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I added the inference rules for alpha existential graphs. 128.113.137.111 14:58, 5 February 2006 (UTC)Reply[reply]

Philip Meguire, October 31 2005. This article is in crying need of examples of existential graphs. Unfortunately, I do not know how to marry the output of graphics software to a Wikipedia entry. For that matter, I can create only alpha graphs on a computer, using boxes rather than ovals. If you would like to marry your graphics skills to my passion for the existential graphs, contact philip.meguire@canterbury.ac.nz

Is offering a link to both the RPI page and the Proof Builder page overkill? The former now offers two applets for proof-building. One of them is my own, I admit.

Changed in the opening line 'invented' to 'proposed' as I believe that there is a semantic clash between 'type of..' and 'invented'. Peirce was not the only one to produce work in this vein and I have added words to this effect in the section on his role.al 16:59, 15 September 2006 (UTC)Reply[reply]

The semantic wedges your propose to drive between "invent, "propose," and "type of" elude me. I believe that Peirce indeed invented graphical logic. There is no evidence that any university library in the USA had a copy of the Begriffschrifft until after WWII. Even the Library of Congress had no copy until 1964. Frege's work was known in the English speaking world exclusively through an appendix in Russell's Principles of Mathematics. Frege's notation has remained un-imitated and unstudied until this very day, despite the rise of diagrammatic logic in the past 20-30 years. This revival of graphical logic owes a great deal to Peirce, and nothing to Frege. More generally, I agree with Hilary Putnam and Hintikka that Frege's importance to the unfolding of formal logic over the past 100 odd years has been overstated, at the expense of that of Peirce and Ernst Schroder. At the same time, I hasten to admit that Peirce's graphical logic had no following at all before the 1960s, when Zeman and Roberts wrote their doctoral dissertations on that logic.132.181.160.42 (talk) 21:37, 17 May 2009 (UTC)Reply[reply]

Somehow this page won't load anymore. It did load recently (last week) but now has errors. However the last edit was 17 Feb. Does anyone know how this can happen? I'd fix it, but at present I don't fully understand the error message or how to do it. If I figure it out, I'll do it... Doctorambient (talk) 23:39, 21 March 2011 (UTC)Reply[reply]

Thank for pointing it out! The article page has been messed up for over a month. Some editor (who certainly seems to have meant well) made an edit that somehow caused the problem, but it's not evident from comparing edits in history how it went wrong. The Tetrast (talk) 23:52, 21 March 2011 (UTC).Reply[reply]

Oh thanks! I thought it was just me who couldn't figure out the problem based on the history. That makes me feel a bit better... Doctorambient (talk) 00:22, 22 March 2011 (UTC)Reply[reply]

The old version of the page looks normal and doesn't show the blanking of most of the page, though both of us saw it with our own eyes earlier today. Possibly the blanking resulted not even from an edit glitch, but from something else later, who knows what. The Tetrast (talk) 02:08, 22 March 2011 (UTC).Reply[reply]