People like Langan long ago fell into the "Intelligence Trap". They
have an exaggerated need to be "right" about everything all the time.
They are usually unable to think about anything from a perspective
other than the one they long ago decided was the "right" perspective.
They don't know how to listen to others. They are usually unable to
restructure the available information in such a way that they can draw
new perspectives from it. Please do not extoll the virtues of anything
as anachronistic and mythical as somebody's supposed "high IQ". I
could put a thinking test in front of him that would defeat him
totally, yet be easily done by a 7 year old.
Kim Jones
It is a physicalism in disguise. There is also a confusion between a
mathematical object as a tool to represent other object, and the other
object.
And using set theory in that setting is a curious choice, given that
set theory is known to flatten the concepts. It is the reason what
mathematician prefer category theory, or specific theories ... I mean
sets? Which sets? It is very unclear how the different notions are
related. I can appreciate its apparent open mind on religion, but I
don't see any effort to solve problems, nor any clarification of
problems. Langan seems not to be afraid of being appreciated by those
who want to be mystified instead of understanding.
But then if you have a link on a real precise theory or results, you
can let us know, but my opinion is that it is not really honest, or if
it is, then it is presented in a very awkward. To give set a
fundamental status is really like saying you should do everything in
FORTRAN. Unless you have a good original reason to use sets, but then
you should give it.
Rereading some parts I am not sure at all he even try to say
something, ... pervert the usual meaning of the terms. He makes
complex simple ideas and hides somehow its naive view of Plato, making
me a bit nervous even on points where I could imagine some sense
there ...
...
Hmm.... Pompous and Boring, if you ask my opinion.
Bruno
I can't say I've ever seen a more extreme example of a narcissist.
--
Stathis Papaioannou
Maybe if he said Fortran IV or Fortran 66, it might have made the
point clearer. I know guys who still program in Fortran 66. The rest
of us have moved on ... Fortran 95 is not a bad language to program in
for instance - and 2003 has some interesting features, although I don't
know of any freely available compilers.
Personally, I went C++ in the early 90s because g++ was available and
the equivalent for Fortran 90 was not (gfortran or g95 arrived by
about 2000 IIRC).
On 02 Jun 2009, at 16:45, ronaldheld wrote:
>
> Bruno:
> Since I program in Fortran, I am uncertain how to interpret things.
I was alluding to old, and less old, disputes again programmers, about
which programming language to prefer.
It is a version of Church Thesis that all algorithm can be written in
FORTRAN. But this does not mean that it is relevant to define an
algorithm by a fortran program. I thought this was obvious, and I was
using that "known" confusion to point on a similar confusion in Set
Theory, like Langan can be said to perform.
In Set Theorist, we still find often the error consisting in defining
a mathematical object by a set. I have done that error in my youth.
What you can do, indeed, is to *represent* (almost all) mathematical
objects by sets. Langan seems to make that mistake.
The point is just that we have to distinguish a mathematical object
and the representation of that object in some mathematical theory.
I will have the opportunity to give a precise example in the 7th
thread later.
In usual mathematical practice, this mistake is really not important,
yet, in logic it is more important to take into account that
distinction, and then in cognitive science it is *very* important.
Crucial, I would say. The error consisting in identifying
consciousness and brain state belongs to that family, for example. To
confuse a person and its body belongs to that family of error too.
All such error are of the form of the confusion between the Moon and
the finger which point to the moon, or the confusion between a map and
the territory.
I have nothing against the use of FORTRAN. On the contrary I have a
big respect for that old venerable high level programming language :)
Bruno
Bruno Marchal wrote:Hi Ronald,On 02 Jun 2009, at 16:45, ronaldheld wrote:Bruno:Since I program in Fortran, I am uncertain how to interpret things.I was alluding to old, and less old, disputes again programmers, aboutwhich programming language to prefer.It is a version of Church Thesis that all algorithm can be written inFORTRAN. But this does not mean that it is relevant to define analgorithm by a fortran program. I thought this was obvious, and I wasusing that "known" confusion to point on a similar confusion in SetTheory, like Langan can be said to perform.In Set Theorist, we still find often the error consisting in defininga mathematical object by a set. I have done that error in my youth.What you can do, indeed, is to *represent* (almost all) mathematicalobjects by sets. Langan seems to make that mistake.The point is just that we have to distinguish a mathematical objectand the representation of that object in some mathematical theory.
Just so I'm sure I understand you; do you mean that, for example, the
natural numbers exist in a way that is independent of Peano's axioms
and
the theorems that can be proven from them.
In other words you could add
to Peano's axioms something like Goldbach's conjecture and you would
still have the same mathematical object?
So what then is the status of the natural numbers? Are there many
different objects in Platonia which we loosely refer to as "the natural
numbers" or is there only one such object and the Goldbach conjecture is
either true of false of this object?
>
> Here, you would have taken the twin primes conjecture, and things
> would have been different, and more complex.
Because, even if it is false, it cannot be proven false by exhibiting an
example?
>
> Note that a theory of set like ZF shed even much more large light on
> arithmetical truth, (and is still incomplete on arithmetic, by Gödel ...).
> Incidentally it can be shown that ZF and ZFC, although they shed
> different light on the mathematical truth in general, does shed
> exactly the same light on arithmetical truth. They prove the same
> arithmetical theorems. On the numbers, the axiom of choice add
> nothing. This is quite unlike the ladder of infinity axioms.
>
> I would say it is and will be particularly important to distinguish
> chatting beings like RA, PA, ZF, ZFC, etc... and what those beings are
> talking about.
>
> Bruno
Do you mean PA talks about the natural numbers but PA+theorems is a
different mathematical object than N?
Brent
Nobody can answer this question in your place.
But if you believe that the principle of excluded middle can be
applied to closed arithmetical sentences, like 99,999% of the
mathematician, then you have to believe that the Goldbach conjecture
is either true or false.
Even intuitionist will admit that Goldabch conjecture is true or
false, given its Sigma_1 character. This means that, about the (true-
or-false) nature of GOLDBACH is doubtable only for an ultrafinitist.
BTW, Goldbach conjecture asserts that all female (even) numbers can be
written as a sum of two primes, except the number two. (I forget the
word "even" in my enunciation above!).
>
>>
>> Here, you would have taken the twin primes conjecture, and things
>> would have been different, and more complex.
>
> Because, even if it is false, it cannot be proven false by
> exhibiting an
> example?
Yes. And this entails that both PA+TPC and PA + (~TPC) could be
consistent, yet one of those theory has to be unsound, or if you
prefer has to enunciate false arithmetical statements (yet consistent
with PA).
"Sound" is relative to the usual understanding of the natural numbers
which is presupposed in any work in mathematical logic or computer
science, like it is presupposed in any part of any physical theory.
That usual meaning is taught in primary school without any trouble.
In model theory, this notion of soundness can be made more precise,
through the notion of standard model of PA for example, but this
presupposes, in the meta-theory, an understanding of that usual notion
of numbers.
Nobody doubts the consistency and soundness of the theories like RA
and PA. (Even Torgny, who fakes that he doubts them for a
philosophical purpose unrelated to our discussion, like he fakes to be
a faking zombie, etc. This is clear from older post by Torgny).
>
>
>>
>> Note that a theory of set like ZF shed even much more large light on
>> arithmetical truth, (and is still incomplete on arithmetic, by
>> Gödel ...).
>> Incidentally it can be shown that ZF and ZFC, although they shed
>> different light on the mathematical truth in general, does shed
>> exactly the same light on arithmetical truth. They prove the same
>> arithmetical theorems. On the numbers, the axiom of choice add
>> nothing. This is quite unlike the ladder of infinity axioms.
>>
>> I would say it is and will be particularly important to distinguish
>> chatting beings like RA, PA, ZF, ZFC, etc... and what those beings
>> are
>> talking about.
>>
>> Bruno
>
> Do you mean PA talks about the natural numbers but PA+theorems is a
> different mathematical object than N?
I am not sure I understand what you mean. PA is an (immaterial)
machine, or a program if you want. I guess that, by PA+theorems, you
mean the set of theorems of PA. In some context we can identify PA and
PA+theorems, because the context makes things unambiguous. But
strictly speaking those are different mathematical object: PA is
finite (well, as I defined it usually), But PA+theorems is infinite.
Both talk about N, and both are different of N. Indeed PA is a finite
(or infinite in the usual first order presentation) set of axioms and
rules, PA+theorems is an infinite set of formula, and N is an infinite
set of numbers. That is very different. Of course both PA and PA
+theorems (your wording) talk really about the structure (N, +, x),
that is the set of numbers N together with its additive and
multiplicative structure, as studied in school.
It is important to distinguish a theory or a machine (usually a finite
object), with the set of statements proved by that theory or machine
(usually an infinite set).
And it is important to distinguish both of them with the semantical
content of those statements produce by that theory or machine. In
metamathematics (or mathematical logic) that "semantical content" will
itself be represented by a mathematical object (a model) in some other
theory (usually set theory, or category theory, or model theory).
With respect to the current thread on the seven step, this is of
course sort of advanced remarks. But mathematical logic is not an easy
subject. Many things which are not distinguished in the usual practice
of mathematics or physics are distinguished by logicians.
Bruno
>
> Bruno:
> I understand a little better. is there a citition for a version of
> Church Thesis that all algorithm can be written in
> FORTRAN?
The original Church Thesis, (also due to Post, Turing, Markov, Kleene,
and others independently)
is this:
A function is computable if and only if it is programmable in LAMDA
CALCULUS.
Then it is an easy but tedious exercise of programing to show that you
can simulate LAMDA CALCULUS with FORTRAN, and that you can simulate
FORTRAN with LAMBDA CALCULUS. So they compute the same functions.
And the same is true with LISP, or JAVA, or ALGOL, or C++, etc... in
the place of FORTRAN.
A thorough introduction to Church thesis, and I would say one far
deeper than usual, is integrally part of the seventh step of UDA. So
we will come back on this soon or later. Church thesis is really the
key and the motor of both UDA and AUDA. I have discovered that it is
rarely well understood, even by many "experts". Like Gödel's theorem,
Church's thesis is often deformed or misused.
Bruno