Drexel dragonThe Math ForumDonate to the Math Forum

Search All of the Math Forum:

Views expressed in these public forums are not endorsed by Drexel University or The Math Forum.

Math Forum » Discussions » sci.math.* » sci.math

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

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]

Posts: 1,968
Registered: 12/4/12
Re: Matheology § 288
Posted: Jun 21, 2013 7:18 PM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

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

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

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"?

Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© Drexel University 1994-2014. All Rights Reserved.
The Math Forum is a research and educational enterprise of the Drexel University School of Education.