> On 3 Mar 2019, at 22:58, Brent Meeker <meeke...@verizon.net> wrote:
> 
> 
> 
> On 3/3/2019 1:37 PM, John Clark wrote:
>> On Sun, Mar 3, 2019 at 2:52 PM Philip Thrift <cloudver...@gmail.com 
>> <mailto:cloudver...@gmail.com>> wrote:
>> 
>> > If a program "represents" a real number (e.g. in the spigot sense), then 
>> > that could be said to "define" it.
>> 
>> But for most Real Numbers there is no such program. 
>> 
>>  > But what does it mean for a real number to be "defined"?
>> 
>> If you can point to a property that a Real Number has that no other Real 
>> number does then it is defined;
> 
> The smallest real number that is not defined.

That is a version of Berry Paradox. Chaitin used it to give a proof of its 
incompleteness theorem (proved a long time before by Post).

It means that we do not have an all encompassing notion of “definable”, a bit 
like Truth. We can, nevertheless, define it for large class of objects.

So, here, “the smallest non definable real number” does not define a number.


Bruno



> 
> Brent
> 
>> a number like PI can be defined and you can approximated it with a 
>> calculation, a Busy Beaver Number can be defined but not approximated, most 
>> Real Numbers can not be defined or approximated and thus most Real Numbers 
>> can not be named.
>> 
>> John K Clark
>> 
>> 
>>  
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