JREF Homepage Swift Blog Events Calendar $1 Million Paranormal Challenge The Amaz!ng Meeting Useful Links Support Us
James Randi Educational Foundation JREF Forum
Forum Index Register Members List Events Mark Forums Read Help

Go Back   JREF Forum » General Topics » Science, Mathematics, Medicine, and Technology
Click Here To Donate

Notices


Welcome to the JREF Forum, where we discuss skepticism, critical thinking, the paranormal and science in a friendly but lively way. You are currently viewing the forum as a guest, which means you are missing out on discussing matters that are of interest to you. Please consider registering so you can gain full use of the forum features and interact with other Members. Registration is simple, fast and free! Click here to register today.

Reply
Old 24th October 2012, 01:32 AM   #41
Natan
Guest
 
Join Date: Oct 2007
Location: Previously known as Simon666
Posts: 2,124
Originally Posted by ServiceSoon View Post
Show me a perpetual motion machine and I'll get you a Nobel Prize.


Superconducting wire. Where is my Nobel Prize? I can add it to the one given to the EU. That's TWO on my desk.
Natan is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 25th October 2012, 05:36 PM   #42
lenny
Muse
 
lenny's Avatar
 
Join Date: Jan 2006
Location: Oxford
Posts: 999
Originally Posted by Roboramma View Post
No, he was simply pointing out that no one is afraid to contemplate laws of physics in which energy is not conserved, which you seemed to be implying.
my apologies if my words were misleading in that direction: i did NOT intend to imply anything of the sort! there are nice counterexamples in the 40's/50's where energy only "statistically conserved."

rather i argued (#18) that no one has "showed conservation of energy", and that it is currently inconceivable that one ever will in many relevant macroscopic scenarios.

TubbaBlubba repeatedly (#19, #24, and i had thought in #38) made naive claims claiming the absence of evidence as evidence of absence
(as you noted in #20).

i took his #38 as supporting Cuddles #30 claim that showing conservation of energy on planetary scales was "quite easy really. Conservation of energy is one of the fundamental bases of all our ideas about physics." which fails Logic 101 as an argument. i first read TubbaBlubba's post as supporting that falasy; i now see he might have intended something else.

what was your intention TubbaBlubba?
__________________
All theorems are true. All models are wrong. All data are inaccurate. What are we to do?
Dubito Ergo Sum
"And oftentimes, to win us to our harm, the instruments of darkness tell us truths, win us with honest trifles, to betray'us in deepest consequence." Banquo
lenny is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 26th October 2012, 05:19 PM   #43
TubbaBlubba
Knave of the Dudes
 
TubbaBlubba's Avatar
 
Join Date: Jul 2010
Location: Communist Kingdom of Sweden
Posts: 8,322
Originally Posted by lenny View Post
my apologies if my words were misleading in that direction: i did NOT intend to imply anything of the sort! there are nice counterexamples in the 40's/50's where energy only "statistically conserved."

rather i argued (#18) that no one has "showed conservation of energy", and that it is currently inconceivable that one ever will in many relevant macroscopic scenarios.

TubbaBlubba repeatedly (#19, #24, and i had thought in #38) made naive claims claiming the absence of evidence as evidence of absence
(as you noted in #20).

i took his #38 as supporting Cuddles #30 claim that showing conservation of energy on planetary scales was "quite easy really. Conservation of energy is one of the fundamental bases of all our ideas about physics." which fails Logic 101 as an argument. i first read TubbaBlubba's post as supporting that falasy; i now see he might have intended something else.

what was your intention TubbaBlubba?
My intention is to not discuss science with people who believe science requires formal logical proofs of theories.
__________________
There are two kinds of fact - the trivially true, and the technically correct.
TubbaBlubba is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 2nd November 2012, 03:18 PM   #44
lenny
Muse
 
lenny's Avatar
 
Join Date: Jan 2006
Location: Oxford
Posts: 999
Originally Posted by TubbaBlubba View Post
My intention is to not discuss science with people who believe science requires formal logical proofs of theories.
so there we do not clash; surely any connection between science and formal proof is tenuous at best.

the question under discussion was an empirical one, specifically whether or not one could establish the conservation of energy on planetary scales.
__________________
All theorems are true. All models are wrong. All data are inaccurate. What are we to do?
Dubito Ergo Sum
"And oftentimes, to win us to our harm, the instruments of darkness tell us truths, win us with honest trifles, to betray'us in deepest consequence." Banquo
lenny is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 3rd November 2012, 01:30 AM   #45
TubbaBlubba
Knave of the Dudes
 
TubbaBlubba's Avatar
 
Join Date: Jul 2010
Location: Communist Kingdom of Sweden
Posts: 8,322
I'm fairly sure planets suddenly being governed by different laws of physics would've been discovered by now.

Deep out in the cosmos, it's tougher, but AFAIK no one has yet come up with a theory that explains the cosmos better than general relativity, which more or less assumes the cosmological principle. Until someone does or it turns on we can't explain the physics of say, distant stars using our established laws, I think we can assume the principle holds true.
__________________
There are two kinds of fact - the trivially true, and the technically correct.
TubbaBlubba is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 10th November 2012, 07:00 AM   #46
lenny
Muse
 
lenny's Avatar
 
Join Date: Jan 2006
Location: Oxford
Posts: 999
the question is an empirical one, limits to what we can measure which apply as much to the earth and the moon as anywhere else.

the point is that while we have stong evidence placinfg constraints on the conservation of energy in the lab, we have no such evidence, nor can we conceive of an experiment that would provide such evidence, that energy is conserved on planetary scales, or "in the sun".

we often do a thought experiment: considering a large sphere around the moon, and argue that the energy moving in through this surface minus the energy moving out, plus the increase in energy inside will sum to zero.
i am not arguing that this is not true; merely pointing out that we have no empirical evidence that it is true. violations vastly greater than those we can rule out in the lab would be undetectable.

we have faith in the conservation of energy on these scales, we believe it holds, but the evidence for it absent.


Originally Posted by TubbaBlubba View Post
I'm fairly sure planets suddenly being governed by different laws of physics would've been discovered by now.
so i do not see how your comment applies to this argument.
__________________
All theorems are true. All models are wrong. All data are inaccurate. What are we to do?
Dubito Ergo Sum
"And oftentimes, to win us to our harm, the instruments of darkness tell us truths, win us with honest trifles, to betray'us in deepest consequence." Banquo
lenny is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 10th November 2012, 07:17 AM   #47
Roboramma
Philosopher
 
Roboramma's Avatar
 
Join Date: Feb 2005
Location: Shanghai
Posts: 7,526
A similar argument suggests that we don't have evidence that conservation of energy holds when I am wearing a tutu (I've never worn a tutu)
__________________
"... when people thought the Earth was flat, they were wrong. When people thought the Earth was spherical they were wrong. But if you think that thinking the Earth is spherical is just as wrong as thinking the Earth is flat, then your view is wronger than both of them put together."
Isaac Asimov
Roboramma is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 11th November 2012, 06:17 PM   #48
quarky
Banned
 
Join Date: Oct 2007
Posts: 20,454
Originally Posted by Roboramma View Post
A similar argument suggests that we don't have evidence that conservation of energy holds when I am wearing a tutu (I've never worn a tutu)
You would look good in a tu-tu.

(hey, it's a scientific fact.)
quarky is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 11th November 2012, 06:28 PM   #49
Ziggurat
Penultimate Amazing
 
Ziggurat's Avatar
 
Join Date: Jun 2003
Posts: 28,005
Originally Posted by lenny View Post
the point is that while we have stong evidence placinfg constraints on the conservation of energy in the lab, we have no such evidence, nor can we conceive of an experiment that would provide such evidence, that energy is conserved on planetary scales, or "in the sun".
That's not really true. The evidence is less direct, but it's not nonexistent.

In particular, there's a very rigorous mathematical theorem which states that for every symmetry in your physical laws there will be a corresponding conservation law. The fact that our laws of physics are translation-invariant (meaning the laws of physics don't vary from location to location) leads to momentum conservation, for example. And the fact that our laws of physics are time-independent leads to the conservation of energy.

If conservation of energy is to be violated, that will require that the laws of physics vary in time. And that would produce signs other than just the violation of energy conservation. It's true that variations could always be too small to observe (but the energy conservation violations would then be correspondingly small), but that problem exists whether you're talking about experiments in lab or observations of distant astronomical phenomena. Our precision may be greater in the lab, but the basic problem remain the same.
__________________
"As long as it is admitted that the law may be diverted from its true purpose -- that it may violate property instead of protecting it -- then everyone will want to participate in making the law, either to protect himself against plunder or to use it for plunder. Political questions will always be prejudicial, dominant, and all-absorbing. There will be fighting at the door of the Legislative Palace, and the struggle within will be no less furious." - Bastiat, The Law
Ziggurat is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th November 2012, 01:27 PM   #50
lenny
Muse
 
lenny's Avatar
 
Join Date: Jan 2006
Location: Oxford
Posts: 999
Originally Posted by Ziggurat View Post
It's true that variations could always be too small to observe (but the energy conservation violations would then be correspondingly small), but that problem exists whether you're talking about experiments in lab or observations of distant astronomical phenomena. Our precision may be greater in the lab, but the basic problem remain the same.
i agree that the basic problem remains the same. apologies if i spoke loosely.

there does seem to be a difference between measurements on the lab, where we can work vary hard to find inconsistency and have not yet found it, and measurements on the scale of a planet which we have never attempted and for which we can only conceive (today) of obtaining a very loose bound on consistency. of course today's laws of physics give us no reason to expect anything different on planetary scales... and defending that last statement leads to circularity.
__________________
All theorems are true. All models are wrong. All data are inaccurate. What are we to do?
Dubito Ergo Sum
"And oftentimes, to win us to our harm, the instruments of darkness tell us truths, win us with honest trifles, to betray'us in deepest consequence." Banquo
lenny is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th November 2012, 03:05 PM   #51
Ziggurat
Penultimate Amazing
 
Ziggurat's Avatar
 
Join Date: Jun 2003
Posts: 28,005
Originally Posted by lenny View Post
of course today's laws of physics give us no reason to expect anything different on planetary scales... and defending that last statement leads to circularity.
Certain kinds of changes in the laws of physics from one location to another will show up even over vast distances. In particular, atomic and molecular spectra are sensitive to the laws of quantum mechanics, and unless the changes happen in very specific ways (or below our detection threshold), then we could see signs of it. That doesn't preclude any possible position dependence to the laws of physics, but it does constrain such changes. Beyond that, though, it's not so much circularity as it is Occam's Razor. The simplest scenario would be universal laws of physics, that accurately describes what we can currently observe, so that's a preferable model to one in which the laws of physics are not universal. Occam's Razor doesn't tell you that the simpler explanation is correct (or even that it's more likely to be correct), but it does tell you to stick with simplicity until it's inadequate. That time has not arrived.
__________________
"As long as it is admitted that the law may be diverted from its true purpose -- that it may violate property instead of protecting it -- then everyone will want to participate in making the law, either to protect himself against plunder or to use it for plunder. Political questions will always be prejudicial, dominant, and all-absorbing. There will be fighting at the door of the Legislative Palace, and the struggle within will be no less furious." - Bastiat, The Law
Ziggurat is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th November 2012, 03:26 PM   #52
quarky
Banned
 
Join Date: Oct 2007
Posts: 20,454
nice.
quarky is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 1st September 2013, 10:51 AM   #53
lenny
Muse
 
lenny's Avatar
 
Join Date: Jan 2006
Location: Oxford
Posts: 999
Originally Posted by Ziggurat View Post
Certain kinds of changes in the laws of physics from one location to another will show up even over vast distances.
yes, i agree. and i also agree with your example.
other "kinds of changes" we cannot detect even locally. i am happy to note both "kinds."

Originally Posted by Ziggurat View Post
Occam's Razor doesn't tell you that the simpler explanation is correct (or even that it's more likely to be correct), but it does tell you to stick with simplicity until it's inadequate. That time has not arrived.
could you help me see how this is relevant to the point in play. i see how it is relevant to rather marvelous evidence that atomic transitions in remote parts of the universe we can see are described by the same "laws of physics" we observe in the lab.

Originally Posted by Ziggurat View Post
The evidence is less direct, but it's not nonexistent.

In particular, there's a very rigorous mathematical theorem which states
maths never provides empirical evidence. no?

(and yes, it is a beautiful theorem)
__________________
All theorems are true. All models are wrong. All data are inaccurate. What are we to do?
Dubito Ergo Sum
"And oftentimes, to win us to our harm, the instruments of darkness tell us truths, win us with honest trifles, to betray'us in deepest consequence." Banquo
lenny is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 1st September 2013, 08:48 PM   #54
WhatRoughBeast
Muse
 
Join Date: Apr 2011
Posts: 951
Originally Posted by lenny View Post
the question is an empirical one, limits to what we can measure which apply as much to the earth and the moon as anywhere else.

the point is that while we have stong evidence placinfg constraints on the conservation of energy in the lab, we have no such evidence, nor can we conceive of an experiment that would provide such evidence, that energy is conserved on planetary scales, or "in the sun".
Unless I've missed something, we can indeed conceive of measurements which place very tight constraints on any possible violations of conservation of energy on a planetary scale. Those measurements have been carried out for some centuries now and are called, collectively, "astronomy".

Assuming that energy and orbital period are related, the existence of a fossil record going back more than 4 billion years suggests that the earth's orbit has remained more or less constant during that time, and 4 billion years is a _long_ time for variations to accumulate. Similarly, historical records of eclipses provide a fairly precise lower bound on such deviations, since the thing about changing orbital period is that the changes in observed position of the orbiting bodies will accumulate.

Now, it's possible that conservation of energy is violated in a cyclical fashion, so that the planetary orbits change first in one direction, then in the other, but in the absence of evidence to support (or even suggest) this, the afore-mentioned Occam's Razor would seem to apply.
WhatRoughBeast is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 8th September 2013, 09:27 AM   #55
lenny
Muse
 
lenny's Avatar
 
Join Date: Jan 2006
Location: Oxford
Posts: 999
Originally Posted by WhatRoughBeast View Post
Assuming that energy and orbital period are related, the existence of a fossil record going back more than 4 billion years suggests that the earth's orbit has remained more or less constant during that time, and 4 billion years is a _long_ time for variations to accumulate. Similarly, historical records of eclipses provide a fairly precise lower bound on such deviations, since the thing about changing orbital period is that the changes in observed position of the orbiting bodies will accumulate.
Agreed, that is a long time. And if we put a number on "more or less" constant, we could place a bound on the loss of "orbital energy" with time, taking into account the retreat of the moon etc.

while the uncertainties in that calculation would, I expect, not provide evidence for an exact balance, it would rule out quite significant departures from (exact) conservation in that case. I was not thinking of "orbital energy" in my posts above, but your example fits.

Again, I am not arguing that energy is not conserved, and i would certainly argue that it is profitable to assume it is conserved. Nevertheless, on large spatial scales this assumption has v little direct empirical support.
__________________
All theorems are true. All models are wrong. All data are inaccurate. What are we to do?
Dubito Ergo Sum
"And oftentimes, to win us to our harm, the instruments of darkness tell us truths, win us with honest trifles, to betray'us in deepest consequence." Banquo
lenny is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Reply

JREF Forum » General Topics » Science, Mathematics, Medicine, and Technology

Bookmarks

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -7. The time now is 01:19 AM.
Powered by vBulletin. Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
2001-2013, James Randi Educational Foundation. All Rights Reserved.

Disclaimer: Messages posted in the Forum are solely the opinion of their authors.