The Reference Frame - Latest Commentshttp://thereferenceframe.disqus.com/The most important events in our and your superstringy Universe as seen from a conservative physicist's viewpointenSat, 20 Dec 2014 04:06:40 -0000Re: The Reference Frame: Ellis', Silk's falsifiability babbling in Naturehttp://motls.blogspot.com/2014/12/ellis-silks-falsifiability-babbling-in.html#comment-1751373900<p>Dear Giotis, no, I haven't, I am avoiding that blog and especially things like the owner's interactions with people whom I consider good physicists because I have always felt that from their viewpoint, the disagreement is just one game and totally different things like those people's comfortable chairs or political ideology are more important for these people than the truth about string theory - and they are "allies" in these things that actually matter to them.</p><p>After lots of experience, I don't trust the honesty of people including Greene, Polchinski and many others when it comes to their interactions with individuals like PW. I think that their interest not to "damage themselves" is far more important than the truth for them. I am sure that if there were not the case, the lying bastard would have been homeless and at least outside Columbia for many, many years.</p><p>BTW Polchinski had a review of dualities some two days ago, I linked to it in the updated version of this blog post above.</p><p>Trackbacks are (semi)automatically added hyperlinks from the arXiv papers' and similar pages that link to external websites that have linked to the paper. ;-)</p><p>I used to care about them for some year in the past, and manually added them using a script, but I think it's a waste of time.</p><p>Of course, PW is a dirty parasite so he uses every opportunity to promote his dishonest rants - links from the arXiv are great. I am the opposite kind of a guy, a good guy who is helping the people to be directed to the arXiv and science in general.</p><p>The trackback traffic has never been a detectable fraction of my traffic. You should understand that the overall arXiv traffic is just 10+ times larger than the traffic of this blog, which means that a single arXiv paper's traffic is 10+ times smaller than the traffic on this blog, and only O(1%) of the visitors of a paper actually click at a trackback. So we are talking about O(1) visitor one may get from a single trackback link under a single paper to one blog, which seems negligible relatively to the thousands of visits, and I just don't want to care about it even though this O(1) visitor could be somewhat more special than the average TRF visitor. But of course, about 10%-20% of the HEP-TH community reads my blog, so there are lots of similar people here, anyway.</p><p>It's not a big issue but I do think that the arXiv administrators have made arrangements that *automatically* add the trackbacks to tons of mostly shitty weblogs including PW's NEW. I was never among the automatic ones and it is even possible that I wouldn't be allowed to "post" the trackback using the online tools I used to use. I haven't tried it for 5+ years and I don't care. All the behind-the-scenes arrangements in similar institutions seem completely immoral and corrupt and I better don't want to learn details because I was *always* shockingly disappointed when I did so.</p><p>So if there is some evidence that Ginsparg or Polchinski or perhaps Witten are actually friends with the Lithuanian Nazi spoiled brat and indirectly help him to promote his anti-science delusions, well, I can imagine it's true but I just don't want to actively torture myself by being reminded it's true. The world is a shitty place.</p>Luboš MotlSat, 20 Dec 2014 04:06:40 -0000Re: The Reference Frame: Ellis', Silk's falsifiability babbling in Naturehttp://motls.blogspot.com/2014/12/ellis-silks-falsifiability-babbling-in.html#comment-1751369277<p>Sorry off topic.</p><p>Lubos have you seen Polchinski's comment for you in PW's blog? What are these trackbacks? Are they important?</p>GiotisSat, 20 Dec 2014 03:57:11 -0000Re: The Reference Frame: Alternative teaching of mathematics: three problemshttp://motls.blogspot.com/2014/12/alternative-teaching-of-mathematics.html#comment-1751319428<p>Mooloo, I am convinced that kneemo is right and you are just wrong.</p><p>First, what one learns as a kid is remembered much more safely than what one learns later. When one learns a language as a kid, he really knows it. The case of algebra is virtually and obviously nearly isomorphic! Algebra *is* a language in this sense, and learning it early turns it into a "native tongue". I haven't forgotten any algebra I have learned when I was 4-14. Nobody does. The problem is that most people don't learn anything at all, often because they're being "shielded" from algebra. Of course that if someone sees some algebraic relationship once in his childhood, he will probably forget it. But if he uses it, like a language, and he should, he will master it like a language.</p><p>Your suggestions that algebra - something that really underlies the whole Universe - is meaningless is just dumb and I won't honor it with an extra response.</p><p>When you say that the Chinese are only "rote learning", you are completely distorting the actual differences. What the Chinese are actually better at is exactly the nontrivial CPU-based pure mathematical intelligence, the g-factor - the equivalent of 10 extra IQ points in these important matters. They may also be "rote learning" but it's a consequence, and not the cause, of their mathematical skills.</p><p>The Chinese may be worse in self-confidence or the ability to verbally impress others, or things like that, and *that* is where their GDP and other disadvantages lie, but your idea that they are inferior in some mathematical skills is just a silly fairy-tale that mathematically inferior nations invent for themselves to look better.</p><p>As Lisa Randall nicely wrote in a book (I forgot the exact wording), some people may spend more time with training a certain skill, but the ability to keep this motivation and patience is a talent, too.</p><p>I am not surprised that it is always possible to find an idiot who will attack me for using the function notation. (Be sure that I would use the same language of functions to explain the same point when I was 12, too.) But what's right about this blog is that when it happens, I can tell you that you are an uneducated idiot worshiping your own ignorance and if you do so repeatedly, I just ban you. The real world of mathematics education is full of idiots like you who really end up having the upper hand and literally prosecute both children and adults for thinking mathematically.</p><p>The point I was making is a mathematical point (it is surely no heresy to make mathematical points when one discusses mathematical problems, is it?) and it is - not surprisingly - most naturally expressed using some mathematical notation. (But I didn't write just meaningful notation - the expressions were parts of full sentences.) I can always translate all these formulae to words but this won't change the essence, just make the whole explanation much longer and less concise.</p><p>For practical reasons, children should be taught mathematical notation, too. It's complete nonsense to suggest that they can't learn to say things like x+y or express some rules using these letters.</p><p>I know very well that most kids - and adults - have poor mathematical skills and the talent can't be created out of thin air. My experience with teaching of not stellar kids is nontrivial. I have been saying the same thing from the beginning. But it may still be shown that they have a certain amount of memory - surely for other things - and they should be made to remember some important mathematical facts because they're really an essential part of the human knowledge and culture with tons of implications in all aspects of life. If you are a math teacher and you are not doing that job, and instead work on your excuses, or if you even team up with those who claim that it is wrong to teach mathematics to the kids, you should be fired.</p>Luboš MotlSat, 20 Dec 2014 02:12:16 -0000Re: The Reference Frame: Alternative teaching of mathematics: three problemshttp://motls.blogspot.com/2014/12/alternative-teaching-of-mathematics.html#comment-1751308037<p>It's a rich puzzle, indeed, more mathematical than e.g. chess, I would say, because of the links to combinatorics, group theory (including reversability) etc.</p><p>But it's still a particular and very special class of puzzles in recreational mathematics. Quite generally, like I wrote in the case of the Hejný method, it seems counterproductive to me if children are led to visualize the word "mathematics" as "recreational mathematics". I know too many adults who are doing that, too, and they of course don't have any clue about the real power of mathematics and its connection with anything in the real world - how to use mathematics to answer some questions that may arise (e.g. how to land on comets or whether it is reasonable to expect to get 8 jokers among 14 cards twice in the afternoon in a well shuffled Canasta pack LOL - the latter is still a recreational topic but it differs from the systematically repeated recreational problems so people don't already understand that it can be approached mathematically, too).</p><p>Recreational mathematics trains one's mind - like the real one can - but it's mostly no good for the real "business" or "work". That's why it's called "recreational". In my opinion, the purpose of mathematics at schools is not to train kids' brains in "any way" - the pure CPU power of their brain is actually maximized when they're toddlers and can't be changed much - it is to make them able to direct their brain CPU power in directions which are important from a mathematical viewpoint.</p><p>Recreational mathematics directs the CPU power in a direction that is not equally important (except for chess masters etc. who can make living out of these things). Recreational mathematics are often contrived special problems invented to look like fun problems with fun solutions - for their entertainment value - and not for the method or the answer's importance for understanding something that actually naturally emerges in life or science.</p><p>The video at the top shows that "solving the Rubic cube" is something that the kindergarten kid mastered much more than 99.999999% of adults. Does that mean that he knows mathematics as an adult now? I don't think so. It is an extremely special skill in recreational activity so it's compatible with his not knowing almost anything about what we call mathematics, unable to use it.</p><p>So Hejný and his folks complain that the teaching of mathematics at school is dominated by the memorization of rules, methods, formulae, equations, whatever. But sorry, this is what the "beef" of mathematics is. Whether someone really understands it or can use all these concepts and relationships creatively depends on his talents and other things, and can't be taught. But there are things that can be taught and should be taught.</p>Luboš MotlSat, 20 Dec 2014 01:49:45 -0000Re: The Reference Frame: Alternative teaching of mathematics: three problemshttp://motls.blogspot.com/2014/12/alternative-teaching-of-mathematics.html#comment-1751302391<p>My opinion is the opposite one. The basic school kids should be exposed to the maximum amount of mathematical concepts that have ever made it to the basic schools. Different kids will get different percentage of the material -perhaps the average could be close to 50%- and this should be considered OK, a sign that they are learning something.</p>Luboš MotlSat, 20 Dec 2014 01:39:03 -0000Re: The Reference Frame: Alternative teaching of mathematics: three problemshttp://motls.blogspot.com/2014/12/alternative-teaching-of-mathematics.html#comment-1751235363<p>I just don't think a person with out knowledge of financial mathematics should be allowed to sign any deal that involves money and time.</p><p>for the same reason a retarded can be guilty of a crime</p><p>if you don't know how interest compound with time you can't be considered a fill fledged adult , as an an-alphabet has some limitations for not be able to read</p>JordanFri, 19 Dec 2014 23:58:17 -0000Re: The Reference Frame: Alternative teaching of mathematics: three problemshttp://motls.blogspot.com/2014/12/alternative-teaching-of-mathematics.html#comment-1751229786<p>Sorry, young students can't learn advanced algebra.</p><p>You can teach them it, and they will be able to do it. And then they will forget it.</p><p>Because along with the ability to learn lots at a young age comes the "ability" to forget almost as quickly. Only practice will embed, and small kids have no ability to focus for long periods in the way required to learn algebra. Human beings have natural ability to learn language with little practice, and some physical skills, but artificial things like Maths are fighting against nature, and we have to learn them the hard way.</p><p>Moreover teaching young kids algebra is stupid. It's a party trick, with no meaning. That's why the Chinese score to well in Algebra tests, but don't do well on real world problems. It's rote learnt only.</p><p>Finally, as a teacher of Mathematics I have learnt the hard way that teaching kids Algebra is only half the battle.</p><p>You have to teach ability to frame a logical sequence of steps, which kids struggle with. We all know that getting an eight year old to explain anything is hard enough, now try to get them to explain an abstract Maths problem so you can follow it! Careful reasoning requires a maturity only found in the older High School kids.</p><p>You also have to teach the language and notation. It's funny Luboš using function notation when explaining how young kids will do a problem! LIke that's how they will do it -- Not! Teaching fifteen-year-olds to understand function notation is far harder than getting them to answer the questions once they understand them! The concepts are natural enough, but the contextualisation is everything.</p><p>I agree with his contention that Maths shouldn't be forced onto those that can't. And that traditional problems aren't the best way to teach. But that doesn't mean that going another way will suddenly make kids able to do Maths a lot better. It's not hard because it's taught badly, it's hard because it is hard.</p><p>(Note, I suspect like most people who read this blog, I have kids good at Maths. I can explain concepts to them and they learn them more or less immediately. If I hadn't learnt the hard way, as a teacher, I would assume most were more or less like that. However, they aren't. A few months teaching at a High School will cure you pretty quickly of funny ideas about how most kids have natural ability at Maths.)</p>MoolooFri, 19 Dec 2014 23:50:27 -0000Re: The Reference Frame: Ellis', Silk's falsifiability babbling in Naturehttp://motls.blogspot.com/2014/12/ellis-silks-falsifiability-babbling-in.html#comment-1751216762<p>Thank you, Lubos. Excellent argument and explanation.</p>jim zFri, 19 Dec 2014 23:31:58 -0000Re: The Reference Frame: Alternative teaching of mathematics: three problemshttp://motls.blogspot.com/2014/12/alternative-teaching-of-mathematics.html#comment-1751147238<p>My opinion is that kids need to "feel" mathematics not learn it. Excuse me while I go and take a bong hit. </p>Bill RysonFri, 19 Dec 2014 21:58:08 -0000Re: The Reference Frame: Alternative teaching of mathematics: three problemshttp://motls.blogspot.com/2014/12/alternative-teaching-of-mathematics.html#comment-1750935170<p>Rubix cubes are an interesting subject to teach. To work out how to solve a cube front scratch you need to understand a bit about groups, and cognates. ie. Change all bar one on a face, rotate the face, reverse the process, and you've flipped or rotated.</p><p>Explainable in a non mathematical way. So are groups with some paper. Turns out to be a rich area far better than a IQ style puzzle.</p><p>You can treat it as art, as all sorts of things.</p><p>Completely abstract, but a fun part of maths.</p>LBFri, 19 Dec 2014 18:04:11 -0000Re: The Reference Frame: Alternative teaching of mathematics: three problemshttp://motls.blogspot.com/2014/12/alternative-teaching-of-mathematics.html#comment-1750930888<p>Do you think they should just learn the present tense and not read literature?</p>LBFri, 19 Dec 2014 18:00:27 -0000Re: The Reference Frame: Alternative teaching of mathematics: three problemshttp://motls.blogspot.com/2014/12/alternative-teaching-of-mathematics.html#comment-1750871192<p>My opinion is that most kids should just learn basic arithmetic and let it go at that.</p>lukeleaFri, 19 Dec 2014 17:24:47 -0000Re: The Reference Frame: Alternative teaching of mathematics: three problemshttp://motls.blogspot.com/2014/12/alternative-teaching-of-mathematics.html#comment-1750670357<p>Advanced mathematics in France did spiral into abstraction.<br>Usually one looks at particulars and becomes familiar with local models or effective theories, then uses this knowledge to generalize and to develop abstract systems that also work for the particular examples. Some mathematicians seem to bypass the particulars and jump immediately to the abstract. An example was Alexander Groethendieck, who was at home with abstractions, but uncomfortable with actual numbers. When someone asked him to show how something worked with an actual prime number, Groethendieck said, "Fine, consider<br>57....". This has since been called a "Groethendieck prime" :)<br>Galois had a similar talent. You need both types of mathematicians.</p>GordonFri, 19 Dec 2014 15:03:01 -0000Re: The Reference Frame: Alternative teaching of mathematics: three problemshttp://motls.blogspot.com/2014/12/alternative-teaching-of-mathematics.html#comment-1750664170<p>I think understanding math is conceptual, and that is the beauty of it, making it quite fun.</p>ChadFri, 19 Dec 2014 14:58:46 -0000Re: The Reference Frame: Ellis', Silk's falsifiability babbling in Naturehttp://motls.blogspot.com/2014/12/ellis-silks-falsifiability-babbling-in.html#comment-1750639148<p>Pure politics incrementally infiltrating science via its very top journals. There are climate justice warriors in charge and anything they can do to install more gatekeepers affords them status. It's the science of psychology that needs to advance to better expose, understand and treat sociopathy. I'm actually long term delighted that the climate scam pulled so many people into intense adoption of trumped up and also irrelevant consensus, in public, because the public can understand it as a politicized fraud and be eventually much more savvy about activist scientists. A youthful backlash is likely going to be the result, one with adequate testosterone behind it unlike most skeptical site activity. Maybe three guys on Twitter are directly challenging alarmist academics, not yet dozens or hundreds.</p>NikFromNYCFri, 19 Dec 2014 14:41:59 -0000Re: The Reference Frame: Ellis', Silk's falsifiability babbling in Naturehttp://motls.blogspot.com/2014/12/ellis-silks-falsifiability-babbling-in.html#comment-1750418061<p><i> It is really interesting to get deeply into these ideas and contemplate the nuances.</i></p><p>Sounds like you want to have a philosophical discussion...</p><p>There really isn't any difference between philosophy, science, and mathematics. What they all have in common is that they try to describe things. All three can create consistent frameworks that may, or may not, correspond with nature. The problem arises when we want to know which of these many frameworks does correspond with nature.</p><p>And just as there are bad philosophers, there are bad scientists and bad mathematicians. Sometimes I think we confuse the discipline with the disciples.</p>Bob FeltsFri, 19 Dec 2014 12:32:43 -0000Re: The Reference Frame: Bang or bounce: a new idea on cyclic cosmologyhttp://motls.blogspot.com/2014/12/bang-or-bounce-new-idea-on-cyclic.html#comment-1750323985<p>Thanks.Some time I will try to really understand Weinberg's proof, although I have lot of respect for Penrose also! What happens during contraction phase (if there is contraction) is still mystery to me. Although Frampton's work is very interesting,it did not resolve problems for me. Personally I would like contraction on Hindu religious ground! Ha, Ha, Ha!!!</p>kashyap vasavadaFri, 19 Dec 2014 11:42:16 -0000Re: The Reference Frame: Ellis', Silk's falsifiability babbling in Naturehttp://motls.blogspot.com/2014/12/ellis-silks-falsifiability-babbling-in.html#comment-1750259994<p>Raphael Bousso also added a good comment this morning.</p>TonyFri, 19 Dec 2014 10:57:44 -0000Re: The Reference Frame: Ellis', Silk's falsifiability babbling in Naturehttp://motls.blogspot.com/2014/12/ellis-silks-falsifiability-babbling-in.html#comment-1750247927<p>Dear NumCracker, there are different strongly coupled regimes, depending on the coupling we mean.</p><p>In weak gravity, classical GR may be linearized but it is a nonlinear theory and when the redshift becomes of order 100%, ideally at the black hole event horizon, it is a situation where classical GR is very strongly coupled. The observation of black holes etc. is evidence that GR works well in that regime.</p><p>One may talk about the strength of the quantum effects, and they get important for the Planck-energy scattering of gravitons and similar situations. Exactly when quantized gravity gets strongly coupled in this sense, it breaks down and string/M-theory is the only framework that can yield any predictions at that point.</p><p>I don't think one can see Planck-energy phenomena directly in any foreseeable-future experiment I can think of - and never in my life, I have believed that it was more likely than not that it would be possible to directly observe strongly-coupled-quantum-gravity in actual experiments. I was familiar with the values of the Planck length, Planck temperature, and other things since the age of 11 or so, a year before I read about string theory for the first time, actually. This whole ideology that one should "want" something like that looks absolutely idiotic to me.</p><p>One doesn't need these experiments to be done in the real world to know that these phenomena may occur in principle. And one doesn't need to actually do such experiments to figure out whether a particular theory breaks down in this regime or not.</p>Luboš MotlFri, 19 Dec 2014 10:49:03 -0000Re: The Reference Frame: Alternative teaching of mathematics: three problemshttp://motls.blogspot.com/2014/12/alternative-teaching-of-mathematics.html#comment-1750229187<p><a href="https://www.khanacademy.org/" rel="nofollow">https://www.khanacademy.org/</a><br><a href="http://venturebeat.com/2014/12/17/khan-academys-learning-tools-appear-in-an-unlikely-place-the-xbox-one/" rel="nofollow">http://venturebeat.com/2014/12...</a></p><p>Khan Academy creates objective competence by being an expert teacher. Soft approaches to learning do not seek to instill objective competence. They are heteronormatism problematizing homosocial othering (slathering pigs with lipstick). The eternal enemy of "good enough" is "better."</p><p>Demand Equal Opportunity!<br>Enforce Equal Opportunity!<br>Inflict Equal Opportunity!</p><p>Hey, Obama - who turned Sony inside out without even having a reliable source of electricity?</p>Uncle AlFri, 19 Dec 2014 10:37:00 -0000Re: The Reference Frame: Ellis', Silk's falsifiability babbling in Naturehttp://motls.blogspot.com/2014/12/ellis-silks-falsifiability-babbling-in.html#comment-1750208417<p>Ok, let's rephrase it in such a different way: GR was never directly tested in its strong field limit, but its perturbative limits were checked out of any doubt. Even the existence of gravitational waves, despite of no direct detection, are settle after PSR B1913+16. Recently BICEP2 has shown quantum gravity perturbations on CMB, but those are still "only semiclassical" effects. Once observational cosmology is progressing quite fast recently, what would be (if one) genuine "string effects" one could (even indirectly) expect to able to observe ?</p>NumCrackerFri, 19 Dec 2014 10:22:18 -0000Re: The Reference Frame: Ellis', Silk's falsifiability babbling in Naturehttp://motls.blogspot.com/2014/12/ellis-silks-falsifiability-babbling-in.html#comment-1750175868<p>SUGRA is a long-distance approximation of string or M-theory - which is almost the same statement as the fact that general relativity coupled to matter is an approximation of string or M-theory. Do you understand these statements?</p><p>I don't understand what it means for a prediction to be "doable out of those SUGRA approximations". SUGRA is a form of general relativity so it is making the predictions that SUGRA or general relativity are doing, like the bending of light in the gravitational field or precession of the Mercury's perihelion or the gravitational redshift. SUGRA is GR with supersymmetry so it adds the predictions of a gravitino (which is massive if the SUSY is spontaneously broken) and some relationship between the couplings.</p><p>Approximately quantized gravity, like SUGRA as an effective field theory, adds things like the Hawking radiation of the black holes, and so forth. The character of the matter fields coupled to this (super)gravity may only be determined by the analysis of the exact string/M-theoretical compactification - it is input for the SUGRA theory (e.g. for G2 compactifications).</p>Luboš MotlFri, 19 Dec 2014 09:59:11 -0000Re: The Reference Frame: Ellis', Silk's falsifiability babbling in Naturehttp://motls.blogspot.com/2014/12/ellis-silks-falsifiability-babbling-in.html#comment-1750170468<p>Apologies, I don't understand what you are saying.</p><p>Soup Nazi earthbound vomit frivolous Paris shines coincidentally dimensionful G-value therapy good jester?</p>Luboš MotlFri, 19 Dec 2014 09:54:58 -0000Re: The Reference Frame: Ellis', Silk's falsifiability babbling in Naturehttp://motls.blogspot.com/2014/12/ellis-silks-falsifiability-babbling-in.html#comment-1750169153<p>I see! However I've read some of your blog posts where M-Theory on G2 manifolds are well approximated by 11D SUGRA compactifications (<a href="http://motls.blogspot.cz/2011/12/learning-from-theory-and-data-about-our.html?m=1)" rel="nofollow">http://motls.blogspot.cz/2011/...</a> ... so I would like to know which (if any) experimental verification/prediction of ST would be doable (at least in principle) out of those SUGRA (low energy) approximations.</p>NumCrackerFri, 19 Dec 2014 09:53:55 -0000Re: The Reference Frame: Ellis', Silk's falsifiability babbling in Naturehttp://motls.blogspot.com/2014/12/ellis-silks-falsifiability-babbling-in.html#comment-1750167598<p>You can stick to the Seinfeld's ridiculously rude character of Soup Nazi and insult anyone who enters your "shop", but that doesn't change any facts in the real world. Quantity such as the above contradicting mile-long mind-vomit can't substitute quality, but I think you should keep doing it. After all, who needs a therapist with a do-it-yourself scribble-therapy. While at it, you can also stick the "dimensionful quantities" or any other frivolous daydreaming by your society of Earthbound idiots up where the Sun shines not. "Unexpected pattern" - at both macroscopic and quantum scales, plus the theoretical G-value "coincidentally identical" to the Paris BIPM's? LOL The royal family is fine thank you. They're sending you best wishes too, and urge you to keep amusing the audience - but don't fly off the handle now, it doesn't mean you're a good jester.</p>OmerbashichFri, 19 Dec 2014 09:52:45 -0000