# True/False Logic Question (may, or may not, involve Bonsai Planets) **URL:** \ **Category:** Factual Questions\ **Created:** [August 11, 2012, 4:08pm UTC](https://boards.straightdope.com/t/true-false-logic-question-may-or-may-not-involve-bonsai-planets/631196 "2012-08-11T16:08:03Z")\ **Posts on this page:** 17\ **Page:** 2
**Author:** ![bobot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bobot/32/21622_2.png) [@bobot](https://boards.straightdope.com/u/bobot)\ **Post date:** [August 12, 2012, 2:11am UTC](https://boards.straightdope.com/t/true-false-logic-question-may-or-may-not-involve-bonsai-planets/631196/21 "2012-08-12T02:11:48Z")
Hey, that’s cool. I was responding to the original post, which did not mention assumptions. Just a nonsensical true or false question. ---
**Author:** ![Rysto](https://avatars.discourse-cdn.com/v4/letter/r/ecccb3/32.png) [@Rysto](https://boards.straightdope.com/u/Rysto)\ **Post date:** [August 12, 2012, 2:16am UTC](https://boards.straightdope.com/t/true-false-logic-question-may-or-may-not-involve-bonsai-planets/631196/22 "2012-08-12T02:16:12Z")
> [@Trinary](#): > > B is obviously false. You never read the Pit, do you? 😛 ---
**Author:** ![clairobscur](https://avatars.discourse-cdn.com/v4/letter/c/839c29/32.png) [@clairobscur](https://boards.straightdope.com/u/clairobscur)\ **Post date:** [August 12, 2012, 4:25am UTC](https://boards.straightdope.com/t/true-false-logic-question-may-or-may-not-involve-bonsai-planets/631196/23 "2012-08-12T04:25:23Z")
> [@bobot](#): > > It’s not a logical question, because it cannot be answered true or false. According to the premise, some groks may be griks. Maybe dosen’t fly. The last part of the sentence (“some groks are griks”) can be true or false. But the whole sentence (“If X then Y” ) is false. ---
**Author:** ![Malacandra](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Malacandra](https://boards.straightdope.com/u/Malacandra)\ **Post date:** [August 12, 2012, 7:05am UTC](https://boards.straightdope.com/t/true-false-logic-question-may-or-may-not-involve-bonsai-planets/631196/24 "2012-08-12T07:05:18Z")
> [@Trinary](#): > > I ran across this question a day or so ago but didn’t see the answer and now it’s bugging the sanity outta me. > > * * * > > If some groks are graks and some graks are griks then some groks are griks. T/F\*\*\* > > If pressed, I’d answer ‘false’ but, the why of it escapes me. Changing the nonsense words to real world examples seemed the way to solve this. However, the following examples appear to conflict. > > * * * > > A: If some dogs are poodles and some poodles are bald then some dogs are bald. > B: If some adults are girls and some girls are infants then some adults are infants.\*\*\* A: All poodles are dogs, so if some poodles are bald then some dogs are bald. B: Not all girls are adults, therefore the “some” girls that are infants may or may not overlap with the girls that are adults (and in this instance, none of the adult girls are infant girls). B therefore refutes the given proposition, and one counterexample is enough, therefore the one-letter answer is “F”. This explains why a well-formed syllogism should be very wary of using “some”… 🙂 ---
**Author:** ![FuzzyOgre](https://avatars.discourse-cdn.com/v4/letter/f/a587f6/32.png) [@FuzzyOgre](https://boards.straightdope.com/u/FuzzyOgre)\ **Post date:** [August 12, 2012, 7:50am UTC](https://boards.straightdope.com/t/true-false-logic-question-may-or-may-not-involve-bonsai-planets/631196/25 "2012-08-12T07:50:57Z")
> [@Trinary](#): > > * * * > > A: If some dogs are poodles and some poodles are bald then some dogs are bald. > B: If some adults are girls and some girls are infants then some adults are infants. > C: If some singers are dancers and some dancers are actors then some singers are actors. > D: If some planets are dwarfs and some dwarfs are bonsais then some planets are bonsais.\*\*\* B has a problem because of the way you stated it. Compare it to A. “girls” is the superset, but you are putting adults into girls, then girls into infants. _ **B: If some adults are girls and some infants are girls then some adults are infants.** _ See how that fixed it? Its false, but it makes sense why. In A you did it correctly, with dogs as the super set, and poodles and bald being sub sets. ---
**Author:** ![Carmady](https://avatars.discourse-cdn.com/v4/letter/c/f04885/32.png) [@Carmady](https://boards.straightdope.com/u/Carmady)\ **Post date:** [August 12, 2012, 8:19am UTC](https://boards.straightdope.com/t/true-false-logic-question-may-or-may-not-involve-bonsai-planets/631196/26 "2012-08-12T08:19:41Z")
The sentence is not true or false, for the simple reason that it is not actually a sentence. Grok, grak, and grik are just placeholders. It is no different than if they left blank spaces instead, except that would make it more clear that it wasn’t a sentence. The question is asking if, were you to replace them with meaningful words, the sentences created would necessarily be true. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [August 12, 2012, 8:28am UTC](https://boards.straightdope.com/t/true-false-logic-question-may-or-may-not-involve-bonsai-planets/631196/27 "2012-08-12T08:28:04Z")
They don’t have to be real words. Even real words may have more than one definition. What’s missing is the definition of the relationship between the words, which cannot be determined from the sentence itself. You can call it false because all graks are not necessarily groks, and all griks are not necessarily graks. But if would better to call it fallacious because it assumes relationships that may not exist. ---
**Author:** ![Trinary](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/trinary/32/3151_2.png) [@Trinary](https://boards.straightdope.com/u/Trinary)\ **Post date:** [August 12, 2012, 12:38pm UTC](https://boards.straightdope.com/t/true-false-logic-question-may-or-may-not-involve-bonsai-planets/631196/28 "2012-08-12T12:38:01Z")
Thanks for the clarity! There are some sharp people hanging out here – I appreciate your time. Incubus, sorry to disappoint – it’s never a true intention. I’ve heard stories that the asteroid belt was created specifically so bonsai planets could exist. It’s just a story, though. Rysto, I expected to be confronted for calling B false, based on examples from the pit! Adult=Infantile, at the very least, on many occasions. As for the silly t/f statement, it is good to learn that venn diagrams show why it is ‘fallacious’. Visuals can be very handy! Thanks again, to everyone. ---
**Author:** ![Malacandra](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Malacandra](https://boards.straightdope.com/u/Malacandra)\ **Post date:** [August 12, 2012, 5:26pm UTC](https://boards.straightdope.com/t/true-false-logic-question-may-or-may-not-involve-bonsai-planets/631196/29 "2012-08-12T17:26:45Z")
> [@Carmady](#): > > The sentence is not true or false, for the simple reason that it is not actually a sentence. Grok, grak, and grik are just placeholders. It is no different than if they left blank spaces instead, except that would make it more clear that it wasn’t a sentence. > > The question is asking if, were you to replace them with meaningful words, the sentences created would necessarily be true. No, if the syllogism were instead “All graks are griks; all griks are groks; therefore all graks are groks” that would be a sound syllogism even if we did not have a clue what griks, graks or groks were. The problem is that when you are told “Some X are Y” you are unable to state whether all Y are X, or only some Y - in other words, whether Y is a subset of X, or there is only an intersection between the set X and the set Y. ---
**Author:** ![Snarky\_Kong](https://avatars.discourse-cdn.com/v4/letter/s/a183cd/32.png) [@Snarky\_Kong](https://boards.straightdope.com/u/Snarky_Kong)\ **Post date:** [August 12, 2012, 6:03pm UTC](https://boards.straightdope.com/t/true-false-logic-question-may-or-may-not-involve-bonsai-planets/631196/30 "2012-08-12T18:03:26Z")
Try this one: “If some men are doctors and some doctors are women, are some men women?” ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [August 12, 2012, 6:13pm UTC](https://boards.straightdope.com/t/true-false-logic-question-may-or-may-not-involve-bonsai-planets/631196/31 "2012-08-12T18:13:40Z")
> [@Snarky\_Kong](#): > > Try this one: “If some men are doctors and some doctors are women, are some men women?” Ok. I’ll try. The answer could be either “Yes” or “No” depending on your definition of “Men” and “Women”. What do I win? You are asking a question there, not making an (il)logical proposition. ---
**Author:** ![tapu](https://avatars.discourse-cdn.com/v4/letter/t/49beb7/32.png) [@tapu](https://boards.straightdope.com/u/tapu)\ **Post date:** [August 12, 2012, 8:01pm UTC](https://boards.straightdope.com/t/true-false-logic-question-may-or-may-not-involve-bonsai-planets/631196/32 "2012-08-12T20:01:19Z")
> [@Incubus](#): > > I am disappointed; I thought this thread would be about the ancient Japanese practice of cultivating tiny planets ☹ Me too —\> ☹ …I just came in for the bonsai planets. I’d like a little place of my own. ---
**Author:** ![Docta\_G](https://avatars.discourse-cdn.com/v4/letter/d/2bfe46/32.png) [@Docta\_G](https://boards.straightdope.com/u/Docta_G)\ **Post date:** [August 12, 2012, 8:11pm UTC](https://boards.straightdope.com/t/true-false-logic-question-may-or-may-not-involve-bonsai-planets/631196/33 "2012-08-12T20:11:50Z")
Just draw a Venn diagram to find the answer. ---
**Author:** ![Carmady](https://avatars.discourse-cdn.com/v4/letter/c/f04885/32.png) [@Carmady](https://boards.straightdope.com/u/Carmady)\ **Post date:** [August 12, 2012, 10:18pm UTC](https://boards.straightdope.com/t/true-false-logic-question-may-or-may-not-involve-bonsai-planets/631196/34 "2012-08-12T22:18:06Z")
> [@Malacandra](#): > > No, if the syllogism were instead “All graks are griks; all griks are groks; therefore all graks are groks” that would be a sound syllogism even if we did not have a clue what griks, graks or groks were. The problem is that when you are told “Some X are Y” you are unable to state whether all Y are X, or only some Y - in other words, whether Y is a subset of X, or there is only an intersection between the set X and the set Y. You mean it would be valid. We could not call it sound, because we can assign no truth value to the premise (all graks are griks and all griks are groks). Other than that, we are in agreement. If we look at the original question as a syllogism, then we can say it is invalid. But we still cannot look at it as a sentence and call it true or false, which was what I said. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 12, 2012, 11:02pm UTC](https://boards.straightdope.com/t/true-false-logic-question-may-or-may-not-involve-bonsai-planets/631196/35 "2012-08-12T23:02:54Z")
We can, however, look at the sentence “If all graks are griks and all griks are groks, then all graks are groks” and assign it the value of “true”. Maybe all graks are griks, and maybe they’re not: We don’t know. But _if_ they are, then the rest follows. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [August 13, 2012, 12:07am UTC](https://boards.straightdope.com/t/true-false-logic-question-may-or-may-not-involve-bonsai-planets/631196/36 "2012-08-13T00:07:11Z")
> [@TriPolar](#): > > Ok. I’ll try. The answer could be either “Yes” or “No” depending on your definition of “Men” and “Women”. What do I win? > > You are asking a question there, not making an (il)logical proposition. OK. If you want to get that pedantic, let’s try it with privatives: “If some law-breakers are men and some men are law-abiding, are some law-breakers law-abiding?”. “If some positive-numbers are fractions and some fractions are negative-numbers, are some negative-numbers positive-numbers?”, ""If some people-shorter-than-4-feet are men and some men are taller-than-6-feet, are some people-shorter-than-4-feet taller-than-6-feet See **Snarky\_Kong** ’s point? ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [August 13, 2012, 12:25am UTC](https://boards.straightdope.com/t/true-false-logic-question-may-or-may-not-involve-bonsai-planets/631196/37 "2012-08-13T00:25:50Z")
> [@Blake](#): > > OK. If you want to get that pedantic, let’s try it with privatives: “If some law-breakers are men and some men are law-abiding, are some law-breakers law-abiding?”. “If some positive-numbers are fractions and some fractions are negative-numbers, are some negative-numbers positive-numbers?”, ""If some people-shorter-than-4-feet are men and some men are taller-than-6-feet, are some people-shorter-than-4-feet taller-than-6-feet > > See **Snarky\_Kong** ’s point? Hay! I pointed it out first! 😉 > [@cmyk](#): > > It’s can be true, but not necessarily so, that: > > Some sheep are small (groks), and some sheep are black (graks), and some sheep are shorn (griks), then some small sheep are shorn. > [@cmyk](#): > > It’s false that: > > Some sheep are tall (groks), some sheep are clean (graks), some sheep are short (griks), **then some tall sheep are short sheep.** > [@cmyk](#): > > Conclusion is “False” to the grok/grak/grik proposition. [Previous page](https://boards.straightdope.com/t/true-false-logic-question-may-or-may-not-involve-bonsai-planets/631196.md?page=1)