tag:blogger.com,1999:blog-17232051.post4579815128651781836..comments2024-03-28T03:16:14.104-04:00Comments on Noahpinion: Theory vs. Data in economicsNoah Smithhttp://www.blogger.com/profile/09093917601641588575noreply@blogger.comBlogger40125tag:blogger.com,1999:blog-17232051.post-86871562002194290532015-10-06T16:32:00.680-04:002015-10-06T16:32:00.680-04:00It's almost like the conceit of economics crea...It's almost like the conceit of economics creating rationalizations for emergent effects of complex systems looks increasingly silly as data becomes increasingly more accessible to falsify such rationalizations. Or wait, maybe that's exactly what it's like. <br /><br />If you spent your life and earned great reputational acclaim for such a rationalization, would you be able to easily let it go in the face of evidence that you were basically an astrologer? It's a tough thing to ask of anyone.jcd222https://www.blogger.com/profile/03597854197694730653noreply@blogger.comtag:blogger.com,1999:blog-17232051.post-14080463417490546122015-10-06T02:00:10.614-04:002015-10-06T02:00:10.614-04:00Good use of the word "wanky", sir
--True...Good use of the word "wanky", sir<br />--TrueBritAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-17232051.post-89304365441728435392015-10-05T23:15:23.439-04:002015-10-05T23:15:23.439-04:00Good MMT book is an oxymoron.Good MMT book is an oxymoron.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-17232051.post-14093301751809661422015-10-05T13:04:18.616-04:002015-10-05T13:04:18.616-04:00The question is not about empiricism, it's abo...The question is not about empiricism, it's about the nature and quality of models to which data is applied.<br /><br /><br />HenryAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-17232051.post-91908515759697713642015-10-05T01:42:54.093-04:002015-10-05T01:42:54.093-04:00rosserjb@jmu.edu:
"If global average tempera...rosserjb@jmu.edu:<br /><br />"If global average temperature were to clearly start declining, some climate models would be found to have been falsified." Please provide a proof of your conjecture.<br /><br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-17232051.post-46983573671644381142015-10-04T18:02:24.621-04:002015-10-04T18:02:24.621-04:00Terry,
If global average termperature were to...Terry,<br /> If global average termperature were to clearly start declining, some climate models would be found to have been falsified. Job security would only hold for those with tenure.rosserjb@jmu.eduhttps://www.blogger.com/profile/09300046915843554101noreply@blogger.comtag:blogger.com,1999:blog-17232051.post-13263002599945112392015-10-04T10:04:10.317-04:002015-10-04T10:04:10.317-04:00Noah unrelated but there is a good MMT book/eBook ...Noah unrelated but there is a good MMT book/eBook here - understanding government finance:<br />http://www.bondeconomics.com/p/books.html?m=0Randomhttps://www.blogger.com/profile/04445772572707818311noreply@blogger.comtag:blogger.com,1999:blog-17232051.post-86622949157162473422015-10-04T00:58:32.765-04:002015-10-04T00:58:32.765-04:00Steve Roth:
Good question. Thanks for giving me t...Steve Roth:<br /><br />Good question. Thanks for giving me the opportunity to clarify. A synopsis follows.<br /><br />When a "prediction" is a proposition and under the probabilistic logic this proposition has a probability of being true. The "probabilistic logic" is a generalization from the classical logic under which the truth values of propositions are replaced by probabilities of these propositions being true. <br />Under the classical logic, information for a deductive conclusion from an argument is not missing. Under the probabilistic logic there is the possibility for a portion of this information (including all of it) to be missing. <br /><br />Science has a theoretical side and an empirical side. Probabilities lie on the theoretical side. The corresponding relative frequencies lie on the empirical side.<br /><br />A "relative frequency" is the ratio of two "frequencies." A frequency is a count of sampling units of a particular description in a sample drawn from the statistical population underlying the associated model.<br /><br />Eliminate the statistical population and there are no frequencies, relative frequencies or probabilities. There is no bothersome probabilistic logic or classical logic. This is the approach that has been taken by global warming climatologists in freeing their field of study from the tyranny of logic.<br /><br />One of the effects is to eliminate falsifability. For a global warming climatologist this has the beauty of enhancing job security.<br /><br />The article at http://wmbriggs.com/post/7923/ provides details on the equivocation fallacy in global warming arguments plus citations to the scholarly literature on this topic.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-17232051.post-2114711451493980002015-10-03T18:11:12.249-04:002015-10-03T18:11:12.249-04:00@Terry Oldberg:
That's very interesting, but....@Terry Oldberg:<br /><br />That's very interesting, but...when is a prediction not a proposition? Is that a well-known thing, in logic, rhetoric, etc.? Love to see links.<br /><br />Google:<br /><br />No results found for "prediction is not a proposition".Steve Rothhttps://www.blogger.com/profile/11895481216028771016noreply@blogger.comtag:blogger.com,1999:blog-17232051.post-3367239191495936032015-10-03T14:48:07.740-04:002015-10-03T14:48:07.740-04:00Though falsifiabililty is popularly associated wit...Though falsifiabililty is popularly associated with the name of Karl Popper it is a consequence of linking the model to logic via the meaning that is attached to the term "prediction." Thus, the phrase "tyranny of popperism" is equivalent to the phrase "tyranny of logic." The link to logic forged when a "prediction" is a kind of proposition.<br /><br />In the literature of global warming climatology, a "prediction" is a kind of proposition and is not a kind of proposition, a possibility because "prediction" is polysemic. When this term changes meaning in the midst of an argument this argument becomes an example of an "equivocation." Though an equivocation looks like a syllogism, it isn't one. Thus, though it is logically proper to draw a conclusion from a syllogism the same is not true of an equivocation. To draw such a conclusion is the "equivocation fallacy." This fallacy is of practical significance because drawing conclusions from equivocations is the sole basis for Obama administration regulatory policy on CO2 emissions.<br /><br />Under the circumstance that a "prediction" is a kind of proposition, it is possible for a climate model to provide a would be regulator of Earth's climate with information about the outcomes from his or her policy decisions in advance of these outcomes; thus, regulation is possible. Under the circumstance that a "prediction" is NOT a kind of proposition, it is impossible for a climate model to provide this information; thus regulation is impossible. Obama administration policy is based upon models of a type that provides no information. Regulation is impossible but is nonetheless being attempted by the Obama administration and at great cost to the economy of the U.S. Imposition of the "tyranny of logic" upon the Obama administration would head off this debacle.<br /><br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-17232051.post-57078986693842488132015-10-03T10:26:44.422-04:002015-10-03T10:26:44.422-04:00The tyranny of popperism impedes the progression o...The tyranny of popperism impedes the progression of knowledge and theory. The graviton may never be detected, but that doesn't render string theory useless or invalid.invalid. Theoretical physicists and economists have the tools to dismiss theories that are patently nonsense, so what remain are theories that are mathematically and logically consistent even if they cannot be adequately falsified. grey enlightenmenthttp://greyenlightenment.comnoreply@blogger.comtag:blogger.com,1999:blog-17232051.post-13994250721955839452015-10-03T09:55:26.337-04:002015-10-03T09:55:26.337-04:00Piketty has on one hand done a lot of empirical wo...Piketty has on one hand done a lot of empirical work and on the other hand put forward one of the best examples of new theoryderp: the theory that as growth slows returns don't therefore wealth accumulates.Tom Warnerhttps://www.blogger.com/profile/11247836188106712069noreply@blogger.comtag:blogger.com,1999:blog-17232051.post-24243962798684597862015-10-02T19:42:47.135-04:002015-10-02T19:42:47.135-04:00Quite (but do look up Mermin if you're unfamil...Quite (but do look up Mermin if you're unfamiliar with him. Most entertaining.).<br /><br />However, physics "envy" isn't the main issue: the real question is whether Economics is Kuhnian (or maybe just Plankian).GrueBleennoreply@blogger.comtag:blogger.com,1999:blog-17232051.post-11555383331752396802015-10-02T16:12:15.234-04:002015-10-02T16:12:15.234-04:00scotra,
Bad example with comparative advantag...scotra,<br /> <br />Bad example with comparative advantage and Leontieff Paradox. That is only a paradox if one believes that there are only two factors of production: aggregate homogeneous labor and aggregate homogenous capital, as in various idiot textbook presentations. The minute one allows for heterogeneous labor, the "paradox" disappears empirically.rosserjb@jmu.eduhttps://www.blogger.com/profile/09300046915843554101noreply@blogger.comtag:blogger.com,1999:blog-17232051.post-72313744579426200432015-10-02T12:49:54.331-04:002015-10-02T12:49:54.331-04:00This is why I said physics isn't actually Popp...This is why I said physics isn't actually Popperian! :-)Noah Smithhttps://www.blogger.com/profile/09093917601641588575noreply@blogger.comtag:blogger.com,1999:blog-17232051.post-17438529826260457042015-10-01T23:59:34.761-04:002015-10-01T23:59:34.761-04:00Noah,
You aren't going back far enough in you...Noah,<br /><br />You aren't going back far enough in your economic history. Mathiness wasn't a feature of the early theorists - Adam Smith, Ricardo JS Mill etc. They described theory based on observation of the natural economic world around them. Mathematical notation then became a useful way to describe how a notional rational economic man would react to a set of circumstances (surrounded by a wide range of caveats - not the least of which being ceteris paribus). At some point the caveats fell away and people started believing that the maths wasn't a neat way to describe some interactions but was actually determining the behaviours.<br /><br />Economics at the moment is grappling with the fact that it keeps believing theory even after it falls at the first empirical test (see, for example, comparative advantage specialisation vs Leontieff Paradox). Even the Coase theorem is actually Coase's strawman explanation of property rights run wild without the body of his article which was about demonstrating that the institutional, legal and political framework, as well as informational asymmetry (or deficiency) would render a 'Coaseian' solution impracticable.scotrahttps://www.blogger.com/profile/04894231118206240839noreply@blogger.comtag:blogger.com,1999:blog-17232051.post-52907277841030319552015-10-01T19:54:43.381-04:002015-10-01T19:54:43.381-04:00If you are going to go on about how physics is emp...If you are going to go on about how physics is empirically "better" than econ, then the very least you should do is look up Einstein's pronouncements about how even in physics (especially in physics ?) empirical evidence always underdetermines theory.<br /><br />Which is why Popperism doesn't actually work, even in physics. Oh yeah, fields of "knowledge" should at least be "theoretically" falsifiable, but just you try to do it when all your instruments and measures are deeply imbedded in your 'theory".<br /><br />What really happens is what Kuhn said: old theories just develop difficulties and problems until they get replaced by new (better ?) theories. Nothing is ever truly falsified. Nothing is ever confirmed.<br /><br />And perhaps you should also look up David Mermin's pronouncements on 'description' versus 'explanation', they are very relevant.GrueBleennoreply@blogger.comtag:blogger.com,1999:blog-17232051.post-80550546032963589692015-10-01T14:33:33.914-04:002015-10-01T14:33:33.914-04:00The qualitative theory of nonlinear differential e...The qualitative theory of nonlinear differential equations, which Poincare more or less invented while investigating and "solving" the three body problem in a 97 page paper.rosserjb@jmu.eduhttps://www.blogger.com/profile/09300046915843554101noreply@blogger.comtag:blogger.com,1999:blog-17232051.post-20786467470834719892015-10-01T11:49:03.161-04:002015-10-01T11:49:03.161-04:00Definitely.Definitely.Noah Smithhttps://www.blogger.com/profile/09093917601641588575noreply@blogger.comtag:blogger.com,1999:blog-17232051.post-79422317730832826482015-10-01T11:06:39.788-04:002015-10-01T11:06:39.788-04:00Much sounds reasonable. There is certainly and in...Much sounds reasonable. There is certainly and influx of data in certain areas of economics, but macro is one major exception. The primary goal is to explain the movement of variables like GDP that have quarterly frequency and persistence. Throw in potential structural breaks, and you have an econometric nightmare. There's not enough data to answer simple questions like 'Is there a unit root in GDP' with any confidence. <br /><br />There is some new data like the Billion Prices Project that might help, but empirical evidence in macro will be weak for the foreseeable future. Hence, macro theory will continue to get plenty of attention.GWhttps://www.blogger.com/profile/04384456925417589121noreply@blogger.comtag:blogger.com,1999:blog-17232051.post-19789313036117969062015-10-01T10:06:00.457-04:002015-10-01T10:06:00.457-04:00What would a "general solution" entail?What would a "general solution" entail?Noah Smithhttps://www.blogger.com/profile/09093917601641588575noreply@blogger.comtag:blogger.com,1999:blog-17232051.post-6442106523278071882015-10-01T10:05:22.817-04:002015-10-01T10:05:22.817-04:00:-)
Was waiting for someone to say that...:-)<br /><br />Was waiting for someone to say that...Noah Smithhttps://www.blogger.com/profile/09093917601641588575noreply@blogger.comtag:blogger.com,1999:blog-17232051.post-1948132996172286042015-10-01T09:55:38.983-04:002015-10-01T09:55:38.983-04:00"In theory there's no difference between ..."In theory there's no difference between theory and practice, but in practice, there is"BobS.https://www.blogger.com/profile/00947797303268752142noreply@blogger.comtag:blogger.com,1999:blog-17232051.post-75886228682920820182015-10-01T09:46:48.256-04:002015-10-01T09:46:48.256-04:00@Anonymous, thanks for your answer... I love it! ...@Anonymous, thanks for your answer... I love it! I don't think I need to tell you I was being a bit tongue in cheek with my comment: It's slightly over the top... I've had that "speech" in my head for a while. I actually have seen physicists (Sean Carroll and Lawrence Krauss come to mind) say something amounting to a statement like this:<br /> <br />"Well, I was hoping they *wouldn't* find the Higgs boson [or whatever], because that would have meant we still had another great puzzle to solve!!"<br /><br />And it occurred to me how different that is from the self assured and mutually far-from-consensus ideas that are out there in econ I see expressed by the corresponding media friendly economists on a regular basis. Of course Krauss and Carroll have lots of opinions on "fringe" ideas in physics too (how many universes ARE there?), but they *usually* (not always!) manage to insert a sizable helping of "this is speculation of course" qualifier into such musings.<br /><br />But I like your answer very much. Another thing I've thought of is that econ might be in the same place medical science was back in the 16th century: the king is sick, so SOMETHING has to me done... and so all the most notable physicians in the kingdom are summoned to examine him and give their advice... and immediately the blood letters start arguing with the ear candlers who argue with the cuppers and maybe even that guy in the corner who thinks maybe the mold on his bread might help (whom everyone else thinks is crazy!). Lol.<br /><br />But there you go, see? Medical science did go though something similar... a need to put it into practice prior to any verified consensus on the fundamentals. And yet they <a href="https://www.sciencebasedmedicine.org/" rel="nofollow">still have to deal with loud angry media savvy ignorant cranks</a>... like the anti-vaxers and the <a href="http://gawker.com/the-food-babe-blogger-is-full-of-shit-1694902226" rel="nofollow">"Food Babe" and her derp "army."</a><br /><br />And physics does get pressure to perform... in times of war (A-bomb, ICBMs, etc) perhaps sooner than they'd like. Perhaps in peace time as well (can we find an engineering solution to green house gasses? ... or for me, living in drought ridden California ... what ever happened to the idea of "seeding the sky" for rain?... unintended consequences not worked out yet perhaps? I guess I can <a href="https://en.wikipedia.org/wiki/Cloud_seeding" rel="nofollow">find out.</a>).<br /><br />@Cesium, I think my comment applies to you as well, if you were addressing me. Thanks.Tom Brownhttps://www.blogger.com/profile/17654184190478330946noreply@blogger.comtag:blogger.com,1999:blog-17232051.post-52690239592373787732015-10-01T09:33:26.497-04:002015-10-01T09:33:26.497-04:00The problem with this post is that it's all th...The problem with this post is that it's all theory and no empirical work.Stephen Williamsonhttps://www.blogger.com/profile/01434465858419028592noreply@blogger.com