Talk:Domain of discourse

ZFC
Presumably, the domain of discourse cannot always be a set. For example, the domain of discourse in ZF set theory would be the collection of all sets. However, this in itself could not be a set since no set can be a member of itself.

Dude. Thats deep.


 * No, a model of ZFC is a set of sets, and that set is the domain of discourse. There is such a thing as a "class model" that is also used in set theory. But ZFC, like any other consistent first order theory, has ordinary models. &mdash; Carl (CBM · talk) 12:54, 7 September 2007 (UTC)

Universe
Should phrase "universe of discourse" be a link to Universe (mathematics)? Are DD and Universe actually the same thing? If yes, should the articles be merged? —Preceding unsigned comment added by Andy.melnikov (talk • contribs) 00:07, 27 July 2008 (UTC)


 * I changed the link so it points to Universe (mathematics) instead of Universe. As for your other questions, I'm not sure. Azurengar (talk) 19:26, 10 March 2013 (UTC)Azurengar

Proposed merge with Universe (mathematics)
The scopes of both articles largely overlap, to the point they can be said to cover the same thing. — Keφr 12:34, 25 May 2014 (UTC)
 * Oppose. 'Domain of discourse' is a philosophical term, not necessarily a mathematical one. --Ancheta Wis   (talk
 * Agree. The fact that you have something formalized in math does not mean that it is different from what you have elsewhere. Fragmenting the knowledge you do not improve the comprehension. --Javalenok (talk) 16:25, 12 July 2014 (UTC)

The term "Universe of Discourse" (UoD) was coined by [|Augustus De Morgan] and appears in his book "Formal Logic-The Calculus of Inference, Necessary and Probable (1847). De Morgan used the term to mean "the whole of the thing that we are talking about." [|George Boole] was De Morgan's student.

Separately, in the UoD of the Relational Model, the term "domain" is used to refer to a [|data type]. For example [|Codd] used the term domain to refer to a pool of values such as "supplier number". The single pool of values may be used in different relations within a single database and the single pool of values may also be used in different databases. The Country Code standard of ISO 3166 is an example of a common pool of values that is shared by many databases. Thus, within the communities of logic and databases, the terms "Universe of Discourse" and "Domain" have distincly different and complementary meanings. Thus, I argue that this page should be merged with "Universe of Discourse". Ken Evans 14:29, 11 October 2015 (UTC) — Preceding unsigned comment added by The ken evans (talk • contribs)
 * Domain of discourse is meaningful in more than one important area of application of logic. The topic should not be assigned ownership by any one of those applications. BlueMist (talk) 09:54, 10 June 2016 (UTC)

Improper citation
"but the name was used for the first time in history by George Boole (1854) on page 42 of his Laws of Thought" should be cited in a foot note and not an inline citation like this — Preceding unsigned comment added by 64.132.229.26 (talk) 20:53, 8 January 2018 (UTC)

Discussion
The expression : the square of every x is different from 2 is not a proposition. — Preceding unsigned comment added by Boutarfa Nafia (talk • contribs) 13:01, 21 March 2022 (UTC)