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Re: Why is model theory needed?

Newsgroups sci.logic
Date 2023-05-30 15:14 -0700
References (4 earlier) <0a37e2de-e793-44e2-872e-d9581812bf29n@googlegroups.com> <19bfbed9-e7c7-40bd-a818-353216387d57n@googlegroups.com> <fafaaa46-33ed-4530-9716-9e7fc88b0ff9n@googlegroups.com> <2d6d76e3-a299-465f-8001-e16be607cfc5n@googlegroups.com> <faa8d758-d957-430b-a9b4-f6992554747en@googlegroups.com>
Message-ID <bc185d98-d4b7-4a52-b966-434b9d57f07fn@googlegroups.com> (permalink)
Subject Re: Why is model theory needed?
From Mild Shock <bursejan@gmail.com>

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See for yourself Dan Christensen is totally crazy. He thinks going 
from predicates aka classes to sets is a generalization. He is 
completely out of his mind. He writes expressis verbis nonsense like:

> Again, ∃x¬Dx tells us only that D is not a universal predicate/set. 
> It is a reasonable assumption in many cases, e.g. not everything 
> is a drinker. Nevertheless, a universal predicate is not ruled out 
> in your "standard" FOL, so ∃x¬Dx is NOT a theorem in that system. 

> The non-existence of a universal set is, however, a theorem in 
> ordinary set theory (see Russell's Paradox) allowing us to 
> generalize. Introducing the equivalent assumption ∃x¬Dx in FOL 
> would also allow us to generalize in FOL, e.g. ∃x¬Dx → ∃x(Dx → ¬∀yDy) .

Why is making  ∃x¬Dx false a generalization? Dan Christensen
doesn't make any sense. Here in this thread we started using
the symbol ▷ for "isa" relationship:

human ▷ mortal 

Usually one considers the left hand side the more special
thing and the right hand side the more general thing. Lets make
another example:

rectangle ▷ parallelogram

Now the question for Dan Christensen. What is more general
sets or predicates. The Quizz is as follows, which of the
following 3 in a single choice is true:

1) sets ▷ predicates?

2) predicates ▷ sets?

3) Neither 1) nor 2) ?

P.S.: There is an agreed result for the above quizz among
mathenaticians and in math text books, which I can later
give a reference. I gave the reference already in  the

thread transfer principle and the Drinker Paradox.
 
Mild Shock schrieb am Mittwoch, 31. Mai 2023 um 00:05:56 UTC+2:
> If Dan Christensen would start with Realism, he would 
> not butcher the Drinker Paradox as he did. Whats the 
> realism behind the absolute infinite of Set(_). Which 
> 
> predicates any set of any cardinal rank. The only cardinality 
> that is needed for the Drinker Paradox is 2 (in words "two"). 
> There are two scenarios which go into Smullyans proof. 
> 
> Now Dan Christensen managed to eliminate one scenario 
> and even calls this a "generalization". Anyway here is 
> a nice paper discussing some Realism inherrent in "truthmaker" 
> 
> Semantics and also inherent in konstruktive Mathematics: 
> 
> Kit Fine versus Martin-Löf 
> Ansten Klev - Logica Yearbook 2016 
> https://www.academia.edu/29993783/Truthmaker_semantics_Fine_versus_Martin_L%C3%B6f 
> 
> Mostowski Collapse schrieb am Montag, 10. April 2023 um 09:02:38 UTC+2: 
> > Currently it seems Model Theory and Algebraic Logic gets 
> > replaced by Truth Maker Theory? Not sure. There is a little 
> > surge in papers right now, isn't it? 
> > 
> > "Truthmaker semantics is a novel formal semantic framework 
> > which has been recently developed in a series of publications 
> > ((Fine, forthcoming), (Fine, 2017), (Fine, 2016)) by Kit Fine 
> > starting from the work done by Van Fraassen’s in (Van Fraassen, 1969) 
> > 
> > Or its just a combination of Model Theory and Algebraic Logic? 
> > In this paper see Theorem 1, the link is made. If you watch 
> > it carefully, you can see both: 
> > 
> > A Truthmaker Semantics Approach to Modal Logic 
> > Giuliano Rosella - 28. April 2021 
> > https://eprints.illc.uva.nl/id/eprint/1792/1/MoL-2019-28.text.pdf 
> > Mostowski Collapse schrieb am Montag, 10. April 2023 um 08:40:33 UTC+2: 
> > > Strictly speaking Algebraic Logic is not the same as Model Theory. 
> > > Thats quite a fallacy to identify Model Theory with Algebraic Logic. 
> > > I hope you don't commit this fallacy? 
> > > 
> > > Some times this fallacy is based on the confusion of the word 
> > > "algebra". The word "algebra" in "Universal Algebra" has not the same 
> > > meaning as the word "Algebraic" in "Algebraic Logic". 
> > > 
> > > You can think about it in terms of "truth makers": 
> > > - Algebraic Logic: Algebra of truth values of the truth makers 
> > > - Model Theory: Algebra of situations the truth makers refer to 
> > > 
> > > But you can combine the two, there is no doubt. And you can 
> > > obtain currious results, like in Set Theory and the Continuum Problem, 
> > > by Smullyan and Fitting. 
> > > Mitchell Smith schrieb am Montag, 10. April 2023 um 04:16:36 UTC+2: 
> > > > If I open Chang and Keisler, there is much more than first-order logic. In fact, they describe model theory as universal algebra combined with logic. One cannot only look at the logic component. Skolem's contribution pushes foundational studies back to the algebraic perspective.

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Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-05-30 15:05 -0700
  Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-05-30 15:14 -0700
    Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-05-30 15:57 -0700
    Re: Why is model theory needed? Dan Christensen <Dan_Christensen@sympatico.ca> - 2023-05-30 18:45 -0700
      Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-05-31 01:42 -0700
        Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-05-31 01:55 -0700
          Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-05-31 02:09 -0700
            Re: Why is model theory needed? Dan Christensen <Dan_Christensen@sympatico.ca> - 2023-05-31 08:21 -0700
              Re: Why is model theory needed? Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-05-31 08:28 -0700
                Re: Why is model theory needed? Dan Christensen <Dan_Christensen@sympatico.ca> - 2023-05-31 08:39 -0700
                Re: Why is model theory needed? Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-05-31 11:50 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-05-31 11:58 -0700
                Re: Why is model theory needed? Dan Christensen <Dan_Christensen@sympatico.ca> - 2023-05-31 13:10 -0700
                Re: Why is model theory needed? Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-05-31 21:12 -0700
                Re: Why is model theory needed? Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-05-31 21:35 -0700
                Re: Why is model theory needed? Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-06-01 11:43 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-01 12:40 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-01 12:54 -0700
                Re: Why is model theory needed? Jeffrey Rubard <jeffreydanielrubard@gmail.com> - 2023-06-01 14:24 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-01 14:55 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-01 15:18 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-03 08:31 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-03 09:10 -0700
                Re: Why is model theory needed? Jeffrey Rubard <rehashedrubard@gmail.com> - 2023-06-02 08:19 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-02 11:20 -0700
                Re: Why is model theory needed? Jeffrey Rubard <rehashedrubard@gmail.com> - 2023-06-03 08:27 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-03 08:31 -0700
                Re: Why is model theory needed? Jeffrey Rubard <rehashedrubard@gmail.com> - 2023-06-03 13:53 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-03 13:57 -0700
                Re: Why is model theory needed? Jeffrey Rubard <rehashedrubard@gmail.com> - 2023-06-03 14:04 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-03 14:13 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-04 07:47 -0700
                Re: Why is model theory needed? Jeffrey Rubard <rehashedrubard@gmail.com> - 2023-06-04 08:26 -0700
                Re: Why is model theory needed? Mild Shock <janburse@fastmail.fm> - 2023-06-04 17:53 +0200
                Re: Why is model theory needed? Jeffrey Rubard <rehashedrubard@gmail.com> - 2023-06-04 15:31 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-04 17:21 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-04 17:30 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-04 17:39 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-04 17:49 -0700
                Re: Why is model theory needed? Jeffrey Rubard <rehashedrubard@gmail.com> - 2023-06-05 08:20 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-05 10:56 -0700
                Re: Why is model theory needed? Jeffrey Rubard <jeffreydanielrubard@gmail.com> - 2023-06-05 13:16 -0700
                Re: Why is model theory needed? Jeffrey Rubard <jeffreydanielrubard@gmail.com> - 2023-06-05 13:17 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-05 15:10 -0700
                Re: Why is model theory needed? Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-06-05 14:07 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-05 15:09 -0700
                Re: Why is model theory needed? Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-06-05 17:51 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-05 22:54 -0700
                Re: Why is model theory needed? Jeffrey Rubard <jeffreydanielrubard@gmail.com> - 2023-06-06 18:44 -0700
                Re: Why is model theory needed? Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-06-06 21:02 -0700
                Re: Why is model theory needed? Jeffrey Rubard <jeffreydanielrubard@gmail.com> - 2023-06-07 11:42 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-07 13:48 -0700
                Re: Why is model theory needed? Mild Shock <janburse@fastmail.fm> - 2023-06-07 23:43 +0200
                Re: Why is model theory needed? Jeffrey Rubard <jeffreydanielrubard@gmail.com> - 2023-06-08 12:14 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-08 12:19 -0700
                Re: Why is model theory needed? Jeffrey Rubard <jeffreydanielrubard@gmail.com> - 2023-06-09 10:54 -0700
                Re: Why is model theory needed? Jeffrey Rubard <jeffreydanielrubard@gmail.com> - 2023-06-09 10:54 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-09 11:35 -0700
                Re: Why is model theory needed? Jeffrey Rubard <rehashedrubard@gmail.com> - 2023-06-09 11:53 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-09 11:58 -0700
                Re: Why is model theory needed? Jeffrey Rubard <jeffreydanielrubard@gmail.com> - 2023-06-09 15:27 -0700
                Re: Why is model theory needed? Jeffrey Rubard <rehashedrubard@gmail.com> - 2023-06-09 11:59 -0700
                Re: Why is model theory needed? Jeffrey Rubard <jeffreydanielrubard@gmail.com> - 2023-06-09 15:27 -0700
                Re: Why is model theory needed? Jeffrey Rubard <jeffreydanielrubard@gmail.com> - 2023-06-06 18:43 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-09 05:18 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-09 05:20 -0700
                Re: Why is model theory needed? Jeffrey Rubard <jeffreydanielrubard@gmail.com> - 2023-06-09 10:53 -0700
                Re: Why is model theory needed? Mild Shock <janburse@fastmail.fm> - 2023-06-09 21:28 +0200
                Re: Why is model theory needed? Jeffrey Rubard <jeffreydanielrubard@gmail.com> - 2023-06-09 15:27 -0700
                Re: Why is model theory needed? Jeffrey Rubard <jeffreydanielrubard@gmail.com> - 2023-06-09 15:28 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-09 15:45 -0700
                Re: Why is model theory needed? Jeffrey Rubard <jeffreydanielrubard@gmail.com> - 2023-06-09 15:51 -0700
                Re: Why is model theory needed? Jeffrey Rubard <jeffreydanielrubard@gmail.com> - 2023-06-09 15:51 -0700
                Re: Why is model theory needed? Jeffrey Rubard <rehashedrubard@gmail.com> - 2023-06-09 15:57 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-09 16:03 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-09 16:09 -0700
                Re: Why is model theory needed? Jeffrey Rubard <rehashedrubard@gmail.com> - 2023-06-09 16:19 -0700
                Re: Why is model theory needed? Jeffrey Rubard <rehashedrubard@gmail.com> - 2023-06-09 16:20 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-09 16:21 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-09 16:28 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-09 16:28 -0700
                Re: Why is model theory needed? Jeffrey Rubard <rehashedrubard@gmail.com> - 2023-06-10 08:25 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-10 09:08 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-10 09:13 -0700
                Re: Why is model theory needed? Jeffrey Rubard <jeffreydanielrubard@gmail.com> - 2023-06-10 12:52 -0700
                Re: Why is model theory needed? Jeffrey Rubard <jeffreydanielrubard@gmail.com> - 2023-06-10 13:21 -0700
                Re: Why is model theory needed? Jeffrey Rubard <rehashedrubard@gmail.com> - 2023-06-11 08:25 -0700
                Re: Why is model theory needed? Jeffrey Rubard <rehashedrubard@gmail.com> - 2023-06-11 08:44 -0700
                Re: Why is model theory needed? Jeffrey Rubard <rehashedrubard@gmail.com> - 2023-06-11 09:06 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-11 10:55 -0700
                Re: Why is model theory needed? Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-06-11 11:54 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-11 13:12 -0700
                Re: Why is model theory needed? Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-06-11 13:59 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-11 15:26 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-11 15:31 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-11 15:34 -0700
                Re: Why is model theory needed? Jeffrey Rubard <jeffreydanielrubard@gmail.com> - 2023-06-10 12:51 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-10 15:13 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-10 15:19 -0700
                Re: Why is model theory needed? Jeffrey Rubard <rehashedrubard@gmail.com> - 2023-06-11 08:25 -0700
                Re: Why is model theory needed? Jeffrey Rubard <rehashedrubard@gmail.com> - 2023-06-10 08:24 -0700
              Re: Why is model theory needed? Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-05-31 13:05 -0700
        Re: Why is model theory needed? Dan Christensen <Dan_Christensen@sympatico.ca> - 2023-05-31 08:15 -0700
          Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-05-31 11:41 -0700
            Re: Why is model theory needed? Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-05-31 11:48 -0700
            Re: Why is model theory needed? Dan Christensen <Dan_Christensen@sympatico.ca> - 2023-05-31 12:52 -0700
              Re: Why is model theory needed? Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-05-31 13:06 -0700
                Re: Why is model theory needed? Dan Christensen <Dan_Christensen@sympatico.ca> - 2023-05-31 13:28 -0700
                Re: Why is model theory needed? Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-05-31 18:53 -0700
              Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-05-31 13:18 -0700
                Re: Why is model theory needed? Dan Christensen <Dan_Christensen@sympatico.ca> - 2023-05-31 13:53 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-05-31 13:58 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-05-31 14:06 -0700
                Re: Why is model theory needed? Jeffrey Rubard <jeffreydanielrubard@gmail.com> - 2023-05-31 14:08 -0700
                Re: Why is model theory needed? Dan Christensen <Dan_Christensen@sympatico.ca> - 2023-05-31 15:57 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-05-31 16:46 -0700
                Re: Why is model theory needed? Dan Christensen <Dan_Christensen@sympatico.ca> - 2023-05-31 17:31 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-01 02:48 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-01 03:02 -0700
                Re: Why is model theory needed? Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-06-01 08:19 -0700
                Re: Why is model theory needed? Jeffrey Rubard <rehashedrubard@gmail.com> - 2023-06-01 08:42 -0700
                Re: Why is model theory needed? Dan Christensen <Dan_Christensen@sympatico.ca> - 2023-06-01 07:07 -0700
                Re: Why is model theory needed? Dan Christensen <Dan_Christensen@sympatico.ca> - 2023-06-01 11:03 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-01 11:08 -0700
                Re: Why is model theory needed? Mild Shock <bursejan@gmail.com> - 2023-06-01 11:14 -0700

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