John, List: JFS: In both graphs in your note below, the thin line may be read as "that"'
Yes, of course; that is obvious from the syntax of the English sentences that I translated into those two graphs--although, as I said in that post, it is a *dotted *line, not a *thin *line. JFS: But neither of those two sentences can be translated to any version of modal logic based on the modal logics by C. I. Lewis or later variations of it. No, of course not; that is obvious from the fact that neither of those two sentences expresses a *modal *proposition, i.e., one that involves possibility or necessity. JFS: They can also be translated to and from Peirce's Delta graphs No, this is incorrect; that is obvious from the fact that such propositions about propositions can already be represented by *Gamma *EGs using the dotted oval/line notation that Peirce introduced in 1903 (LF 2/1:166), which is isomorphic with the thinly drawn oval/line notation that he used in 1898 (RLT 151). In 1911, he did not need a new Delta part of EGs in order to deal with *metalanguage*; according to his own explicit statement in R L376, he needed a new Delta part of EGs in order to deal with *modals*, due to his dissatisfaction with the cuts (including broken cuts) of 1903 and the tinctures of 1906. With that in mind, in your candidate for Delta EGs, how would you scribe the graph for "A thinks that B is *possibly *true"? Or will you continue refusing to provide *any *examples of how you would represent (and reason about) even *very simple* modal propositions, despite my multiple requests? By contrast, I am happy to show you how I would scribe that graph in my candidate for Delta EGs based on R 339:[340r] (1909). [image: image.png] Regards, Jon Alan Schmidt - Olathe, Kansas, USA Structural Engineer, Synechist Philosopher, Lutheran Christian www.LinkedIn.com/in/JonAlanSchmidt / twitter.com/JonAlanSchmidt On Wed, Mar 13, 2024 at 4:51 PM John F Sowa <[email protected]> wrote: > Jon, > > In both graphs in your note below, the thin line may be read as "that"' > > A thinks THAT C is a good girl. > > A is claiming THAT A is thinking THAT C is a good girl. > > Both of those sentences and both of those EGs can be translated to and > from the IKL logic of 2006, which uses the symbol "that" to represent > metalanguage. They can also be translated to and from Peirce's Delta > graphs, which can be translated to and from the IKL logic. > > But neither of those two sentences can be translated to any version of > modal logic based on the modal logics by C. I. Lewis or later variations of > it. > > John >
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