On Friday, January 25, 2019 at 6:27:44 AM UTC-6, Bruno Marchal wrote:
> On 24 Jan 2019, at 15:19, Philip Thrift <cloud...@gmail.com <javascript:>> 
> wrote:
> On Thursday, January 24, 2019 at 7:14:15 AM UTC-6, Bruno Marchal wrote:
>> On 23 Jan 2019, at 19:01, Philip Thrift <cloud...@gmail.com> wrote:
>> On Wednesday, January 23, 2019 at 5:52:01 AM UTC-6, Bruno Marchal wrote:
>>> On 22 Jan 2019, at 01:49, Philip Thrift <cloud...@gmail.com> wrote:
>>> One of the oddest of things is when physicists use the language of 
>>> (various) theories of physics to express what can or cannot be the case. 
>>> It's just a language, which is probably wrong.
>>> There is a sense in which the Church/Turing thesis is true: All out 
>>> languages are Turing in their syntax and grammar. What they refer to is 
>>> another matter (pun intended).
>>> They refer to the set of computable functions, or to the universal 
>>> machine which understand that language. But not all language are Turing 
>>> universal. Only the context sensitive automata (in Chomski hierarchy) are 
>>> Turing universal. Simple languages, like the “regular” one are typically 
>>> not Turing universal. Bounded loops formalism cannot be either.
>>> But the notion of language is ambiguous with respect to computability, 
>>> and that is why I prefer to avoid that expression and always talk about 
>>> theories (set of beliefs) or machine (recursively enumerable set of 
>>> beliefs), which avoids ambiguity. 
>>> For example, is “predicate calculus” Turing universal? We can say yes, 
>>> given that the programming language PROLOG (obviously Turing universal) is 
>>> a tiny subset of predicate logic. But we can say know, if we look at 
>>> predicate logic as a theory. A prolog program is then an extension of that 
>>> theory, not something proved in predicate calculus.
>>> Thus, I can make sense of your remark. Even the language with only one 
>>> symbol {I}, and the rules that “I” is a wff, and if x is wwf, then Ix is 
>>> too, can be said Turing universal, as each program can be coded by a 
>>> number, which can be coded by a finite sequence of I. But of course, that 
>>> makes the notion of “universality” empty, as far as language are concerned. 
>>> Seen as a theory, predicate calculus is notoriously not universal. Even 
>>> predicate calculus + the natural numbers, and the law of addition, 
>>> (Pressburger arithmetic) is not universal. Or take RA with its seven 
>>> axioms. Taking any axiom out of it, and you get a complete-able theory, and 
>>> thus it cannot be Turing complete.
>>> Bruno
>> Here's an example of a kind of "non-digital" language:
>> *More Analog Computing Is on the Way*
>> https://dzone.com/articles/more-analog-computing-is-on-the-way
>> *The door on this new generation of analog computer programming is 
>> definitely open. Last month, at the Association for Computing Machinery’s 
>> (ACM) conference on Programming Language Design and Implementation, 
>> a paper  <https://people.csail.mit.edu/sachour/res/pldi16_arco.pdf>was 
>> presented that described a compiler that uses a text based, high-level, 
>> abstraction language to generate the necessary low-level circuit wiring 
>> that defines the physical analog computing implementation. This research 
>> was done at MIT’s Computer Science and Artificial Intelligence Laboratory 
>> (CSAIL) and Dartmouth College. The main focus of their investigation was to 
>> improve the simulation of biological systems. *
>> *Configuration Synthesis for ProgrammableAnalog Devices with Arco*
>> https://people.csail.mit.edu/sachour/res/pldi16_arco.pdf
>> *Programmable analog devices have emerged as a powerful*
>> *computing substrate for performing complex neuromorphic*
>> *and cytomorphic computations. We present Arco, a new*
>> *solver that, given a dynamical system specification in the*
>> *form of a set of differential equations, generates physically*
>> *realizable configurations for programmable analog devices*
>> *that are algebraically equivalent to the specified system.*
>> *On a set of benchmarks from the biological domain, Arco*
>> *generates configurations with 35 to 534 connections and 28*
>> *to 326 components in 1 to 54 minutes.*
>> - pt
>> Intersting.
>> Yet, that does not violate the Church-Thesis, even if very useful FAPP. 
>> But such computations arise in arithmetic, either directly, or through a 
>> infinite sequence of approximations. If all decimals of the analog 
>> phenomenon needs to be taken into account, then we are out of my working 
>> hypothesis, and even evolution theory becomes wrong, as evolution and life 
>> becomes sequences of miracles. But the goal of the authors here is not 
>> learning anything in metaphysics, just doing efficacious machine. In that 
>> case mechanism explains the plausible necessity of such moves, including 
>> quantum computations (which also do not violate Church’s thesis).
>> Bruno
> I don't believe in (or know what are) miracles (although a real 
> hypercomputer - one you could give any statement of arithmetic to - e.g. 
> *Goldbach's 
> conjecture*  -  and it could check through all - infinite number of -  
> integers and tell you "true" or "false" within the hour - would be 
> basically a miracle), but I do think that* substrate matters*.
> Hence in the PLTOS view (program, language, transformer/compiler, object, 
> substrate), *substrate* can't be eliminated in the semantics of *program*. 
> In other words, in *real programming*, there are no such things as 
> substrate-independent programs.
> Because you assume some primary substrate. And then you need, coherently, 
> to assume no-mechanism. No problem, but the current evidence favours 
> Mechanism, and there has never been any evidence for substrate. Adding 
> substrate in the picture makes the mind-body problem almost non soluble, at 
> least without invoking some precise non computationalist theory of mind. I 
> start from the computationalist of mind, shows that we have to derive a 
> phenomenology of matter in a special (self-referentially based) manner, and 
> nature seems to confirm this. The illusion of matter is easier to explain 
> once we have a theory of consciousness, than to derive a theory of 
> consciousness from some notion substrate (which are conceived usually as 
> being inert).
> We are working in different theories. You might think about a way to 
> motivate your ontological commitment in some primitive substance. The books 
> in physics does not provide such motivation, as they do not aboard the 
> mind-body problem (even if Everett Quantum Mechanics already look like a 
> solution to the mechanist mind-body problem).
> Bruno
Just to note that the "substrate" terminology is used in computing (as 

  *Programmable analog devices have emerged as a powerful **computing 
*  for performing complex neuromorphic **and cytomorphic computations. * 

It's a word combined with "computing" like love and marriage.

- pt

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