Re: William T. Parry gets rid of Disjunction introduction

On 03/07/2026 17:50, olcott wrote:
> On 7/3/2026 3:22 AM, Mikko wrote:
>> On 02/07/2026 17:40, olcott wrote:
>>> On 7/2/2026 1:29 AM, Mikko wrote:
>>>> On 01/07/2026 18:06, olcott wrote:
>>>>> On 7/1/2026 1:53 AM, Mikko wrote:
>>>>>> On 30/06/2026 16:55, 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.
>>>>>>
>>>>>> A break from reality is a break from reality, no matter whether
>>>>>> the semantics is ignored or considered. Though if there is no
>>>>>> semantics, even any ignored one, there is no connection to
>>>>>> reality to break.
>>>>>>
>>>>>
>>>>> Ignoring semantics is always a break from reality.
>>>>
>>>> So is any semantics other than real world semantics.
>>>
>>> Hypotheticals are useful for making decisions.
>>
>> Which is an example of the usefulness of a break from reality. It
>> als shows that calling a break from reality "psychotic" without
>> further consideration.
> 
> That Donald Trump might start WW III is a hypothetical
> that can possibly be is useful.

Whether Donald Trump will start WW III is not yet known, so that
cannot be called an example of counter-factual.

> That Donald Trump is the one and only Lord and Savior Jesus Christ
 > is a hypothetical that cannot possible be making it useless.

Maybe, but irrelevent as you did not claim it be useful when you
presented it.

-- 
Mikko