Just a note, I've bowed out of the above discussion, but when Banno is ready to move on, I'm all in.

Exactly!

yep

It's abnormal to be normal — magritte

Normal is a bullseye no dart ever hits.

Sometimes trolls try really hard to get you to respond to them. Toxic stuff.

You are not a good faith interlocutor and I shall now avoid you. — AmadeusD

:up:

It's probably a collision of possible worlds.

I like that. That allows the logician to add on any ontology she likes, or just be anti-metaphysical.

Is there a problem with calling them possible worlds?

When I was in Catholic grade school, we'd be shown films displaying sinners writhing in flames. The Church has grown soft, it seems. — Ciceronianus

They were just trying to scare you.

Your claim that he'll is the absence of God is contrary to Scripture and tradition. — Ciceronianus

That's the Catholic view:

By definition, according to the Catechism of the Catholic Church (CCC), paragraph 1033, hell is “[the] state of definitive self-exclusion from communion with God and the blessed.” — here

There is no one Christian tradition. It's all over the place.

It's normal to be abnormal.

Therefore, what is needed is another way to understand modal logic without using modal logic. — RussellA

We all use modal logic pretty regularly. This was just an effort to understand modal expressions extensionally. It seems to work pretty well. Obviously this kind of philosophy isn't for everybody. :grin:

Yes that's exactly the problem. What we know as the independent, physical world, source of empirical observations, can no longer be accepted as such. It gets barred off as a sort of unreal illusion, and what we're left with is an extreme idealism where the ideas (possible worlds) are the reality. — Metaphysician Undercover

:grimace: I didn't see that coming!

It's very neat. But yes, quite mad. — Banno

:lol:

Others find it less convincing. — Banno

I'm not sure how popular Lewis' view is. It's kind of nutty.

All ancient civilizations exhibited religious tolerance (except the Jews). If you traveled to another region of the known world, your first task was to find the local temple and pay homage to their gods. The Romans were like everyone else in this.

Isaac Asimov said that the Jews invented religious intolerance and became the world's first victims of it in the 6th Century BCE when the Babylonians invaded and specifically attempted to destroy Judaism. Christianity inherited this preoccupation with truth. You're supposed to realize that the gods you've been worshiping aren't real. And Northern Europeans did realize that. The destruction of paganism didn't happen at the end of a Roman sword. The pagans destroyed their own culture(s). They burned it all.

Kripke (Naming and Necessity):
Proper names refer rigidly to the same individual across worlds.
Necessity is primitive and tied to rigid designation.
Modality is not reduced to something non-modal; it is taken as metaphysically basic.


Lewis (Modal Realism / counterpart theory):
Worlds are concrete; individuals do not literally exist in more than one world.
Identity across worlds is determined via counterpart relations.
Modality is reduced to quantification over concrete worlds.

Shared Logic / Semantics
Possible worlds semantics: Both use worlds as the basis for evaluating modal statements.
Quantified modal logic: Both accept first-order quantification over individuals.
Transworld reference: Both presuppose a way to interpret identity or counterparts across worlds.
Truth-at-a-world: Both define modal truth in terms of what holds at particular worlds.
Accessibility relations: Both can accommodate structured relations between worlds (for temporal or metaphysical distinctions).
Formal rigour: Both agree that modal claims can be modelled systematically, independent of metaphysical interpretation. — Banno

Which do you think is closer to approximating the way we really think about modality?

Could be. It was a regular practice in the monasteries founded by the descendants of those barbarian tribes. — Ciceronianus

Benedict was Italian. :cool:

I think it's because Rome was repeatedly sodomized by its enemies until it laid down and died.

True, although isn't there an extra conundrum with direct realism: that if it's true, then it must be false (by virtue of what we observe about how the senses work).

In the 9th Century, if you wanted to see a library, a school, some sort of hospital, you'd need to go to the local monastery. The monastery was built like a fortress in a world where buildings weren't built to last, and they didn't last due to the workings of the economy. Semi-nomadic warlords destroyed things for a living and paid their troops with the loot. It was the clergy who appealed to the warlords to give Europe a break and go wreak havoc in the holy land. And when these crusades resulted in a larger Greek presence in Europe, it was the clergy who welcomed their knowledge. Only the clergy could read and write.

Everything around you was built on their shoulders. I'm sure you have some snarky comment to make about that. I don't give a shit.

I'm skipping over some of the exploration of Lewis' theory to answer the obvious question: "Is Lewis serious?" The answer is: yes.

2.1.5 A Brief Assessment of Concretism
Lewis's theory is particularly commendable for its striking originality and ingenuity and for the simple and straightforward answers AW1 and AE1 that it provides to our two questions QW and QE above. Furthermore, because worlds are (plausibly) defined entirely in nonmodal terms, the truth conditions provided by Lewis's translation scheme themselves appear to be free of any implicit modality. Hence, unlike many other popular accounts of possible worlds (notably, the abstractionist accounts discussed in the following section), Lewis's promises to provide a genuine analysis of the modal operators.

Perhaps the biggest — if not the most philosophically sophisticated — challenge to Lewis's theory is “the incredulous stare”, i.e., less colorfully put, the fact that its ontology is wildly at variance with common sense. Lewis faces this objection head on: His theory of worlds, he acknowledges, “does disagree, to an extreme extent, with firm common sense opinion about what there is” (1986, 133). However, Lewis argues that no other theory explains so much so economically. With worlds in one's philosophical toolkit, one is able to provide elegant explanations of a wide variety of metaphysical, semantical, and intentional phenomena. As high as the intuitive cost is, Lewis (135) concludes, the existence of worlds “ought to be accepted as true. The theoretical benefits are worth it.”

Additional discussion of, and objections to, concretism can be found in the supplemental document — ibid

As a science fiction fan, the idea of modal realism doesn't seem all that strange. Protagonists are forever waking up in the wrong world, with much drama resulting. But on what basis do I accept the idea? According to Lewis, in spite of it's being ontological inflation, it's the simplest explanation for the way we think about modality. I think I agree with this.

Determinism seems to suggest that everything that happens, happens necessarily - implying there is no actual contingency in the world. This would mean there are no true possibilia.

Do you agree? — Relativist

Something like that. But we still think in terms of possibility.

I'm a dyed-in-the-wool determinist, by which I mean it's embedded in the way I see the world, morality, the way I assess my own past. Fate, basically. But that doesn't interfere with my understanding of modal logic.

It comes up in our recent discussion about disability. Some identify a disability as an essential feature of a person, and so to judge the lack of capability is to judge the person. The alternative is to think about disability as contingent. It's still the same person, with or without a particular set of challenges. So I think in terms of fate, but also distinguish between what's at the core of a person, the subject (so to speak), and the orbiting circumstances.

I'm aware that Heidegger would object to separating the two out in that way. After all, it's two sides of one coin. But Heidegger failed to see that we don't live our lives in that realm of unity. The intimate experience of life is infinite space in between.

So except for RussellA's last question here, we're ready to move on to section 2, right?

2. Three Philosophical Conceptions of Possible Worlds

So survival of the fittest?
— frank

Bit of a black-white fallacy I think. I'm pressing against survival of the least fit as a mode - not suggesting we do the Nazi thing. But I think it patently odd (and probably a bad thing, overall) that we train our best and brightest to put themselves in harm's way (well, 60 years ago this would hit a lot harder) and do our absolute best to pour resources into retaining the worst(you really need to read this word in context and not ascribe some mora position to me because of an emotional reaction here of us, in terms of species-level survival and progress. There is almost no way that doesn't leave a bad taste in mouths - but it seems obvious. — AmadeusD

So maybe you'd favor a plan that splits resources between improving access and doing medical research, recognizing that research is expensive up front, but keeps giving downstream.

Btw, there's a disable actress in the recent Wicked movies. She lost the ability to walk when she was 11 due to an automobile accident. So by research, we could also mean focusing on safety issues.

That's a useless and baseless assertion if I've ever seen one. — Metaphysician Undercover

Dude. I could resurrect Frege and transport him to your house to explain to you what an abstract object is and you still would maintain some other baloney you made up.

Platonist. It assumes an idea "all possible worlds" which is unknown to us, independent. — Metaphysician Undercover

No, it doesn't.

:up:

All hail the Golden Dawn

At this exact moment in time, when I write “swan”, I know without doubt what my concept of a swan is.

However, with time, as I learn new things about swans, my concept of a swan will change. However, I will still use the same word “swan”. — RussellA

This wouldn't be a problem for first order logic. When your concept of a swan changes, the interpretation in your model changes. No biggie.

In a way, quantum physics allows for dismissed of the fabric of materialism or its reinterpretation. — Jack Cummins

Chomsky says physicalism's first transformation was Newton and the idea of a force. In fact, Newton was accused by his contemporaries of importing woo into science. In response, he reiterated that he didn't know what gravity is made of, he was just describing what it does. So by the time quantum theories came along, we were already used to expanding "material" to include things that people in the past wouldn't have thought of as physical.

Experience has to be understood in that way, including the 'reality of the psyche', as Jung suggested. That is why religious and mythology are important aspects of 'truth'. In Western culture, mainstream religion development a metaphysical approach which was fairly concrete. This led to an interpretation of spirituality based on material principles, such as the emphasis on the 'resurrection' of Jesus as being physical. But, that is not the only way of thinking and it is possible that consciousness is not entirely dependent on the physicality of the body as the apparatus. — Jack Cummins

I agree and disagree with this. I think religion, mythology, and philosophy became sanctuaries for exploration of the nature of consciousness for cultural reasons. There was a drive toward eliminative materialism that had the effect of forcing the topic out to the periphery of rational inquiry. So at this point the very idea of bringing it back into the realm of science confuses people.

I think the same sorts of questions could be asked about ordinary language use. If Paul talks about x, what guarantees that Paul knows what his words mean?

Btw, this:

The Idea of "two" for example, is supposed to have real meaning, independent from human minds, — Metaphysician Undercover

is straight up incorrect. This is the type of thing Meta just pulls out of his butt.

Would you want to dumb that down a tad?

I am empathetic to the nth for those for whom better design would be advantageous, but I am also empathetic to the fact that those of us who do wish to 'race forward' in historical terms probably shouldn't be beholden to that framework. — AmadeusD

So survival of the fittest?

What about something simple, like 2+2=4? Isn't that discoverable through pure reason? — RogueAI

I think so.

I think Kripke would say the value of pi is necessarily 3.14..., but this is known a posteriori.

then aren't mathematical truths also logically true? — RogueAI

What do you mean by "logically true"?