tag:blogger.com,1999:blog-22973357.post1739529577240004148..comments2023-09-27T07:44:19.769-04:00Comments on Sabine Hossenfelder: Backreaction: The number-crunchers. How we learned to stop worrying and love to code.Sabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger22125tag:blogger.com,1999:blog-22973357.post-35934303620294651922015-08-02T00:20:35.031-04:002015-08-02T00:20:35.031-04:00We've been well past the era of closed form so...We've been well past the era of closed form solutions for some time. I remember some popular physics book, I think by Steven Weinberg, saying that we can tell the sophistication of a gravitational theory by the N at which the N-body problem has no closed form solution. Newton's fails at N=3, Einstein's at N=2, and many popular quantum gravity theories fail at N=1 or even N=0.<br /><brKaleberghttps://www.blogger.com/profile/05283840743310507878noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-15223403528175862402015-07-22T14:31:05.616-04:002015-07-22T14:31:05.616-04:00Here's another weird coincidence! I wrote this...Here's another weird coincidence! I wrote this comment before reading Zephir's:<br /><br />You know it was this whole train of thought which led me to the idea of bi-simulation on non-well-founded sets - which I have unsuccessfully tried to convey to you and, through you, to Renate Loll. So, I'll express it here and then drop it forever!<br /><br />As so eloquently expressed in SmolinPonderSeekDiscoverhttps://www.blogger.com/profile/00913503952284529871noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-49467653418853052002015-07-21T20:00:58.479-04:002015-07-21T20:00:58.479-04:00This is the evolution, which is not difficult to p...This is the evolution, which is not difficult to predict (for example here https://www.reddit.com/r/Physics_AWT/comments/2htmk5/science_graduates_are_not_that_hot_at_maths_but) It's the increasing complexity of formal models and decreasing cost of computer time, which will force the physicists to orient itself to numeric calculations and even simulations, despite some of them are still proud Zephirhttps://www.blogger.com/profile/06010623752049244967noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-89300527908641531172015-07-21T15:08:26.920-04:002015-07-21T15:08:26.920-04:00Believe it or not I wrote this comment before I re...Believe it or not I wrote this comment before I read Arun's comment, it's purely coincidental . . . <br /><br />I thought this issue was settled long ago!?! Numerical methods have really been indispensable to science since the 70's with the parallel advent of more efficient computation and dynamical chaos. How did Feigenbaum discover Universality in phase transitions? And in my PonderSeekDiscoverhttps://www.blogger.com/profile/00913503952284529871noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-35540513073241222262015-07-21T14:19:35.410-04:002015-07-21T14:19:35.410-04:00I read a story years ago (unfortunately I cannot r...I read a story years ago (unfortunately I cannot remember the title) that imagined a future where numerical solving programs grew in power to the point where they answered fundamental questions. However, just like Chris Anderson's quote above <i>"... and science can advance even without coherent models, unified theories, or really any mechanistic explanation at all."</i>, the Michael Mussonhttps://www.blogger.com/profile/17360143418083381579noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-69075352949590240152015-07-21T13:32:24.253-04:002015-07-21T13:32:24.253-04:00"Correlation supersedes causation"
someo..."Correlation supersedes causation"<br />someone needs to tell all those machine learning researchers working on causal graphical models they are wasting their time - or, perhaps, now that Causation has become a going concern within wheel houses proximate to Chris Andersen's own, it isn't such a useless thing to study after all. I'm not trying to put him down for it- decidingregretacleshttps://www.blogger.com/profile/00849406662712673245noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-23930436898906117692015-07-21T05:52:51.906-04:002015-07-21T05:52:51.906-04:00Quite an interesting story about your grandmother....Quite an interesting story about your grandmother. She would have been about the same generation as my parents. I well remember our dad meticulously balancing his checkbook by hand, back in the 1950s. Even attending High School between 62-65 we did all calculations by hand. When my older brother bought a pocket calculator in the early 70s, for 200 dollars, it was an absolute marvel.<br /><br David Schroederhttps://www.blogger.com/profile/18048116250413347228noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-12964224667868426482015-07-20T20:25:21.561-04:002015-07-20T20:25:21.561-04:00Slightly off-topic, but not entirely, the movie Ex...Slightly off-topic, but not entirely, the movie Ex Machina is highly recommended for artistic elegance and thought-provoking subject matter.Robert L. Oldershawhttps://www.blogger.com/profile/15396555790655312393noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-12166573026704608512015-07-20T14:37:55.876-04:002015-07-20T14:37:55.876-04:00Facial recognition is something your eyes & br...Facial recognition is something your eyes & brain do automagically. But trying to replicate that with computer and camera requires both computation and analytic understanding. E.g., <a href="https://en.wikipedia.org/wiki/Eigenface" rel="nofollow">Eigenfaces</a>Arunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-68824318076348991052015-07-20T14:35:12.588-04:002015-07-20T14:35:12.588-04:00You need to be able to prove error bounds on your ...You need to be able to prove error bounds on your numerical computation, which is presumably well-understood in the case of standard functions.<br /><br />I'm assuming that the existence proof (that the computation is meaningful) already exists.<br /><br />Numerical computations slso need to give insight into limiting cases, asymptotic forms, and how input parameters or boundary conditions Arunhttps://www.blogger.com/profile/03451666670728177970noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-33886164669615424792015-07-20T13:35:17.685-04:002015-07-20T13:35:17.685-04:00Chris, you not have to go very far in algebra. Mat...Chris, you not have to go very far in algebra. Matiyasevich theorem (1970) negatively solves the Hilbert's tenth problem.Nicolas Pouparthttps://www.blogger.com/profile/17722878242014554884noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-62462627908378405782015-07-20T12:28:10.889-04:002015-07-20T12:28:10.889-04:00Isn't there a more fundamental difference, in ...Isn't there a more fundamental difference, in term of "complexity class" or "hardness", between problems (e.g. differential equations) having analytical solutions vs. those having none? For example, if the solution can be expressed as y = f(x) with f a polynomial function, we can evaluate it at any point with finite accuracy in polynomial time. Would this be true if we Chrishttps://www.blogger.com/profile/05513930613221402247noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-73065847099568975522015-07-20T11:44:26.604-04:002015-07-20T11:44:26.604-04:00Even more strange is when mathematics itself requi...Even more strange is when mathematics itself requires the use of the computer to validate a theorem like the four-color theorem, first of its kind. Such a solution has widely divided the community of mathematicians, is that still the mathematics when the mathematical demonstration itself is not verifiable by a human? The validation moves from the verification of theorem to the validation of the Nicolas Pouparthttps://www.blogger.com/profile/17722878242014554884noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-49390700402742643602015-07-20T11:20:29.167-04:002015-07-20T11:20:29.167-04:001) HyperChem Lite, costing less than a textbook, m...1) HyperChem Lite, costing less than a textbook, mm+ calculates exact 3-D molecular structures in seconds. Terrifically wrong structures for carbonyls and methylidenes can occur. Verify hardware and software with wetware.<br /><br />2) "<i>If a computer came up with just the right string theory vacuum to explain the standard model and offered you the explanation that the world is made of Uncle Alhttps://www.blogger.com/profile/05056804084187606211noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-23605711289937153102015-07-20T10:43:46.531-04:002015-07-20T10:43:46.531-04:00JimV: yes, this is exactly what I mean!JimV: yes, this is exactly what I mean!Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-56195249015271363832015-07-20T10:37:20.708-04:002015-07-20T10:37:20.708-04:00Elsewhere on the Internet I was having an argument...Elsewhere on the Internet I was having an argument in which one of the responses was that the (gravitational) N-body problem can't be solved by analytical functions but must be computed numerically. I had a similar thought to yours about the difference between analytical functions and numerically-calculated ones. I recalled that when I studied Trigonometry in high school I was given a JimVhttps://www.blogger.com/profile/10198704789965278981noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-81248760935085796162015-07-20T09:43:45.694-04:002015-07-20T09:43:45.694-04:00"If a computer came up with just the right st..."If a computer came up with just the right string theory vacuum to explain the standard model and offered you the explanation that the world is made of strings to within an exactly quantified precision, what difference would it make whether the headline was made by a machine rather than a human? Wouldn’t you gain the exact same insight?"<br /><br />It's the journey that is rewardingGiotishttps://www.blogger.com/profile/01538762241438887298noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-56407565087939193702015-07-20T07:52:03.224-04:002015-07-20T07:52:03.224-04:00Yep, my mom confirms it was Göttingen.Yep, my mom confirms it was Göttingen.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-85965185805966345792015-07-20T07:26:47.984-04:002015-07-20T07:26:47.984-04:00I believe it was Göttingen, at least that's wh...I believe it was Göttingen, at least that's where she lived later, but she moved a lot during the war times and I might confuse the story. (Will have to ask my mom.)Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-11838011422785085992015-07-20T05:53:39.328-04:002015-07-20T05:53:39.328-04:00Myers is a self-described “media ecologist” which ...<i>Myers is a self-described “media ecologist” which makes you think he’d have heard of search engine optimization. Unfortunately, when queried “gap generation” it takes Google 0.31 seconds to helpfully bring up 268,000,000 hits for “generation gap.”</i><br /><br />An even worse example (but not from media ecologists) is a band (actually a duo) called <a href="https://en.wikipedia.org/wiki/Boy_%Phillip Helbighttps://www.blogger.com/profile/12067585245603436809noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-84738719890786467462015-07-20T04:49:44.816-04:002015-07-20T04:49:44.816-04:00At which observatory did she work?
At which observatory did she work?<br />Phillip Helbighttps://www.blogger.com/profile/12067585245603436809noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-61282004504542622642015-07-20T04:49:28.335-04:002015-07-20T04:49:28.335-04:00" I too recall life without Google, when “vir...<i>" I too recall life without Google, when “viral” meant getting a thermometer stuffed between your lips"</i><br /><br />Or elsewhere.<br />Phillip Helbighttps://www.blogger.com/profile/12067585245603436809noreply@blogger.com