Talk:Conditional statement

Errors

This article contains some very dubious statements, backed up by references without pages. It appears the author has fallen into error by failing to understand modal logic. See Wikipedia:Articles for deletion/Strict conditional. -- 202.124.74.211 (talk) 11:36, 18 December 2011 (UTC)

Added page numbers to citations

I have added page numbers to the citations, directing the reader to the mentioned content. Hopefully this will clear up any issues people may have, and will direct them to sources where they may learn about the content in detail. — Preceding unsigned comment added by Hanlon1755 (talk • contribs) 19:39, 18 December 2011 (UTC)

The article is still wildly wrong. The references come from books where "conditional statement" is used with both modal and non-modal meanings. Given the fact that this article is redundant, I'm PRODing it. -- 202.124.72.121 (talk) 01:38, 19 December 2011 (UTC)

Noteworthy and Reliable References

Everything is cited, look at the sources yourself. They are highly respected, notable, published references. There are page numbers cited; look at the pages yourself! The reason I created this article is because I myself became confused on the topic. I have since researched the topic well, and have come to a full understanding of the material. This page is meant to clear up any confusion that other people may have, as I did. Everything is accurate. Learn the subject yourself. Much of the material in this article is NOT included on the article for strict implication. People learn what conditional statements are in high school, before they ever come across the terminology "strict conditional." What is it that you think is "wildy wrong" about the material? Say precisely what it is, please. Maybe I can clear up your concerns here. Hanlon1755 (talk) 03:58, 19 December 2011 (UTC)

On a mission

The sources cited do not WP:VERIFY the author's WP:POV and admitted WP:SYNTHESIS. See WP:Articles for deletion/Strict conditional, Talk:Strict conditional and Talk:Material conditional for comments from multiple editors on the factual inaccuracies and tendentious editing by the author of this article, an WP:SPA who, contrary to the WP:CONSENSUS of each forum they've shopped, continues to compete with Strict conditional, an article that's been collaboratively edited for well over 7 years. The user has been encouraged to make contributions to that article, but whereas the wholesale replacement of the article's text with their own is not an option, they've resurrected their version here, yet again.—Machine Elf ¹⁷³⁵ 10:50, 15 January 2012 (UTC)

I did not admit to any synthesis. You want me to contribute to the article "Strict conditional," but when I do, per your own words, it would be synthesis. I cannot, per your own view, make contributions to the article "Strict conditional." You are contradicting yourself. That is why I have contributed to this article instead. The synthesis you allege in the article "Strict conditional" is not synthesis when put into this article because the cited sources explicitly refer to the "conditional statement." Hanlon1755 (talk) 22:12, 15 January 2012 (UTC)

Problems

It's not clear if this article is talking about natural-language sentences or propositions. Also, the main reference is a pair of geometry textbooks: not really the best reference for logic. And further wikification is needed. -- 202.124.73.201 (talk) 13:16, 16 January 2012 (UTC)

Non-specialist User Feedback

Hi, I am not a logic specialist. I am interested in conditional statements in relation to causality and cognitive mechanisms such as behavioural conditioning. I found the "conditional statement" page very helpful. Whereas the "material conditional" page was too rich in specialist jargon for me. 217.155.205.34 (talk) 22:53, 17 January 2012 (UTC)

And given your interest in "cognitive mechanisms", your comments on the cognitive processes that took place during the recent Afd for this page will be appreciated. History2007 (talk) 22:01, 2 February 2012 (UTC)

The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the move request was: not moved; parenthetical qualifier (and singular instead of plural) are correct form on Wikipedia. -- JHunterJ (talk) 12:13, 15 February 2012 (UTC)

---

Requested move

Conditional statement (logic) → Conditional statements in logic –

During the fabulous Afd discussion for this page Arthur Rubin made a comment that was both logical and informed. The new page name is based on that suggestion. To be upfront, the problems I see here are many fold, and the page rename is the first step in fixing the problems, so it will not be the total embarrassment that it is now. This is not an unduly complicated topic. However, it is an utter embarrassment for Wikipedia that may need to get listed on David Letterman's "top 10 Wikipedia embarrassment", if he does such a segment.

My suggestion would be that if/when a rename takes place, Machine Elf 1735 and Hanlon1755 voluntarily step back and let Arthur Rubin and/or CBM rewrite the new page from scratch - should take no more than a few hours. Believe me Machine Elf 1735 and Hanlon1755, it will help both of your blood pressures to step back here. Neither of you will have to have a win/loss emotion and there will be three winners, the two of you and the hapless Wiki-reader who may stumble on this hapless page. History2007 (talk) 22:01, 2 February 2012 (UTC)

History2007, in lieu of explaining your rhetorical faux pas at the AfD, you obnoxiously shut down any response by “washing your hands” of it and removing it from your watch list. Funny how you voted “strong keep”, but now you're calling for a total rewrite* under a different title… “fabulous”?

WP:LETGO: Absent any justification, you're claiming it's some kind of “embarrassment” to all Wikipedia. In fact, you're claiming your claim is so ridiculously self-evident, it's fit for Letterman's top 10.

WP:BAIT: the pathos is yours, and if that's all you've got, then indeed, ad hominem would be a big step up. I'm not intimidated, and I'm not averse to defending a more moderate view of how bad the article I nominated sucks. While I think it still falls short of either title, I've no preference, and I'd certainly welcome a rewrite* by Arthur Rubin and/or CBM.

(*) In fairness to the contributors, of whom Hanlon is no longer the sole member, it's more appropriate to welcome everyone's contributions, be they modest or extensive.

Much of the article has already been copied to material conditional, so perhaps the question of turning it into a disambiguation page should enter this discussion? Otherwise, isn't it just a matter of following convention? I'll gladly defer to anyone who would speak to that, thanks.—Machine Elf ¹⁷³⁵ 07:37, 3 February 2012 (UTC)

Well, fabuolous. Here is what you need to do Machine Elf :

• First, read the page on sphygmomanometer. Then ask yourself why a Wikipedia article on such a simple topic has 4 bright colored tags on it. Then read, the sphygmomanometer page again.

If a simple article has 2 "expert needed" tags on it, something is wrong and in this case also an embarrassment. So let someone else fix it. The rename would make it better than a disambig page because it would allow for a top level explanation. It is a simple solution for an even simpler topic. I see no need for a fanfare here. History2007 (talk) 08:39, 3 February 2012 (UTC)

You don't hear “I'd certainly welcome a rewrite*”? I tagged the article with expert needed, and I didn't have to add it back myself when it was removed… Your inability to admit you're wrong must make it very embarrassing to agree with me so completely. Why not take your own sarcastic advice, and reread your "Strong Keep" until that sinks in? A sphygmomanometer is a blood pressure meter: are you going to carry on with lame jokes and mock concern for my allegedly high blood pressure? Is that what's going to turn me into some kind of out-of-control hot-head who'll prevent improvements to the article? No one on Wikipedia, least of all me, cares who you WP:DONTLIKE personally, or who brings to mind that you've embarrassed yourself. I'd be mortified if I were you, but if it's any consolation, I doubt Letterman will say anything.—Machine Elf ¹⁷³⁵ 13:07, 3 February 2012 (UTC)

So I guess you are in favor of a rewrite. And I think a rename before that will be good as suggested in the Afd. Good. Not let someone else just do it. History2007 (talk) 13:29, 3 February 2012 (UTC)

Open to rewrite under conditions; against rename. I don't have any objection to a rewrite, so long as it agrees with the two ideas that not all if-then statements are material conditionals and that not all material conditionals are if-then statements. I think the article title as it now stands, "Conditional statement (logic)," is better for organizational purposes than is "Conditional statements in logic." Many Wikipedia articles use a title with a term in parenthesis to distinguish it from other articles under the same name. For example, "Set" on Wikipedia has articles related to the set in mathematics (Set (mathematics)), the set in computer science (Set (computer science)), and even the set in C++ (Set (C++)). This article should follow this same uniform format. The proposed title is also more of a phrase than it is a title. Furthermore, the proposed title neither implies nor suggests anything more or less of the article. For these reasons I am against renaming the title from "Conditional statements (logic)." Hanlon1755 (talk) 22:16, 4 February 2012 (UTC)

The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

What is Logical conditional?

I disagree with Arthur_Rubin and History2007 about their desire to redirect all possible titles to one article. What is Logical conditional (edit | talk | history | links | watch | logs) now? It is a redirect to "material conditional". How material conditional is starting?

The material conditional, also known as material implication, is a binary truth function.

Is logical condition a truth function? Yes (in Boolean logic), Yes (in classical propositional calculus), No (in intuitionistic logic), No (in proof theory). Please, propose something acceptable, otherwise I will revert redirecting an article not deleted at AfD, although I think that current version is not focused on the topic. Also, confirm please that this message is seen and Arthur_Rubin or History2007 think about reply, not just dropped "Conditional statement (logic)" from the watch list. Incnis Mrsi (talk) 08:44, 14 February 2012 (UTC)

Yes, your intuitionistic point is valid, but the chaotic treatment in the page needing a rewrite did not do justice to it anyway. Would you like to write 5 clean paragraphs that clarify this issue and let us be done with the discussion which will have 50 paragraphs? That would be the best way. Thanks. History2007 (talk) 10:56, 14 February 2012 (UTC)

I agree with Incnis Mrsi; this article needs to be reverted. The whole point of having this article is that logical conditionals (Conditional statements (logic)) are not necessarily material, if ever. It should not at all be a redirect to material conditional. It was mentioned in the various discussions at Talk:Material conditional, Talk:Conditional statement (logic), Talk:Strict conditional, WP:Articles for deletion/Strict conditional, and WP:Articles for deletion/Conditional statement (logic), that this article may be a WP:CFORK of material conditional or strict conditional. I strongly disagree that this article is a content fork of material conditional for the aforementioned reason. At worst, it's a content fork of strict conditional. The fact that Arthur_Rubin made this a redirect to material conditional shows his lack of understanding for the motivation for having this separate article. I quote Arthur_Rubin in WP:Articles for deletion/Conditional statement (logic), "As noted above, it's a WP:POVFORK of strict conditional..." If anything, he should have made it a redirect to strict conditional! I support reverting the page to an article not deleted at Afd. Hanlon1755 (talk) 14:36, 14 February 2012 (UTC)

Ok, I will self-revert based on the intuitionistic point. But let us delete 90% of this abomination in any case, so something better can come in. As is, it runs against WP:Lede anyway, given that it has a long quote there, over 4 short paragraphs, etc. and much of it needs to be axed. History2007 (talk) 14:46, 14 February 2012 (UTC)

I agree about the lede. I think it's too long, confusing, and complex. As I've said in the previous section, I'm open to a rewrite. Hanlon1755 (talk) 15:03, 14 February 2012 (UTC)

Ok, let us have a raffle to see who will rewrite... I think just 5 clean paragraphs will be enough. History2007 (talk) 15:17, 14 February 2012 (UTC)

I don't know what you mean by a raffle, but I have simplified the lede. Feel free to edit (although I do think it's fine as it now stands). Hanlon1755 (talk) 15:41, 14 February 2012 (UTC)

• Comment I would support a redirect to material conditional. The intuitionistic point isn't really valid: there are a number of ways of restricting the valid proofs of $p\rightarrow q$, including relevance logic and intuitionistic logic, but they still define versions of the material conditional, and aren't discussed here anyway. -- 202.124.74.80 (talk) 02:16, 15 February 2012 (UTC)

It is not clear what you mean by "restricting" the "valid proofs" of "$p\rightarrow q$." You are making this discussion unnecessarily complex. Frankly, I don't need to know what you're talking about there. What is fact is that not all conditional statements in logic are material conditionals (as I've referred to both Barwise and Etchemendy, and Hardegree on the matter in previous discussions), so redirecting this page to material conditional is wrong. People who want to learn about "conditional statements in logic" aren't just looking for "material conditionals," and so such a move is unstrategic and unorganized. Hanlon1755 (talk) 03:22, 15 February 2012 (UTC)

Not only don't you understand me, you don't (as far as I can see) understand those sources. And conditional statements in logic (as opposed to in natural language) are generally some form of material conditional, so the redirect is reasonable. -- 202.124.72.23 (talk) 06:33, 15 February 2012 (UTC)

Regarding intuitionistic logic, Peirce's law is an example of an implication which is true by truth tables, but not provable using intuitionistic rules. However, the implication here is still a form of material implication. -- 202.124.72.23 (talk) 06:38, 15 February 2012 (UTC)

I understand my sources fine. Conditional statements in logic are not always material, and I disagree that they are generally material. Hanlon1755 (talk) 21:48, 15 February 2012 (UTC)

You've been asserting that for a while, Hanlon1755, but you have failed to back up that rather unusual theory. -- 202.124.72.80 (talk) 05:10, 16 February 2012 (UTC)

I've backed it up multiple times by now. I know by personal experience, that redirecting the "general concept of conditional statement in logic" to "material conditional" is misleading. Because of Wikipedia, I had believed for years that material conditional was what I was looking for. I was actually looking for strict conditional. Any reasonable person who wants to look up conditional statements in logic will be misled into believing that material conditional is the only type of "conditional" in logic, which is just untrue. If this page is to be redirected to material conditional, "Material conditional" should at least have a disclaimer at the top stating that this is only one type of conditional in logic (even if the most generally used), and that there are in fact other types of conditionals used in logic. The reader may be interested in these other types! Hanlon1755 (talk) 22:45, 18 February 2012 (UTC)

Your statements and beliefs have to date not constituted "backing up," I'm afraid. I do agree that we could use an article summarising and comparing treatment of implication in intuitionistic logic, relevance logic, and classical logic. However, this article is not it, and I think your strong emotions on the subject preclude you from writing it. I think it's best to redirect to "material conditional" at this time. That seems to be the WP:CONSENSUS -- 202.124.74.219 (talk) 23:30, 18 February 2012 (UTC)

• The AfD did not preclude redirection, which most certainly is the consensus, and by quite a wide margin. Incnis Mrsi, Conditional statement would be the place to address WP:CONCEPTDAB.–Machine Elf ¹⁷³⁵ 21:05, 15 February 2012 (UTC)
• JHunterJ, the redirect issue has nothing to do with the "requested move", which had no merit to begin with.—Machine Elf ¹⁷³⁵ 21:20, 15 February 2012 (UTC)

  My edit summary referred to the AFD (Wikipedia:Articles for deletion/Conditional statement (logic)), not the move request. -- JHunterJ (talk) 16:34, 16 February 2012 (UTC)

Well, as I said, the AfD doesn't preclude a redirect: the closing statement, (in short "not deleted"), implies something should be done with the title… It doesn't say anything about redirection, it only mentions turning it into a dab, although I take it that's not the same as a WP:CONCEPTDAB per se… Perhaps Incnis Mrsi would still be opposed, but as indicated at Proj Math, conditional statement would be better for WP:CONCEPTDAB, and there've been several recent contributions to it. Sorry if I'm overlooking anyone who would find it completely unacceptable apart from Hanlon (currently blocked for 3RR). Assuming History still defers to Arthur Rubin (as do I) that's at least 2 to 1 in favor, counting the 5 IPs at 202.124.*.* as only one user; 96.33.171.225 is Hanlon, btw. So, it's not as wide as I thought, but it's nothing to be dismissed, and it's not a bad turn–out considering the only article that links here is material conditional… Safe to say I'm not spilling any WP:BEANS if I point out that anyone can undo a redirect… Could you elaborate on what quality and/or quantity of consensus should suffice?—Machine Elf ¹⁷³⁵ 22:30, 16 February 2012 (UTC)

Conditions for acceptable solution

I explained in a section above why the solution defended by Machine_Elf_1735 and an unregistered dynamic user is unacceptable. But another disambiguation page, as Hanlon1755 proposed, is not acceptable too. There is one already, and it is not overcrowded. Now I establish the following interim state and try to raise a support for it from WikiProject Mathematics.

1. Conditional statement (logic) redirects to a disambiguation page. No one should alter it before discussion.
2. There appeared no objections against (eventual) creation of WP:CONCEPTDAB-like article. Therefore, some usable drafts may be placed to Conditional statement dab page, even without a strict conformance to WP:MOSDAB guideline.
3. No one should change Logical conditional redirect (which is used as an alias to "material conditional" for years) before discussion, and there should be no mass edits to remove such inbound links.
4. Material conditional will be hatnoted to warn about "logical conditional" redirect.

Thank you for attention. Incnis Mrsi (talk) 08:38, 20 February 2012 (UTC)

I support all that -- it was pretty much the consensus position after the article that was here got into trouble. My only suggestion is that drafts of a WP:CONCEPTDAB-like article start on a suitable talk page (probably Talk:Conditional statement), rather than edit-warring on that existing dab page. My main reason is that debatable material is fine on a talk page; people can suggest changes without altering the original proposal, thus avoiding an edit war.

I have no intention of working on a WP:CONCEPTDAB-like article any time soon, given the history of conflict, but I presume such an article might split into model-theoretic aspects (truth tables, Kripke semantics, etc.), proof-theoretic aspects (intutionistic conditionals, BCI and BCK logics, $\vdash$, etc.), and applications (a brief mention of conditional sentences). -- 202.124.75.40 (talk) 10:02, 20 February 2012 (UTC)

Making the case

Hanlon, rather than go through the edit-revert-block loop yet again, can you please explain your case here? I understand that your main thesis is that conditionals in mathematics are strict conditionals. However, as yet you have convinced nobody of this. Please try to convince at least one or two of us. -- 202.124.75.40 (talk) 09:49, 20 February 2012 (UTC)

Consider the conditional statement "If I am on an island, then I am on Nantucket." This conditional statement is false; a counterexample exists. I could be on an island, but on Oahu instead. The set of all possible cases in which I am on an island is not a subset of the set of all possible cases in which I am on Nantucket.

Let p = "I am on an island," and q = "I am on Nantucket." Suppose p and q are true. I am on an island, and I am on Nantucket.

• The material conditional p → q is true. The hypothesis p is true and the conclusion q is true. The statement is of the form T → T, which is T. This corresponds to the first row on the truth table for material conditionals.
• The strict conditional p → q is false. A counterexample exists; I could be on an island, but not on Nantucket. Therefore it is not true that every time I am on an island, that I am on Nantucket.

The material conditional p → q is true, but the strict conditional p → q is false. The same syntactic statement p → q has a different truth value depending on whether it is expressing a material conditional, or a strict conditional. Therefore there is a fundamental difference between a material conditional and a strict conditional.

But remember our stipulation at the beginning? We concluded the conditional statement "If I am on an island, then I am on Nantucket" is false. This agrees with our finding about the strict conditional p → q. The conditional statement can't be the material conditional because the material conditional p → q turned out to be true. That contradicts what we said about the conditional statement p → q at the beginning.

Generally when we say "If p, then q" we mean that every time p is true, that q is true. We mean that it is impossible that p is true and q is false. We do not mean "not-p or q." We mean that "not-p or q" is always true. We mean that "not-p or q" is necessary. Hanlon1755 (talk) 17:10, 20 February 2012 (UTC)

So what? For a point of view of first-order logic it means that ∀x: q(x) → p(x), but p(x) → q(x) is somewhere false. Certainly, ∀x: p(x) → q(x) is stronger than just p(x) → q(x) for some given x, and the quantified formula may be false. What do you miss is just that if one says something like "if p, then q", the formal translation usually is like ∀x: p(x) → q(x). I can say "if… then…", but I really assume a quantifier. It is one of the reasons for which I proposed to write a CONCEPTDAB article. Incnis Mrsi (talk) 19:49, 20 February 2012 (UTC)