Franklin,
Jeff’s post just now is probably more useful than what I’m about to say, but since I wrote it before I saw Jeff’s I might as well post it anyway … Yes, I understand that “material implication” is now the more common term for the Philonian view of conditionals; I just don’t use that term because I don’t see that it clarifies the issue. Peirce says that Duns Scotus “threw considerable light upon” the Philonian/Diodoran controversy (and thus on “material implication”) by making the distinction between “simplex” and other conditionals. My understanding is that the “simplex” conditional is more obviously well suited to the Philonian point of view because it relates only to the “hic et nunc” rather than to general conditions. Peirce doesn’t want the ordinary or common-sense usage of the conditional form to interfere with comprehension of the strictly logical issue, so he avoids that by focusing on the conditional “de inesse” instead. Taking a strictly Philonian view of the conditional perspective seems requisite for Peirce’s very definition of negation. Since I have never taken a course in formal logic, it was not immediately obvious to me why negation has to be formally defined at all, but Peirce appears to see the conditional, or “if -> then”, as logically simpler or more elementary than negation or “not.” So he appears to derive the sign for negation in EGs from the sign for the conditional; and just to isolate the concept of the conditional from everyday language, which is inexact, he narrows the focus to the more artificial concept of the conditional de inesse. There are probably logicians aboard who could explain this better than I, but my own interest in this close study is to make it easier to follow for non-logicians or “amateur” logicians like myself. For us, EGs are not easy to swallow, but I want to make every effort to see their importance for myself, before I accept or reject Peirce’s opinion of their importance for pragmatism and philosophy generally. Having said that … Jeff, I’ll hunt for that Bellucci article you mentioned. Gary f. From: Franklin Ransom [mailto:pragmaticist.lo...@gmail.com] Sent: 25-Oct-17 16:51 To: peirce-l@list.iupui.edu 1 <PEIRCE-L@list.iupui.edu> Subject: RE: [PEIRCE-L] Lowell Lecture 2.4 Gary F, If I try to picture the Philonian and Diodoran interpretations in terms of truth value tables, they essentially correspond to material and strict implication, respectively. But I'm not sure how the distinction between ordinary consequence and simplex de inesse fits in. Would that have more to do with modal logic (possible vs...actual?), which the gamma graphs aim to treat of, and which you are suggesting is where the Philonian or material approach becomes problematic? -- Franklin
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