[PEIRCE-L] Delta Existential Graphs (was The Proper Way in Logic)

Jon, List I am now busy preparing slides for a Zoom talk on Feb 28, sponsored by Ontolog Forum. (I'll forward a copy of the announcement to P-List, if anyone is interested.) But first, I'll respond to some of your doubts. JFS> The entire letter L376 is about Delta graphs and applications of

Re: [PEIRCE-L] Delta Existential Graphs (was The Proper Way in Logic)

John, List: I sincerely appreciate this clarification of your thought process underlying your conjecture that "The primary subject of L376 is Delta graphs." I am not yet persuaded, but I now intend to review the entire letter carefully in light of your proposed interpretation. Again, on my current

Re: [PEIRCE-L] Delta Existential Graphs (was The Proper Way in Logic)

Jon, The single most important innovation of Delta graphs is an operator for metalangage or metalogic. Just that one operator, when added to ordinary first-order logic, makes it possible to define a wide range of modal logics and logics for probability. In fact, Peirce's modal logic of 1903 a