This Sentance Is False!!! - Page 2

DigitalDave · 2004-10-13, 02:21 AM

Sentance = Sentence ...?

or maybe statement ...?

or maybe ... "this sentence is ironic ...?

Klaas Bil · 2004-10-13, 08:36 AM

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UNIquelyCanadian · 2004-10-13, 09:51 PM

I won't be tricked into posting anything on this thread.

UNIquelyCanadian · 2004-10-13, 11:19 PM

I don't think it matters what I think!

KJ-52 · 2004-10-14, 10:13 AM

Would you all stop posting like I have?!

Andrew

Klaas Bil · 2004-10-14, 01:06 PM

Quote:

Originally posted by UNIquelyCanadian
I don't think it matters what I think!

This one is not paradoxical. It allows you to think all sorts of thoughts, just not the thought that any of it matters.

You mean "I think it doesn't matter what I think".

Klaas Bil

uni-catgirl · 2004-10-14, 02:42 PM

ok, so i have never posted anything on here yet so i hope i am doing this right. but you guys who like these things, you should go to the website www.thisisbroken.com it has some really funny things on it.
lindsey

cline · 2004-10-14, 05:14 PM

"This sentence is false" is called Eubulides Paradox. Others include the Liar's Paradox, "I am lying", and Socrates' Paradox, "one thing I know is that I know nothing."

A related and even more confounding subject is mathematical completeness and consistency. "This statement can not be proven or refuted" can neither be proven nor refuted in any consistent mathematical theory (i.e. a theory without contradictions). Kurt Goedel is the mathematician who formalized this statement, and also proved that a mathematical theory that can prove its own consistency, is necessarily inconsistent.

This is deep stuff and it can take a while to really get it. Douglas R. Hofstadter wrote a book called "Goedel, Escher, Bach: An Eternal Golden Braid" that uses lots of clever example to discuss incompleteness. Good reading if you want to pursue the subject. A puzzle filled approach to Goedel's theorem is Raymond Smullyan's "The Lady or the Tiger? And Other Logic Puzzles." These are fun books, not dry textbooks, so if you are interested in paradoxes you may enjoy them.

One of Smullyan's books (maybe the one mentioned above) examines Epimenides Paradox in great detail. Epimenides is quotes as having said, "All Cretans are liars...One of their own poets has said so." He poses logical puzzles set on an island in which half of the inhabitants always tell the truth and half always lie. I actually thought about bringing up these puzzles in another thread, but sometimes discression is the better partof valor.

Ken

Catboy · 2004-11-11, 08:41 PM

I personnally hate those little keychains with stupid bumpersticker-like catchphrases, like "All men are created eaqual, too bad." They piss me off so in a hypocritical fasion i thought up this keychain:

"Don't take advice from keychains"

Its somewhat aparadoxal, I think...

gerblefranklin · 2004-11-11, 11:01 PM

Quantum Mechanics. If it doesn't seem absolutely wrong to you, then you haven't understood it yet.

I always thought Godels (with an umlaut, of course

) theorem stated that it is impossible to create a system of math that does not allow for imaginary numbers, etc.

My favorite non-paradox has to do with perpetual motion. This one is fun to figure out why it doesn't work. BTW, you can assume you can convert matter and energy with 100% efficiency every time (and vice versa).

You take a block of lead and you drop it off of a skyscraper. Before it hits the ground, you convert it to a single ultra-high energy gamma ray, and reflect the gamma ray back up to the top of the skyscraper, where it is then immediately converted back into a block of lead, and the cycle repeats.

This seems to be in violation of thermodynamics, except for a small part of relativity. If it helps, you could ask: Does a clock on the top of a skyscraper run at the exact same rate as a clock on the bottom? Also, why does all light approaching the event horizon of a black hole become infinitely blueshifted? Finally, what happens to light as it climbs away from a black hole? Does it redshift or blueshift? (By the way, a blueshift in light means that the frequency of the waves increases, and they carry more energy. A redshift is the exact opposite)

James_Potter · 2004-11-11, 11:36 PM

A friend of mine went to Canada and saw a sign that said
Caution: Public Notice.

Care to explain that one...?

caw89 · 2004-11-13, 03:10 AM

Quote:

Originally posted by Catboy
I personnally hate those little keychains with stupid bumpersticker-like catchphrases, like "All men are created eaqual, too bad." They piss me off so in a hypocritical fasion i thought up this keychain:

"Don't take advice from keychains"

Its somewhat aparadoxal, I think...

There is one of those I like that was on a lighter at spencers."Heaven wont take me and hell is to afraid I'd take over"

tomblackwood · 2004-11-13, 06:41 AM

Quote:

Originally posted by James_Potter
A friend of mine went to Canada and saw a sign that said
Caution: Public Notice. Care to explain that one...?

It's true. Public notice all sorts of stuff...

Klaas Bil · 2004-11-13, 10:54 PM

Quote:

Originally posted by gerblefranklin
This one is fun to figure out why it doesn't work.

I think the solution is: the ray is coming from the block of lead that is moving away from the top of the skyscraper. Therefore it arrives there redshifted and the energy is decreased correspondingly.

That explains how you do not gain energy. But if you assume 100% efficiency in all steps in a process, perpetual motion (with zero energy gain, just continuation of something) is easily achieved.

Klaas Bil

cline · 2004-11-14, 05:39 AM

Quote:

Originally posted by gerblefranklin
I always thought Godels theorem stated that it is impossible to create a system of math that does not allow for imaginary numbers, etc.

Imaginary numbers aren't necessary for a consistent theory. The only numbers used or assumed in Goedel's theorem are natural numbers (0,1,2 ...), which are used to number formulas in the target theory.

Quote:

My favorite non-paradox has to do with perpetual motion. This one is fun to figure out why it doesn't work. BTW, you can assume you can convert matter and energy with 100% efficiency every time (and vice versa).

You take a block of lead and you drop it off of a skyscraper. Before it hits the ground, you convert it to a single ultra-high energy gamma ray ...

You lost me here. You can't conserve both energy and momentum with this conversion. The block's momentum equals its energy (E) divided by velocity, but the photon's momentum is E/c, where c is the speed of light. The block is falling at much less than the speed of light, so momentum isn't conserved. Conservation of momentum is a fundamental property of physics, so your assumption is invalid.

That's as far as I got.

Ken

2004-10-13, 02:21 AM	#16
DigitalDave Registered User Join Date: Sep 2004 Location: lalaland Posts: 1,217	Sentance = Sentence ...? or maybe statement ...? or maybe ... "this sentence is ironic ...? __________________ My will to live was stronger than my will to die. - Iggy Pop That which does not kill me, makes me stronger. - Friedrich Nietzsche 1899 If it's popular, then what's it got to do with us? - Mens room wall My Gallery Last edited by DigitalDave; 2004-10-13 at 02:27 AM.

2004-10-13, 09:51 PM	#18
UNIquelyCanadian Static Long Jump ~ 2.0 Meters Join Date: Aug 2004 Location: Cochrane, Ontario, Canada Age: 24 Posts: 1,174	I won't be tricked into posting anything on this thread. Last edited by UNIquelyCanadian; 2004-10-13 at 09:52 PM.

2004-10-14, 10:13 AM	#20
KJ-52 Registered User Join Date: Feb 2004 Location: Lancaster County, PA Age: 31 Posts: 386	Would you all stop posting like I have?! Andrew __________________ Now posting from my friends house, and not paying for it : )

2004-11-11, 08:41 PM	#24
Catboy Roadkill Join Date: Oct 2002 Location: Scattered across the freeway. Age: 23 Posts: 4,190	I personnally hate those little keychains with stupid bumpersticker-like catchphrases, like "All men are created eaqual, too bad." They piss me off so in a hypocritical fasion i thought up this keychain: "Don't take advice from keychains" Its somewhat aparadoxal, I think... __________________ Rest in pieces.

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2004-10-13, 08:36 AM	#17
Klaas Bil Sir Prince of Newsgroupia Join Date: Jan 2003 Location: Zoetermeer, Netherlands Age: 59 Posts: 2,303	This page intentionally left blank.

2004-10-13, 11:19 PM	#19
UNIquelyCanadian Static Long Jump ~ 2.0 Meters Join Date: Aug 2004 Location: Cochrane, Ontario, Canada Age: 24 Posts: 1,174	I don't think it matters what I think!

2004-10-14, 02:42 PM	#22
uni-catgirl unicyclist Join Date: Oct 2004 Location: Ham Lake, Minnesota Age: 29 Posts: 3	ok, so i have never posted anything on here yet so i hope i am doing this right. but you guys who like these things, you should go to the website www.thisisbroken.com it has some really funny things on it. lindsey

2004-10-14, 05:14 PM	#23
cline Physics Inspector Join Date: Apr 2004 Location: Northern Colorado Posts: 57	"This sentence is false" is called Eubulides Paradox. Others include the Liar's Paradox, "I am lying", and Socrates' Paradox, "one thing I know is that I know nothing." A related and even more confounding subject is mathematical completeness and consistency. "This statement can not be proven or refuted" can neither be proven nor refuted in any consistent mathematical theory (i.e. a theory without contradictions). Kurt Goedel is the mathematician who formalized this statement, and also proved that a mathematical theory that can prove its own consistency, is necessarily inconsistent. This is deep stuff and it can take a while to really get it. Douglas R. Hofstadter wrote a book called "Goedel, Escher, Bach: An Eternal Golden Braid" that uses lots of clever example to discuss incompleteness. Good reading if you want to pursue the subject. A puzzle filled approach to Goedel's theorem is Raymond Smullyan's "The Lady or the Tiger? And Other Logic Puzzles." These are fun books, not dry textbooks, so if you are interested in paradoxes you may enjoy them. One of Smullyan's books (maybe the one mentioned above) examines Epimenides Paradox in great detail. Epimenides is quotes as having said, "All Cretans are liars...One of their own poets has said so." He poses logical puzzles set on an island in which half of the inhabitants always tell the truth and half always lie. I actually thought about bringing up these puzzles in another thread, but sometimes discression is the better partof valor. Ken

2004-11-11, 11:01 PM	#25
gerblefranklin Registered User Join Date: Aug 2003 Posts: 1,865	Quantum Mechanics. If it doesn't seem absolutely wrong to you, then you haven't understood it yet. I always thought Godels (with an umlaut, of course ) theorem stated that it is impossible to create a system of math that does not allow for imaginary numbers, etc. My favorite non-paradox has to do with perpetual motion. This one is fun to figure out why it doesn't work. BTW, you can assume you can convert matter and energy with 100% efficiency every time (and vice versa). You take a block of lead and you drop it off of a skyscraper. Before it hits the ground, you convert it to a single ultra-high energy gamma ray, and reflect the gamma ray back up to the top of the skyscraper, where it is then immediately converted back into a block of lead, and the cycle repeats. This seems to be in violation of thermodynamics, except for a small part of relativity. If it helps, you could ask: Does a clock on the top of a skyscraper run at the exact same rate as a clock on the bottom? Also, why does all light approaching the event horizon of a black hole become infinitely blueshifted? Finally, what happens to light as it climbs away from a black hole? Does it redshift or blueshift? (By the way, a blueshift in light means that the frequency of the waves increases, and they carry more energy. A redshift is the exact opposite)

2004-11-11, 11:36 PM	#26
James_Potter Registered User Join Date: Apr 2003 Location: The skinny part of Idaho Age: 24 Posts: 10,606	A friend of mine went to Canada and saw a sign that said Caution: Public Notice. Care to explain that one...?

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