Here are some nice riddles, and they even have a decent storyline within them:
twinbear.com/riddles.html
My question: who can solve the third riddle, Lying Defeeted?
I can 
Would you rather I send you a private message so I do not ruin it for everyone?
Yeah I think that would be best, and you made me curious for your answer
SPOILER ALERT: MY RESPONSE HERE CONTAINS THE ANSWER TO THIS RIDDLE.
the third man has purple soles, because he is lying about the second man having purple soles, because the second man must be telling the truth because the first man must have said “i have green soles” because, if he had purple soles he would have lied and said green, and if he had green he would have told the truth and said green, so we know that the first man stated that he has green soles, necessarily. therefore, as i stated, the second man tells the truth, hence he has green soles. therefore, the third man lies when he says the second man has purple soles, ergo the third man has purple soles.
Nice try 
](https://www.ilovephilosophy.com/uploads/default/original/2X/7/7c349bf1053f368a5729d053e1e91215f22ce66c.gif "Brick wall"){kind=small}
ill propose a new riddle here; i dont know if its on that website that you reference in the OP, but even if it is i still have not been able to satisfactorily understand how to resolve the riddle. its called the Surprise Quiz Paradox:
"the student then replies “but then, if we know the quiz cannot be on friday or thursday, we know it cannot also be on wednesday either, for the same reason. likewise, it cannot be on tuesday either”. the professor agrees, saying “yes, you seem right.”
This rests on an assumption: that
- if a quiz is expected on a certain morning, then it will not be a suprise (if this is not the case, the logic fails)
However, the rest of the story says the following:
- every morning the class will expect the test.
If 1) and 2) obtain then a suprise test is indeed logically impossible. So long as both obtain, there will be no ‘solution’. This should not be that suprising though - what the story has said is that the class has started thinking in a certain way that will cause them to expect the test every morning. So long as this is true and the first premiss also accepted - there will be no suprise test. This is no paradox however, because neither premiss is uncontestable.
There are two possible escapes:
First - reject the first premiss. This may be done by arguing that a suprise test is a suprise test so long as the class don’t know that it will occur on the given day. Even if they expect it, it is still to be considered a suprise so long as they didn’t know for sure it would happen that day. This makes the suprise test possible on any day - seeing as the professor could well have been lying to them, or get ill, or something else could occur that stopped the test from happening. Thus even on friday it would count as a suprise, even though the entire class expected the test.
Second - reject the second premiss. This could be done by arguing that the class no longer expected the test - because they had proved the element of suprise impossible and expected the professer to give up. Or they just forgot about the test, or something like that.
Of course, the solutions are ‘mundane’, but they show the weakness: whilst both premisses look buyable as the story presents them, they are in fact not necessarily sound, as stating them explicitly reveals. What the story says is that if you accept (1), and there is a situation where the class have got in to thinking in a way that will cause them to expect the test every morning, then there will be no suprise tests. Yeah - thats certainly true. But the trickery in the paradox is that it makes it look like it makes all suprise tests impossible: which it doesn’t - because even if you buy in to 1), 2) is at best a contingent truth.
p.s. nice one on that first paradox. Problem solved! =D>
Liked these when I was a kid:
The Riddles of ‘The Hobbit’.
This thing all things devours:
Birds, beasts, trees, flowers;
Gnaws iron, bites steel;
Grinds hard stones to meal;
Slays king, ruins town,
And beats high mountain down.
What has roots as nobody sees,
Is taller than trees
Up, up it goes,
And yet never grows?
No-legs lay on one-leg, two legs sat near on three legs, four legs got some.
An eye in a blue face
Saw an eye in a green face.
‘That eye is like to this eye’
Said the first eye,
‘But in low place
Not in high place.’
Alive without breath,
As cold as death;
Never thirsty, ever drinking,
All in mail never clinking.
It cannot be seen, cannot be felt,
Cannot be heard, cannot be smelt.
It lies behind stars and under hills,
And empty holes it fills.
It comes first and follows after,
Ends life, kills laughter.
Thirty white horses on a red hill,
First they champ,
Then they stamp,
Then they stand still.
A box without hinges, key or lid,
Yet golden treasure inside is hid.
Voiceless it cries,
Wingless flutters,
Toothless bites,
Mouthless mutters.
Riddle poetry is one of the oldest and finest traditions in the English language. Much of Anglo Saxon poetry is in riddle form (as Tolkien well knew).
Check out these - from the exeter book penelope.uchicago.edu/~grout/enc … gmata.html
And if you like them - try this : amazon.co.uk/Exeter-Book-Rid … 0140433678
(if one is starting to learn to write poetry, riddle poetry may well be the best place to start)
Did anyone do the first…?
Anyway - SPOILERS
Okay - let’s work back.
3 says “Sir, he has purple soles.” of 2.
Calling him a liar.
So, if 3 was truthful, then what 2 said prior must have been a lie.
ie. man 2 said “He said he has green soles.” of 1.
But, then man 1 must have answered the question “Sir, what color are your soles?” (according to 2) by saying “I have purple soles” - ie. “I am a liar”
Which is impossible.
Paraphrase. “Are you a liar or a truthteller…?”
“I am a liar” → If he’s a liar, then he can’t say this. If he’s a truthteller he wouldn’t say it either. So - that’s an impossible answer.
so, 2 must have been telling the truth - because the only answer he could have heard from man 1 is “I have green soles”.
Which means man 3 is lying, and therefore has purple soles.
Was threetimesgreat wrong - we have the same answer I think…?
As to ThreeTimesGreat’s riddle. I’m sure Brevel’s right, but it would seem to me that the “retro-progressive expectation” loophole posed by the student only works with chains of consecutive days.
ie. on thursday you know there will not be a quiz on friday, and on wednesday you know there won’t be a quiz on thursday, but cannot be sure about friday because you haven’t encountered thursday yet.
So, though it couldn’t be on Monday or friday, it could be on any other day.
Er. Maybe.
you say that “but cannot be sure about friday because you haven’t encountered thursday yet”, but we CAN be sure about friday, because the non-quiz nature of friday is a necessary fact given the initial conditions of the situation. consider:
A) it is a fact that there will be a quiz on monday or tuesday or wednesday or thursday or friday. one of these five days, and only one, will have a quiz on it. it is not the case that the quiz will be on a day outside of this week, and it is not the case that there will be no quiz, or more than one quiz.
B) the nature of the quiz is that the students will not be able to leave class the day before and cram-study that night for the quiz the following morning: the professor wishes to “catch the students off guard” in order to test their knowledge randomly or spontaneously. this is why the professor doesnt tell the students which day the quiz is on, and only tells the students that there WILL be a quiz. the students cannot know the day before that there will be a quiz the following day.
(in addition to this, IF the quiz is on a pre-friday day then it is necessarily true from A that there is no quiz on friday… however, if the quiz is not monday-thursday then the quiz necessarily must be on friday, which, as the students KNOW THIS prior to it actually being friday (i.e. the night between thursday and friday) then this voilates B)-- so, given the initial conditons A and B, “the quiz is on friday” is necessarily false in all possible cases, thus we can certainly conclude that it is false even when we have not yet reached thursday.
A and B both seem perfectly plausible and seem not to entail any contradictions. now, we cant just say that “they can expect the quiz every day”, because this is only re-framing the initial problem: attempting to solve the dilemma by saying that the students just expect the quiz “every day” and hence it is not a surprize, fails because even if the students go into each day expecting a quiz, on friday they will KNOW for CERTAIN that the quiz is that day (regardless of any level of their expectations earilier in the week or on that day), and this will defeat the purpose of the surprize quiz-- it violates B, and hence is not a viable option. A and B are facts of the situation, and any attempt to solve the dilemma which contradicts A or B is insufficient, because it is just changing the parameters of the problem itself (this is assuming that A and B cannot be shown to entail a contradiction, which up to this point they have not).
no matter how much the students do or do not expect a quiz any or all days of the week, the quiz cannot be on friday because this violates B above. however, GIVE THIS CONCLUSION, which seems unavoidable and necessary given A and B in conjunction, we are led immediately to the conclusion that “the quiz cannot be on thursday either”, FOR THE SAME REASON. basically, the quiz cannot be on friday because it cannot be on saturday, and BEING ON FRIDAY itself presupposes necessarily travelling through monday-thursday without having had the quiz, which itself necessarily presupposes a violation of B above. however, for this same reason, the quiz cannot be on thursday because it cannot be on friday. the reducion to monday is easy to follow at this point:
a. the quiz is on friday
b. the quiz is on thursday
c. the quiz is on wednesday
d. the quiz is on tuesday
e. the quiz is on monday
as long as B and A exist in conjunction, we know that ‘a’ above is false by necessity. for a to be true would mean that B itself is false, because the students would know the day before that the quiz was on that day and would hence be able to cram-study for it, as it would not be a surprize upon walking into class.
given A and B, we conclude ¬a. given A, B and ¬a, then, we conclude ¬b. likewise all the way to ¬e.
now, of course the students could study every day and thus be prepared for the quiz no matter what day it is on; however, this doesnt change the problem, because the students will still GO INTO THE DAY OF THE QUIZ NOT KNOWING IF THE QUIZ WILL BE THAT DAY (except for on friday!), and from there we are left with the same reduction, from a to e…
I’m sorry, that’s a lovely reply, but the whole scenario has now exceeded my “who gives a shit” capacity.
Well you’re not the only curious one here now. =D>
Your overcomplicating the problem. All the story says is that:
the students have reasoned in a way that causes them to expect the quiz to be on every single morning they get there. So in one week (monday to friday) if they will exoect the quiz every morning, AND you equate “suprise quiz” with meaning “unexpected on the morning it occurs” then the suprise quiz is impossible. And, indeed, given these assumtions it is impossible (logically impossible).
But so what? The fact that the kids have reasoned in a way that causes them to expect the quiz every morning they turn up is contingent, not necessary.
There is no actual logical fact that the quiz can not be on friday: it is all in the minds of the quiztakers.
Honestly - read it again - its not even that complicated. Your just conectrating too much on the logic without considering the general obvious side of things.
In essence the fallacy that the paradox invites you to commit is mistaking a contigent relation: (i.e. the students have realised the quiz can’t be on friday, ergo they will expect it on thursday, ergo they will expect it on wednesday etc) with a logical relation (thie quiz can’t be on friday, therefore, it can’t be on thursday etc). The contingent relation is true, the logical one false.
Basically - take a break - sit back - its all a play on words!
Good riddles on that web page. I’ve arrived at River City now, but have not read it yet. Anyway, I was wondering if I’d solved the “Three’s a Crowd” riddle. I will type my answer in a very small font size; to read it, copy and paste it somewhere.
[size=10]$33.34 + $33.33 + $33.33[/size] ← Here it is!
the logical relation is true as well, given the parameters of the example. its a logical problem, thats the point of these sorts of riddles.
This is more of a paradox than a riddle, but it is kind of cute and I like it.
It’s not a lie if Pinocchio doesn’t know the truth. He’s just guessing.
But the fact that he made a statement (regardless of whether or not he’s guessing) means that it has to be either true or false.