Note that I said 'a certain amount' when I refered to the figuring out. I don't accept your weaseling. It's not the job of climatologists to perform ANY economic analysis: most of them haven't taken a single class in the field. Sure, they could learn, but what for? That's what, you know, actual economists are for, and it just takes time away from their actual field of expertise.
Besides, I'd expect any good climatologist to be good enough with math that balancing a budget is rather easy What a remarkably dumb statement.
but what the article states is "Antarctic ozone hole is 30% smaller than it was during the previous RECORD year". My emphasis. 5-10% beyond a record year would be acceptable. 30% beyond a record year (which yields 60-70% beyond the average) is a BIG DEAL. 30% beyond the record year is not 60-70% beyond the average: you're confusing the signs. The current hole is 30% SMALLER than last year's LARGEST size — i.e., closer to the average size.
We've seen interannual jumps of 30% in ozone hole size before (e.g., here); it's within the range of natural variation, and as such, does not indicate some total failure of the models.
You see, I'd also expect [climatologists] to be able to perform a certain amount of economic analysis and at least try to identify the 'best bang for the buck' methods for reducing pollution. That's what economists, policy analysts, and engineers are for — not climatologists. Climatologists can tell you what kind of climate you might get with a given policy, but they aren't suited to running economic cost/benefit analyses (except for the rare few who specialize in both and collaborate with economists).
Just sticking to the subject of TFA:
The prophets of 1970 said: [...] The ozone hole will get larger and eventually allow kill 80% of life on the planet Really? "Kill 80% of life on the planet"? Who said that in 1970? Hell, it wasn't until 1985 that the ozone hole was even measured.
As for saying that the ozone hole would get larger... it DID get larger. And why hasn't it been more of a problem? Because we reduced CFC emissions in the Montreal Protocol and slowed its growth. See, e.g., this graph, and notice how the growth trend just about flatlines not long after 1989 (when the Montreal Protocol went into effect).
I find it fascinating that a post with no actual supporting facts managed to get modded all the way to 5, on the basis of nothing but libertarian cheerleading. Come on, where is the evidence that private companies can manage airport security with less hassle than TSA? All we have here is a naked assertion.
It's worse than that. The Nash equilibrium poker strategy is one that can be beaten, but in order to play this strategy, you must never take advantage of your opponent's mistakes. As soon as you adapt to your opponent's mistakes, your strategy is no longer certain to be unbeatable. Yes, all it does is guarantee you the best possible worst-case outcome, not the best possible outcome. You're not even guaranteed to "win".
Secondly, any use of random numbers creates the possibility of an insider using cooked randomness to establish a covert channel. If there is an insider in airport security, there are far, far easier ways to communicate with an accomplice than mucking about with covert channels embedded in random number generators!
I know that port security has been looking into these same game theory approaches for inspecting shipping containers. "Common sense" may get some results, but with some actual analysis, you can do even better in a mathematically demonstrable way.
So, in order to improve airport security you give "vast amounts" of classified data about airport security to a collection of grad students to input into a program that produces allegedly randomized output. Uh, there are plenty of grad students with security clearances: they work on classified research projects, like this one. You think you can't have a clearance if you are a student or something?
Or do you think there's something wrong with giving classified data to people with security clearances, just because they're also grad students?
So now, instead of only annoying us, these checks will annoy us and leave other areas vulnerable... Other areas are already vulnerable. The point is to maximize security with limited resources: how do you organize spot checks with a finite number of guards, cameras and people to watch them, etc.
Obviously, if was feasible to guard everywhere at all times, there would be no need for such a scheme.
"Yeah, the 4th floor bathroom checked out okay 27 times before breakfast, but a group of heavily-armed guys went unchallenged as they climbed the perimiter fence and boarded a transatlantic flight. Oops, our bad." That's a nice strawman, but no reasonable security strategy is going to put a heavy emphasis on checking a particular bathroom while totally ignoring perimeter security. If you want to attack this scheme, you have to show that there's a better strategy which operates using the same resources. You don't even know what their strategy is. Making up some stupid strategy and suggesting it's similar to what they're really using is not very honest.
If you figure this is a sizable force, and that all of them use the randomization software, four years worth of recon (TFA gave that as a time period for pre-strike operations) ought to give the terrorist enough information to know where these "random points" are. You're missing the point. The analysis assumes that the terrorist already knows that information anyway. The adversary is assumed to have perfect information about the randomization strategy, where the checkpoints are, etc. Then a randomization strategy is designed to minimize failures even in light of this information.
How do they account for the fact that there will always be an area that these security forces don't patrol because no one told the computer that the place exists. That is a better point, but we don't know whether there have been lapses in specifying the layout of the airport. (Of course, there will always be security holes that nobody has thought of at all, but obviously it is hard to guard against those with ANY security method.)
I read a fascinating article in the Freeman comparing train security, mostly privately done, with airports security, done by the government. The key difference was that when it was done commercially the inconvenience to customers was quite minimal. On the other hand when the government runs it, it is very inconvenient for customers. Why do you think this? You mean this article?
It's comparing apples and oranges, as far as I can tell. It describes private security companies and "posses" pursuing known perpetrators in the 19th century. This is essentially police work, and is a quite different issue from preventing unknown threats from boarding in the first place. It claims that going after criminals is better than screening large numbers of non-criminals. Well duh, the problem is to find out who the criminals are, in a way that safely prevents them from carrying out whatever acts they're trying to carry out.
The article also says the private companies also sent guards on trains to foil robberies and such. Well, that's what federal air marshals are for. We've already got those. The article appears to be arguing that we just need the air marshals, and don't need any airport screening. Well, that's debatable, but as far as I am concerned, it doesn't have much to do with private vs. government security.
I think the situation with train robbers vs., say, suicide bombers is quite different. The article gives an example of train robbers who threatened to blow up the train if they weren't allowed to escape. Well, that's quite different from a guy who intends to die with everyone else: he's got no reason to negotiate. If you let him on with a bomb, you've already lost, unless you're really, really counting on those air marshals or helpful passengers (a la Richard Reid). It's a harder security problem.
Finally, the article says that the railroads booted troublemakers off the premises instead of letting them board the trains. It also says that federal law prohibits airlines from doing the same. I don't understand this; I've certainly read news stories about suspicious passengers being removed from planes, and of course TSA can prevent them from boarding in the first place.
Now, I am not trying to argue in favor of draconian airport screening, but I think the differences between security against train robbers and security against airline terrorists have more to do with the completely different settings and goals, rather than private vs. government administration of the security measures.
Randomize checking so that an attacker can't predict the next check and avoid it? That's what I would do, too. Can I be a high-paid security consultant now? The point is not that the strategy is random, but that the randomization is optimized to be robust against an adversary who knows what your randomization scheme is. That's what the game theory is for: it's a classic mixed strategy.
Remember, there are many ways to be random: check area X Y% of the time; perform check W Z% of the time, etc. What should Y and Z be? How do you balance the occurrence of Type I and Type II errors? Some strategies are better than others: there's a reason why game theory was invented.
Try reading the study; the results are not trivial.
"Third" option? Don't be obtuse. There is a huge portfolio of options to deal with global warming, including but not limited to:
1. Conservation 2. Reuse/recycling 3. Energy sources which emit less CO2 as byproducts (nuclear and non-nuclear) 4. Technologies/manufacturing processes which emit less CO2 as byproducts 5. Technologies which use existing energy more efficiently 6. Land use changes 7. Carbon sequestration 8. Climate geoengineering 9. Adaptation / vulnerability reduction
Any realistic approach will involve a combination of solutions. Nuclear power is not a panacea. And even conservation does not equal "making people go without": it's possible to use fewer material resources and energy than the average person/company with essentially no additional hardship.
That may be debated, but it also poses a false dilemma by presuming that nuclear power is the only possible means of addressing global warming: you have to pick one or the other. That too is debatable.
I don't understand why the environmentalists aren't clamoring for more nuke plants. Some of them are. They're not a homogeneous group, you know. But it's not as if nuclear power is a perfect technology without any drawbacks, either.
But it isn't: it was designed from the very beginning to be experimentally identical to the standard interpretations of quanutm mechanics. The linearity of QM means that you cannot ever perform an experiment to detect other worlds because they do not interact.
That's not true. Different "worlds" cannot interact with each other, due to the linearity of quantum mechanics. By design, there is no experiment in MWI which can detect the branching of the multiverse. That was the whole point of Everett's relative state formalism: to construct an interpretation which is identical to ordinary quantum mechanics (but which has, supposedly, a simpler conceptual framework).
First, this is unpublished work (i.e., there has been no formal peer review): it was presented at a conference.
Deutsch himself did not present, according to the speakers list. The New Scientist mentioned his collaborators Wallace and Saunders, who presented the following talks:
David Wallace Probability in the Everett interpretation: state of play
I will review the current state of the probability problem. My main focus will be on the attempts by David Deutsch and myself to provide a proof of the Born Rule starting from Everettian assumptions, but I will also attempt to locate these attempts within the more general framework of the probability problem.
Simon Saunders 'The Everett interpretation
I shall present an overview of quantum mechanics in the Everett interpretation, that emphasises its structural characteristics, as a theory of what exists. In this respect it shares common ground with other fundamental theories in physics. As such its appeal is conservative; it makes do with the purely unitary equations of quantum mechanics as exceptionless and universal. It also makes do with standard methods for extracting 'high level' or 'emergent' ontology, the furniture of macroscopic worlds, from largish molecules on up. It would appeal all the more if it made do with standard epistemological principles too - for example, in the context of inductive statistical confirmation, with standard Bayesian epistemology. But this links to the question of the interpretation of probability in the Everett interpretation, and here the theory seems anything but conservative. It is a common complaint that the approach leaves no room at all for talk of uncertainty. I shall argue, again on conservative interpretative practises, that this claim is incorrect. Chance events are, indeed, revealed in a surprising light - as quantum branchings - but they are the more perspicuous, and their properties and quantitative measure better explained, in light of that. Neither one of those abstracts sounds like it is giving any theoretical or experimental support to the "many worlds interpretation" over other interpretations. At best, they purport to show how MWI is compatible with probability theory — a far lesser claim.
Indeed, it is impossible to give Everettian MWI any precedence over other interpretations, because by construction Everett made the MWI experimentally identical to conventional interpretations of QM.
Deutsch is famous for claiming that MWI is empirically distinguishable from other interpretations, but again, this is not actually possible. You have to read the fine print. I read one of his books years ago where he made that claim, and IIRC there was some footnote which explained that he wasn't actually talking about Everett's MWI, but some modification of quantum mechanics he has proposed which is compatible "in spirit" with the actual MWI. Well, fair enough, but it's not really legitimate to claim that he's talking about the MWI anymore: he's talking about his own theory (which has no experimental support).
Stars don't form from pair creation. As another poster suggested, what you may be thinking of is matter forming from inflationary reheating. The resulting gas later collapsed into stars.
One of the sharpest critiques of string theory is that it isn't really one theory -- it's many, many theories (something like 10^500), depending on how the hidden dimensions are wrapped up.
That's not a critique of string theory, and it's not true either.
String theory is one theory, but with many, many ground states.
This doesn't make it any worse than existing physics such as the Standard Model, which really is one theory out of the infinitely many possible quantum field theories you can write down.
But therein lies the problem: no matter how an experiment turns out, one can cook up a version of string theory that agrees with it!
That's not true. In fact, it's harder to cook up a string theory to explain an experiment than it is to cook up a quantum field theory: there are low energy effective field theories you can write down that can't be obtained from any string theory.
What we really need is a meta-theory (M-theory?) that tells us *which* string theory to use, but so far it doesn't exist.
It would be nice, but we don't really "need" it. There is no such meta-theory which tells us that the Standard Model is the "right" quantum field theory, but that doesn't make the Standard Model or QFT useless. It just means that you have to do experiments to determine which one is right (or rather, which ones are not wrong). Welcome to science.
For this to be the case, it would have to predict something that is experimentally verifiable.
It is no harder to produce testable string models than it is to produce testable particle models (within QFT).
The only problem is in producing string models which differ in their predictions, in an experimentally verifiable way, from those of QFT models.
Quite frankly, the only good thing that I see here is that there might be an end to String Theory a.k.a. the "theory" that sucks up most of the money for research
It is given the funding it has for good reason. It can do anything QFT can do, plus more, and unlike QFT it is consistent with the laws of gravity. In addition it has created new approaches to ordinary gauge theories, quantum chronodynamics, and condensed matter physics.
What do you think of Lee Smolin's The Trouble With Physics? Are his criticisms of string theory on target?
I haven't read the book, but if you dig through Jacques Distler's blog, he doesn't come off too well when defending them. If you tell me which specific criticisms you had in mind, I might know more about those.
What about how string theory has changed the culture of cosmology?
Can't say.
My understanding of science is that theories must explain observed phenomena, predict future phenomena, and provide realistic ways in which a theory may be falsified. Given that: Is this a reasonable definition of what must go into a cosmological theory?
Sure.
Can string theory be said to be a "theory" at all, given that with 10**500 possible different cosmoses it's possible to explain away any correlation or discorrelation just as "we're looking at the [right|wrong] universe"?
String theory is a framework within which you can write down specific models. So is quantum field theory. The Standard Model is one such example of a QFT model. You can write down string models like the Standard Model too. They are no less predictive or scientific. The issue is whether you can write down string models which can be experimentally distinguished from existing QFT models. If you can, then string theory is useful. If you can't, then it's not as useful, but it's also no less scientific than QFT. You can write down infinitely many QFT models.
The last I heard, the various string theories were background dependent. Is this as big a problem as I suspect it is? If not, why not?
The underlying M theory does not depend on any specific choice of background, as specific string theories are equivalent to other string theories in completely different backgrounds. Perturbing about a specific background is computationally convenient, but not an essential part of string theory.
Slashdot Mirror
We've seen interannual jumps of 30% in ozone hole size before (e.g., here); it's within the range of natural variation, and as such, does not indicate some total failure of the models.
As for saying that the ozone hole would get larger
I find it fascinating that a post with no actual supporting facts managed to get modded all the way to 5, on the basis of nothing but libertarian cheerleading. Come on, where is the evidence that private companies can manage airport security with less hassle than TSA? All we have here is a naked assertion.
Bring high power rifles with steel jacketed bullets.
I know that port security has been looking into these same game theory approaches for inspecting shipping containers. "Common sense" may get some results, but with some actual analysis, you can do even better in a mathematically demonstrable way.
Or do you think there's something wrong with giving classified data to people with security clearances, just because they're also grad students?
Obviously, if was feasible to guard everywhere at all times, there would be no need for such a scheme. "Yeah, the 4th floor bathroom checked out okay 27 times before breakfast, but a group of heavily-armed guys went unchallenged as they climbed the perimiter fence and boarded a transatlantic flight. Oops, our bad." That's a nice strawman, but no reasonable security strategy is going to put a heavy emphasis on checking a particular bathroom while totally ignoring perimeter security. If you want to attack this scheme, you have to show that there's a better strategy which operates using the same resources. You don't even know what their strategy is. Making up some stupid strategy and suggesting it's similar to what they're really using is not very honest.
It's comparing apples and oranges, as far as I can tell. It describes private security companies and "posses" pursuing known perpetrators in the 19th century. This is essentially police work, and is a quite different issue from preventing unknown threats from boarding in the first place. It claims that going after criminals is better than screening large numbers of non-criminals. Well duh, the problem is to find out who the criminals are, in a way that safely prevents them from carrying out whatever acts they're trying to carry out.
The article also says the private companies also sent guards on trains to foil robberies and such. Well, that's what federal air marshals are for. We've already got those. The article appears to be arguing that we just need the air marshals, and don't need any airport screening. Well, that's debatable, but as far as I am concerned, it doesn't have much to do with private vs. government security.
I think the situation with train robbers vs., say, suicide bombers is quite different. The article gives an example of train robbers who threatened to blow up the train if they weren't allowed to escape. Well, that's quite different from a guy who intends to die with everyone else: he's got no reason to negotiate. If you let him on with a bomb, you've already lost, unless you're really, really counting on those air marshals or helpful passengers (a la Richard Reid). It's a harder security problem.
Finally, the article says that the railroads booted troublemakers off the premises instead of letting them board the trains. It also says that federal law prohibits airlines from doing the same. I don't understand this; I've certainly read news stories about suspicious passengers being removed from planes, and of course TSA can prevent them from boarding in the first place.
Now, I am not trying to argue in favor of draconian airport screening, but I think the differences between security against train robbers and security against airline terrorists have more to do with the completely different settings and goals, rather than private vs. government administration of the security measures.
I believe this (PDF file) is a draft of the study being discussed in TFA, or at least is closely related research.
Remember, there are many ways to be random: check area X Y% of the time; perform check W Z% of the time, etc. What should Y and Z be? How do you balance the occurrence of Type I and Type II errors? Some strategies are better than others: there's a reason why game theory was invented.
Try reading the study; the results are not trivial.
"Third" option? Don't be obtuse. There is a huge portfolio of options to deal with global warming, including but not limited to:
1. Conservation
2. Reuse/recycling
3. Energy sources which emit less CO2 as byproducts (nuclear and non-nuclear)
4. Technologies/manufacturing processes which emit less CO2 as byproducts
5. Technologies which use existing energy more efficiently
6. Land use changes
7. Carbon sequestration
8. Climate geoengineering
9. Adaptation / vulnerability reduction
Any realistic approach will involve a combination of solutions. Nuclear power is not a panacea. And even conservation does not equal "making people go without": it's possible to use fewer material resources and energy than the average person/company with essentially no additional hardship.
That may be debated, but it also poses a false dilemma by presuming that nuclear power is the only possible means of addressing global warming: you have to pick one or the other. That too is debatable.
But it isn't: it was designed from the very beginning to be experimentally identical to the standard interpretations of quanutm mechanics. The linearity of QM means that you cannot ever perform an experiment to detect other worlds because they do not interact.
That's not true. Different "worlds" cannot interact with each other, due to the linearity of quantum mechanics. By design, there is no experiment in MWI which can detect the branching of the multiverse. That was the whole point of Everett's relative state formalism: to construct an interpretation which is identical to ordinary quantum mechanics (but which has, supposedly, a simpler conceptual framework).
Deutsch himself did not present, according to the speakers list. The New Scientist mentioned his collaborators Wallace and Saunders, who presented the following talks: David Wallace
Probability in the Everett interpretation: state of play
I will review the current state of the probability problem. My main focus will be on the attempts by David Deutsch and myself to provide a proof of the Born Rule starting from Everettian assumptions, but I will also attempt to locate these attempts within the more general framework of the probability problem. Simon Saunders
'The Everett interpretation
I shall present an overview of quantum mechanics in the Everett interpretation, that emphasises its structural characteristics, as a theory of what exists. In this respect it shares common ground with other fundamental theories in physics. As such its appeal is conservative; it makes do with the purely unitary equations of quantum mechanics as exceptionless and universal. It also makes do with standard methods for extracting 'high level' or 'emergent' ontology, the furniture of macroscopic worlds, from largish molecules on up. It would appeal all the more if it made do with standard epistemological principles too - for example, in the context of inductive statistical confirmation, with standard Bayesian epistemology. But this links to the question of the interpretation of probability in the Everett interpretation, and here the theory seems anything but conservative. It is a common complaint that the approach leaves no room at all for talk of uncertainty. I shall argue, again on conservative interpretative practises, that this claim is incorrect. Chance events are, indeed, revealed in a surprising light - as quantum branchings - but they are the more perspicuous, and their properties and quantitative measure better explained, in light of that. Neither one of those abstracts sounds like it is giving any theoretical or experimental support to the "many worlds interpretation" over other interpretations. At best, they purport to show how MWI is compatible with probability theory — a far lesser claim.
Indeed, it is impossible to give Everettian MWI any precedence over other interpretations, because by construction Everett made the MWI experimentally identical to conventional interpretations of QM.
Deutsch is famous for claiming that MWI is empirically distinguishable from other interpretations, but again, this is not actually possible. You have to read the fine print. I read one of his books years ago where he made that claim, and IIRC there was some footnote which explained that he wasn't actually talking about Everett's MWI, but some modification of quantum mechanics he has proposed which is compatible "in spirit" with the actual MWI. Well, fair enough, but it's not really legitimate to claim that he's talking about the MWI anymore: he's talking about his own theory (which has no experimental support).
Stars don't form from pair creation. As another poster suggested, what you may be thinking of is matter forming from inflationary reheating. The resulting gas later collapsed into stars.
A quiz full of misleading and false claims is supposed to be convincing?
But good job on getting your science from Googling for Geocraft websites, there.
One of the sharpest critiques of string theory is that it isn't really one theory -- it's many, many theories (something like 10^500), depending on how the hidden dimensions are wrapped up.
That's not a critique of string theory, and it's not true either.
String theory is one theory, but with many, many ground states.
This doesn't make it any worse than existing physics such as the Standard Model, which really is one theory out of the infinitely many possible quantum field theories you can write down.
But therein lies the problem: no matter how an experiment turns out, one can cook up a version of string theory that agrees with it!
That's not true. In fact, it's harder to cook up a string theory to explain an experiment than it is to cook up a quantum field theory: there are low energy effective field theories you can write down that can't be obtained from any string theory.
What we really need is a meta-theory (M-theory?) that tells us *which* string theory to use, but so far it doesn't exist.
It would be nice, but we don't really "need" it. There is no such meta-theory which tells us that the Standard Model is the "right" quantum field theory, but that doesn't make the Standard Model or QFT useless. It just means that you have to do experiments to determine which one is right (or rather, which ones are not wrong). Welcome to science.
For this to be the case, it would have to predict something that is experimentally verifiable.
It is no harder to produce testable string models than it is to produce testable particle models (within QFT).
The only problem is in producing string models which differ in their predictions, in an experimentally verifiable way, from those of QFT models.
Quite frankly, the only good thing that I see here is that there might be an end to String Theory a.k.a. the "theory" that sucks up most of the money for research
It is given the funding it has for good reason. It can do anything QFT can do, plus more, and unlike QFT it is consistent with the laws of gravity. In addition it has created new approaches to ordinary gauge theories, quantum chronodynamics, and condensed matter physics.
Your questions weren't addressed to me, but ...
What do you think of Lee Smolin's The Trouble With Physics? Are his criticisms of string theory on target?
I haven't read the book, but if you dig through Jacques Distler's blog, he doesn't come off too well when defending them. If you tell me which specific criticisms you had in mind, I might know more about those.
What about how string theory has changed the culture of cosmology?
Can't say.
My understanding of science is that theories must explain observed phenomena, predict future phenomena, and provide realistic ways in which a theory may be falsified. Given that:
Is this a reasonable definition of what must go into a cosmological theory?
Sure.
Can string theory be said to be a "theory" at all, given that with 10**500 possible different cosmoses it's possible to explain away any correlation or discorrelation just as "we're looking at the [right|wrong] universe"?
String theory is a framework within which you can write down specific models. So is quantum field theory. The Standard Model is one such example of a QFT model. You can write down string models like the Standard Model too. They are no less predictive or scientific. The issue is whether you can write down string models which can be experimentally distinguished from existing QFT models. If you can, then string theory is useful. If you can't, then it's not as useful, but it's also no less scientific than QFT. You can write down infinitely many QFT models.
The last I heard, the various string theories were background dependent. Is this as big a problem as I suspect it is? If not, why not?
The underlying M theory does not depend on any specific choice of background, as specific string theories are equivalent to other string theories in completely different backgrounds. Perturbing about a specific background is computationally convenient, but not an essential part of string theory.