tag:blogger.com,1999:blog-8216971263350849959.post558505794847740025..comments2023-08-07T16:41:49.660+02:00Comments on Die Klimazwiebel: Can Philosophy enlighten climate science?eduardohttp://www.blogger.com/profile/17725131974182980651noreply@blogger.comBlogger42125tag:blogger.com,1999:blog-8216971263350849959.post-47525342616483926352014-06-06T09:48:36.596+02:002014-06-06T09:48:36.596+02:00You are repeating yourself without answering my sp...You are repeating yourself without answering my specific questions.@ReinerGrundmannhttps://www.blogger.com/profile/12759452975366986236noreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-13187537988812153952014-06-06T09:35:06.321+02:002014-06-06T09:35:06.321+02:00Just for technical info - this blog is normallly n...Just for technical info - this blog is normallly not moderated, but after some time, postings are closed for comments -and this one is closed- so that at all additional comments must be ok'd by hand. This takes a little time, but all comments are published after no more than, say 18 hours. Sorry for inconvenience.<br />It happens quite often that ad-like comments are sent to old postings.Hans von Storchhttps://www.blogger.com/profile/08778028673130006646noreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-58395972763315454452014-06-06T00:40:45.371+02:002014-06-06T00:40:45.371+02:00'What do you mean by that?'
I meant that...'What do you mean by that?' <br /><br />I meant that if you look at current literature in the philosophy of science and metaphysics it will be evident that Cartright's view is not one people are bothering with or bothered by.Nicholas Shackelhttps://www.blogger.com/profile/08546205932263959250noreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-61742432253000010212014-06-06T00:39:01.644+02:002014-06-06T00:39:01.644+02:00I shouldn't have said 'what she calls fund...I shouldn't have said 'what she calls fundamentalists' but just 'fundamentalists' in the sense of believe in fundamental laws. I don't see Moriarty denying anything I am saying but rather agreeing with exactly my point when I said that any world of with fundamental laws but sufficient complexity will give an appearance as of her dappled world. <br /><br />Will you please get rid of the stupid proof you're not a robot nonsense in your commenting system. You should be wasting our time like that.Nicholas Shackelhttps://www.blogger.com/profile/08546205932263959250noreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-78153344540640294762014-06-04T20:51:17.000+02:002014-06-04T20:51:17.000+02:00#37
"if you look at current literature in th...#37<br /><br />"if you look at current literature in the philosophy of science and metaphysics it will be evident that Cartright's view is not one people are bothering with or bothered by."<br /><br />What do you mean by that? That I should look at the citation index? At a selection of top journals? And what would these articles tell me? That Cartwright is criticised a lot, or that she is not mentioned at all?<br /><br />Still, I am puzzled by your statement that "it is true most philophers of science, and also metaphysicians, are what she calls fundamentalists"<br /><br />As you will have perhaps noticed, <a href="http://blogs.nottingham.ac.uk/makingsciencepublic/2014/05/25/science-is-not-what-you-want-it-to-be/" rel="nofollow">Philip Moriarty vehemently denies this</a>.@ReinerGrundmannhttps://www.blogger.com/profile/12759452975366986236noreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-19828962397495653492014-06-02T11:46:48.532+02:002014-06-02T11:46:48.532+02:00On the whole we don't do surveys of opinion in...On the whole we don't do surveys of opinion in philosophy (although I suspect if we could aid a stream of funding worth billions of pounds by doing so we would) but if you look at current literature in the philosophy of science and metaphysics it will be evident that Cartright's view is not one people are bothering with or bothered by. Furthermore, I gave you a direct reason for why her view is false: any world of with fundamental laws (to use her terminology) but sufficient complexity will give an appearance as of her dappled world. Really she is just running a very old kind of anti-realist argument based on under-determination by evidence. In the end all these arguments just come back to inductive logic doesn't guarantee the truth of the conclusion given the truth of the premisses. So I really don't think you or anyone should be basing anything on her philosophy of science. Complexity and the mathematical chaos of non-linear dynamical systems alone suffices for the kind of points being made.Nicholas Shackelhttps://www.blogger.com/profile/08546205932263959250noreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-88288113692717549522014-06-02T11:19:25.420+02:002014-06-02T11:19:25.420+02:00Nicholas
not sure I get your point(s). You seem t...Nicholas<br /><br />not sure I get your point(s). You seem to be saying something about other scholar's views of Cartwright, and Cartwright's characterization of others. Is this correct?<br /><br />Can you provide some evidence for the 97% claim? <br /><br />And what do YOU make of her propositions?@ReinerGrundmannhttps://www.blogger.com/profile/12759452975366986236noreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-54307105778797598112014-06-02T10:26:32.435+02:002014-06-02T10:26:32.435+02:00I think you should know that 97% of philosophers o...I think you should know that 97% of philosophers of science think Cartright's position is false (OK, I chose the percentage for its resonance with another claim, but it is true most philophers of science, and also metaphysicians, are what she calls fundamentalists). Fundamental laws can easily give the appearance of her dappled world just through complexity.Nicholas Shackelhttps://www.blogger.com/profile/08546205932263959250noreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-61842962782411489812013-11-17T12:06:19.584+01:002013-11-17T12:06:19.584+01:00Karl Kuhn
'Economists are well aware of the p...Karl Kuhn<br /><br />'Economists are well aware of the problem of inherent value judgments in economic analysis...'<br /><br />The problem may start even before analysis, through the definition and framing of an issue. Many concepts have a built in 'positivity' (here used as 'normativity'). Think of employment (good)-unemployment (bad).<br /><br />Climate change is regarded by many as 'bad'. Those who refuse to do so point to climate as a natural process, and we usually find nature 'good', or indifferent (can be 'good' and 'bad').<br /><br />Terms like climate catastrophe and Klimaschutz (climate protection) are inherently value laden. If this is the case, the nice distinction between positive and normative science crumbles. Scientists would need to police their language, trying to find neutral concepts which then could be used for evaluation (in terms of supporting or opposing them, seeing the as 'good' or 'bad' ). <br /><br />The same problem appears with descriptors of discussants in the climate debate, skeptics are not happy being called 'deniers', advocates sometimes object being called 'advocates', and mainstream scientists (and 'advocates') somehow want to share in the virtue of skepticism, thus denying the term 'skeptic' to 'deniers'.<br /><br />Perhaps the philosophy of language (or plain linguistics) can be helpful here?@ReinerGrundmannhttps://www.blogger.com/profile/12759452975366986236noreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-89117540669605838752013-11-12T15:12:06.722+01:002013-11-12T15:12:06.722+01:00As an economist, I do not take offense at HvW'...As an economist, I do not take offense at HvW's characterisation of scholarly work in economics ("The majority of scholary work in economics seems to be based on, or accept, a particular school of economic thought. There are many, and many of them seem to employ fundamental normative values and/or beliefs that have no epistemic base."). I am aware that this is quite representative for the perception of economics by other disciplines. But this perception is basically about normative economic analysis which explicitly (!) contains value judgments, otherwise it would not make sense. Positive economics - on which normative economics are then based - by contrast, should not contain value judgments ... at least that's the idea.<br /><br />Nicely explained here if you can sacrifice the 5 min:<br />http://www.youtube.com/watch?v=QDtx4E1yo7g<br /><br />Economists are well aware of the problem of inherent value judgments in economic analysis, maybe because they have been in the policy advice business quite some time already. And we don't mind being called ideologues or heartless penny-pinchers and the like as long as we are allowed to respond (ie not demonized).Karl Kuhnnoreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-1460004858718570722013-11-08T10:11:17.960+01:002013-11-08T10:11:17.960+01:00hvw
even with the less absolute qualifiers you ar...hvw<br /><br />even with the less absolute qualifiers you are making sweeping statements. It is perfectly OK to say that this is what you believe but you cannot accuse social scientists of inherent bias (thus exempting yourself) but then go on and profess in an opinionated way about the social sciences.<br /><br />I am on record of saying that in some instances we can see motivated reasoning among scientists and social scientists but one needs to document them.<br /><br />It is true that some sciences have the methodological option of performing experiments but there are caveats. One is 'experimenters' regress', the other is that not all sciences can use experiments to settle disputes. Climate scientists have one planet (no 'control' planet), the same applies to social sciences. They try to find or construct 'natural' experiments, mainly by using comparative methodology.<br /><br />Regarding underdetermination, you seem to assume that Betz sneers at the concept. He does not. This is what he has to say about underdetermination reigning in climate science:<br /><br />'Different methodological approaches which avoid the underdetermination problem have been developed in the philosophy of science during the last century... these approaches, though possibly yielding insights when applied to other disciplines, are inapplicable to climate science—a failure which explains why underdetermination reigns in climatology.'<br />'Underdetermination, model-ensembles and surprises: On the epistemology of scenario-analysis in climatology', J Gen Philos Sci (2009) 40:3–21 DOI 10.1007/s10838-009-9083-3@ReinerGrundmannhttps://www.blogger.com/profile/12759452975366986236noreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-20669653024287731452013-11-08T00:33:32.264+01:002013-11-08T00:33:32.264+01:00Reiner,
maybe you should concentrate less on find...Reiner,<br /><br />maybe you should concentrate less on finding imperfect qualifiers of statements but rather try to understand. I said "The majority of scholary work in economics seems to be ..". Feel free to add any amount of "often", "not always", "with exceptions", "to my knowledge", etc. instead of grabbing an "always" from a preceding post.<br /><br />["You point to 'articles' of mine ..."]<br />I was indeed referring to your publication list on your university homepage.<br /><br />["With regard to the difference between economists and physicists .."]<br />You disagree that (in principle, almost, as commonly accepted) all questions in physics can be settled by experimental evidence, while this is not true for Economics? Interesting.<br /><br />"Do you think current economic debates are led by Marxist economists fighting the Neo-liberals? Or was it Keynesians...?"<br />Wonder what makes you think this?<br /><br />["Underdetermination"]<br />I was referring to your quote of Betz in the other thread here: "The common core of both versions is a kind of underdetermination thesis." because it is related to the claim of the necessary involvement of non-epistemic values in scientific results.<br /><br />hvwnoreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-80907450378733574412013-11-07T22:28:55.902+01:002013-11-07T22:28:55.902+01:00hvw
I am disappointed. You should try harder: you...hvw<br /><br />I am disappointed. You should try harder: you make very strong claims ('Economics seem to be <b>always</b> based on an ideological fundament and that seems to be true for most of the other social sciences too') without a shred of evidence. In my scepticism about mainstream economics I might agree with you in a facile way but the onus is on you I am afraid. Did you hope for an ideological agreement here?<br /><br />You point to 'articles' of mine to substantiate your claim about the 'social sciences' which honours me in a way (who would have thought that my publications could serve as a proxy for the state of social science!). But these are blog posts (or did you really mean you read my past four journal articles and your comment was about them?)<br /><br />With regard to the difference between economists and physicists you suggest the latter would 'settle their dispute by an elegant experiment...one day'. So there is hope for this tribe, why not for others?<br /><br />Do you think current economic debates are led by Marxist economists fighting the Neo-liberals? Or was it Keynesians...?<br /><br />Not sure I understand your point about underdetermination and maybe I have not expressed myself clearly when pointing to the discussion about this concept. The underdetermination thesis holds that no theory is completely determined by empirical evidence, and that there is always more than one theory that is able to explain a given dataset.@ReinerGrundmannhttps://www.blogger.com/profile/12759452975366986236noreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-89300911427485996752013-11-07T21:54:37.219+01:002013-11-07T21:54:37.219+01:00Reiner,
The majority of scholary work in economic...Reiner,<br /><br />The majority of scholary work in economics seems to be based on, or accept, a particular school of economic thought. There are many, and many of them seem to employ fundamental normative values and/or beliefs that have no epistemic base. Neo-liberals and Marxists won't settle their dispute by an elegant experiment, as string-theorists and proponents of loop quantum gravity might, one day.<br /><br />As for other social sciences, just look at your own publication list :). While your latest article seems to be an example of "trying to keep the values out", the preceding four could not have been written without axiomatically adopting certain values and beliefs and a lot of it actually consists of stating such beliefs. That is not bad in any way, but it is the privilege of the social sciences.<br /><br />['underdetermination']<br />I guess the answer to that one has been provided recently by Gregor Betz?<br /> <br /><br /> hvwnoreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-28084849471113417542013-11-07T17:16:12.130+01:002013-11-07T17:16:12.130+01:00hvw
'Economics seem to be always based on an ...hvw<br /><br />'Economics seem to be always based on an ideological fundament and that seems to be true for most of the other social sciences too. That explains how they arrive at the same time at completely contradictory predictions based on the same data.'<br /><br />Do you have evidence for singling out the social sciences?<br />Recently Hans von Storch posted on the concept of 'underdetermination' which is a concept that applies to all sciences. @ReinerGrundmannhttps://www.blogger.com/profile/12759452975366986236noreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-85722191109876253282013-11-07T10:07:25.875+01:002013-11-07T10:07:25.875+01:00Eduardo, #21
I do not really understand your first...Eduardo, #21<br /><i>I do not really understand your first point, but maybe we are talking past each other. ...</i><br /><br />Yes, I think we are. Maybe because you are a scientific realist and I am leaning towards instrumentalism and have a hard time to identify and distinguish these "fundamental laws". However, examples where prediction based on "phenomenological laws" is superior are abundant. Most of hydrology and its successful predictions are based on Darcy's law, a posterchild for a "phenomenological law". How much "fundamental" law goes into tomorrow's weather forecast (given that the primitive equations do not count as "fundamental")?<br /><br /><i>My impression is that policy makers do not pay much attention to scientific predictions. They act only if the scientific argumetation help them win elections</i><br /><br />Given the poor performance of politics to act on results from climate science, I can very much understand your frustration, which must be the reason for this nihilistic comment. Yet, you can't deny that fortunately we live in a society where many political decisions are strongly influenced by rational considerations based on scientific results. Maybe the reason for this is that a politician who obviously (to the electorate) acts irrationally will loose elections. That'd be an argument to push outreach activities in climate science though.<br /><br />Your example of "economic predictions" appears misplaced to me, because these "predictions" are of a fundamental different sort than even the most "wobbly" predictions in the natural sciences. Economics seem to be always based on an ideological fundament and that seems to be true for most of the other social sciences too. That explains how they arrive at the same time at completely contradictory predictions based on the same data. [This is a topic fitting the next thread, maybe answers should be placed there] In most economics the underlying ideology is clear. However, when it comes to work related to climate change, the climate-economists and -sociologists frequently "forget" to identify their normative assumptions, which makes them often appear so ridiculously hypocritical when, at the same time, they complain about the IPCC not reporting in a "value-free" manner.hvwnoreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-84299920053528542772013-11-03T17:55:57.486+01:002013-11-03T17:55:57.486+01:00Reiner,
I have not read enough of Cartwright'...Reiner,<br /><br />I have not read enough of Cartwright's writing to tell how supportive or contrary I would consider my views to be. What I tried to do is to describe thoughts of a (former) theoretical physicist who likes to ponder also the philosophy of science.<br /><br />My views may often be at least partially supportive as my experience is that many issues can be described correctly in many different ways that appear contradictory in a superficial consideration. That's true within the "exact science" of physics to much larger degree than most realize. In the case of well understood physics all alternatives must, however, lead ultimately to the same results for concrete well defined cases.<br />Pekka Pirilähttp://pirila.fi/energynoreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-84811272704573264742013-11-03T13:55:57.412+01:002013-11-03T13:55:57.412+01:00Pekka
thanks for your elaborate comments of examp...Pekka<br /><br />thanks for your elaborate comments of examples which I take to be rather supportive of Cartwright's position.<br /><br />You express, however, a belief that such problems in science will best be solved by scientists, not philosophers. I think no one doubts this. The question is if philosophy can provide a conceptual toolkit to understand these problems.@ReinerGrundmannhttps://www.blogger.com/profile/12759452975366986236noreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-12157021394390491582013-11-01T22:56:29.525+01:002013-11-01T22:56:29.525+01:00The involvement of the social sciences and humanit...The involvement of the social sciences and humanities in support of CAGW provoked me to look at the extent of the scientific method and integrity in those disciplines. To my horror, CAGW looks good in comparison. <br /><br />Perhaps CAGW and similar memes flourish in the generations of social science and humanities students turned out by the universities. For the skeptics, CAGW may just be a short term skirmish with the major campaign being against academic disciplines not strongly embracing the scientific method.<br /><br />Perhaps the scientific method is the major defence against all too common human failings, but that is probably a question for the social sciences and humanities.Peter Bobroffhttps://www.blogger.com/profile/07917114710485190305noreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-67682596958622345762013-10-31T16:39:35.141+01:002013-10-31T16:39:35.141+01:00@Eduardo
Thank you very much for your reply. Now ...@Eduardo<br /><br />Thank you very much for your reply. Now it is more clear what you try to say.<br /><br />I wonder if Cartwright is so clear in what SHE tries to say. I like to read Karl Popper and I had to read Kant. But what Richard Feynman says is what I can live with. Imho Cartwright has nothing new to say.<br /><br />Nobody really believes anymore in natures laws the way she pretends they/we do, imo.<br /><br />If YOU are so straightforward in your thinking, why would you need philosophy? The complexity and inaccuracies are part of the process of understanding, not an obstacle.<br /><br />Kind regards<br /><br />YephAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-91385509008969052562013-10-31T13:31:25.464+01:002013-10-31T13:31:25.464+01:00an interesting post over at Judit Curry:
http://ju...an interesting post over at Judit Curry:<br />http://judithcurry.com/2013/10/30/implications-for-climate-models-of-their-disagreement-with-observations/<br /><br />She quotes Briggs:<br /><br />"if the predictions derived from a theory are probabilistic then the theory can never be falsified. This is so even if the predictions have very, very small probabilities. If the prediction (given the theory) is that X will only happen with probability &epsilon (for those less mathematically inclined, ε is as small as you like but always > 0);, and X happens, then the theory isnot falsified." <br /><br />So we have to settle on a minimum value of epsilon above which we still believe the model?<br /><br />Another interesting quotation from this post:<br /><br />“In then addressing the question of how GCMs have come to occupy their dominant position, we argue that the development of global climate change science and global environmental ‘management’ frameworks occurs concurrently and in a mutually supportive fashion, so uniting GCMs and environmental policy developments in certain industrialised nations and international organisations. The more basic questions about what kinds of commitments to theories of knowledge underpin different models of ‘complexity’ as a normative principle of ‘good science’ are concealed in this mutual reinforcement. Additionally, a rather technocratic policy orientation to climate change may be supported by such science, even though it involves political choices which deserve to be more widely debated.”<br /><br />I think this is all spot-on what is discussed here by hvw and Eduardo.Karl Kuhnnoreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-20274777247148281792013-10-31T12:35:25.687+01:002013-10-31T12:35:25.687+01:00hvw,
I do not really understand your first point,...hvw,<br /><br />I do not really understand your first point, but maybe we are talking past each other. For me, if a law is just phenomenological (my understanding here is an equation that fits the available observations) , its predictive power is very much in doubt. It may be right outside its rage of 'interpolation' or maybe not. There is not solid ground to claim it has predictive power. This is different for a fundamental law, as Newton probably understood.<br /><br />Concerning your second points, we have other examples in which predictions are clearly very bad, and yet policy is based on such predictions, usually with huge sums involved. Economic predictions are very wobbly; many of the mechanism that drive economics are not well understood. For instance, it is not certain how Quantitative Easing acts on aggregate demand, and yet the FED pumps huge amounts of money. Angela Merkel navigates 'auf Sicht'. My impression is that policy makers do not pay much attention to scientific predictions. They act only if the scientific argumetation help them win electionseduardohttps://www.blogger.com/profile/17725131974182980651noreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-55106360525235158482013-10-30T20:24:32.900+01:002013-10-30T20:24:32.900+01:00Eduardo,
Cartwright, as I see it, refers to other,...Eduardo,<br /><i>Cartwright, as I see it, refers to other, more fundamental, issue (next comment). Hvw may see it differently, though.</i><br /><br />No, I see this pretty much the same way. The only disagreement with you seems that I do not share your interpretation of Cartwright that predictive power stems (only?) from the "fundamental" laws.<br /><br />I think this discussion is a distraction from the more relevant, yet related questions, which are important for the climate change debate. Other commenters have mentioned a number of environmental models as examples. I would think it more interesting to ask 1) What makes us trust (or distrust) predictions of environmental systems, and 2) How is the level of trust related to our willingness to act on those predictions?<br /><br />Weather prediction stands on epistemologically much more solid feet than climate prediction, because we know its performance very well, in probabilistic terms. And we act on severe weather warnings. An epidemiological model about a newly discovered virus might be as shaky as climate prediction, yet we likely act on it. What is the difference? Isn't there room for the social sciences to explain something? Has it to do with the personal responsibility of decision makers if they ignored the epidemiologist’s warnings? Maybe we overestimate the relevance of more reliable predictions for political decisions (I guess that is what von Storch and Krauss say)? Should that then not be reflected in research priorities? If a researcher had the possibility to bracket climate sensitivity more closely, say from a range of 3 to 1 degree C. she would definitively go for it (probably does it right now) and count that as enormous success. But would that scientific breakthrough be reflected in policy? Would that change anything at all?<br />hvwnoreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-14919540866723002632013-10-30T15:25:09.021+01:002013-10-30T15:25:09.021+01:00I try to illustrate my interpretation of Cartwrig...I try to illustrate my interpretation of Cartwright. Newton's law of gravitation is that two point masses attract each other with a force proportional to their mass and inversely proportional to the squared distance. We encounter here already two problems: one is that the law is formulated using 'objects' that clearly do no exist (nobody has seen a point mass; what is a force? ). Thus, to achieve a prediction that can be compared to real observations, the law has to be augmented with further 'interpretations' and attached strings. For instance, that the forces exerted by the infinite number of 'point masses' that form a whole solid body can be added. In other words that the attractive force with which of a minuscule portion of the Earth at the equator attracts a minuscule portion of the Moon at its pole, can be added to all other minuscule forces to calculate the total attractive force. <br />One can see that a physical law is a law with a lot of strings attached to it. It is formulated in terms of abstract concepts that do not exist and have to be some how translated (mapped) to the real world. <br /><br />The second, more fundamental problem, is the following: where does this law come from ? Obviously, it comes from Newton's brain. How can we tell that this law 'exist' in nature and is universal, and not simply a formula that Newton concocted and that happened to match the phenomena he observed at his time ? Newton though his law was fundamental and universal. we know now that it is not the case - as there are observations that do not match his predictions, mostly at large cosmological scales or in high precision measurements close to the Earth. For that we need the theory of general relativity - which is formulated din totally different terms and using totally different concepts. Now imagine that Einstein and Newton had lived in the same epoch and that both had put forward their theory at the same time. The available observations at that time could not tell which theory was correct, and so we would think that both were just concocted formulae to describe the observe phenomena, but being so different, at least one could not be fundamental. <br />You can ask your self the following question. When we eventually meet inhabitants of other galaxies, will they have the same 'fundamental' theories as we have ? <br /><br />Cartwright argued that our theories are just formulae that fit the observations, but they are no way fundamental - other civilizations will have other formulae. They are useful, because they allow us to make predictions .. until they fail.eduardohttps://www.blogger.com/profile/17725131974182980651noreply@blogger.comtag:blogger.com,1999:blog-8216971263350849959.post-82538792188002896562013-10-30T14:52:27.574+01:002013-10-30T14:52:27.574+01:00@ Yelph,
Sorry for the lack of clarity. There are...@ Yelph,<br /><br />Sorry for the lack of clarity. There are two different levels of 'complexity'. Let me give you two examples:<br /><br />In one example we know the governing laws, but the solution of these laws is mathematically too difficult. Three bodies, for instance the sun, the Earth and the Moon, attract one another via the well known Newton law of gravitation. The exact prediction of their trajectories is impossible because, although the laws are known, they are in this case mathematically intractable. Thus, further assumptions that render the problem easier are needed. In this case, that one of the bodies is much larger than the other two. This further assumption allows to determine the trajectories, but then this prediction is only approximate. <br /><br />The vast majority of real problems in physics are of this kind. The laws are known, but intractable. The confusion may arise because at school we only learn of those problems that are solvable (the harmonic oscillator, two bodies under gravitation, etc). But this short list very much contains all that can be solved exactly (= an exact prediction is possible)<br /><br />A second example is when the physical problem itself is complex that the laws are not known. For instance, the flow of fluids. In this case, we only know approximate laws, which in turn are also difficult to solve in general and require further simplifying assumptions. However, you have to consider that, even with these uncertainties, we can build planes and ships. The key aspect here is , however, that in these cases we can perform experiments, test our assumptions, correct if necessary, etc. In climate science this is, obviously, much more difficult. <br /><br />Additionally, you have to be aware that all 'computer' solutions are intrinsic approximate. s illustration, computers do not know what the numbers pi or square root of 2 are. these are irrational numbers that require infinite digital representations (pi=3.1415....etc). A computer can hold only a truncated, finite, representation of pi, and thus it is only approximate. <br /><br />This is what I was trying to say. Physics and even more so computerized physics is an approximate science. Cartwright, as I see it, refers to other, more fundamental, issue (next comment). Hvw may see it differently, though.eduardohttps://www.blogger.com/profile/17725131974182980651noreply@blogger.com