Re: William T. Parry gets rid of Disjunction introduction

On 6/30/2026 9:55 AM, olcott wrote:
> On 6/30/2026 3:10 AM, Mikko wrote:
>> On 29/06/2026 16:55, olcott wrote:
>>> On 6/28/2026 4:32 AM, Mikko wrote:
>>>> On 27/06/2026 21:29, olcott wrote:
>>>>> On 6/27/2026 1:24 PM, dbush wrote:
>>>>>> On 6/27/2026 2:03 PM, olcott wrote:
>>>>>>> On 6/27/2026 12:54 PM, dbush wrote:
>>>>>>>> On 6/27/2026 11:11 AM, polcott wrote:
>>>>>>>>> On 6/27/2026 2:08 AM, Mikko wrote:
>>>>>>>>>> On 26/06/2026 15:49, olcott wrote:
>>>>>>>>>>> On 6/26/2026 1:49 AM, Mikko wrote:
>>>>>>>>>>>> On 26/06/2026 04:32, olcott wrote:
>>>>>>>>>>>>> William T. Parry, Entailment Logics
>>>>>>>>>>>>> gets rid of Disjunction introduction
>>>>>>>>>>>>> to prevent the principle of explosion
>>>>>>>>>>>>>
>>>>>>>>>>>>> A simple logical matrix and sequent calculus for
>>>>>>>>>>>>> Parry’s logic of Analytic Implication
>>>>>>>>>>>>>
>>>>>>>>>>>>> The main and distinctive feature of PAI (and of the many
>>>>>>>>>>>>> systems of analytic implication belonging to its ilk) is
>>>>>>>>>>>>> the rejection of the classically valid principle of Addition,
>>>>>>>>>>>>> sometimes also referred to as Disjunction Introduction. In
>>>>>>>>>>>>> other words, the principle leading from a formula ϕ to a
>>>>>>>>>>>>> disjunction of the form ϕ ∨ ψ, where ψ is an arbitrary
>>>>>>>>>>>>> formula. Parry blamed on this principle the derivability
>>>>>>>>>>>>> of the paradoxes of strict implication—given that it is
>>>>>>>>>>>>> famously featured in Lewis’ derivation of an arbitrary
>>>>>>>>>>>>> formula ψ from a contradiction of the form ϕ ∧ ¬ϕ.
>>>>>>>>>>>>>
>>>>>>>>>>>>> https://philarchive.org/archive/SZMASL
>>>>>>>>>>>>
>>>>>>>>>>>> He also gets rid of an efficient way to convince people who 
>>>>>>>>>>>> don't
>>>>>>>>>>>> understand much of logic.
>>>>>>>>>>>
>>>>>>>>>>> As I recently showed in another post. I figured
>>>>>>>>>>> all this out on my own. I didn't even know that
>>>>>>>>>>> anyone else ever did this. I just knew that when
>>>>>>>>>>> trying to find out what is deduced from a set of
>>>>>>>>>>> premises that you cannot pop in another sentence
>>>>>>>>>>> from out of nowhere and get a correct conclusion.
>>>>>>>>>>>
>>>>>>>>>>> By popping in another sentence from out of nowhere
>>>>>>>>>>> (as it shows above) the principle of explosion is
>>>>>>>>>>> derived.
>>>>>>>>>>
>>>>>>>>>> The usual meaning of proof is a sequence of statement where 
>>>>>>>>>> eachstatement either is a premis or follows from one or more 
>>>>>>>>>> earlier
>>>>>>>>>> statements 
>>>>>>>>>
>>>>>>>>> Except with Disjunction introduction, that is its problem.
>>>>>>>>
>>>>>>>> So you're saying that in the following natural language statement:
>>>>>>>>
>>>>>>>
>>>>>>> It is a key issue in that it creates the
>>>>>>> psychotic break from reality known as the
>>>>>>> Principle of Explosion, otherwise it may
>>>>>>> make no difference at all.
>>>>>>>
>>>>>>> Stay on topic or I will block you.
>>>>>>
>>>>>> Explain in detail how the below which you dishonestly trimmed is 
>>>>>> off- topic.
>>>>>>
>>>>>
>>>>> The topic is how Disjunction introduction enables the
>>>>> Principle of Explosion.
>>>>
>>>> It does not. In any sensible logic every tautology is provable.
>>>> Then the principle of explosion follows.
>>>
>>> POE is unprovable in both of these more sensible systems
>>> of logic.
>>
>> THe expression "these system" above does not denote.
>>
> 
> Parry’s logic of Analytic Implication
> 
> Relevance Logic
> https://plato.stanford.edu/entries/logic-relevance/
> 
>>> The POE is an actual psychotic break from
>>> reality when one pays full and complete attention to
>>> the underlying semantics and does not stupidly take
>>> semantics out of logic and put it in a separate model.
>>
>> No, it is not. The principle of explosion is about consequencies
>> of a false premise, which already is a break from reality even
>> when no consequence is inferred.
>>
> 
> Only because semantics is ignored.
> There is nothing semantically meaningful about a
> contradiction that derives anything at all besides FALSE.
> 
> There is nothing semantically meaningful about FALSE
> that derives anything at all besides FALSE.

False, as you have admitted otherwise on the record (see below):

On 6/28/2026 11:56 PM, dbush wrote:
 > On 6/27/2026 11:34 PM, dbush wrote:
 >> On 6/27/2026 11:23 PM, olcott wrote:
 >>> On 6/27/2026 9:02 PM, dbush wrote:
 >>>> On 6/27/2026 9:53 PM, dbush wrote:
 >>>>> On 6/27/2026 9:49 PM, olcott wrote:
 >>>>>> On 6/27/2026 8:42 PM, dbush wrote:
 >>>>>>> On 6/27/2026 9:40 PM, olcott wrote:
 >>>>>>>> On 6/27/2026 8:29 PM, dbush wrote:
 >>>>>>>>> Given that the following natural language statement is true:
 >>>>>>>>>
 >>>>>>>>> --------------------------------------
 >>>>>>>>> Earth is the third planet from the sun.
 >>>>>>>>> --------------------------------------
 >>>>>>>>>
 >>>>>>>>> In the following natural language statement:
 >>>>>>>>>
 >>>>>>>>> --------------------------------------
 >>>>>>>>> At least one of the following statements is true:
 >>>>>>>>> - Earth is the third planet from the sun.
 >>>>>>>>> - <X>
 >>>>>>>>> --------------------------------------
 >>>>
 >>>> Given that <X> is any *truth bearing* natural language statement,
 >>>> does there exist a statement X such that the condition "At least one
 >>>> of the following statements is true" is false?
 >>>>
 >>>
 >>> Head games will be ignored.
 >>>
 >>
 >> Explain in detail how this is a head game.
 >>
 >> Failure to either answer the above question or explain how it is a
 >> head game in your next reply or within one hour of you next post in
 >> this newsgroup will be taken as your official, on-the-record admission
 >> that Disjunction introduction is in fact truth preserving and valid,
 >> and therefore so is the Principle of Explosion.
 >>
 >
 > Let the record show that Peter Olcott made the following post in this
 > newsgroup:
 >
 > On 6/28/2026 10:52 PM, olcott wrote:
 >  > Q also can't bake a birthday cake, this does not make
 >  > Q in any way "incomplete" relative to what it was
 >  > defined to do.
 >  > ...
 >
 > And more that one hour has passed with no attempt to answer the above
 > question or explain why it is a head game.  Therefore, as per the above
 > criteria:
 >
 > Let The Record Show
 >
 > That Peter Olcott
 >
 > Has *Officially* Admitted:
 >
 > That Disjunction introduction is in fact truth preserving and valid, and
 > therefore so is the Principle of Explosion.