Re: Is the Continuum Hypothesis a) really true or really false, or b) something else ?

[John Clark]

On Wed, May 16, 2018 at 6:29 AM, Bruno Marchal  wrote:

​
>> ​>> ​
>> A Turing Machine knows no theories
>
>
> ​> ​
> I have no clues why you say so.
>

I say so because a Turing Machine knows nothing excepts what state it
should go into, if it should write a 1 or a 0, and if it should move left
or right or halt. That's it. And yet it can calculate anything that can be
calculated provided that it just follows the laws of physics when it moves
and it uses a minimum amount of energy (that can also be calculated) and
produces entropy whenever it changes one symbol to another.

​> >​
>> and it operates under the laws of physics
>
>
> ​>​
> That is a confusion between a Turing
> ​Machine
>  and a physical implementation of a Turing machine.
>

And for years you have been confused by the difference between the 2
different types of Turing Machines, the Turing Machines that can make a
calculation and the Turing Machines that can not. I like the type that can.

*​> ​I​​n which metaphysical theory would you define what is a *real*
> machine. *


I don't deal in metaphysical theories, that's your thing not mine, but I'll
be happy to exactly define what a *real* machine is in a clear unambiguous
way. A real Turing Machine is a Turing Machine that can actually make a
calculation.


> ​*> ​*
> *when we assume Aristotle’s metaphysics​ [...]*
>

Bruno, I really want to know, why do you keep talking about those stupid
ignorant ancient Greeks who didn’t know where the sun went at night? You
seem incapable of writing an entire post without talking about them
regardless of the subject.

​> ​
> The laws of physics he nothing to do with the laws of computability and
> computation. I suggest you read the original papers of the discoverers of
> the universal machine (reprinted for example in Martin Davis
>

If Martin Davis 's paper can make a calculation then send it to Apple, they
would get much better battery life out of their next generation iPhone if
they just stuff the paper inside it instead of a energy hungry microchip.

​> ​
> *What I said was only that if a computer find an even number not sum of
> two primes, I would believe the computer over a proof in ZF.*
>

I would trust the computer more than the axioms too, I would because I
think physics always tells the truth, but that is not why you also trust
the computer over the axioms;  you gave your reason  for doing so but I
couldn't make any sense out of it.
​ ​


> *​> ​The reason is that the negation of Goldbach conjecture is sigma_1,
> so​ ​if a computer can refute Goldbach, so can ZF. You were assuming
> implicitly that ZF is inconsistent.*
>

Why don't you believe the ZFC axioms are still consistent , Goldbach is
still true, and all computers are always wrong when they say a particular
very large even number is not the sum of two primes?

​>>​
>> ​If two physical theories try to explain the same phenomena then they
>> are ALWAYS contradictory,  otherwise they'd be the same theory,
>
>
> ​> ​
> *Of course not. QM, for example, came up with different theories, proved
> to be equivalent, but they are still different (cf Heisenberg versus
> Schoredinger, versus Feynmann),*
>

​
None of these things contradicted the other, they are saying the same thing
with different words (or equations).

​> ​
> *you have to explain how that primary matter makes “more real” some
> computations, and "less real” others.*
>

No, it would be nice to know why but I am under no obligation to
explain why a real Turing Machine uses energy, produces entropy, and makes
calculations, but a description of a Turing Machine in a closed book can do
none of those things; I just have to observe that is the way things are.

 John K Clark

​


>
>
>

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Re: Gödel and the unreality of time

[Bruno Marchal]

> On 15 May 2018, at 21:52, Lawrence Crowell  
> wrote:
> 
> On Monday, May 14, 2018 at 10:52:51 AM UTC-5, telmo_menezes wrote:
> https://edwardfeser.blogspot.fr/2018/05/godel-and-unreality-of-time.html 
>  
> 
>  The Gödel universe is a net rotating universe. The whole spacetime is 
> rotating, which means the Kerr effect dominates over standard gravitation. 
> This results in closed timelike curves. This spacetime violates the averaged 
> weak energy condition (AWC) T^{00} ≥ 0 of Hawking and Penrose, which means 
> quantum fields are not bounded below. The anti-de Sitter (AdS) spacetime 
> violates the averaged weak energy condition as well. However, its conformal 
> structure is such that on a local causal patch closed timelike curves are 
> removed. 
> 
> The Gödel universe most likely does not exist, or at least we are not in that 
> spacetime. Since it violates the AWC quantum particles can emerge from the 
> vacuum. With the AdS spacetime causal wedges can generate entire cosmologies. 
> I am not sure if the Gödel universe can do this. Generally this is regarded 
> as a pathological spacetime, one that is maybe removed by a superselection of 
> states in quantum gravitation.
> 
> I am not sure this means time does not exist. It would mean in a way that 
> time has no global properties, but locally it would still have meaning. On a 
> frame with a short enough duration there is not time looping it seems 
> plausible that time can be defined

The point of Gödel is that some solution of Einstein GR theory can admit 
circular time. Gödel was skeptical about time, but also on the whole of 
naturalism. Eventually Einstein understood why we can choose mathematics when 
interested in fundamental question.

Gödel is the one who showed that the computation are realised in arithmetic, 
and makes the point clearly in a footnote, but he missed the Church-Turing 
thesis, and mechanism. Well Gödel did 99,9%. But Post, Turing and Church got 
the universal “thing”.

Gödel does not seem to have been really interested in cosmology, but he did 
have some interest in theology, as explained in the books by Hao Wang. Yet, 
neither its “Gödel ‘sRotating Universe”, nor his proof of the existence of 
(St-Anselmus’) god, were taken seriously by him. It was just models (solutions) 
of theories/equations to illustrate philosophical/metaphysical points: notably 
here the disparition of time, and the fact that theology can be done rigorously.

An interesting book on Gödel and Einstein on Time  is “A World Without Time, 
the ForgottenLegacy of Gödel and Einstein”, by Palle Yourgrau (Allan 
Lane-Penguin 2005, London). Apparently Einstein was forbidden to even think 
about quantum mechanics !). And Einstein seems to have forbid to itself to 
search for a relation between incompleteness and the quantum, but with 
mechanism this comes as a gift on the plate of the relative self-reference.

Bruno 


> 
> LC 
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Re: Looking for an exposition of a variant of the MUH

[Bruno Marchal]

> On 12 May 2018, at 22:23, Brent Meeker  wrote:
> 
> 
> 
> On 5/11/2018 9:01 PM, Dustin Wehr wrote:
>> I'm a big fan of Tegmark's 2007 article The Mathematical Universe, but I 
>> believe he got a couple details wrong, and those details are interfering 
>> with my attempts to interest friends. So, I'm looking for an exposition of 
>> the Mathematical Universe Hypothesis, of a similar or shorter length, that 
>> omits those details, so that I have something I can recommend to others 
>> without qualification. I can recommend Tegmark's Consciousness is a 
>> Mathematical Pattern TED talk without qualification, but I need something 
>> that goes further, particularly for people with a STEM background. 
>> 
>> There should be nothing about the Computable Universe Hypothesis. There 
>> should be nothing about Gödel's incompleteness theorems, unless it's to 
>> explain why they do not pose a problem.
>> 
>> Ideally there is no claim about the MUH being testable. What would be 
>> wonderful, in its place, is an admission that the MUH is probably 
>> unfalsifiable, followed by a persuasive argument for why we should reset our 
>> expectations when it comes to entertaining/evaluating a theory of everything.
> 
> Richard Dawid has written a book advocating an approach to science that 
> abandons Popper's dictum.
> 
> https://www.amazon.com/String-Theory-Scientific-Method-Richard/dp/1107449618/ref=sr_1_7
>  
> 
> 
> 
> I, however, found it less than persuasive.  But I also found the MUH 
> incoherent.  I understand Tegmark has more recently retreated to a 
> Computational Universe Hypothesis which may be coherent, but still wrong.


A computable universe would entail computationalism in cognitive science, but 
this has been shown to entail the impossibility of a computational universe (by 
the fact that we get the first person indeterminacy under our substitution 
level). So A computable universe does not make sense, with or without Mechanism.

Tegmark is mathematicalist, like computationalism entailed (since long), but he 
applies computationalism wrongly. Like Chalmers, he seems to dismiss the 
mechanist first person indeterminacy. His mathematicalism seems still to much 
tainted by Aristotle theology (physicalism).

Bruno



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