On 8 November 1913, Peirce described a version of EGs that is identical to the 1911 version. See the copy below. My summary:
A universe of discourse is described by the graphs scribed on a sheet of assertion (AKA phemic sheet). The structure and meaning of an EG is determined by five conventions [plus a default convention 0]: 0. Conjunction (AND) is the implicit logical operator that relates the graphs scribed in any area. 1. The existential quantifier (there exists something) is represented by a heavy dot. 2. A heavy dot extended to a heavy line asserts the identity of the objects denoted at each end. 3. A bifurcation of a line (a ligature) to form a teridentity asserts the co-identity of the objects denoted at the three ends. 4. Shading an area negates whatever is scribed in that area. 5. Evaluation of a nest of negations proceeds from the outside-in (endoporeutic). This implies that a nest of two negations, such as "not-(A not-B)", is equivalent to a conditional "if A then B". This confirms my reply to Francesco on June 10. In that note, I showed that any logical or philosophical idea expressed in or explained by any EGs prior to June 1911 could be expressed or explained as well or better by the EGs of R670 and L231. Since Peirce's version of 1913 is identical to the 1911 EGs, the more complete specification of L231 would be his best and final version. John ------------------------- Peirce described a version of EGs in the excerpt dated 8 November 1913 of "Letters to F. A. Woods" (L477, July 1911 to December 1913): Of course, not only are two terms often connected by a bond of relational identity as in "son's wife" (represented by the graph (Fig...) and in "wife's son" (Fig...) but also every term is bound to the real universe, though in my graphs this is only represented by the term's being scribed on the sheet, which denotes the universe. Then only about four conventions more complete the definition of the method of representation. These are: First, that a heavy dot stands for something or a real object. Second, dot prolonged into a heavy line asserts the identity of the objects denoted by its extremities. Third, a node of point of bifurcation of such a line asserts the co-identity of the three ends; and co-identity is the more usual meaning of the word 'and'. (Fig...) Fourth, shading an area of the phemic sheet denies whatever is scribed on that area. Fifth, the interpretation proceeds endogenously [endoporeutic]. That is, Fig... means "It is false that A is false while B is true", i.e. "If A is true so is B" and the interpretation is not B is true and A is false which would be an exogenous interpretation, i.e. beginning in the inside and proceeding outward.
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