Jon AS, List,
Before getting into any speculation, I'll mention some undeniable facts: 1. R699 has the title "Assurance through reasoning", it begins with a paragraph about necessary deduction and probable deduction, and it contains a summary of the EG system from the early days up to and including recto/verso semantics. It also includes a story about a paradise without negation as support for deriving negation from a scroll (for material implication) plus a blot (representing the pseudograph) that shrinks to a invisble, but still present dot. 2. Five days after finishing (or stopping) R669, Peirce began R670 with the same title and a similar opening paragraph. But the system omits many features of R699, and replaces them with a new foundation, which Peirce presents in a clean presentation in L231, which he begins five days after finishing R670. This is my summary, and I'm stating it only to highlight the critcal points in two brief paragraphs. But every sentence in it could be replaced by excerpts from the threee MSS. When I used the title "Peirce's own tutorial" in my 2011 article in Semiotica, I was misled by the erroneous date of 1909 on R514, which I used instead of L231. But now that we know the correct date and provenance, all available evidence shows that L231 is Peirce's best and final version. There is only one minor objection that is easily dismissed: Some people, including Ahti, have used the derivation of negation from a scroll plus pseudograph in some writings. But that point is irrelevant. In mathematics (which includes formal logic), any proof that starts with a definition of A as B can be carried out in exactly the same steps by starting with a statement that A is equivalent to B. If you look through the literature of math & logic, different authors often derive exactly the same theories by starting with different choices of primitives and definitions. But as long as every definition in one is an equivalence in the other, the two theories are identical. There may be some people who need a bit of explanation of these points, but there is no mathematician or logician on earth who could refute them. John
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