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Post Info TOPIC: Anyone like paradoxes?


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Anyone like paradoxes?


This is a fun paradox my old roommate told me:

In the old west, a man was convicted of murder and was with the town honest and just town judge and his lawyer for his sentencing. "You have been convicted of murder and I sentence you to execution by hanging, as per the law." Stated the judge. "However, here are the terms of your execution. Today is Sunday. One day this week, you will be hung at high noon. But you will not know the day of your execution until the day comes. On the eve of your execution, you will not know that tomorrow is your hanging."

Stepping out of the courthouse, the lawyer gives the sad man a laugh of triumph. "You've gotten off! Don't you see? The judge is a perfectly honest judge. He says you will not know the night before your execution that you will be hung on the morrow, but that you will be hung one day this week. So let's say the whole week passes by and we come to Friday night. Saturday is the only day left in the week, so that must be the day of your hanging. However, you will know Friday night that your hanging is on the morrow, so the judge's word is not honest and you cannot be hung. So Saturday is out, and Friday is the last possible day you can be hung. But if Thursday night comes and you are still alive, then you will know that Friday is your execution in advance, thus eliminating Friday as your execution day. Therefore Thursday is the last possible day you can be hung, except that you'll know Wednesday night, and so forth until tonight! So you see, you cannot be hung according to the Judge's honest word!"

The convicted man confidently is escorted back to his jail cell, certain of his liberty. However, the sheriff drags him from his cell on Wednesday morning to be hung at high noon. The man is completely surprised!

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Understander of unimportant things

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I guess I don't see a paradox here. Sounds more like a lawyer with faulty reasoning.

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Wise and Revered Master

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Only a lawyer would see this as a get out of jail free card. Anyone with common sense would know that the Reaper was coming.

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Jason



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I love paradoxes. Maybe its the mathematician in me.

Ah, the famous unexpected hanging paradox, it bugged me for weeks. (The envelope paradox, and Newcombs paradox bugged me even more.)
So the judge said
1: You will die this week
2: You won't expect it.

The lawyer makes the argument that if there is only one day left and he is still alive, because of statement #1, that must be the day he dies on. He surely would expect it then, but this would violate statement #2. So he cannot be executed on the last day, because it would be expected. However, here's the catch, once you suppose this you are no longer holding statement #1 to be true. Your argument is now invalid. In a sense, once you reason you cannot be executed on a day because it would be expected, you can then be executed on that day because it would be unexpected.

Lets simplify the problem. Suppose I have two boxes, #1 & #2. #1 must be opened before #2. One of them has $100 in it. The person who put the money in one of the boxes says that if you can open a box, knowing perfectly well it has the money in it before looking, that you can keep the money, otherwise he keeps it.
Well, would the person setting it up put the money in box #2? If it were in box #2 then you could open it knowing full well the money is in the box because it's the only one left, and you get the money instead of him. With the lawyers logic you would say that this means that the money cannot be in box #2, so it must be in #1, but then you use the same logic, and it can't be in box #1 either. But once you accept that it isn't in #2 or #1, then the person setting it up can put it in either box, and you would be suprised.

I guess it boils down to the concept of something being expected being ill-defined. The truth or falsity of the statements by the judge can both be true, because it is still possible to be hanged unexpectedly on the last day. Otherwise it would be a real paradox.

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Hot Air Balloon

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The ultimate paradox is two simple words...


"More Cowbell."

--Ray

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". . .the most famous is never get involved in a land war in Asia, but only slightly less well-known is this: never go in against a Sicilian when death is on the line!"

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Future Queen in Zion

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Yeah, I thought of Iocaine powder, too. That's more of a riddle, though... Still, anytime one can quote Princess Bride, it is good to do so. biggrin.gif

-- Edited by hiccups at 14:12, 2007-10-16

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...anybody wanna peanut?

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Wise and Revered Master

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rayb wrote:

The ultimate paradox is two simple words...


"More Cowbell."

--Ray




Don't Fear the Reaper!!!



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Jason



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I often wondered what it meant in the Article of Faith when it says that the earth will receive its paradoxical glory... (hey, that one's for you Coco -- consider it as you would the Sock of Al Bundy...)

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Wise and Revered Master

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How about this for a paradox!



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Jason



Hot Air Balloon

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heh.. it's in Italian. I caught about half the words...

--Ray


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Jason, where do you find this stuff? weirdface.giflaughing.gif

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Wise and Revered Master

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My wife says I'm a treasure trove of useless information. And that movie was definitely useless information. So is it possible to be your own grandpa?

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Jason



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And to think people would be interested in discussing my take on the unexpected hanging paradox. biggrin

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Wise and Revered Master

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That was too complicated a Paradox. Now wondering if it is possible to be your own grandpa is something even a redneck with a third grade education can contemplate.

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Jason



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Jason, do you mean "wondering if it is possible to be your own grandpa is something ONLY a redneck with a third grade education can contemplate"?

Sorry...I couldn't resist. I myself find the song pretty funny. It all makes sense except for the fact that the step-daughter of the son marrying the son's dad. That just sounds like a double case of cradle-robbing to me.

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Pt314, I liked your explanation. The judge must have been counting on the lawyer explaining that the man was off scot-free so he wouldn't be expecting to die. If the lawyer had kept his mouth shut, maybe the convicted man wouldn't have figured it out!

I am confused by all this genealogy conversation.

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Janey wrote:

Pt314, I liked your explanation. The judge must have been counting on the lawyer explaining that the man was off scot-free so he wouldn't be expecting to die. If the lawyer had kept his mouth shut, maybe the convicted man wouldn't have figured it out


But if the convicted man didn't figure it out, he would be hanged unexpectedly as well.

 



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Heres another one.

Suppose you are given envelopes, and you are told that one has twice as much money in it than the other one. You open one of the envelopes and are given the option to keep the money in that one, or to swich envelopes. Is it in you interest to switch?

If you open up the first envelope, and it has $100 in it, then the other envelope has either $50 or $200. The expected value of this is $125, which is better then $100 right? Or you can look at it as a 50% chance of losing $50, or a 50% chance of gaining $100. So it's in your interest to switch.

However you can make the same argument that it is better to switch, irregardless of how much money is in the envelope. If the envelope you opened has x in it, the other one has 2x or 0.5x in it. The expected value of switching is 1.25x.

But then why bother opening the envelope in the first place, if it is in your interest to always switch? But this doesn't make any sense, the two envelopes are on the same footing aren't they? biggrin

-- Edited by Pt314 at 08:32, 2007-10-18

-- Edited by Pt314 at 08:33, 2007-10-18

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I think that may only work if there is the risk of coming away with nothing or losing something.

One comes to the table with no risk, and is assured of walking away with at least $50 that they didn't have before. Hence, there is no disincentive to gamble at getting more than the $100.

For it to be a paradox, and I admit my understanding of paradox may be wrong, wouldn't the person who is given the envelopes also have to be a stakeholder with the risk of having to owe something or lose what they have put in?

It is kind of like that really old game show, Let's Make A Deal.

Or that short story, The Lady, or The Tiger.

-- Edited by Cat Herder at 11:05, 2007-10-18

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Oh yeah, like one envelope has 50 dollars and the other has a bill for $25?

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Keeper of the Holy Grail

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"paradoxical glory..." rofl.gif Yeah, it's dumb, but I find that amazingly funny.

Pt- You are WAAAY over my head, boy! But I can tell you this- irregardless does not need the "ir" in front of it. It's not even a real word - it's just that people use that as a sort of mutated combination between regardless and irrespective. So just drop the "ir"... sort of ties in with Ockham's Razor, don't it? That's math, right?

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The envelope choice between gaining or owing wouldn't work because if you open the envelope, you know immediately which one you have. Either you have the money and keep it, or you have a bill and your switch it.

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No, the whole point is that when you open the envelope you don't know if its the one with less money, or more money. All you know is that one envelope has twice as much as the other one. Both envelopes have cash, neither has a bill.

Suppose you open one of the envelopes and it has $50 in it. You have no idea if the other envelope has $25 or $100 in it. You can keep the $50 or take a shot of getting $100. If the other envelope doesn't have $100 it has $25. It's in your interest to switch isn't it? The expectation of switching is $((100 + 25)/2) = $62.50  which is greater then $50, so you should switch. But that doesn't make sense, thats why its a paradox. Where is the problem with the reasoning?

-- Edited by Pt314 at 16:02, 2007-10-18

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The expectation of switching is $((100 + 25)/2) = $62.50 which is greater then $50, so you should switch. But that doesn't make sense, thats why its a paradox.
Oh, I see.  I guess when it is put that way, it makes sense as being a paradox because the abstract $62.50 switch expectation is not the same thing as the reality based 50% chance (probability) the result is only $25.00.

I don't think mathematically.  I'm conceptual.  And, I am also very risk averse when it comes to chance.

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It seems to me the only thing you've learned is that Caesar is a "salad dressing dude."
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