On Sun, Dec 16, 2018 at 10:22 PM Brent Meeker <[email protected]> wrote:

>
>
> On 12/16/2018 4:39 PM, Jason Resch wrote:
>
>
>
> On Sun, Dec 16, 2018 at 5:53 PM Brent Meeker <[email protected]> wrote:
>
>>
>>
>> On 12/16/2018 1:56 PM, Jason Resch wrote:
>>
>>
>>
>> On Sun, Dec 16, 2018 at 3:28 PM Brent Meeker <[email protected]>
>> wrote:
>>
>>>
>>>
>>> On 12/15/2018 10:24 PM, Jason Resch wrote:
>>>
>>>
>>>
>>> On Sat, Dec 15, 2018 at 11:35 PM Brent Meeker <[email protected]>
>>> wrote:
>>>
>>>>
>>>>
>>>> On 12/15/2018 6:07 PM, Jason Resch wrote:
>>>>
>>>>
>>>>
>>>> On Sat, Dec 15, 2018 at 7:57 PM Brent Meeker <[email protected]>
>>>> wrote:
>>>>
>>>>>
>>>>>
>>>>> On 12/15/2018 5:42 PM, Jason Resch wrote:
>>>>>
>>>>> hh, but diophantine equations only need integers, addition, and
>>>>>> multiplication, and can define any computable function. Therefore the
>>>>>> question of whether or not some diophantine equation has a solution can 
>>>>>> be
>>>>>> made equivalent to the question of whether some Turing machine halts.  So
>>>>>> you face this problem of getting at all the truth once you can define
>>>>>> integers, addition and multiplication.
>>>>>>
>>>>>>
>>>>>> There's no surprise that you can't get at all true statements about a
>>>>>> system  that is defined to be infinite.
>>>>>>
>>>>>
>>>>> But you can always prove more true statements with a better system of
>>>>> axioms.  So clearly the axioms are not the driving force behind truth.
>>>>>
>>>>>
>>>>> And you can prove more false statements with a "better" system of
>>>>> axioms...which was my original point.  So axioms are not a "force behind
>>>>> truth"; they are a force behind what is provable.
>>>>>
>>>>>
>>>> There are objectively better systems which prove nothing false, but
>>>> allow you to prove more things than weaker systems of axioms.
>>>>
>>>>
>>>> By that criterion an inconsistent system is the objectively best of all.
>>>>
>>>>
>>> The problem with an inconsistent system is that it does prove things
>>> that are false i.e. "not true".
>>>
>>>
>>>> However we can never prove that the system doesn't prove anything false
>>>> (within the theory itself).
>>>>
>>>>
>>>> You're confusing mathematically consistency with not proving something
>>>> false.
>>>>
>>>
>>>  They're related. A system that is inconsistent can prove a statement as
>>> well as its converse. Therefore it is proving things that are false.
>>>
>>>
>>> But a system that is consistent can also prove a statement that is false:
>>>
>>> axiom 1: Trump is a genius.
>>> axiom 2: Trump is stable.
>>>
>>> theorem: Trump is a stable genius.
>>>
>>
>> So how is this different from flawed physical theories?
>>
>>
>> The difference is that mathematicians can't test their theories.
>>
>
> Sure they can:  A set of axioms predicts a Diophantine equation has no
> solutions.  We happen to find it does have a solution.  We can reject that
> set of axioms.
>
>
> Then the axioms must have also included enough to include Diophantine
> equations (e.g. PA) so you have added axioms making the system inconsistent
> and every proposition is a theorem.  The only test of the theory was that
> it is inconsistent.
>

There is also soundness <https://en.wikipedia.org/wiki/Soundness> which I
think more accurately reflects my example above.

Jason

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