04:20, Pierz wrote:
> > OK, so I've read the UDA and I 'get' it,
> Wow. Nice!
> > but at the moment I simply
> > can't accept that it is anything like a 'proof'.
> Hmm... (Then you should not say "I get it", but "I don't get it"). A
> proof is only something presented as a proof. You can only say: here
> is the flaw, (in case you have found one). I guess that is what you
> did, or thought you did.
> > I keep reading Bruno
> > making statements like "If we are machine-emulable, then physics is
> > necessarily reducible to number psychology", but to me there remain
> > serious flaws, not in the logic per se, but in the assumptions.
> > Bruno says that "no science fiction devices are necessary, other than
> > the robust physical universe".
> To get the step-7. But that robust universe assumption is discharged
> in the step 8. Which I have explained with more details (than in
> sane04) on this very list:
> > He also claims that to argue that the
> > universe may not be large or robust enough (by robust I assume he
> > means stable over time) to support his Universal Dovetailer is "ad
> > hoc and disgraceful". I think it is anything but.
> By robust I mean expanding enough to run the UD.
> It is disgraceful with respect to the reasoning. But if for some
> reason, you believe that there are evidence that the physical universe
> does develop the infinite running of a UD, then you can skip the last
> (and most difficult) step 8. Physics is already a branch of computer
> science/number theory, in that case.
> This is funny: if we have evidence that the physical universe has a
> never ending running UD, then we can from step 7 alone conclude that
> physics is a branch of number theory. And by Occam, we don't need to
> assume the primitive physical universe.
> But we don't, and I doubt we can, have such an evidence. The UD
> running is very demanding. Not only the universe must expand
> infinitely, but in a way which connect solidly all its parts. Better
> to grasp the step 8 (the movie graph argument).
> > To describe such an
> > argument as "disgraceful" is to dismiss with a wave of the hand the
> > entirety of modern cosmology and physics, disciplines which after all
> > have managed to produce a great deal more results in the way of
> > prediction, explanation and tangible benefits than Bruno's theory (I
> > insist it is a theory and not a 'result').
> Yes, it is the theory known as "mechanism". The theory that the brain
> is a natural machine. The result is that physics emerges from
> numbers, or combinators, or from any first order specification of a
> universal machine, in the sense of theoretical computer science
> (branch of math).
> > As a computer science
> > expert, I assume Bruno is aware of modern computational approaches to
> > physics. Such approaches explicitly forbid any kind of 'infinite
> > informational resolution' as is required by Bruno's theory.
> Where is this required?
> Note that as a corollary of UDA we can show that the physical universe
> is not a computable object, a priori.
> The computational approach to physics can have many interesting
> application, but it can't tackle the mind body problem. But to get
> this, it is better to grasp UDA first.
> > The
> > information content of the universe is seen as being a fundamental
> > quantity much like energy, constantly transforming but conserved over
> > the whole system in the same way energy is.
> There is no assumption about the universe in the theory. We assume
> only that the brain (or the generalized brain, that is the portion of
> observable things needed to be emulated for my consciousness to be
> preserved) is Turing emulable.
> UDA assumes the existence of brains and doctors, and thus on some
> physical reality, but not on a primitive physical reality. At the
> start of the UDA, we are neutral on the nature of both mind and
> > This computational
> > approach indeed seems to be the *basis* for much of Bruno talks about
> > (computability, emulability and so on are all fundamental ideas), but
> > then he flies in the face of it by proposing some kind of automated,
> > Platonic computation devoid of any constraints in terms of state
> > memory or time.
> Computation is a mathematical notion, discovered by Post, Turing, etc.
> It is based on the notion of state memory, time steps, etc. It is not
> base on physical implementation of those notion (unlike engineering).
> > Let's take a look at the UD. Obviously this is not an 'intelligent'
> > device,
> You are right. It is very dumb. It is not even Turing universal, and
> it computes in the most complex possible way the empty function (it
> has no input, it has no output).
> > beyond the intelligence implicit in the very simple base
> > algorithm. It just runs every possible computer program.
> > Random
> > computer programs are made of and produce *static*, they are a random
> > arrangement of bits.
> There is no randomness in the work of the UD.
> > Now clearly, we know that if you look at a large
> > enough field of static, you will find pictures in it, assemblies of
> > dots that happen to form structured, intelligible images.
> OK. But they are not related by computations. Neither in the first
> person views, nor in the third person views.
> > Likewise in
> > the field of random computed algorithms, very very occasionally one
> > will make some kind of 'sense', although the sense will naturally be
> > entirely accidental and in the vast, vast majority of cases will give
> > way a moment later to nonsense again.
> The only randomness which might appear comes from the first person
> indterminacy, and the fact that we acnnot know in which computation we
> are. This leads to the "white rabbit" problem, but the computation
> themselves are not random at all, and the WR problem is basically the
> problem to which physics is reduced too, at the conclusion of the
> > So when the UD runs through its
> > current sequence of programs, what it is really doing is just
> > generating a vast random field of bits.
> I have not the slightest clue why you say that. It is provably false.
> No program can generate randomness in this third person way. The
> randomness ¨possible* can only appear from the first person (emulated
> in the UD) perspective.
> The UD generates, to give an example, the program emulating the
> Heisenberg matrix of the Milky Way, at the level of string theory, and
> this with 10^(10^(10^(10^(10^9999999))))) digits. Notably. Actually it
> does it also with 10^(10^(10^(10^(10^9999999))))) + 1 digits, and
> 10^(10^(10^(10^(10^9999999))))) + 2 digits, etc.
> The point here is that all those running are not random structures. In
> fact, there is no randomness at all.
> > Nonetheless, each of these
> > individual programs needs to have potentially infinite state memory
> > available to it (the Turing machine tape). Now the list of of programs
> > run by the machine continues to grow with each iteration as it adds
> > new algorithms, so it takes longer and longer to return to program 0
> > to run the next operation.
> Right. Note that such delays are not perceptible for the emulated
> > As it needs to run *all* programs, a
> > necessarily infinite number, it requires infinite time, but for some
> > reason Bruno thinks this is not important.
> It is utterly important.
> This why the first person indeterminacy bears on a continuum, despite
> the digitalness of all present factors.
> You attribute me things which I never say, here. n the contrary, the
> fact that the UD never stops is crucial.
> > Either it has infinite
> > processing speed as well as memory, or it has infinite time on its
> > hands.
> The UD* (the infinite trace or running of the UD) is part of a tiny
> part of arithmetical truth (the sigma_1 arithmetical truth).
> Step 8 makes the physical running of the UD irrelevant.
> UD and UD* are mathematical notion (indeed arithmetical relations).
> > Fine. But then we can simply dispense with the UD altogether and just
> > gather up its final results,
> This does not make any sense. A non stopping program does not output
> > which is an infinite field of static, a
> > giant digital manuscript typed by infinite monkeys. Everything capable
> > of being represented by information will exist in this field, which
> > means it is capable of "explaining" everything. And nothing.
> I think you miss the step 3: the first person indeterminacy. I think
> you miss also the arithmetical non random dynamic of the UD. You are
> confusing an infinite set of information, with an infinite non random
> and well defined particular computation.
> > We have to deconstruct the notion of "computation" here. Computation
> > is the orderly transformation of information.
> I can agree, although information is more an emerging notion. It is
> not used in the definition of computation.
> > But the UD's orderliness
> > is the orderliness of the typing monkey.
> Not at all. It is the orderliness of the computations. Or the
> orderliness of the sigma_1 sentences and the logic of their
> probability/consistency (as it is made completely transparent in the
> AUDA: the translation of the UDA in arithmetic, or in the language of
> the Löbian machine).
> > If it is orderly at all, it
> > is by mistake.
> It is 100% orderly.
> > By talking about it the UD as performing computation
> > more intelligence is implicitly imputed than this hypothetical device
> > possesses.
> Where? The existence of the UD is already a theorem of Peano
> Arithmetic. Robinson arithmetic *is* a UD. You need only the
> intelligence for grasping addition and multiplication. The UD has been
> And besides, the physical and psychological (theological,
> biological,..) order are brought by the machines from inside the
> running of the UD. The UD's intelligence is not needed.
> > Yes, it would generate every possible information state,
> > and...
> read more »
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