Editing Three-valued logic (section)

==Pre-discovery==
Around 1910, [[Charles Sanders Peirce]] defined a [[Many-valued logic|many-valued logic system]]. He never published it. In fact, he did not even number the three pages of notes where he defined his three-valued operators.<ref>{{Cite web |title=Peirce's Deductive Logic > Peirce's Three-Valued Logic (Stanford Encyclopedia of Philosophy/Summer 2020 Edition) |url=https://plato.stanford.edu/archIves/sum2020/entries/peirce-logic/three-valued-logic.html |access-date=2024-05-15 |website=plato.stanford.edu}}</ref> Peirce soundly rejected the idea all propositions must be either true or false; boundary-propositions, he writes, are "at the limit between P and not P."<ref>{{Cite web|last=Lane|first=R.|date=2001|title=Triadic Logic|url=http://www.commens.org/encyclopedia/article/lane-robert-triadic-logic |website=Commens |url-status=live |archive-url=https://web.archive.org/web/20231206040847/http://commens.org/encyclopedia/article/lane-robert-triadic-logic |archive-date= Dec 6, 2023 }}</ref> However, as confident as he was that "Triadic Logic is universally true,"<ref>{{cite web
	| url = https://iiif.lib.harvard.edu/manifests/view/drs:15255301$645i
	| title = Logic : autograph manuscript notebook, November 12, 1865-November 1, 1909
	| last = Peirce
	| first = Charles S.
	| date = 1839–1914
	| website = hollisarchives.lib.harvard.edu/repositories/24/digital_objects/63983
    | publisher = Houghton Library, Harvard University
	| access-date = May 15, 2023
	| quote = Triadic Logic is universally true. But Dyadic Logic is not aboslutely false
}}</ref> he also jotted down that "All this is mighty close to nonsense."<ref>{{cite web
	| url = https://iiif.lib.harvard.edu/manifests/view/drs:15255301$638i
	| title = Logic : autograph manuscript notebook, November 12, 1865-November 1, 1909
	| last = Peirce
	| first = Charles S.
	| date = 1839–1914
	| website = hollisarchives.lib.harvard.edu/repositories/24/digital_objects/63983
	| publisher = Houghton Library, Harvard University
	| access-date = May 15, 2023
}}</ref> Only in 1966, when Max Fisch and Atwell Turquette began publishing what they rediscovered in his unpublished manuscripts, did Peirce's triadic ideas become widely known.<ref>{{Cite web|last=Lane|first=Robert|title=Triadic Logic|url=http://www.digitalpeirce.fee.unicamp.br/lane/p-trilan.htm|access-date=2020-07-30|website=www.digitalpeirce.fee.unicamp.br}}</ref>