# Partly wrong or completely wrong - opinion poll, but feel free to use formal logic. **URL:** \ **Category:** In My Humble Opinion\ **Created:** [January 11, 2013, 12:44pm UTC](https://boards.straightdope.com/t/partly-wrong-or-completely-wrong-opinion-poll-but-feel-free-to-use-formal-logic/646852 "2013-01-11T12:44:19Z")\ **Posts on this page:** 15\ **Page:** 2
**Author:** ![MichaelEmouse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/michaelemouse/32/101_2.png) [@MichaelEmouse](https://boards.straightdope.com/u/MichaelEmouse)\ **Post date:** [January 12, 2013, 5:09am UTC](https://boards.straightdope.com/t/partly-wrong-or-completely-wrong-opinion-poll-but-feel-free-to-use-formal-logic/646852/21 "2013-01-12T05:09:36Z")
Left, True, when someone says “The wait staff at Laughting Jack’s are always friendly” it’s implicitly understood that it’s meant to say “They’ve always/nearly always been friendly so the odds are high they will be if you go there”. In such situations, since the unstated conclusion: Therefore if you want friendly wait staff, Laughing Jack’s is a good place to go" is still true in all ways that matter. However, the context which likely gave rise to this question is Todd Akin. As you know, Todd Akin said that it’s “really rare” for a legitimate rape to result in pregnancy. In such a situation where the unstated conclusion is “Therefore there shouldn’t be a rape exemption to an abortion ban” how true the premise is very much matters since the conclusion (at least partly) hinges on it being “really rare”. It therefore matters if it’s really rare or just less likely. “Less likely” =/= “really rare”. Or, to put it another way, two situations: 1)If I say that you never get cramps if you warm up before sports when in fact it gives you a 1% chance of getting cramps, it would be fair to say it’s partly true. 2) If I say that you never catch AIDS if you wear a condom when in fact it gives you a 1% chance of getting AIDS, it would not be fair to say that it’s partly true. There are some matters that require more than everyday heuristics. To give a physical example: If, when I throw a baseball into a net, I only make very basic, fuzzy calculations of momentum, kinetic energy, air resistance and gravity in my head, that’s ok. If I’m launching a satellite into space, I have to be a lot more precise. Using rocket-launching heuristics when throwing a baseball would be ridiculous. Using baseball-throwing heuristics when launching a rocket would also be ridiculous even though they’re both fundamentally the same action. ---
**Author:** ![TATG](https://avatars.discourse-cdn.com/v4/letter/t/50afbb/32.png) [@TATG](https://boards.straightdope.com/u/TATG)\ **Post date:** [January 12, 2013, 5:42am UTC](https://boards.straightdope.com/t/partly-wrong-or-completely-wrong-opinion-poll-but-feel-free-to-use-formal-logic/646852/22 "2013-01-12T05:42:16Z")
All x are F. But while this holds for all (of a squillion) x, it doesn’t hold for one. Given this, the sentence is false, but not as wrong as it could be. I guess that means not completely wrong. ---
**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\ **Post date:** [January 12, 2013, 5:51am UTC](https://boards.straightdope.com/t/partly-wrong-or-completely-wrong-opinion-poll-but-feel-free-to-use-formal-logic/646852/23 "2013-01-12T05:51:48Z")
> [@Left\_Hand\_of\_Dorkness](#): > > I think formal logic is unhelpful in deciding this. > > Let’s say I tell someone, “The wait staff at Laughing Jack’s are always friendly.” The truth value of this is not important: what’s really important to my audience is the utility value of the statement. They can take that statement to mean that, if they’d like to deal with friendly wait staff, they should consider eating at Laughing Jack’s; they can also take it to mean that, if they want to know what I consider to be friendly wait staff, they should consider what the wait staff at Laughing Jack’s are like. > > Of course someone could answer, “Technically you’re totally wrong, because two years ago there was a waiter there who’d just broken up with his girlfriend and when I stiffed him on the tip he glared at me. Therefore your absolute statement is completely wrong, QED.” > > But the correct response to that person isn’t to say, “You’re right, and my statement was completely wrong.” The correct response is to say, “Why are you always such a douche?” If you had said “The wait staff at Laughing Jack’s are always friendly. **There are no exceptions.** ” then the glaring waiter would have shown your statement to be flat-out wrong. However, you didn’t say “There are no exceptions,” and in the circumstances, you almost certainly didn’t mean to imply it. So under the circumstances I’d agree with your analysis. In certain contexts though, such as mathematics and logic, “there are no exceptions” is understood. ---
**Author:** ![BigT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bigt/32/12044_2.png) [@BigT](https://boards.straightdope.com/u/BigT)\ **Post date:** [January 12, 2013, 1:42pm UTC](https://boards.straightdope.com/t/partly-wrong-or-completely-wrong-opinion-poll-but-feel-free-to-use-formal-logic/646852/24 "2013-01-12T13:42:31Z")
I find it odd that most people are voting “completely wrong.” That’s just not how language works, in my experience. Everyone keeps citing the exceptions, like mathematics or logic, where they specifically use language differently. But, in most cases, most people would only think of themselves as partly wrong. For example, if my mom says that all dogs have fur, and I point out a bald one, she doesn’t think she was completely wrong. ---
**Author:** ![Siam\_Sam](https://avatars.discourse-cdn.com/v4/letter/s/d78d45/32.png) [@Siam\_Sam](https://boards.straightdope.com/u/Siam_Sam)\ **Post date:** [January 12, 2013, 2:35pm UTC](https://boards.straightdope.com/t/partly-wrong-or-completely-wrong-opinion-poll-but-feel-free-to-use-formal-logic/646852/25 "2013-01-12T14:35:45Z")
Well, all _true_ X are Y. ---
**Author:** ![Just\_Ed](https://avatars.discourse-cdn.com/v4/letter/j/e19b73/32.png) [@Just\_Ed](https://boards.straightdope.com/u/Just_Ed)\ **Post date:** [January 12, 2013, 2:53pm UTC](https://boards.straightdope.com/t/partly-wrong-or-completely-wrong-opinion-poll-but-feel-free-to-use-formal-logic/646852/26 "2013-01-12T14:53:11Z")
> [@BigT](#): > > I find it odd that most people are voting “completely wrong.” That’s just not how language works, in my experience. Everyone keeps citing the exceptions, like mathematics or logic, where they specifically use language differently. But, in most cases, most people would only think of themselves as partly wrong. > > For example, if my mom says that all dogs have fur, and I point out a bald one, she doesn’t think she was completely wrong. I voted “Completely Wrong” mostly because of the phrasing of the OP, including the priming statement “feel free to use formal logic.” I’d agree that in colloquial usage, such as statements like your dogs example or the previous waitstaff example, there is a different mechanism at work, but the phrases in the OP are constructed in such a way as to indicate a more formal application of logic. I’ve no doubt the results would be different if the poll were done using colloquial language. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 13, 2013, 1:09am UTC](https://boards.straightdope.com/t/partly-wrong-or-completely-wrong-opinion-poll-but-feel-free-to-use-formal-logic/646852/27 "2013-01-13T01:09:34Z")
> [@TATG](#): > > Given this, the sentence is false, but not as wrong as it could be. I guess that means not completely wrong. No - just curious as to how people perceive this scenario. I think I probably ruined it by adding the comment about formal logic, however. ---
**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\ **Post date:** [January 13, 2013, 1:12am UTC](https://boards.straightdope.com/t/partly-wrong-or-completely-wrong-opinion-poll-but-feel-free-to-use-formal-logic/646852/28 "2013-01-13T01:12:49Z")
Some exceptions are trivial, foolish, and pedantic. When someone said “All men are capable of rape,” the exception of a quadriplegic patient, or a newborn baby, or someone whose entire pelvis has been amputated, isn’t valid in the context of the dispute. It’s pointlessly persnickety. It isn’t relevant to the real point. Much more meaningful objections can be (and should be, and have been) made to the declaration. Point to real men who have patience, wisdom, moral strength, self-control, and personal honor. Don’t hide behind facile sophistry when there are meaningful things that can be said. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 13, 2013, 12:26pm UTC](https://boards.straightdope.com/t/partly-wrong-or-completely-wrong-opinion-poll-but-feel-free-to-use-formal-logic/646852/29 "2013-01-13T12:26:00Z")
Had I not specified the bit about formal logic (and also, depending on where I went to ask the question), I think the answers might have been different. “All swans are white” is an entirely false statement, once it is established that some swans are not white. However, if only a fairly small proportion of swans are in fact non-white, the way in which the statement “All swans are white” defines the domain - that is, it describes a world full of white swans, may be perceived as _mostly correct_. People will answer differently, I think, depending on whether they are considering the logical validity of the statement, or the degree by which the subject of the statement matches reality - and these two things are not exactly the same. ---
**Author:** ![TATG](https://avatars.discourse-cdn.com/v4/letter/t/50afbb/32.png) [@TATG](https://boards.straightdope.com/u/TATG)\ **Post date:** [January 13, 2013, 2:35pm UTC](https://boards.straightdope.com/t/partly-wrong-or-completely-wrong-opinion-poll-but-feel-free-to-use-formal-logic/646852/30 "2013-01-13T14:35:08Z")
> [@Mangetout](#): > > No - just curious as to how people perceive this scenario. I think I probably ruined it by adding the comment about formal logic, however. I don’t understand what the “no” refers to. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 13, 2013, 4:30pm UTC](https://boards.straightdope.com/t/partly-wrong-or-completely-wrong-opinion-poll-but-feel-free-to-use-formal-logic/646852/31 "2013-01-13T16:30:11Z")
> [@TATG](#): > > I don’t understand what the “no” refers to. Sorry - I don’t know what happened there - I was trying to respond to **Senegoid** ’s question in post #18\* - No idea how I managed to hit the Quote button on your post. Sorry. \ ***Senegoid** asked: > [@](#): > > Are you trying to develop a critique of Cognitive Behavioral Therapy? ---
**Author:** ![handsomeharry](https://avatars.discourse-cdn.com/v4/letter/h/e9c0ed/32.png) [@handsomeharry](https://boards.straightdope.com/u/handsomeharry)\ **Post date:** [January 15, 2013, 4:35pm UTC](https://boards.straightdope.com/t/partly-wrong-or-completely-wrong-opinion-poll-but-feel-free-to-use-formal-logic/646852/32 "2013-01-15T16:35:05Z")
> [@StGermain](#): > > To me, the middle statement isn’t untrue. > > [ul] > [li]Puppies are always Qute (P is always Q)[/li][li]Puppies are occasionally Old English Sheepdogs. (P is occasionally O)[/li][/ul] > > There is nothing that states that O and Q are varieties of the same thing. It’s not like [ul] > [li]Puppies are always dogs (P is always Q)[/li][li]Puppies are occasionally cats. (P is occasionally O)[/li][/ul] > > StG I’ll go with this. I don’t think that ‘occasionally’ would exclude “always”. ---
**Author:** ![Cheesesteak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cheesesteak/32/3694_2.png) [@Cheesesteak](https://boards.straightdope.com/u/Cheesesteak)\ **Post date:** [January 15, 2013, 4:58pm UTC](https://boards.straightdope.com/t/partly-wrong-or-completely-wrong-opinion-poll-but-feel-free-to-use-formal-logic/646852/33 "2013-01-15T16:58:57Z")
> [@Mangetout](#): > > Consider any absolute statement of the general form: > > [ul] > [li]All X are Y[/li][li]P is always Q[/li][li]A leads invariably to B[/li][/ul] > > Subsequently, exceptions are found; that is, it turns out: > [ul] > [li]Only most X are Y[/li][li]P is occasionally O[/li][li]A sometimes leads directly to Z, not B[/li][/ul] If we’re talking different grades of wrongness, these are clearly less wrong than statements with the following exceptions: [ul] [li]X is never Y[/li][li]P is always O, never Q[/li][li]A leads directly to Z, not B[/li][/ul]Those are absolutely, hilariously, wrong, where one should question the sanity / intelligence of the person making the claim. Your initial list is of a person making an absolute claim when it is merely highly probable. Wrong, but not nearly as wrong as some possible alternatives. “All swans are white” is wrong but not nearly as wrong as “Swans are tall ducks” ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 15, 2013, 5:14pm UTC](https://boards.straightdope.com/t/partly-wrong-or-completely-wrong-opinion-poll-but-feel-free-to-use-formal-logic/646852/34 "2013-01-15T17:14:33Z")
> [@handsomeharry](#): > > I’ll go with this. > I don’t think that ‘occasionally’ would exclude “always”. That was an unintentional loophole, as already discussed. ---
**Author:** ![Strinka](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/strinka/32/512_2.png) [@Strinka](https://boards.straightdope.com/u/Strinka)\ **Post date:** [January 15, 2013, 6:07pm UTC](https://boards.straightdope.com/t/partly-wrong-or-completely-wrong-opinion-poll-but-feel-free-to-use-formal-logic/646852/35 "2013-01-15T18:07:04Z")
Depends on what form of logic you’re using. If you’re using [Aristotelian logic](http://en.wikipedia.org/wiki/Term_logic), or something else that uses the [law of the excluded middle](http://en.wikipedia.org/wiki/Law_of_excluded_middle), it doesn’t make any sense for something to be “partly wrong”. A statement is either true or false, and if it’s not true it has to be false. There are no gradations. But if you’re using something like [fuzzy logic](http://en.wikipedia.org/wiki/Fuzzy_logic), or [probabilistic logic](http://en.wikipedia.org/wiki/Probabilistic_logic), then things can be partly wrong. And I would say that the statement “All X are Y” is false to the extent that, well, it isn’t true. So, if 99% of X are Y, then it is 1% false. If 50% of X are Y then it’s 50% false and if 1% of X are Y then it’s 99% false. And there are other forms of logic besides those, but I don’t know how they would apply to this question. [Previous page](https://boards.straightdope.com/t/partly-wrong-or-completely-wrong-opinion-poll-but-feel-free-to-use-formal-logic/646852.md?page=1)