I knew a guy who claimed that if we don't go over to the Mayan calendar, the world will end. — frank

One day the world will end, and we won't know why it will end until it does end. Until then, the jury is out as to whether the guy you knew is correct.

I know that argument, but that's the stupid argument from logical necessity, like God can be created by syllogism.

My novel contribution to the field of Cartesian analysis that appeared for the first time here argues that God is required in order to avoid to solipsism, an inherently incoherent position. That is, feel free to be an atheist, but your position is incoherent.

Descartes saved us from the unsalvagable pits of eternal and infinite skeptism by reminding us that God would not allow for such. There being no other way out, God becomes the only way for such salvation.

That's my contribution to the field.

So I see Descartes as claiming not faith but knowledge of God's existence -- and this need not even counter faith. Especially at the time scientists and theologians weren't far apart. In a way I'm trying to bring out "the spirit of the times" by focusing on the prima facie meaning to put Descartes in the context of the Enlightenment. — Moliere

If you're distinguishing between faith and knowledge, you'll have to define those terms. If we accept that knowledge requires a justified true belief, it would seem that the distinction between faith and knowledge would somehow hinge on the justification element. Those who believe in God based upon faith do not admit to having no justification for their faith, but they might use personal conviction, religious text, mystical feeling, or even pragmatic reasons to justify that faith. Some might even suggest an empirical basis (as in their experience of reality leads them to believe there must be a God), so that question is somewhat complicated.

That's not to say there are not differences between the justificaitons used by the faithful and those who are not of faith, but it's difficult to say one "knows" something and the other doesn't. What I think those who question those of faith really are attacking is the "truth" element, meaning they simply think there is no God and there is no way you can "know" something that isn't true. So, if you say Descartes knows there is God, then you are saying there is a God because to know something means it must be true.

My main point here isn't to suggest that Descartes made an intentional argument proving God by arguing that failure to accept God led to an incoherent solipsitic position. I just think that by working backwards and seeing what Descartes required to avoid solipsism you can come to the conclusion that God is necessary for Descartes to avoid that.

I do see the similarities with Kant's approach, but I also see the differences. With Kant, as it pertains to time, he argued that you could not begin to understand something without placing it in time. That is, an object outside of time is meaningless.

With Descartes, there is an private language argument problem that can suggest a complete incoherence to solipsism. https://iep.utm.edu/solipsis/#:~:text=The%20Incoherence%20of%20Solipsism,-With%20the%20belief&text=As%20a%20theory%2C%20it%20is,his%20solipsistic%20thoughts%20at%20all . What this would mean is that if God is necessary to avoid solipsism and solipsism is incoherent, then you need God to avoid incoherence.

Whether you want to go down that road, I don't know. I'm not necessarily arguing that a godless universe would result in a complete inability to understand anything, but, even if I did, I still see a distinction between that sort of incoherence and the one Kant references when he says time is imposed on objects and therefore a necessary element of the understanding.

This whole argument here has expanded as I've thought about it, so maybe there is a good argument that human understanding is impossible without God if one follows Descartes' reasoning. This wouldn't mean there is God. It would just mean you can't know anything without God.

How does faith get us out of the cogito? — Moliere

I'm not sure I understand what you're asking. I was saying faith gets us out of solipsism, which is the net result of the Cartesian method of complete skepticism. The cogito leaves us with just knowing that the single mind of the single doubter is all that exists. To get beyond that, you have to have faith. That's what Descartes indicated by his reliance upon God.

But maybe I didn't fully understand your question.

So, if I have you right, you're making the argument that he's more targeting atheists in saying that if they do not believe in God then this is all they can know, and given that they know more than that, they ought consider believing in God. Sort of like the Secret Atheist, but instead he's dressing it up for the church while talking to his contemporaries too. — Moliere

I just think that what Descartes did was to doubt all basic foundations and then all he had left was knowledge of his self as a doubting thing. That is a solipsitic conclusion. In order to get himself back to where he could have some knowledge of the world and of other minds, he pulled in God and used God to form the foundation for all knowledge of the world.

If you buy into this approach, God becomes necessary in order to avoid solipsism. It doesn't mean God exists. It just means that you cannot know anything without God's existence (except knowing that you exist as a not knowing thing).

Many find Descartes problematic because they believe he has doubted that which no person would actually doubt and that he has created a fabricated quandary and from that Western philosophy has gone down this road of trying to prove that which no person truly doubts. I don't find Descartes problematic at all because I never doubted that the foundation for our beliefs was faith and that without faith you will have nothing but doubt. Perhaps the opposite of doubt is faith.

Do you think anything can be inferred from the cogito, whatsoever — Moliere

A reasonable inference is that God is necessary in order to avoid solipsism.

That seems to be the larger argument he was making.

Well, given that Sartre is talking about radical doubt as being given to us only through time reference (something like Kant's intuitions I feel) there is nothing other to hang experience off of is there?

'Rely' is probably the sticky word here. Sartre likes to make words less like words. — I like sushi

I understood Sartre here to mean (and I don't think he was terribly clear) that doubt must occur in the past, present, and future for it to be real doubt. So, if I doubt a pen is in front of me, I have to doubt all that I previously knew of pens, the current pen I see, and the future pen that I have grown accustomed to seeing over time. I can't just say I question the pen's existence in the here and now and that be the radical and complete doubt Descartes is looking for.

On the Kant intuition issue, I don't think Sartre was suggesting that we must doubt time if we want to be radical skeptics. I think he was saying we must doubt an object in all phases of time: past, present, and future. The pen never was, is not, and never will be. I don't think he's suggesting we doubt our Kantian intuitions. In fact, all the Kant is committed to saying about time is that we think there is time, which doesn't give any external reality to it. That is, a radical skeptic would not be required to say there is time, but would only say he thinks there is time, which is consistent with solipsism.

So the question: Must the cogito rely upon a notion of the past and future in order for its doubt to make sense?

If so then it seems the skeptic must at least admit of knowledge of time. And so cannot be universally skeptical. If we know about time then just how could there be an Evil Demon behind the appearances? Is it outside of time? If so then the cogito has nothing to do with it, as per the argument. — Moliere

I think it's correct to assume that we cannot understand the world without reference to time, and so the Cogito must be understood within the context of time.

However, that does not mean that the Cogito proves that time exists, nor does it suggest that Descartes failed in his attempt to be infinitely skeptical by assuming the existence of time. It only means that an understanding of the world is impossible without placing events within time.

This approach I'm arguing is consistent with Kant's view that time does not necessarily exist outside humans because it is a form of intuition necessary for our perception of reality, but not an inherent property of the world itself.

To truly win a war requires permanent occupation. We can destroy a government and devastate an economy, but unless we're prepared to colonize and occupy, all we can do is destroy and allow it to rebuild under a new set of leadership.

France colonized Vietnam and held it until Japan took it over until they lost it to Hiroshima, and then the US didn't want it to go Comminist so the whole wrangling in their politics that was supposed to end with allowing the Vietnamese to democratically choose their course. More US meddling and then war, but the point is the US never wanted to take over Vietnam. They just wanted them to do as they were told. Had the US wanted to annex it for statehood, that'd be a different story, but even then, colonies are hard to hold. The British Empire couldn't hold and neither could the USSR.

As to the difference between the material conditional and informal notions of the conditional, that point has been gone over and over and over. If there is something more you want to say about, no one is stopping you. — TonesInDeepFreeze

Why are you telling me that no one is stopping me?

And I gave you information about modus ponens, consistency and arguments too, to clear things up for you after your confused comment about them. — TonesInDeepFreeze

Thank you for reminiscing, but that's not what my last post was about.

I've said it maybe fifty times in this forum: Ordinary formal logic with its material conditional does not pertain to all contexts. But that is not a basis that one should not say how ordinary formal logic handles a question and not a basis that one should not explain ordinary formal logic to people who are talking about it without knowing about it. — TonesInDeepFreeze

This is not responsive to anything I've said. I know you want to keep saying over and over what formal logic dictates, but my post was referring to how ordinary language handled conditionals and how that was distinct from formal language. I didn't suggest we should jettison formal logic or that it lacked value because it was distinct from the ordinary way we speak.

For a foreigner like me, it is complicated to understand America's core values. Following your views and posts, it seems that an American core value is gun freedom; also, you are against censorship, but you would avoid having a LGTBIQ flag in your classroom; then, you claim that it is essential to have different beliefs, but some of you label as 'Communist' the working model of Mondragón (Spain) for not being capitalist enough. 

A core value... complicated, mate.

For me, it is to have a strong national healthcare system. So, to you is carrying a M-16 in your big polluting Ford truck. — javi2541997

I'm not sure what you mean by "core value." Gun ownership is a 2nd Amendment right and free speach is a 1st Amendment right, so those could be classified as core values. The 1st Amendment doesn't guarantee the right to teachers to fly whatever flag or post whatever poster in their classroom they want, so I don't see the hypocrisy there. Government buildings can have designated purposes, and it's not clear why it would be appropriate to have an LGBT flag hanging in the classrom or why it'd be appropriate to fly a right wing oriented flag.

America is a capitalist country, which makes it less Marxist than other countries, which I guess is just true. I don't know how much time Americans spend thinking and commenting upon the working model of Spain, but, to the extent it is more communistic than the US, that would likely not be something many Americans would want to emulate.

The US does have strong national healthcare. Your concern is over affordability and accessibility. That is not a Constitutional issue in the US, but it is true that a very large number of people do not want a government controlled healthcare system in the US.

The M-16? Sure, we all walk around with fully automatic rifles. As to the attack on the Ford truck, you've not just ridiculed the rednecks you envision bouncing around on the back roads with their rebel flags, but also the union workers who built those vehicles who @T Clark just lamented were leaving the Democratic party for this very reason.

If everyone who thinks differently than you is forced to listen to lectures about how stupid they are, then they'll stand behind Trump and laugh as he gives them the middle finger. And that's precisely what he represents.

Another suggestion would be to allow the Democrat voters the power to choose their own candidate. Obama won because he pushed Hillary aside by actually being popular. Personality matters. Just affixing a (D) at the end of someone's name isn't going to assure them votes. The Republican process is a free for all, which is making it ironically a much more democratic process.

We might correct them, "well, actually ~Q." "Your reasoning is spot on and logical, it just happens to be that ~P, so while your reasoning is valid, the argument you presented is unsound." — NotAristotle

Yes, there is a difference between an unsound argument that arises from an incorrect fact as opposed to one that arises from a contradiction.

- If I go to the store, I will buy milk, I went to the store, so I bought milk. That's true, unless I forgot to buy milk.

- If I go to the store, I will not have gone to the store, I went to the store, so I didn't go to the store. That statement is never true regardless of what I do. The reason it's never true is because "If I go to the store, I will not have gone to the store" is logically equivalent to "I did not go to the store."

In your case, you DO have the memories. — AmadeusD

I'm really not following. I'm not just trying to be difficult. Why do you lose memories when you teleport and why do you posit that I have a continuous memory from birth to now? You're distinguishing your example from mine, and I don't see how teleporting erases memory and I don't see why moving slowly through life preserves it.

I thought teleporting challenged identity because it was not possible to show what of the same matter existed from Point A to Point B. Everything disappeared and went away and then popped back. I get how that causes an indentity problem.

But if I go from Point A to Point B over 50 years and not a single same cell or single same memory exists from age 1 to age 50, then don't I have the same identity problem as you noted in the teleporting?

And then how isn't all this Ship of Theseus problems?

What is going on here is not a pedantic mismatch between English and some esoteric academic exercise. Rather, there are ambiguities in the English use of "If... then...", "...or..." and various other terms that we must settle in order to examine the structure of our utterances in detail. — Banno

I consider the logical conditional a performative, as exists in an algorithmic way.

Consider, "If X = 4, then Y = 7." That is , if we set X at 4 then Y is set at 7. We could not program if we could not make such statements. If P then Q results in the occurence of Q when P is the case necessarily. I consider this an analytic operation and consistent with computer logic in programming (as far as I know about programming).

I consider the linguistic conditional not an indication of what is or what will be, but a hypothetical counterfactual that does not indicate, but hypothosizes. Because it does not indicate, we don't speak in the indicative mood, but in the subjunctive, as in what we wish, hope, or hypothesize about.

As in: "If I were President, I would lower taxes." This is not represented as P -> T. That would overstate the meaning of my speculative statement. Note the "were," not "was." This is a counterfactual (it hypothethesizes an antecedent that did not occur), not a logical conditional.

"If I was President, I lowered taxes" makes more sense as a formal conditional.

If I was President, I lowered taxes
I was President
ergo I lowered taxes

But not:

If I were President, I would lower taxes
I were President
ergo I would lower taxes

What does it mean that I were President versus I was President? I think the meaning is critical in changing from the formal indicative conditional to the non-formal linguistic subjunctive conditional.

My thoughts at least.

It just gives us the extremely uncomfortable conclusion that (for example) in a situation of teletransportation, you die. You don't come to in place 2. You simply die. Someone new, with your same memories, exists in place 2. — AmadeusD

Why do I have to use teleportation? Why can't I just say I existed as a baby at Time 1, Location 1 and now I'm at Time 1,000 at Location 1,000? This creates the same situation. I have nothing in common with myself across all those times and locations, not even a consistency of memory. Do I die and get reborn every time I shed my old body for my new one?

You don't have to interrupt the time/space continuim to create these questions. I still think they're just Ship of Theseus problems dealing with identity.

There would be two people who each identify as being Michael, and we would identify one as being the original and the other as being a copy (and they would perhaps identify themselves the same way). — Michael

Are you identifying the brain as Michael, or just the contents of that brain? If I download a pdf to your computer, why does the original RAM where the pdf was stored matter in terms of pdf identity? Does it matter if I cut and paste the pdf or if I copy and paste the pdf in terms of where the true pdf is?

When Frank reads my post and you read my post, which post is the original that is being read?

I'd say the program is the code regardless of where it's stored in terms of identifying the program.

The brain in the jar is you if it contains your thoughts, which is why a vegetative brain is no different than you arm. Your essence isn't the brain. It's what the brain happens to be storing, which means you could be you in someone else's brain or on a USB drive.

What we then need to do is itemize all your thoughts, emotions, perceptions, and whatever else is stored in that hard drive and then zap them dead one at a time. Once you stop being you, we can then know what essential thought made you you once and for all. But we're talking about internal feeling now, not brains. The brain is just vehicle with a person behind the wheel in your example, but not the person itself, right?

Any position which entails a) I am the person with a body, b) I am not the person in the jar, or c) I am both the person with a body and the person in the jar is wrong. — Michael

If you were in a vegetative state on a table and your brain was removed to the jar, there'd be no distinction between the you on the table and the you in the jar. That is, there is a position that entails you are the person with the body, you are the person in the jar, and you are the person in the body and the jar. If you say you are not both on the table and in the jar, then which one is you?

The reason we get this result is because you are equating the brain to the contents of the brain, namely the memories and the phenomenal state of consciousness. That is, you are positing your memories and consciousness as your essence, and so when I remove those things from the brain, the body tissue and brain tissue become equal under an essence analysis.

But that creates even more complexities because even if those memories and the feeling of personal identity linked to your being Michael were to corrupt, we'd still say you were Michael. That is, if we took your brain out and put in the jar and that made you think you were someone else, we'd still assert yourself to be you because you had the same brain. But who is the person on the table?

And then suppose we could download your brain contents to another brain such that it replicated the mental contents of the first one and gave that other entity the exact feeling of Michaelness you have? Would we have two Michaels? What if the download from Michael 1 to Michael 2 was an actual transfer such that Michael 1 was empty of thoughts once Michael 2 was filled up? Who would be Micheal then?

I would re-write your statement to be: If I am my brain, then "Any position which entails a) I am the person with a body, b) I am not the person in the jar, or c) I am both the person with a body and the person in the jar is wrong."

We then just have to find situations where the antecdent is not satisfied or at least calls it into question.

I think that if we take any one part of the Ship of Theseus and replace it with a new part then it's still the Ship of Theseus, but that if we "replace" my head (and brain) with a new head (and brain) then it's no longer me, it's someone else. I'm the disembodied head living in a jar like in Futurama. There certainly can't be two of me, which would seem to follow from NOS4A2's position. — Michael

I don't know. I think you can play with these analogies to come up with anything, which is why essentialism is hard to maintain in any form. If you awoke with all your memories in Jane's body, you'd say you were you now in Jane's body even if your brain matter were entirely different. You also say you're you today even though you share no atom in common with your childhood self. If you lost all your memories when you were 10 years old and now had all new memories at 30 years of age, you'd still say you've maintained identity over time even though you share neither memories or cells with your former self.

If you took boards off the Ship of Theseus and rebuilt a new ship with those boards slowly (as you also replaced boards on your original ship), you could argue you've simply moved the ship piece by piece, and you could also argue that the other ship remained the Ship of Theseus because it maintained the same design and functionality over time. That is, you'd end up with two Ships of Theseus.

I'm not denying the significance of brains and memories in how they define identity, but there's always a counterexample that can be found to whatever definition you arrive at.

What would be the implications if we would say for any given argument under all values of the antecedent the conclusion may not result in a logical contradiction or the argument will be deemed invalid? — Benkei

This goes back to my pedantry comments. I can't see how it could matter if we designated a name for that special class of modus ponens described in the OP, where it is structurally consistent with modus ponens but is logically inconsistent. This thread strikes me as more of a primer in formal logic nomenclature than in logic qua logic.

If I woke up with amnesia or hallucinating I was Jesus, with no accurate Hanover memory, I'm still Hanover.

Isn't this just a Ship of Theseus question?

Most - I think all - lies are soluble in appropriate analysis. — tim wood

An example: I was speaking to a Russian woman who's been in the US for decades. Her recollection of the "Miracle on Ice" when the US won the Olympic gold in hockey was that the Soviet team was paid off. She said there was no way a top rated professional team could lose to amatuers. She said for the right money, they'd have had sex with each other (her words).

What fit my narrative was freedom over oppression and that Americans can win if they just believe. What fit her narrative was that her team was superior but her nation was corrupt. I hadn't thought about it before, but who knows what actually happened? We have no evidence of cheating, so I go with the US version, but my guess is that Russians rolled their eyes at the result while the US cheered.

And so if I'm as entrenched in US culture as Trumpians are in Trump culture, I can't imagine things being other than they appear. Does this give rise to conspiracies? Of course it does, but that's what breeds this post truth thing.

In the Truth Era, I wonder how much truth there was, or were we just more accepting due to homogenuity of ideology.

Cite some representative samples of my "unclear" "jargon laden style and weird grammatically abbreviated sentences". Thanks. — 180 Proof

Just playing.

But we've never trusted Russian elections or Iranian news. We've never agreed upon basic facts with our enemies. My question is whether the change is in what we take to be Truth as opposed to who our enemies are now. We find our enemies next door now, when we used to have to go far.

Isn't distrust just a symptom of polarization of viewpoints as opposed to something new?

What I know of Taylor appears in your quote, so feel free to fill in the details of what I don't know.

How is Taylor not consistent with Cartesianism? Taylor says we cannot offer a meaningful description of the human condition without describing our drivers for moral behavior. To be sure, our desire for morality and appreciation of it is unique among the other creatures in the world, or, if not truly unique, hyper developed comparatively. For that reason, I'd agree with Taylor regarding the idea we must analyze morality if we want to analyze people.

What I don't see though is why I could not be a Cartesian and fully agree with Taylor. Cartesian dualism posits a mind that has a free will that is subject to moral evaluation. Wouldn't Descartes agree with Taylor's assessment of the significance of understanding morality if one wanted to understand humanity then?

Per Descartes, if the self is defined as having free will, and it is through this free will that morality arises, then to understand the self would require an understanding of morality, and this would be in agreement with Taylor, true?

I wonder though how much Truth there was in the Truth Era as opposed up our current Post Truth Era. How much of is it that we just don't have a unified worldview and therefore we lack a subjectively consistent perspective?

Did the US and USSR.agree on the facts? Do Israel and Hamas agree on the facts? Do the Southern Baptists and atheists agree on the facts?

That is, is the Post Truth era really just a Post Common Ideology Era? We're used to people far away disagreeing with us on basic facts, but isn't a substantial part of this change just caused by our no longer agreeing with our neighbors?

From my perspective, the prior Trump election wasn't stolen. The arguments otherwise (which I hear among the educated where I live) are completely idiotic. But does the US Constitution really say anything about abortion? Are transsexuals truly women? Did Harris really have a chance like we were told? Not from your perspective, but what is the Truth?

Why do the murky areas of Truth always seem to land consistently with Ideology?

This isn't to dispense with the idea that there is Truth, but it is to suggest we've always found Truth/God on our side. We're just frustrated because we don't worship a common god.

But that's policy, not identity. But then you go on to say people voted because of their identity as republicans. It could be both of course, but you seem to be inconsistent as to which you consider more causal. — bert1

I think you read where I said that people vote Republican because they are Republican to suggest it's just a matter of party identity. There may be some of that, but that's not really what I meant. I meant they are Republican because they believe in Republican ideology.

Just like the reason Christians (for example) go to church. They go because they're Christian, meaning they believe in Christianity, not just because it's their team.

I get how you read what I said as you did, but it's not what I meant.

This poll tells us what the left believes the right believes.

If the right told you the only reason you voted for Harris was because you didn't like Trump and because all you wanted was a woman, how might you respond? I think you'd say you voted Democrat because you are Democrat.

A Trump vote was anti-woke, pro police, pro immigration control, pro reduced taxes, pro reduced regulation, pro Israel, pro life, pro drilling for oil, among other things.

Believe it or not, over 50% of the population voted Republican because they are Republican.

Mine was funny. Yours is disturbing.

If you awoke with your brain in a different body, and you were a hot girl, I'd be all over that.

Now we're even with the disturbing posts.

This scenario isn't that far fetched actually as this video analysis shows. It's only a few minutes and worth a watch, particularly at around 1:40.

Is this not why it's an extrovert's world?

How do we approach Betty Sue, that most intimidating creature? Do we walk right up to her and speak our heart? Never!

We have our friend send a note, or today we text, or maybe we set up an entire online meeting system where we can interact with her picture. If we do decide to directly approach, we drink a few pints to be sure our inhibitions are weakened.

And this is good to a point. Friendship groups like this one get formed, even marriages. But the other side is that friends meet up to do nothing but stare at their phones. People can't walk down the street without bumping into each other as they check their messages. Bodies in the wild, minds far away.

We're the addict who learned to cure our social limitations only to no longer know how to socially interact without our crutch. We have forgotten we evolved doing this in an entirely different way for 1000s of years. Successfully.

That's ambiguous. It could mean two things: — TonesInDeepFreeze

You make a valid point.

(C) and (D) are WRONG (see below). — TonesInDeepFreeze

I appreciate the deep analysis, but can you just draw me some Venn diagram circles with 1, 2, 3, and 4s on them and then I can see what can be what? It's easier on my visual brain.

We're actually debating what terms each of us can make up and the best terms that would describe whatever we're trying to say. I'll defer to yours with my backwards name and provide myself a translator so we can speak the same language. In truth, I think we largely follow what each other are saying at this point.

What I mean by "incoherent" is that which is "expressed in an incomprehensible or confusing way; unclear." @Michael's rendition of what "incoherent" might look like includes gibberish, which is a new additon to this conversation, so it might require an entirely different term. We could then start inserting such non-linguistic items such as the smell of lilac and that weird feeling of deja vu in as premises. Everyone loves a good emoji as well, so that could go in there too.

In any event, "Gloobelfooble" could indeed be a statement, inasmuch as A can be statement and Q can be a statement.

If Gloobelfooble, then Q
Gloobelfooble
Q

You're claiming the statement "that's a valid conclusion" is a category error because conclusions can't be valid or not valid, but only true or false. It'd be like asking what kind of document my cat is, for example.

The statement "that's a valid conclusion" does make sense, so I would think a listener who hears that would realize immediately that the person speaking isn't using the term "valid" as a term of art, but must mean something else.

But regardless of how you get there, the conclusion "arguments can be both valid and invalid" is false. — Michael

Can we say the conclusion is valid or do we reserve the term "valid" only to argument forms and not to conclusions?

No 3 is a 4 because no argument can be both valid and invalid. — Michael

I get that, but a 3 permits explosion, which can force anything anywhere.

Then all 3s imply that 3 is a 4.

It's not raining and it's raining therefore it's not raining.. So yeah, it's "incoherent" in that its premises are inconsistent. — Michael

Accepting that definition of "incoherent," we can then say we have (1) valid and coherent arguments and (2) valid and incoherent arguments.

We can also have (3) valid and sound arguments and (4) valid and unsound arguments.

Would you agree that:

A. All 3s are 1s, but not all 1s are 3s?
B. All 2s are 4s, but not all 4s are 2s.
C. No 1s or 3s are 4s or 2s.
D. No 4s or 2s are 1 or 3s.

(Venn diagram is: 3 is a circle within the 1 circle and 2 is a circle within a 4 circle).

The OP is a 2, but not all 2s are a 4, so just calling it valid but unsound doesn't capture its special class.

Maybe we should could call 2s a "NotAristotle" after the creator of this thread. Or, is there already another name for 2s.

Disagreement with what I've said here?

Candidly, there can't be any sensible doubt that the argument in the OP is valid for formal propositional logic. So in order for those who claim it is invalid to be correct, there must be more than one form of validity, and hence logical pluralism follows. — Banno

That is true, but shouldn't there be a distinction not just between "valid but not sound" but also between "valid but incoherent"?

For example:

If P then not Q
P
not Q

This is valid. It is sound if P and ~ Q are true. Unsound if not.
If P and Q are the same thing such that:

If P then not P
P
Not P

This is valid and not sound, but also not coherent.

As in, "If I went to the store, I did not go to the store, and I went to the store, so I did not go to the store." That is valid, but meaningless. I have no idea what you did, whether you went to the store, didn't go to the store, and I can't understand how your going to the store made you not go to the store."

And that was the debate for 20 pages I suppose. The pluralism might not be over "validity" if you wish to protect that term to only reference formal structure, but perhaps over soundness if you want to speak of what synthetically is false versus what is analytically false.

This conversation is pedantic and legalistic if I'm understanding it correctly. We all can agree with what truth tables show and what logic dictates, but the battle might be over terms, but I might misunderstand because that was the extent of my disagreement.

The incoherently true statement is also distinct from the vacuously true statement. As in, "if Tokyo is in Spain, then the Eiffel Tower is in Bolivia." There the antecedent cannot ever be satisfied, so it can never be true, but it's impediment to truth is due to a synthetic falsehood, but that's unlike the OP where the antecedent is premised to be false.

I'll let you guys better explain it to me if I've misunderstood this, but the contradiction and the incoherence that follows is what trips this issue up to me at least.