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Topic: Matheology § 288
Replies: 15   Last Post: Jun 22, 2013 12:23 AM

 Messages: [ Previous | Next ]
 fom Posts: 1,968 Registered: 12/4/12
Re: Matheology § 288
Posted: Jun 21, 2013 7:18 PM

On 6/21/2013 7:44 AM, Julio Di Egidio wrote:
> "Julio Di Egidio" <julio@diegidio.name> wrote in message
> news:kpunob\$l93\$1@dont-email.me...

>> "Alan Smaill" <smaill@SPAMinf.ed.ac.uk> wrote in message
>> news:fwehagtm58s.fsf@eriboll.inf.ed.ac.uk...

>>> "Julio Di Egidio" <julio@diegidio.name> writes:
>>>> "fom" <fomJUNK@nyms.net> wrote in message
>>>> news:C6KdnZCccIjltVzMnZ2dnUVZ_t6dnZ2d@giganews.com...
>>>>

>>>>> "Numbers count themselves"
>>>>
>>>> Indeed, how else?

>>>
>>> What does pi count?
>>> Isn't it a number?

>>
>> pi counts pi, of course...

>
> << Edward Nelson criticizes the classical conception of natural numbers
> because of the circularity of its definition. In classical mathematics
> the natural numbers are defined as 0 and numbers obtained by the
> iterative applications of the successor function to 0. But the concept
> of natural number is already assumed for the iteration. >>
>
> <http://en.wikipedia.org/wiki/Ultrafinitism#Main_ideas>
>
> Julio
>
>

For better or for worse, I have spent a great deal of time
trying to understand "logical foundation" as, apparently,
rejected by Brouwer.

In "logic" there is a problem with denotation and reference.

For "logic" to be applicable, there is a problem of unique
reference. While 'x=x' may have ontological interpretation,
'x=x' also has a semantic or metalinguistic interpretation
according to which the singular term 'x' has a consistent
usage.

It may be that there is some *given* system of names -- I
could accept that if I knew them. But, I do not.

So, I am left with generating a system of names (If
they denote, I am speaking of a consistent global
labeling. Otherwise, I am speaking of a collection
of distinct inscriptions.).

I do not see how to divorce an ordinal sequence from
a sequence of names introduced for the purpose of
"logic". That is, after the first "naming symbol" is
utilized, it is removed from possible naming symbols
because of the uniqueness criterion.

This is the problem of merely "purporting reference"
without considering what is presupposed. One may
have a geometry or a linear order. In either case,
verification of the semantic requirement involves
serialization.

One may reject a "logical foundation" personally. But,
that does not remove the need to prove that someone who
does accept "logical foundation" is assuming natural
numbers when all they are doing is "naming".

If I accept that mathematics reduces to the logical
species of natural numbers, then perhaps Nelson (and
his predecessors, the Brouwerian "pre-intuitionists"
who gave the same criticism) are correct.

For what this is worth, Frege *defined* zero. The
role of the Dedekind-Peano axioms had been that of
a necessary condition to be fulfilled. Nelson's
criticism merely applies to views where the axioms
are taken to be "definitions-in-use".

Logic involves priority, and Nelson's statement
is debatable on these grounds.

I do not disagree that the naming of numbers
has a correspondence with the count of names.
But, because of Cantor's insights and investigations
of infinity, ordinality and cardinality are not
taken to be the same thing.

What does Nelson mean by "natural number"?

Date Subject Author
6/20/13 Alan Smaill
6/20/13 LudovicoVan
6/21/13 LudovicoVan
6/21/13 Tanu R.
6/21/13 LudovicoVan
6/21/13 Tanu R.
6/21/13 LudovicoVan
6/21/13 Tanu R.
6/21/13 fom
6/21/13 LudovicoVan
6/22/13 fom
6/22/13 fom
6/22/13 fom
6/21/13 Tanu R.