tag:blogger.com,1999:blog-447603865959500290.post3003636295747681493..comments2024-03-28T02:54:46.537-04:00Comments on The TOF Spot: America's Next Top Model -- Part IITheOFloinnhttp://www.blogger.com/profile/14756711106266484327noreply@blogger.comBlogger23125tag:blogger.com,1999:blog-447603865959500290.post-18054800896811383912019-01-29T15:16:41.180-05:002019-01-29T15:16:41.180-05:00yesyesTheOFloinnhttps://www.blogger.com/profile/14756711106266484327noreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-34840014593767862092019-01-29T10:29:09.321-05:002019-01-29T10:29:09.321-05:00Hi.
Are you the author of the first image? (Organi...Hi.<br />Are you the author of the first image? (Organized simplicity, Disorganized complexity, Organized complexity), I would lie to cite it on a work.arquitecsolhttps://www.blogger.com/profile/11598372642188045652noreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-75053810082999781442014-05-02T02:26:21.125-04:002014-05-02T02:26:21.125-04:00This comment has been removed by a blog administrator.Anonymoushttps://www.blogger.com/profile/13261300731756671992noreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-35116663959671636282014-03-15T17:46:52.549-04:002014-03-15T17:46:52.549-04:00Classic case Number 1:
The "Paraffin Test&qu...Classic case Number 1:<br /><br />The "Paraffin Test" (famous from 40's film noir). Dip someone's hand in paraffin. Peel the paraffin off. See if it fluoresces. If so, they just fired a gun. Why? because the gunpowder residue embedded in the paraffin and extracted from the hot, open pores fluoresces.<br /><br />Unfortunately that is where the "science" stopped. Then it became a tool for prosecutors. Periodically they would get anomalous results. <br /><br />Turns out that some cosmetics fluoresce as do farm chemicals. But they kept using it. It was "scientific". <br /><br />They had "forensic scientists" appear and testify at each trial about how the test was "generally accepted".<br /><br />The accuracy with which the "model" fitted "reality" was tested by the number of convictions. If you can show a 95% conviction rate using the paraffin test, that is proof that it is a reliable scientific test. <br /><br />Classic case Number 2: The "Castro Case" (ca. 1987) in which a DNA test using a fuzzy Western Blot was used to convict Mr. Castro. The prosecution claimed the probability of the DNA coming from someone other than Castro was ~1 in 5 billion, based on the population frequency of several pairs of matching bands in Castro's blood and in the blood found on the victim. <br /><br />When questioned on how they determined whether any pair of bands "matched", they said they took a vote in the lab, and if two out of three "forensic scientists" thought the bands matched then they matched. <br /><br />So they got a 2/3ds popular vote on maybe five pairs of bands, and based on that they told the jury there was a 1 in 5 billion chance of error on the DNA test.<br /><br />Chilling.Shysternoreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-10685656229121314582014-03-12T23:42:16.202-04:002014-03-12T23:42:16.202-04:00"The real reason why Copernicus raised no rip..."The real reason why Copernicus raised no ripple and Galileo raised a storm, may well be that whereas the one offered a new supposal about celestial motions, the other insisted on treating this supposal as fact. If so, the real revolution consisted not in a new theory of the heavens but in 'a new theory of the nature of theory'. <br />The Discarded Image (CS Lewis)<br />---------------------------------------------------------------------------------------------<br />Are theories merely useful or are they true in some sense?<br />One one hand, clearly more than one theory may explain the same phenomena, thus the theories can not pretend to the truth. <br />On another hand, we have theological reasons to believe that God wants us to know the truth, he has set the cosmos open to us, the cosmos reveals the glory of God etc. So the theory has some claims on the truth.<br /><br />So, interestingly, philosophically, the scientific theories can not be more than useful while theologically, they may be true or point to the truth. Gyanhttps://www.blogger.com/profile/09941686166886986037noreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-38366925206814177502014-03-11T13:33:46.501-04:002014-03-11T13:33:46.501-04:00It might be a matter of what stage in the game he ...It might be a matter of what stage in the game he was considering; it's possible (I don't know) that you could re-introduce the problem once you move from naked eye observation to telescope observation (which allows you to recognize the phases of Venus). But the Ptolemaic system had a lot of tools to allow re-calibration for new measurements -- circles didn't have to be strictly concentric, they could be slightly tilted, and new circles could always be added -- so I'm not sure exactly how the argument would work.<br /><br />What's going on here is an interesting puzzle I'll have to look into at some point. Looking around, I find one source (Gunnar Andersson's Criticism and the History of Science) making the opposite claim -- i.e., that both the Ptolemaic and the Copernican systems suggested more variation in the brightness of Venus than we actually get (with Galileo being able to explain why Venus is nearly constant in brightness). Of course, if that's the case, as Andersson recognizes, then we deal with the problem of measurement precision -- on its own it could be explained by the limitations of naked eye observations, or atmospheric effects, or the like. Brandonhttps://www.blogger.com/profile/06698839146562734910noreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-67586889216391459392014-03-11T01:33:36.148-04:002014-03-11T01:33:36.148-04:00I have taken the brightness problem in Ptolemaic s...I have taken the brightness problem in Ptolemaic system from Koestler's The Sleepwalkers. I may be recalling the factor of eight wrongly and need to recheck. Gyanhttps://www.blogger.com/profile/09941686166886986037noreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-63131626780349315442014-03-11T00:42:58.814-04:002014-03-11T00:42:58.814-04:00Accounting for variation in apparent brightness wa...Accounting for variation in apparent brightness was one of the things the Ptolemaic system was deliberately designed to do, and one of the reasons it was taken to work so well. It was celebrated for its ability to handle the problem. You have to keep in mind that the apparent brightness of Venus in reality does not depend on distance alone but on the phases of Venus as well, so that actual variation is much, much smaller than real distance alone would indicate. I'm not sure where you get the eightfold variation; surely the difference is closer to two or three times. (It's also unclear to me why you are bringing in the inverse square law for light; are you speaking solely of the post-Kepler situation?)Brandonhttps://www.blogger.com/profile/06698839146562734910noreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-89852096819866095552014-03-10T23:56:46.834-04:002014-03-10T23:56:46.834-04:00This comment has been removed by the author.Brandonhttps://www.blogger.com/profile/06698839146562734910noreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-86406349237973629992014-03-10T23:25:47.446-04:002014-03-10T23:25:47.446-04:00Could epicycles of Venus, for instance, account f...Could epicycles of Venus, for instance, account for eightfold variation, I believe, in the apparent brightness of Venus?<br /><br />For epicycle is only a perturbation on the circle, and its radius must be smaller than the circle radius. Take circle radius as unity and epicycle radius as 0.2, Then the distance Venus-Earth goes from 0.8 to 1.2. And brightness going as square of distance would be 0.64 to 1.44, A factor of 2. <br /><br />You would need pretty big epicycles to account for brightness variations. And were they really fitting the curve for the brightness?Gyanhttps://www.blogger.com/profile/09941686166886986037noreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-52744431851598835982014-03-10T15:55:51.844-04:002014-03-10T15:55:51.844-04:00This was precisely the revolution: astronomy moved...This was precisely the revolution: astronomy moved from the math department to the physics department. The fundamental contribution of the telescope was that it allowed people to see the heavenly bodies as actual physical places.<br /><br />"To know the causes of things." In the medieval period this was called the "propter quid." The "quia" were what we call the facts/observations.TheOFloinnhttps://www.blogger.com/profile/14756711106266484327noreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-3577976442252335562014-03-10T15:51:45.055-04:002014-03-10T15:51:45.055-04:00They took care of that with the epicycles, which b...They took care of that with the epicycles, which brought the planets closer and farther.TheOFloinnhttps://www.blogger.com/profile/14756711106266484327noreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-80752784227005246692014-03-10T07:24:49.892-04:002014-03-10T07:24:49.892-04:00"A model is a mechanism to assign probabiliti..."A model is a mechanism to assign probabilities to propositions p, given evidence E:"<br /><br />A rather instrumental view. A physicist would rather talk in terms of understanding. A model helps us to understand the system.<br /><br />And what does "probability" mean here? <br />If I assign a probability, say 0.3, to a proposition X, what precisely I have done?Gyanhttps://www.blogger.com/profile/09941686166886986037noreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-5742959937061867422014-03-10T03:00:26.976-04:002014-03-10T03:00:26.976-04:00Newton, or rather Kepler invented Astrophysics. Th...Newton, or rather Kepler invented Astrophysics. The ancients were doing Astronomy. <br />There is a difference here that is overlooked by the word "model" for both. <br /><br />Astronomy describes What Astrophysics seeks to know Why.<br />Kepler, by his three laws, launched the concept of a force that keeps the planets in their orbits. <br />The goal of Science generally and Physics particularly is to know the causes of things. That an ellipse would take place on such and such time is a statement of Astronomy but the ellipse occurs because of Moon interposing between Sun and Earth is a more physical statement. Gyanhttps://www.blogger.com/profile/09941686166886986037noreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-15077263561402493122014-03-10T02:54:43.465-04:002014-03-10T02:54:43.465-04:00Didn't the Ptolemaic model had a known but ign...Didn't the Ptolemaic model had a known but ignored problem with the varying brightness of the planets as seen from the Earth? Gyanhttps://www.blogger.com/profile/09941686166886986037noreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-60215216642509993792014-03-07T11:38:26.197-05:002014-03-07T11:38:26.197-05:00"Context uncertainty" calls to mind an o..."Context uncertainty" calls to mind an old joke:<br /><br />A lawyer objected, and the judge asked why. When the lawyer finished explaining, the judge replied. "You reason eloquently, sir, and your argument is compelling. I sincerely hope you one day try a case in which it may be relevant. Overruled."<br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-28814562151911915572014-03-06T17:37:14.121-05:002014-03-06T17:37:14.121-05:00Your remarks are quite well-taken and I would like...Your remarks are quite well-taken and I would like to cite them in Part III when I get around to it.<br /><br />I generally avoid too much math here for two reasons: 1) most of the readership is not into it and 2) I have a hard time writing equations on Blogspot. I usually have to write them out as an Object in PowerPoint, then save the slide as a jpeg image and insert it using the "picture" button. TheOFloinnhttps://www.blogger.com/profile/14756711106266484327noreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-27488629020381149972014-03-06T16:04:51.985-05:002014-03-06T16:04:51.985-05:00a few disjointed remarks:
1. It might be helpful ...a few disjointed remarks:<br /><br />1. It might be helpful to relate the remarks about the scope of Newton's model to the (unremarked AFAICS) scope of the Copernican model. One of the nice things about Newton's model is that it covered more things (some existing things, like comets, and some easy-to-imagine things, like Jules Verne's voyage to the moon) in a consistent way. The old astronomical models performed impressively well (especially when no one as careful as Tycho Brahe was checking them) but one of their limitations was they treated as essential distinctions things that Newton blew past.<br /><br />2. You wrote "That is, there is always more than one way to skin a cat -- and more than one way to model a situation." You give examples of one sense in which this is true. There is another sense in which this is true: models can look very different and still come to similar or even exactly-equal results. E.g., Hamiltonian mechanics, Lagrangian mechanics, and Newtonian mechanics look very different, and it's not just superficial: their mathematical plumbing is so different that a problem that is easy to solve in one is hard to solve in another. But they are exactly equal, no different than Roman numerals vs. Arabic numerals. A similar precisely-the-sameness apparently exists between the Feynman, Schwinger, and Tomonaga representations of QED, but it's very hard to see: one of the things that Freeman Dyson is known for is showing it.<br /><br />This apparently caused a lot of confusion in early quantum mechanics (1920 or so) as people disagreed over things which later turned out to mean the same thing in practice. I studied quantum mechanics in the 1980s, and encountered the lingering fallout from this: especially a tendency to be very impatient about possibly-superficial disagreements about representation of things, and jump quickly to asking whether there is any essential disagreement about what will be observed when a particular experiment is performed.<br /><br />3. You might want to point interested readers at http://yudkowsky.net/rational/technical/ which says some useful related things (about uncertainty and partial correctness, e.g.) at a more detailed level than you are likely to, because while it tries to be easy to read it makes much heavier use of equations and numerical examples than I remember seeing on your blog.<br /><br />(I think Curry is right to ask many of those uncertainty questions, but while I understand why you choose to write at the avoid-equations-and-numbers level, I don't understand why she seems to want to investigate only at the avoid-equations-and-numbers level. Besides the Yudkowsky Bayesian-lite page above, or a text like Jaynes' _Probability Theory_, the machine learning people have done a lot of quantitative inference stuff that bears on the questions of inference and attribution, importantly including quantitative information-theoretic generalizations of Occam's Razor which seem to bear rather directly on Curry's investigations of we can sensibly conclude from climate models, and about them. See e.g. http://stellar.mit.edu/S/course/6/sp08/6.080/courseMaterial/topics/topic1/lectureNotes/lec20/lec20.pdf and Gruenwald _the Minimum Description Length principle_ for pointers into the two main ways I am aware of --- which are closely related, but not as equivalently identical as e.g. the Newton/Lagrange/Hamilton example I gave above. Curry is a professor of atmospheric sciences and coauthor of a book on thermodynamics; it seems as though the basics of either the VC or MDL approaches should should be fairly lightweight math compared to her background, especially the fluid mechanics.)<br />William Newmanhttps://www.blogger.com/profile/14336821309402794016noreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-16871514209359308702014-03-06T15:17:34.157-05:002014-03-06T15:17:34.157-05:00It certainly clarifies how writing "The Wrec...It certainly clarifies how writing "The Wreck of the River of Stars" might be a diversion after long days at the office. Seems like going to an Aquinas conference ought to be tax deductible as professional development....Xena Catolicanoreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-25658365040256998302014-03-06T13:10:58.325-05:002014-03-06T13:10:58.325-05:00No. Ijust couldn't find a photo of Ed on the I...No. Ijust couldn't find a photo of Ed on the Internet!<br /><br />The Walker paper was the source for much of the skeleton of the post. His "taxonomy" of uncertainties "by location" is pretty much the standard. The Curry/Webster paper discusses the uncertainties applied to climate models. <br />TheOFloinnhttps://www.blogger.com/profile/14756711106266484327noreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-68988569184151923632014-03-06T11:53:10.071-05:002014-03-06T11:53:10.071-05:00I usually avoid saying "thank you for this po...I usually avoid saying "thank you for this post" so as to avoid cluttering up your comments page, but this was a truly exceptional outline; thank you for this post.<br /><br />Is that Schrock book the best introduction to Context Uncertainty you could recommend?roystgnrhttps://www.blogger.com/profile/01462833587905117761noreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-30925050081771614852014-03-06T09:10:40.995-05:002014-03-06T09:10:40.995-05:00Fraught with danger, obviously. Peril even!
I ha...Fraught with danger, obviously. Peril even!<br /><br />I have often claimed to be fraught with certainty, but most people insist that's a vice on my part.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-447603865959500290.post-8115297391210086962014-03-05T21:23:14.172-05:002014-03-05T21:23:14.172-05:00Oddly enough, Holmes misquotes that biblical refer...Oddly enough, Holmes misquotes that biblical reference. He actually says "bricks without clay". My sister quoted it a while back and I was sure she was wrong, but then I discovered no, Holmes (or Doyle) was, and she was quoting their misquote correctly.Sophia's Favoritehttps://www.blogger.com/profile/02871625814389904112noreply@blogger.com