Precautionary measures

Nassim Taleb, who is the originator of the Black Swan theory, is – amongst others – the author of a short essay called Climate models and precautionary measures. The basic premise seems to be that because this is a global issue,

we should ask “what would the correct policy be if we had no reliable models?”

Essentially

We have only one planet. This fact radically constrains the kinds of risks that are appropriate to take at a large scale. Even a risk with a very low probability becomes unacceptable when it affects all of us – there is no reversing mistakes of that magnitude.

In a basic sense, I think this is correct. It might seem trite and cliche, but we do have only one planet. This is the only planet on which we can currently, and for the foreseeable future, survive. In fact, for all we know, the only life in the universe may exist in a thin shell around a small rocky planet, orbiting a yellow-ish star, in the outer parts of a galaxy we call the Milky Way.

Although the above quote does mention irreversibility, I think you can even make a somewhat stronger argument. It’s not only that there would be no reversing some low-probability, high-risk event, it’s that climate change itself is probably irreversible on relevant timescales. Our current understanding is that a reasonable fraction of our emissions will stay in the atmosphere for millenia. If you can’t imagine anything between catastrophe and nothing to worry about, you’re not thinking.

Also, the suggestion that we should consider what we’d do if we did not have climate models is an interesting idea. If we didn’t have climate models, we’d still have an understanding that we could change our climate by an amount comparable to the change between a glacial and an inter-glacial, and do so on a timescale considerably faster. Even without climate models we may well conclude that pushing a complex system that hard and that fast, may lead to some rather unexpected, and potentially very negative (for us), outcomes. Maybe we shouldn’t do so?

As you can probably imagine, Judith Curry doesn’t really agree with Nassim Taleb and co-authors’ conclusions, even though she likes his writing on risk. This appears to be because Judith doesn’t see climate change as a ‘ruin’ problem. If anything, she seems to suggest that AGW may be delaying a future ice age. However, this creates an interesting issue. The essay points out that

The scale of the effect must be demonstrated to be large enough to have impact. Once this is shown, and it has been, the burden of proof of absence of harm is on those who would deny it.

I think there is indeed evidence that there is a possibility of severe and negative impacts. It’s also the case that we now have options, and do have viable alternatives to fossil fuels (on that note, Kevin Anderson’s recent post is quite interesting). Hence, if people are going to claim that there is no chance of ‘ruin’, and that the solutions could do more damage to our societies than climate change itself, the onus should be on them to show this, not to simply assert it.

I’ll finish with a comment. The problem with the precautionary principle is that it’s simply a blunt tool; it essentially says that we should avoid something without specifically saying how. On the other hand, we regularly hear that we should stop arguing about the science and start discussing solutions. I agree with this and it seems, broadly at least, consistent with what this essay is saying; it’s clear that there is a risk of potentially severe impacts, therefore it’s time to accept this and to start focussing on how best to minimise the chance of these impacts materialising.

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72 Responses to Precautionary measures

  1. the suggestion that we should consider what we’d do if we did not have climate models is an interesting idea.

    Without climate models the uncertainty would be larger, the risks of climate change larger and the arguments for fast reductions in greenhouse gases even stronger.

    One irony is that climate models reduce the uncertainty by improving the scientific understanding of the climate system. Without climate models we would still know that the Earth warms when we increase greenhouse gasses. The greenhouse effect can be directly measured by looking at the infra red radiation from the sky. When you make that bigger, it gets warmer. When you put on a second sweater, you get warmer. We know it gets warmer from simple radiative transfer computations. We know that CO2 influences temperature by studying past climates.

    The climate models have about the same climate sensitivity as those simple radiative transfer computations and the estimates from past climates. It could have been different because the climate is more complicated than the simple radiative transfer computation. It could have been different because the increase in greenhouse gasses goes so fast this time. That all those climate sensitivity estimates fit together reduces the uncertainty, especially the uncertainty from the unknown unknowns.

    Without climate models it would be very hard to estimate all the other changes in the climate system. The increases in precipitation and especially increases in severe precipitation, in floods, in droughts, in the circulation patterns, how fast sea level rise will go. Without climate models these risks would be much higher, without climate models we would have to adapt to a much wider range of changes in weather and climate. This would make adaptation a lot more intrusive and expensive.

    Without climate models and climate research in general the risks of changing our climate would be larger. We would need to be more careful, the case for reductions of greenhouse gas emissions would have been stronger.

    Especially for mitigation sceptics advocating adaptation-only policies, climate research should be important. Adaptation needs high-quality local information. For a 1000-year event such as the downpour in South Carolina earlier this year or the record precipitation this week in the UK, we may have to life with the damages. If this will happen much more often under climate change, we will have to change our infrastructure. If we do not know what is coming, we will have to prepare for everything. That is expensive. Reductions in this uncertainty save money by reducing unnecessary adaptation measures and by reducing damages due to effective adaptation.

    People who are against mitigation policies should be cheering for climate research, rather than try to defund it or harass scientists for their politically inconvenient message. Let’s be generous and assume that they do not know what they are doing.

    More in my post: Fans of Judith Curry: the uncertainty monster is not your friend.

  2. dana1981 says:

    Yeah the risk management argument is really a no-brainer. In my talks I also point out that while the consequences of inaction (or insufficient action) are in many cases irreversible, the mitigation policies are entirely reversible. For example, if we decide the climate policy we’ve implemented is overly strict/expensive in cutting emissions, we can loosen or throw out the policy. On the other hand, if it turns out we haven’t done enough and ice sheets collapse into the ocean, permafrost melts, there’s widespread species extinctions, etc., there’s no going back.

    The only justification for inaction would be if we’re certain that very bad consequences won’t occur. Some deniers believe they have that certainty, but that’s only because they deny the vast body of contradictory evidence. Curry actually argues the opposite. Her argument is that ‘hey, maybe it won’t be so bad, we just don’t know,’ but that just shows she doesn’t understand risk management. Her only potentially valid argument is this:

    the current focus on CO2 emissions reductions risks having a massively expensive global solution that is more damaging to societies than the problem of climate change.

    But that’s a bad argument because there are potential policies that wouldn’t be ‘massively expensive’ (e.g. revenue neutral carbon tax), and again, that’s something we have complete control over, unlike the consequences of unmitigated climate change. Plus there’s a 95% consensus among economists that cutting emissions is the way to go.

    Curry so badly misunderstands basic risk management that we made a cartoon about it.

    http://www.skepticalscience.com/graphics.php?g=106

  3. Bård says:

    I think I agree with the gist of this, but it seems to be the case that Taleb’s writings on “fat tails” should be taken with generous doses of scepticism.
    See this blog: http://www.inexactchange.org/

    I guess there could be a problem the other way of falling into a kind of “ecological panic” as Timothy Snyder talks about, but IMO the the increased prosperity won with with cheap fossil fuels are more than offset by excesses and inequality(injustice). Resource rich areas aren’t always a blessing to it’s inhabitants).

  4. Victor,
    I should have linked to your post. I will remember next time 🙂

    Dana,
    Yes, you make a good point about being able to reverse the policies if we decide they’re too severe. So, globally the policy impacts are reversible, while the climate impacts probably are not.

  5. Bard,
    We should take everything with a generous does of skepticism 🙂 In this context, though, I think the evidence for fat tails is indeed weak in the sense that, for example, climate sensitivity probably doesn’t have a fat tail. However, a fat tail isn’t necessary for the possibility of severe risks to be sufficient for us to consider doing something to avoid that outcome.

  6. Following the recent severe flooding in the north of England, the Environment Minister highlighted the need for better modelling …

    Truss highlighted the unprecedented nature of the rainfall that has caused the flooding in Cumbria and Lancashire. She said: “Climate change is factored into all the modelling work the Environment Agency does but clearly in the light of this extreme weather we are going to have a look at that modelling and make sure it’s fit for purpose for future decisions.”

    http://www.theguardian.com/environment/2015/dec/07/labour-attacks-fall-flood-management-spending-storm-desmond

    No, not GCM type modelling, but another class of models … rain falling on fields, collecting, and flowing … and flooding.

    Models, damn them. They get everywhere. Well they do if one is a responsible member of … the Government, local resilience network, or anyone position needing to make informed decisions on investment in responding to events.

    The snarky comments about computer models is so far off the mark one wonders what world these commentators live in. Who exactly is it, do they imagine, who keep the lights on and how do they manage it?

    We will also need models for our evolving energy networks. We can today remotely turn off your air source heat pump at scale to help control demand and make renewables viable by smoothing demand and supply. More models. More IT.

    What I think is so crucial about the models is the ability to (a) explore ‘what if’ scenarios and (b) in real time (when appropriate e.g. for floods or electricity networks) to monitor on-going actuality.

    Something what I wrote earlier in Praise of Computer Models …

    http://essaysconcerning.com/2015/05/24/in-praise-of-computer-models/

  7. Having read all of NNTaleb’s books, I am completely behind his ideas on risk. I’ve said this before and I’ll say it again: in business you should never take a gamble that puts your company in existential threat. It’s a rule I followed throughout my career, and a business I was involved with never failed while I had influence. For me it follows through to all areas of life.

    NNTaleb made a small fortune during various financial crashes when he worked for banks as a ‘quant’. OK, he’s a big-head; but I’d take his view on this subject over that of any ‘rational optimist’ you’d care to name.

  8. Willard says:

    > As you can probably imagine, Judith Curry doesn’t really agree with Nassim Taleb and co-authors’ conclusions.

    Yet Nassim’s black swans was all the rage at Judy’s in 2011:

    The framework associated with setting a CO2 stabilization target focuses research and analysis on using expert judgment to identify a most likely value of sensitivity/ warming and narrowing the range of expected values, rather than fully exploring the uncertainty and the possibility for black swans (Taleb 2007) and dragon kings (Sornette 2009). The concept of imaginable surprise was discussed in the Moss-Schneider uncertainty guidance documentation, but consideration of such possibilities seems largely to have been ignored by the AR4 report. A key issue is to identify potential black swans in natural climate variation under no human influence, over time scales of one to two centuries.

    http://judithcurry.com/2011/05/02/anticipating-the-climate-black-swan/

    Almost five years ago, “to identify potential black swans in natural climate variation under no human influence, over time scales of one to two centuries” was a key issue.

  9. Bård says:

    ATTP: Hence, if people are going to claim that there is no chance of ‘ruin’, and that the solutions could do more damage to our societies than climate change itself, the onus should be on them to show this, not to simply assert it.
    Let’s take the Green Revolution. It could conceivably(without luxury of hindsight) have gone horribly wrong. We could have found other (probably more radical) ways to deal with the problem we were facing. If something is wildly improbable, like ruining the planet, why should the onus be on those saying that that scenario isn’t worth thinking too much about? It’s like proving a negative, or something, am I mistaken? You yourself said that climate sensitivity probably didn’t have a fat tail. Even this being the case, this is of course not to say that we shouldn’t worry about the 2-6C scenarios which are indeed conceivable and horrible enough.

    I could maybe conceive that if GDP is your primary concern, solving the AGW problem in at least some scenarios could be worse (to GDP) than a more “business as usual” approach.

  10. Bard,

    If something is wildly improbable, like ruining the planet, why should the onus be on those saying that that scenario isn’t worth thinking too much about?

    Well, because there’s a difference between it being improbable, but possible, and it being essentially impossible. Bear in mind that the risk doesn’t just depend on climate sensitivity, but also on what emission (and hence concentration) pathway we follow. Remember that even RCP6 has more than a 1% chance of more than 4oC warming by 2100.

  11. AnotherJames says:

    Bard,
    Your graph does not make sense. Percentage of GDP? Which countries? Suppose it is the USA, then even a 99th percentile cyclone would not affect the entire population. If it were Bangladesh it might. Most of those postulated effects are local, but climate change is not. That 1% for 1 degree is the estimated effect on the GLOBAL economy. Furthermore it is cumulative and nonlinear – more damage the next year, and a 3 degree rise is not just 3 times a one degree rise.

  12. The chart is from here, but the data is from this this paper, which I think paints a slightly different picture to what you might get from the chart alone.

  13. In fact, the abstract of the paper says:

    The data reject hypotheses that disasters stimulate growth or that short-run losses disappear following migrations or transfers of wealth. Instead, we find robust evidence that national incomes decline, relative to their pre-disaster trend, and do not recover within twenty years. Both rich and poor countries exhibit this response, with losses magnified in countries with less historical cyclone experience. Income losses arise from a small but persistent suppression of annual growth rates spread across the fifteen years following disaster, generating large and significant cumulative effects:…….
    …..Linking these results to projections of future cyclone activity, we estimate that under conservative discounting assumptions the present discounted cost of “business as usual” climate change is roughly $9.7 trillion larger than previously thought.

  14. Joshua says:

    There is a directly inverse relationship between Taleb’s focus on climate change specifically, and Judith’s criticism of his thinking. ‘Prolly just a coincidence..

  15. Taleb’s premise is mistaken: the existential risk of losing the ony planet we have to AGW remains zero .

    The policy argument is about the acceptable limits of biogeogrphic change on a planet whose surface temperature spans an equator to pole range of about one degree C per two degrees of latitude , at rates approximating a few degrees of latitude per century.

  16. Russell,

    the existential risk of losing the ony planet we have to AGW remains zero .

    Of course, but this isn’t really about existence of the species.

  17. Andrew dodds says:

    Russell

    There is, though, a non zero chance of losing all the major ice sheets, which is commensurate with near total economic loss.

    In any case, it still remains to be shown that – given sufficient research investment and capital investment at current interest rates – fossil fuels are the cheapest source of energy. If that is not true, then fixing global warming becomes GDP positive and this entire thread moot.

  18. Andrew,

    In any case, it still remains to be shown that – given sufficient research investment and capital investment at current interest rates – fossil fuels are the cheapest source of energy.

    Indeed. It’s clear that we’re not paying the full cost of using fossil fuels. If we were to add a suitable carbon tax (based on the potential future cost discounted to today) it’s probable that fossil fuels wouldn’t be the cheapest in all circumstances. It would probably also incentivise the development of alternatives, bring their cost down even further.

    That’s kind of what I was trying to get at in the post: given that we now have alternatives, or potential alternatives, the onus should be on those who think that we should not yet do anything to show that the actual risk of severe outcomes is sufficiently small, not on those who think we should do something to further clarify what risks we actually face.

    However, I do think it is probably that a carbon tax alone would be insufficient to ensure that we have some chance of meeting the targets (assuming that we think we should do so). As Kevin Anderson points out in this post we will need to decarbonise quite rapidly if we do want some chance of meeting those targets (or keeping warming below the targets). Hence it seems quite probable that if we’re serious we’ll need to think about whether or not we really can sustain the kind of lifestyles that those in the developed world have come to expect. I suspect it is this issue that is a major factor in why we seem reluctant to really address this.

  19. BBD says:

    ATTP

    I suspect it is this issue that is a major factor in why we seem reluctant to really address this.

    We can’t even really talk about it. Just not done, old chap.

    Great KA article btw. Thanks for the link.

  20. Certainly strongly discouraged, mainly through accusations of it being an attempt to impose a Socialist World government (although, this may now be changing to Facist authoritarianism – it all gets rather confusing after a while).

  21. Willard says:

    > the existential risk of losing the ony planet we have to AGW remains zero

    Quite true:

    I don’t think Nassim requires a strict reading of “losing the only planet we have.”

  22. Andrew dodds says:

    Yes, we’ll crush the human spirit under the jackboot of ‘slightly higher energy prices, for a while, after which we’ll have a more secure supply, and stop sending billions of eurodollarpounds to people who have vowed to destroy our decadent civilisation (Ed: are we doing this right?)’

  23. Willard says:

    If only we could control biogeographic change the way we control ClimateBall exchanges.

    Oh, wait.

  24. The potential existential loss is to the world as we know it, or perhaps more like, the world as we’d like it to be.

  25. Willard says:

    If only we could control biogeographic change the way Nigel can control FOI laws.

    Oh, wait:

  26. Willard says:

    To return to Nassim, let’s look at these two questions:

    If something is wildly improbable, like ruining the planet, why should the onus be on those saying that that scenario isn’t worth thinking too much about? It’s like proving a negative, or something, am I mistaken?

    The first is easy to answer: because it’s basic risk management. As long as you don’t have everything to lose, you try to keep your skin in the game. In Nassim’s own wording:

    There is no make after the lose. Hence an asymmetry; losses and gains do not offset each other in some conditions; there is no netting of costs versus benefits. And what is the condition? The mere probability of hitting the insolvency point which we can call by the respectable mathematical name “absorbing barrier” but is commonly known in no less scholarly circles of gambling and speculation as “uncle point” or “throwing in the towel”. If your country is a former member of the Ottoman Empire, odds you will call this uncle point an “aman”, which is an expression thought by non-Turks to be usually uttered by Turks upon failed Turkish enterprises. Warren Buffet –as well as literally anyone who survived in the risk taking business –has a version of it: “In order to succeed, you must first survive.” My own version has been: “never cross a river if it is on average four feet deep.”

    http://fooledbyrandomness.com/rationality.pdf

    While Nassim’s Twitter feed makes me cringe both by his self-promoting grandiosity and his bland, repetitive aspersions, one does not simply counter his ideas by responding in kind, however more politely that could be, like Merberg did in the cited post above. Principia Mathematica may not be the best example of a math book, BTW.

    So the basic idea is that the main priority for an agent should be survival. The only strategy that matters for that agent is one that gives the best prospects of survival. (This answer the second point about proving a negative: it’s more about prudence than having to prove anything.) The “his” can refer to a specie if we want to go beyond pure individual selfishness and cover collective action.

    Perhaps the tension between collective action and individual choice is a soft spot in Nassim’s argument. At the very least, this is where all the libertarian exploits concentrate. We can suspect that reactionary claptraps come from there too:

    I’ve told Nassim that he may be reinventing linear logic. He did not respond.

  27. The Very Reverend Jebediah Hypotenuse says:

    Seitz:

    Taleb’s premise is mistaken: the existential risk of losing the ony planet we have to AGW remains zero .

    On the contrary – I think the premise is that the existential risk of the planet losing the only “we” we have to AGW is non-zero.

    As that great philosopher, George Carlin, put it:

    The planet isn’t going anywhere. WE are!
    We’re going away. Pack your shit, folks. We’re going away. And we won’t leave much of a trace, either. Maybe a little Styrofoam … The planet’ll be here and we’ll be long gone. Just another failed mutation. Just another closed-end biological mistake. An evolutionary cul-de-sac. The planet’ll shake us off like a bad case of fleas.

    Humans are merely the Earth’s way of adding a layer of plastics and other carbon-rich compounds to the sediments.

  28. Eli Rabett says:

    Taleb’s premise is mistaken: the existential risk of losing the ony planet we have to AGW remains zero .

    Think of climate change as the tamper for thermonuclear war and you get a different answer.

  29. Bård says:

    Willard,

    The first is easy to answer: because it’s basic risk management. As long as you don’t have everything to lose, you try to keep your skin in the game.

    What do you mean by everything to lose? I thought that was a strange framing, setting one loss against another. It seems to me that by the logic of that kind of thinking no one should engage in travelling by car, eating fast-food, moving to Australia (too many snakes) etc. Those things would associate, after all, with practically infinite risks (for premature death), and let’s say, hypothetically, one had the hindsight after being killed, by any of those things; wouldn’t one choose to substitute a “wrong choice” a million times over!? But we don’t think like that in real life, because it’s actually quite absurd. After the obvious measures to minimize risks one would be left to chase ever smaller decreases in risk by ever larger efforts.

    I guess this could/will be taken as an ad-hominem, but most of us are non-experts in the various fields and need some heuristics, like credentials etc. I thought Merberg did a good job of exposing how little math-clout he carries.

    Principia Mathematica may not be the best example of a math book, BTW.

    Excuse me, you don’t think the contributions of Newton to the field of calculus was significant?
    (obviously it’s not the math book of choice to most of us these days, but that’s missing the context of his statement.)
    Taleb is trying to set out a new course for his field and a new thinking about these things. That should have been reflected by high-quality/exact reasoning in his book. Instead it’s mathiness, as Merberg describes. I haven’t read that book, but the little exposure/facts I have suggests he’s right in his judgement/views.

    So the basic idea is that the main priority for an agent should be survival. The only strategy that matters for that agent is one that gives the best prospects of survival.

    I don’t think I agree with this reasoning, partly as outlined above. It’s the manner of survival as well as just surviving. You wouldn’t expend huge energy to avoid the very off-chance possibility of extinction if that put you in very serious discomfort. So, I think, most agree we shouldn’t do all we can to avoid climate change by all means necessary, even though it may stand the best chance of seriously putting our future survival at risk. There will probably always be trade-offs. But I agree, as has been said, that this is mostly a moot point in this discussion (since we’re very much on one extreme in regards to emission intensity etc.), and our current trajectories will be bad for all kinds of premises and consequences. My example with GDP etc. was mostly just playing devil’s advocate.

  30. Bard,

    What do you mean by everything to lose? I thought that was a strange framing, setting one loss against another. It seems to me that by the logic of that kind of thinking no one should engage in travelling by car, eating fast-food, moving to Australia (too many snakes) etc. Those things would associate, after all, with practically infinite risks (for premature death),

    Except you minimise those risks. The risk of dying doing everyday activities is quite low because we’ve put effort into making it unlikely. Cars are now very safe, as are planes, etc. The point about climate change is that the risk essentially depends on how much we emit. We can minimise by emitting less. You keep suggesting that the risk is very low, but this isn’t strictly true. We can certainly burn enough fossil fuels to make it quite likely that the damage will be extremely severe. Maybe we should accept this and work out how to avoid doing so, just as we’ve done with many other activities that carry risk.

    It’s the manner of survival as well as just surviving.

    Except you can apply exactly the same argument to AGW itself. If all that we were worried about is whether or not we could survive, AGW doesn’t present much of a risk. The risk is really to how we live, not whether or not we’ll live.

  31. I like to think of the risk management problem in more everyday terms. No one thinks their house will burn down. But they are willing to spend a meaningful amount of money to address that risk, both in preventative measures and in insuring against the economic consequences of such a loss. It is, for any particular homeowner, and improbable loss, but it isn’t completely implausible.

    How is climate change different. If you spend a % of your household income insuring against things that you don’t think will happen, why wouldn’t a similar expenditure (say, 1% of GDP) make sense to prevent AGW?

  32. Pete best says:

    I think that Kevin Andersen has summed it up nicely. Although the Paris agreement is seemingly a good one, its not binding and getting from A to B is a unknown path down to each country to initiate and ind their way to a low carbon future. Personally I always thought it was down to the western nations asking people to change their lifestyles (although I know its a last resort when all else fails which it looks like it will) but we ask for this sacrifice last of all, first off is the electricity grid, then once that is done with we look at transport (cars first, then trucks and then planes and shipping last) and then at heating homes and businesses (or maybe that as well). Efficiency gains of course alway a bonus if people buy electric cars or hybrids but its slow going.

    To put it simply, I can see the optimism but 3-4C is more liekly and even then we wont be living as we do now without significant breakthroughs in technology.

  33. Kevin O'Neill says:

    Rick W writes:”If you spend a % of your household income insuring against things that you don’t think will happen, why wouldn’t a similar expenditure (say, 1% of GDP) make sense to prevent AGW?”

    Selfishness. It’s *your* house. If it burns down *you* suffer the loss. OTOH, it’s your grand or great-grand or great-great-grand children’s lifestyle that is possibly threatened. He who has the most toys wins. You’re asking me to forego some toys. Shame on you.

  34. Willard says:

    > What do you mean by everything to lose? I thought that was a strange framing, setting one loss against another.

    The point behind Nassim’s asymmetry is there’s no way you can set losing the skin you got against any reward the game has to offer. Losing a game just ain’t the same as losing yourself as a player.

    ***

    > Excuse me, you don’t think the contributions of Newton to the field of calculus was significant?

    Here’s the Principia Mathematica I had in mind:

    PM, as it is often abbreviated, was an attempt to describe a set of axioms and inference rules in symbolic logic from which all mathematical truths could in principle be proven. As such, this ambitious project is of great importance in the history of mathematics and philosophy, being one of the foremost products of the belief that such an undertaking may be achievable. However, in 1931, Gödel’s incompleteness theorem proved definitively that PM, and in fact any other attempt, could never achieve this lofty goal; that is, for any set of axioms and inference rules proposed to encapsulate mathematics, either the system must be inconsistent, or there must in fact be some truths of mathematics which could not be deduced from them.

    https://en.wikipedia.org/wiki/Principia_Mathematica

    Here’s where PM appears:

    Certainly, mathematics is a powerful tool for gaining insight into the natural world, but Taleb’s “Precautionary Principle” is no Principia Mathematica. It would be overly generous to call it a mathematical argument; “The Precautionary Principle” would be more accurately described as mathiness1. Rather than set out a rigorous argument, it uses things that feel like mathematics – graphs, equations, and technical definitions – to provide a veneer of rigor to an ideological agenda. Critically, it lacks the precision of language and the careful attention to assumptions that lie at the foundation of mathematical reasoning.

    http://www.inexactchange.org/blog/2015/07/24/the-mathiness-of-nassim-nicholas-taleb/

    Even if we accept that mathematical logic is a part of mathematics (arguing that point with mathematicians suffices to show it’s not trivial), I find it strange that The Logicist Manifesto is invoked in a joust of gentle browbeating.

    Merberg’s argument proceeds by proving a negative existential, BTW.

    ***

    > It seems to me that by the logic of that kind of thinking no one should engage in travelling by car, eating fast-food, moving to Australia (too many snakes) etc.

    It seems to me that slippery slopes are even worse than rhetorical questions, Bard. At least yours show why it matters to distinguish collective from individual action.

    I’m not sure anyone argued that eating fast-food once would kill you. You have a cite?

  35. Bård says:

    Except you can apply exactly the same argument to AGW itself. If all that we were worried about is whether or not we could survive, AGW doesn’t present much of a risk. The risk is really to how we live, not whether or not we’ll live.

    You have my agreement there in that. My point is that we should argue from the degrees, not the extremely unlikely off-chance scenarios (say 10C, total plant death, or something) and/or using the reasoning of “questionable” theorists. Of course we should take into consideration the possibility of unknown unkowns etc. as part of the precautionary principle, but those considerations cannot be completely unbounded.

  36. Willard says:

    > using the reasoning of “questionable” theorists.

    Don’t be shy, Bard. I’m sure you can call him Nassim.

  37. Bard,

    You have my agreement there in that. My point is that we should argue from the degrees, not the extremely unlikely off-chance scenarios (say 10C, total plant death, or something)

    Okay, but I don’t think anyone is arguing about unlikely off-chance scenarios specifically. However, you can assign a probability of crossing some threshold, given a certain future pathway. For example, RCP8.5 has a greater than 50% chance of more than 4oC by 2100. RCP6, on the other hand, is around 1%. Is 1% still too big? In many circumstances it still would be. Is it in this case?

    Essentially, though, this is the kind of thing one can do. Of course, one can also consider what it will take to achieve a target and include that in the analysis. How much should we spend to reduce the chance of some severe negative outcome to below some threshold? I’m not suggesting it’s easy, but we seem to still be in a situation where there are still some vocal people who are arguing that we really shouldn’t be doing anything.

  38. Willard says:

    Merberg’s usage of “mathiness” may deserve due diligence. The concept comes from this editorial:

    From my paper:

    The style that I am calling mathiness lets academic politics masquerade as science. Like mathematical theory, mathiness uses a mixture of words and symbols, but instead of making tight links, it leaves ample room for slippage between statements in natural versus formal language and between statements with theoretical as opposed to empirical content.

    http://paulromer.net/mathiness/

    This tidbit will relish GRRRROWTH fans:

    I focus on mathiness in growth models because growth is the field I know best, one that gave me a chance to observe closely the behavior I describe. For growth theorists, the choice between price-taking and monopolistic competition is our version of the conflict between the geocentric and heliocentric models. The point of this paper is not to explain, yet again, why I think that price-taking models are too restrictive. The larger point is that after more than two decades, the two sides have failed to make progress in resolving their disagreement, and hardly seem to care. Even worse, in defending their positions, the economists I cite in this paper are not living up to basic standards for what constitutes acceptable mathematical theory.

    Or how to be judge and party in one single step.

    I saved the lede for last:

    The point of the paper is that if we want economics to be a science, we have to recognize that it is not ok for macroeconomists to hole up in separate camps, one that supports its version of the geocentric model of the solar system and another that supports the heliocentric model. As scientists, we have to hold ourselves to a standard that requires us to reach a consensus about which model is right, and then to move on to other questions.

    Climate science might provide an existential proof that Romer’s desideratum rests more on scientism than on realistic expectations.

  39. Bård says:

    Willard,
    You’re of course right about PM. And although it’s not something many would read, it’s my impression it was very important in informing epistemiology of mathematics. A ground-breaking work, literally (even though the promised land never could be reached). Not esoteric or vague as I have perceived Taleb’s thinking to be. I don’t mind metaphysics being both those things, but one shouldn’t mislabel one’s work or it’s relevance.

    A lot of what you said I honestly didn’t understand, some of it I think I disagree with and other things I’m sure I disagree with. That’s ok with me.

  40. Bård says:

    Willard,
    regarding your last post. I agree that scientism can be “a terrible affliction” and seems to strike too many and inflict hubris amongst other ailments.

    The problem is that Taleb seems to have inflicted himself with maybe an opposite hubris, and appropriate quaint probabilistic theories that don’t hold water.

  41. Willard says:

    That’s OK with me too, Bard:

    I’ll write a little something on tu quoques this week-end, with this episode in mind.

    ***

    Here’s why I think Moberg relies on a negative existential proof:

    While the “Precautionary Principle” pays some lip service to mathematical precision, the bulk of the argument is made only on the colloquial level. Moreover, this fuzziness is essential to the argument. It serves to hide mathematical errors and dubious unstated assumptions.

    http://www.inexactchange.org/blog/2015/07/24/the-mathiness-of-nassim-nicholas-taleb/

    I could not find where Moberg discusses the mathematical errors and the dubious unstated assumptions. Par for the course in the GMO wars. The comment thread quickly degenerated, and Moberg had to revise his comment policy accordingly.

    In any case, Moberg not only argues that there’s no there there in Taleb’s argument, but that there can’t be a there there. That’s a special kind of negative exitential. It’s an argument from impossibility.

    For all its merits, the Principia Mathematica were not principles of decision making, and therefore are of another nature than Nassim’s work.

  42. Eli Rabett says:

    PM was a very high school thing in Eli;s circle, but it essentially fails because it cannot establish its assumptions.

  43. Even more High School, Eli:

    http://www.logicomix.com/en/index.html

    ***

    Some thoughts on Romer’s rant:

    Do the guys Romer calls out play a little faster and looser with definitions and rely more on hand-wavey arguments? Oh, I’m sure they do – but that’s because they’re famous old guys. Writing down hand-wavey stuff is a privilege afforded to famous old guys in every academic discipline I know of. In econ, it gets politely published in top journals, but all the hotshot young people just sort of shake their heads anyway, and the only net effect is to pad out the length of the journals. Are the guys Romer calls out more political than the average economist? Maybe.

    http://noahpinionblog.blogspot.com/2015/05/paul-romer-on-mathiness.html

    Some thoughts on Romer’s mathiness:

    I apparently completely misunderstood Paul Romer’s comment about “mathiness”. My original interpretation was that Romer was upset about obfuscating political assumptions that aren’t substantiated empirically by using fancy math. But then I started reading some of his appendix (pictured above). I was completely wrong.

    Paul Romer is upset about the technical rigor of those political assumptions. If the function Lucas and Moll (2014) used allowed you to exchange the order of the limits everything apparently would have been fine! Unfortunately, it turns out that Romer’s takedown of Lucas and Moll is the true mathiness.

    http://informationtransfereconomics.blogspot.com/2015/05/the-irony-of-paul-romers-mathiness.html

    Even harsher words:

    Superficially, Romer’s diatribe against mathiness may recall Nicolas Georgescu-Roegen’s principled objection to unhinged “arithmomorphism.” But any perceived resemblance is purely coincidental.

    http://econospeak.blogspot.com/2015/05/mathiness-and-growthiness.html

    Look, a leftist squirrel!

  44. Willard – If I’ve read Romer, correctly he’s upset at a group of economists mistaking the map for the territory Or perhaps more strongly, intentionally leading others to believe the map is the territory. As he states:

    Presenting a model is like doing a card trick. Everybody knows that there will be some sleight of hand. There is no intent to deceive because no one takes it seriously. …

    When I learned mathematical economics, a different equilibrium prevailed. Not universally, but much more so than today, when economic theorists used math to explore abstractions, it was a point of pride to do so with clarity, precision, and rigor..

    Empirical evidence betrays many economic models – or at least lays bare that their assumptions are not relevant to the world we live in. Assuming the cow is spherical is a model and no matter how precise the equations, no matter how rigorous the math, it will not change the fact that the cow is indeed *not* spherical.

    Or to be more economically specific, Brad Delong writes:

    And I think Noah misses this. Paul objects not to simplified microfoundations, and not to math, but rather to “mathiness”, which is restricting your microfoundations in advance to guarantee a particular political result and hiding what you are doing in a blizzard of irrelevant and ungrounded algebra.

    Once the model is presented as reality, or informing us about something in the real world, it behooves us to remember the assumptions that lie behind it and to also check for empirical validation/falsification.

  45. > Once the model is presented as reality, or informing us about something in the real world, it behooves us to remember the assumptions that lie behind it and to also check for empirical validation/falsification.

    I think Pr. Romer’s criticism goes deeper than that, O’Neill. He uses the old science/politics wedge and appeals to “norms of science”:

    Because norms about right and wrong are so deeply engrained, we are typically unaware of what our own norms are. We also fail to anticipate that others might have different norms. I suggested in my Mathiness paper that to understand the norms of science, it helps to consciously contrast them with the norms of politics.

    http://paulromer.net/protecting-the-norms-of-science-in-economics/

    Patronization sometimes succeeds (Kahneman did alright), but Pr. Romer’s adds too much Curry to my taste, e.g.:

    About math: I have an undergraduate degree in physics. I’ve seen clear evidence that math can facilitate scientific progress toward the truth.

    About truth and science: My fundamental premise is that there is an objective notion of truth and that science can help us make progress toward truth.

    If you do not accept this premise, I’m sure that there are people who would be happy to debate it with you. I’m not interested. I’m busy.

    It’s unclear to me what Pr. Romer means exactly by “an objective notion of truth” and by “science can help us make progress toward truth.” There are objective notions of truth which are not compatible with convergentist conceptions of science. Should I find a word that end with “-iness” to characterize Pr. Romer’s shaky normativity?

    Later on, Pr. Romer corrected his “I have an undergraduate degree in physics” by ” studied physics as an undergraduate.” Lars quotes this excerpt and offers this e-card:

    Source: https://larspsyll.wordpress.com/2015/05/19/paul-romer-is-busy/

    Matias is less subtle:

    Sure enough, there are important elements in economic theory that cannot be easily formalized, and that does not mean that objective understanding is impossible. I haven’t seen the formalization of the concept of mode of production, but that does not mean that the definition of capitalism is devoid of meaning. My two cents.

    * This has been amended in the last version. Now reads: “I studied physics as an undergraduate.” As it turns, some economists DO have physics envy. But you know what this means. He knows math people. He is an authority. Arguments of authority are so sciency, aren’t they?

    http://nakedkeynesianism.blogspot.com/2015/05/some-brief-thoughts-on-paul-romer-and.html

    ***

    Mind you, Nassim et al.’s response to blogospheric criticisms is no less petty:

    Evidence of bad faith […] We wondered how someone can make an elementary mistake, one that would flunk an undergrad […] There are other severe errors.

    https://www.dropbox.com/s/4kr7mp0d507h7x2/response-7-29-15.pdf?dl=0

  46. Compare and contrast Pr. Romer’s “I have an undergraduate degree in physics” with Jeff’s “I’m a math guy”:

    Yes I am unfortunately a math and science guy with a BS in engineering and a small chunk of graduate education. My skills have contributed to building a fairly large company which produces products that are absolutely #1 in the world in efficiency due to math and software I helped create. I’m published in multiple fields, am named in 10 to 15 patents and happen to run a climate blog where the public can bash on me without understanding much of the world themselves. You can tell me if that is enough for you.

    https://noconsensus.wordpress.com/2015/12/15/yet-another-blog-kerfuffle/#comment-223865

    To which I responded:

    For what it’s worth, Jeff, you’ve done enough to earn “code ninja” and “data thug[.]” You’re a number[s] guy alright. Next time, please don’t confuse math and numbers.

    And what it’s worth is not much for this discussion. You’re showing your biceps, while gorillas prefer to show the whiteness of their teeth.

    https://noconsensus.wordpress.com/2015/12/15/yet-another-blog-kerfuffle/#comment-223865

    Appealing to one’s own authority is seldom a good ClimateBall ™ move. You become your own ball, i.e. a legitimate target for the discussion that ensues. For no good reasons, most of the time, since appeal to our own authority works best implicitly. Authority is like charisma: if you need to tell others you have it, chances are that you don’t have it. Which leads me to my Daily Donald:

    Trump’s vulnerability (like his strength!) is that his appeal is entirely personal, entirely based on the expectation that he’s a winner who will win. He’s an alpha male, the top dog, the guy with the balls and the leverage to get the good deals, the guy who can’t be intimidated, the self-made, independent guy who’s not afraid to say what everybody’s thinking. “I play to people’s fantasies,” he wrote in The Art of the Deal. “People may not always think big themselves, but they can still get very excited by those who do. That’s why a little hyperbole never hurts.”

    http://www.vox.com/2016/1/8/10732496/donald-trump-implode

    All these beautiful speech patterns will live on forever and ever in the miraculous singularity we call the Internet.

  47. Willard – your criticisms seem irrelevant to the central claim; some economists are using math to obfuscate the assumptions inherent in their models.

    Whether Romer has a degree in physics is irrelevant. Whether he once claimed to have a degree in physics is irrelevant. His criticism is not an appeal to authority. ‘Rational Expectations Equilibrium’ and ‘Real Business Cycle’ theories are what;’s being discussed. As one of the main actors in the development of Endogenous Growth Theory, Romer’s comparison of “equilibrium” then and now is not an appeal to authority, just a scene setting. Anyone can delve into the models in question, read the papers, and see exactly what’s going on. They have. They’ve found the sleights of hand. Empirical evidence also says the models are wanting.

    Krugman also has written on the subject:

    Paul Romer has been writing a series of posts on the problem he calls “mathiness”, in which economists write down fairly hard-to-understand mathematical models accompanied by verbal claims that don’t actually match what’s going on in the math.

    Krugman also agrees with Romer that in the beginning there was both transparency and substantive reason to believe in the models developed by Lucas et al..

    So Lucas came up with a story: it was all about imperfect information. Faced with a shock to nominal demand, producers couldn’t tell how much was just a money fluctuation and how much a real change in demand for their particular product, to which they should respond by changing output. So they would engage in signal extraction, making the best possible estimate; this would lead in aggregate to an upward-sloping aggregate supply curve, but only because of rational confusion. And this in turn had strong policy implications: you might see a relationship between money and output, but it would disappear if you tried to use it.

    It was a lovely, intellectually interesting and exciting approach. It was also quite wrong.

    The wrongness took a few years to become irrefutable. By the early 1980s, however, it was overwhelmingly clear that rational confusion couldn’t explain business cycles, either empirically or theoretically…

    The failure of REE led to the development (sic) of RBC. And as Krugman wrote in a column 5 years ago:

    Our problem, in short, isn’t lack of nifty new ideas; it’s the refusal of too many economists to face up to the fact that some of their preferred theories don’t work, a fact that has been obvious for decades.

    What Romer is pointing out is that rather than admit these theories have failed, a school of economists obfuscates their failures with *mathiness*.

  48. > ‘Rational Expectations Equilibrium’ and ‘Real Business Cycle’ theories are what;’s being discussed.

    Not only, and not even mainly. Pr. Romer’s post is entitled mathiness, and here is the main point of the paper, as stated in his blog post:

    The point of the paper is that if we want economics to be a science, we have to recognize that it is not ok for macroeconomists to hole up in separate camps, one that supports its version of the geocentric model of the solar system and another that supports the heliocentric model. As scientists, we have to hold ourselves to a standard that requires us to reach a consensus about which model is right, and then to move on to other questions.

    Leibniz could not have said it better.

  49. Willard, I think you’ve bolded the wrong section: “we have to recognize that it is not ok for macroeconomists to hole up in separate camps, one that supports its version of the geocentric model of the solar system and another that supports the heliocentric model.

    When a model has been proven wrong it either has to be recognized as being wrong, pretending otherwise is not science. It’s not the sun. It’s AGW. This is how science works. This is Romer’s ‘objective notion of truth’ – the heliocentric model is ‘truth’ and the geocentric is not. The scientific standard that Romer supports requires that some scientists have to stop acting as if geocentrism is still a valid scientific theory – otherwise they’ve ceased being scientists.

  50. > Whether Romer has a degree in physics is irrelevant. Whether he once claimed to have a degree in physics is irrelevant.

    I agree that Pr. Romer’s authority claim is not relevant to his Growth argument. I’m even willing to grant him that his technical point is correct, even if I’ve already quoted someone who looked into Pr. Romer’s appendix and found it lacking. Yet he made the claim.

    Not only Pr. Romer “once claimed” he had a degree in physics, he said so in reaction to his post:

    Protecting the Norms of Science in Economics
    18 May, 2015

    This claim is relevant to the “scienciness” part of his critique. He’s playing academic politics with his argument, however sciency he tries to portray his normative concerns. Talk about “norms of science” deserves better than pure obliviousness about the “academic politics” it publicly condemns and in which he eo ipso participates.

    Don’t get me wrong: I don’t mind this kind of armwrestling at all. This is what I study after all.

  51. > I think you’ve bolded the wrong section

    Both sections say basically the same. The one I underlined is more general, and does not beg the question at hand.

    Let’s say if I can simplify my argument.

    First, you show that your competitor’s model is wrong. Second, you attract a base of researchers who agree with you and are willing to work under your own model. Third, you occupy the institutions and create a whole research programme based on it. Fourth, you criticize your competitors’ models, going full meta-peer-review mode if you dare. Mixing the fourth and the first step (i.e. in the very same paper!) is too unbecoming to work.

    Bear in mind that I don’t even dispute Pr. Romer’s conception of economics as a science, and grant him all the truth he begs. Others may not extend the same courtesy.

  52. Willard says:

    OK. I’m now quite convinced that Pr. Romer is (or at least was) pulling a Curry:

    If you know me and think about the costs and benefits I’m facing, I think you will conclude that the most likely explanation for my decision to raise these issues is that I am genuinely trying to come to grips with what has gone wrong in macro-economics and that I am truly committed to science as the noblest human achievement. If you think about the costs I’ll pay for raising these concerns, including the cost of damaged relationships with people that I like, I think you will conclude that a personal commitment to science is the only thing that could be big enough to offset these costs.

    But then, if I have any integrity at all, I have to hold myself to the standard I’m proposing for others. In another twitter exchange, someone linked to a commencement address by Richard Feynman that described what this type of integrity entails:

    http://paulromer.net/feynman-integrity/

    To justify a socially awkward move by portraying it as a self-sacrifice on the altar of INTEGRITY ™ is just too much for me.

    Interestingly, this connects with Nassim Taleb’s point about precautionary measures. Pr. Romer’s is going all in with his reputation capital whence he could have kept most of his stack of chips by refraining from going ad hominem. As an individual choice, I can understand it as some form Promethean incentive that evolution preserved for our specie. As a collective choice, it would lack basic prudence and be unconscionable.

  53. Andrew dodds says:

    The problem is, far more so than the physical sciences, economic theories translate directly into political choices. So abandoning a economic theory means abandoning a set of political policies, which may be inconvenient.

    Hence, mathiness..

  54. Pingback: How Man’s Effect On Nature Will Change Your Life | Wibble

  55. Willard – It’s not the sun. It’s AGW. Supporting failed models is not science. Obfuscating their failure is not science. This is Romer’s argument.

    Again, what motivates him to speak out at this time is irrelevant.

  56. Pete Best says:

    so the argument is – uncertainty means do less/nothing until we know more or do more because uncertainty means what we do know will become worse.

    Maybe we can do a review of what 0.8C has already done, oh we cant because like a smoker who knows that statistically he is more likely to get ailments and general health issues from smoking we cannot tell them exactly when they will contract them or tell them which cigarette will cause these issues. They might not get ill at all, they might not die from smoking either and in some small cases it might even have a small benefit from smoking (protection against certain diseases) and so it is with climate change, statistically speaking all of the ailments of a warming changing climate can bring wont all be bad, wont all be ascribed to GHG emissions either and although we know the future is bleaker rather than brighter with all these GHG emissions we should continue as we are until we know more.

    The precautionary principle is just risk cast into a language we can all grasp, similar to the tragedy of the commons and for that we should be grateful.

  57. oneillsinwisconsin,

    Willard – It’s not the sun. It’s AGW. Supporting failed models is not science.

    Sure, but showing that a model has failed is presumably far easier when you have fundamental laws of nature (mass conservation, energy conservation,….) than it is in a field where no such laws exist. How do you demonstrate that a model has failed in those circumstances?

  58. Willard – Romer writes:

    If the participants in a discussion are committed to science, mathematical theory can encourage a unique clarity and precision in both reasoning and communication. It would be a serious setback for our discipline if economists lose their commitment to careful mathematical reasoning.

    I focus on mathiness in growth models because growth is the field I know best, one that gave me a chance to observe closely the behavior I describe. For growth theorists, the choice between price-taking and monopolistic competition is our version of the conflict between the geocentric and heliocentric models.

    Price-taking vs monopolistic competition. We know that price-taking (perfect competition) does not exist in the real world. Models that assume perfect competition can inform us, but cannot be mistaken as reflecting the real world just as aqua planet models can inform us only so far vis a vis earth. To pretend otherwise is not science. To obfuscate the assumptions (mathiness) is not science.

  59. Willard says:

    O’Neill,

    The analogy you emphasize conveys scienciness more than anything. I’d need to dust up my Koyré and my Kuhn, but my recollection is that proponents of the heliocentric models did not win by flogging their competitors in the lichurchur. It was won with telescopes and discoveries, not with a formal apparatus, which came later anyway.

    Here are the basic components of the Copernician revolution metaphor:

    David Luban has analysed four different sides of the metaphorical usage, deriving from different aspects of the Copernican Revolution as it is understood in the history of science, and its wider impact on thought:

    – a sense of uprootedness within cosmology;
    – a way of representing the path of reason and Enlightenment;
    – mistrust of common sense as a guide to truth;
    – a world-picture based on scientific laws rather than narratives.

    https://en.wikipedia.org/wiki/Copernican_Revolution_(metaphor)

    Pr. Romer’s not the first to pull that trick. Kant tried to sell his Metaphysics with that gimmick in his Prolegomena. One does not simply win that kind of debate by hinting that you’re the new Galileo. Or Newton: the concept of mathiness looks more analogous to the Principia.

    Scientists say the darnednest things about history of science.

    ***

    Perhaps I’ll need to construct the concept of scienciness. What I want to identify is the appeal to a conception of science to settle a scientific debate. Something like:

    (0) I’m right.
    (1) You’re not a scientist.
    (2) If you were a scientist, you’d accept (0).

    This kind of ad hominem is more or less self-refuting, because the “scientific method” usually presumed excludes that kind of argument. Until we can find some kind of Howard-Curry (not that Curry, another one with a programming language name) isomorphism between the meta and the object language of science, scienciness it is.

    Pr. Romer’s concept of mathiness introduces a subvariant.

    (3) I can’t even tell if your work makes sense because it’s not real maths.
    (4) Even if what you say makes sense, you mislead by obfuscating your assumptions.
    (5) Once you correct (3) or (4), (2) and (1) dissolves and (0) obtains.

    Step (4) is interesting because it goes beyond Galileo. This time, it echoes Plato’s criticisms of the Sophists. I can’t really blame Pr. Romer for doing so: I hold that econometrics is the new sophistry.

    I’d be more interested to see when Pr. Romer shifts between (3) and (4). Tracking down his concept of mathiness should be the best way to reveal the scienciness.

    TL;DR – One does not simply do Sound Science ™ in Mordor by appealing to the scientific method.

  60. Willard says:

    Seems that not all economists view macro as a science except when they need to storify their discipline:

    Economists like to strike the pose of a scientist. I know, because I often do it myself. When I teach undergraduates, I very consciously describe the field of economics as a science, so no student would start the course thinking he was embarking on some squishy academic endeavor. Our colleagues in the physics department across campus may find it amusing that we view them as close cousins, but we are quick to remind anyone who will listen that economists formulate theories with mathematical precision, collect huge data sets on individual and aggregate behavior, and exploit the most sophisticated statistical techniques to reach empirical judgments that are free of bias and ideology (or so we like to think).

    Having recently spent two years in Washington as an economic adviser at a time when the U.S. economy was struggling to pull out of a recession, I am reminded that the subfield of macroeconomics was born not as a science but more as a type of engineering.
    God put macroeconomists on earth not to propose and test elegant theories but to solve practical problems. The problems He gave us, moreover, were not modest in dimension. The problem that gave birth to our field—the Great Depression of the 1930s— was an economic downturn of unprecedented scale, including incomes so depressed and unemployment so widespread that it is no exaggeration to say that the viability of the capitalist system was called in question.

    http://scholar.harvard.edu/files/mankiw/files/macroeconomist_as_scientist.pdf

    This citation comes from a comment at Noah’s, reminding people that this Freshwater finger pointing is first and foremost academic.

  61. BBD says:

    How do you demonstrate that a model has failed in those circumstances?

    You sacrifice a goat and examine the entrails. Obvs.

  62. Eli Rabett says:

    Kuhn nailed this when he pointed out that the difference between science and other things is that scientists reach a consensus. Others don’t

    http://rabett.blogspot.com/2015/12/normal-science.html

  63. Willard says:

    I’m not sure if Kuhn’s framework allows revolutions to proceed by social shaming.

    A non-scientific interlude:

  64. Andrew dodds says:

    I think the key problem for economics as a science is that you can’t tie economic theories back to physics.

    Geology is likewise complex, messy, has very incomplete data and competing theories that are very hard to prove or disprove. But within that, every hypothesis has to pass the ‘does it make physical sense’ test. Are we violating conservation laws? Thermodynamics? It may not be possible to write an equation of plate tectonics, but it is possible to explain without physical violations.

    But with economics, there is no sense of this physics tie back. When economists start with the physical basis of the economy and start deriving financial behaviour from that, they will be doing science. Then, any claim from the model is at least physical. Admittedly, this is a hard problem.

  65. Vinny Burgoo says:

    What have you got against extispicy, BBD? It is endorsed by the current scientific consensus on climate change (e.g. AR5 WG2 14.2.5, which says that ‘[e]fficacy of scientific knowledge can be improved by calibration with indigenous knowledge’, which knowledge the IPCC says elsewhere includes divination), so don’t be such a bigot.

  66. Willard says:

    Following through all the blog posts on mathiness, I stumbled upon this gem:

    http://andolfatto.blogspot.com/2015/06/in-after-mathiness-of-discontent.html

    No quote. The whole of it made me laugh.

  67. Willard – Dietz Vollrath writes:

    Okay, smart guy. What is Romer’s point? I think it is this: math is not science.

    Here’s how the science on this would work. Collect data on the growth rate, number of innovations produced, and/or productivity growth. Test whether countries/states/firms that operate with price-taking grow at the same rate as those that operate with market power over ideas. If they do grow at the same rate, then you fail to reject the price-taking theory of innovation. You don’t accept it, you fail to reject it. And then you go on your way scrounging for more data to see if that particular test was just a result of sample noise.

    If the price-taking market doesn’t grow or produce innovations, then you reject the price-taking theory. And then you go on your way scrounging for more data to see if that particular test was just a result of sample noise.

    Let’s say that you fail to reject the price-taking theory. Now what? Now you start pulling out other predictions from both theories, preferably ones where they differ. And you test those predictions. If you could reject the market power theory predictions, but fail to reject the price-taking predictions, then you’d probably conclude that price-taking is the better explanation of innovative activity (but new data could overturn that). And vice versa. I’m not saying this is easy (how do you identify which economies are price-taking versus market power?), but this is how you’d do it.

    That’s the science. That doesn’t mean the math is worthless. You have to have the math – the model – in order to come up with the predictions and hypotheses that we’re going to test with the data. Without the model we don’t know how to interpret what we see. Without the model, we don’t know what tests to run. So a paper like Lucas and Moll is useful in allowing us distinguish what a price-taking world might look like compared to a market power world.

    Here is where we reach the crux of Romer’s argument, to me. Most people, including many inside academia who should know better, assume that math equals science. And rather than remind readers that math is not equal to science, authors often play along with that fiction. They play along by using very complicated math – “mathiness” – making their idea look more “science-ish”. They let people believe their model shows how the world does work, rather than how it might work.

    What Romer has pointed out, and what has been known for decades, is that there is not perfect competition. If the objective were to show, as Volrath writes, “what a price-taking world might look like compared to a market power world” there would be no critique. The models are being touted/used by some economists as proxies for *this* world. And they do so not just ignorantly, but willfully hiding the basic assumptions.

    I don’t know what your point is or is supposed to be. That economics isn’t a science? So what, it’s still a field of study. Denying known facts is still denying known facts. We don’t live on an aqua planet. The stars do not rotate around the earth. It’s not the sun. There is not perfect competition.

  68. Willard says:

    > The models are being touted/used by some economists as proxies for *this* world. And they do so not just ignorantly, but willfully hiding the basic assumptions.

    Like here, perhaps:

    Here is a thought experiment to understand Lucas’s paragraph. Suppose that a virus kills every human being on the planet except those below the age of, say, 8 but leaves intact all physical capital and all scientific books and papers. Now suppose that these survivors are somehow able to continue to educate themselves until they become adults but without guidance from parents or teachers. Would they be able to advance the technological frontier at the same rate as previous generations? If we go by Romer’s model, the answer would be yes since the years of schooling (usually considered a proxy for human capital) and the stock of public knowledge have not changed. Is Lucas unreasonable in arguing that the answer should instead be no, that the inter-generational transfer of knowledge through human interaction is important, and that to capture this we need overlapping generations rather than infinite-lived agents? Sorry, but I am siding with Lucas on this one. And to me this is a much more important issue than the choice of pricing protocol.

    http://andolfatto.blogspot.com/2015/06/in-after-mathiness-of-discontent.html?showComment=1433279152115#c8062744014687799374

    All teh modulz are stoopid, not just the climate modulz. Some are useful. Semi-empirical modulz should be meant to be fit for purpose, not true. If you want validity-preserving machines, do logic.

    ***

    > I don’t know what your point is or is supposed to be.

    I have no evidence that you even read what I write. I have evidence that you side with Pr. Romer because teh Krug said he was the good guy in the story. There’s no need to pretend you interact with me, you know: you can simply continue to cut and paste swaths of stuff in complete obliviousness that your current stance cautions the whole line of auditing products, starting with its shaming devices.

    My basic point is that Romer’s move lacks prudence. One argument is that his appeal to the “scientific method,” besides being caricatural (economics is no physics), is ad hominem, which makes little pragmatic sense if you wish to abide by the scientific method. Another argument is that his concept of mathiness lacks clarity.

    All the episodes of this whole charade belongs to what I would call “scienciness.”

    The argument David Andolfatto puts forward in his blog post was that if you read Lucas, Pr. Romer’s mathiness argument is at best uncharitable regarding Lucas. To show this, all he did is go read Lucas’ article. David also links to Deitz Vollrath’s take on this, BTW.

    In a nutshell, what I see is an eminent professor going to war with a water gun, risking his name (and economics as a whole along the way) for no commensurable reward, notwithstanding that his ill temper makes comparison with Newton possible. A dream-like parallel to Taleb’s point about precautionary measures.

    ***

    One could argue that Taleb’s Twitter behavior also lacks prudence. Many did. Here’s one of his replies:

    According to this, the more skin you put in the game, the less you risk in terms of reputation. Which seems to imply that you can act like an asshole all you want as long as you put enough skin in the game. Taleb rediscovers courage, which is a precondition to any virtuous action, just to conflate it with temerity, an unreasonable or foolhardy contempt of danger or opposition.

    Sometimes, good intentions are just not good enough.

    That there’s always ClimateBall ™ players to take sides without even reading will always be beyond me.

  69. Willard – I have read most, if not all, of the links you’ve used. That I don’t find some of them very convincing – and often self-contradictory (Andolfatto)- should be self-evident. Mostly they miss the issue entirely.

    The last two paragraphs of Andolfatto are:

    Let me conclude now by returning to Romer. I’m still not absolutely sure what the mathiness critique is really all about. I think that Romer might just be frustrated (possibly with some justification) that his ideas haven’t swept away his competition. Because his ideas are so firmly rooted in logic and evidence, the only thing that can evidently explain the continued resistance is academic politics shrouded in a cloak of mathiness.

    Well, that’s one interpretation and, who knows, maybe there’s an element of truth to it. But my preferred interpretation is that what we seem to have here is simply a healthy clash of ideas competing in the marketplace for ideas. Let’s not get too frustrated when our preferred (and obviously superior) theory does not sweep away the competition.

    Romer has not been cryptic on the subject. Andolfatto isn’t trying very hard to engage.

    For instance, here’s Romer:

    You can boil my claim about mathiness down to two assertions:
    1. Economist N did X.
    2. X is wrong because it undermines the scientific method.
    #1 is a positive assertion, a statement about “what is …”#2 is a normative assertion, a statement about “what ought …”

    As you would expect from an economist, the normative assertion in #2 is based on what I thought would be a shared premise: that the scientific method is a better way to determine what is true about economic activity than any alternative method, and that knowing what is true is valuable.
    In conversations with economists who are sympathetic to the freshwater economists I singled out for criticism in my AEA paper on mathiness, it has become clear that freshwater economists do not share this premise. What I did not anticipate was their assertion that economists do not follow the scientific method, so it is not realistic or relevant to make normative statements of the form “we ought to behave like scientists.”

    Does Andolfatto – or any of your other links — actually address the substance in a meaningful, understandable way?

    I’ve read Steve Williamson – one of Andolfatto’s links – basically write that Romer is wrong because there is no objective truth. Fine, if you believe that sort of thing, but not worth my time.

  70. Willard says:

    > Does Andolfatto – or any of your other links — actually address the substance in a meaningful, understandable way?

    They all do, in their own way. I appreciated Andlfatto’s style, and I believe his sanguinity counters well Pr. Romer’s Very Serious stance. And no, Williamson’s point is not that there’s no objective truth. It’s that most of Pr. Romer’s norms for science are dubious at best. I’d rather say they stink scienciness.

    What you identify as relativism could be a metaphor I find beautiful, perhaps because it illustrates my main tactical point perfectly:

    Think of truth as existing at the top of a mountain. Once we get to the top of the mountain we’ll know it, as we’ll be able to see a long way, but while we’re climbing the mountain we’re in a fog, and we can’t see the top of the mountain. But we might be able to discern whether we’re moving up, down, or just sitting in one place. Paul thinks that we can’t just let scientists run loose to take various paths up the mountain with different kinds of gear, and with different companions of their choosing. According to him, we have to organize this enterprise, and it’s absolutely necessary that we write down a set of rules that we will abide by, come hell or high water. And when he says “reputational equilibrium” most economists will know what he has in mind – there will be punishments (imposed by the group) for deviating from the rules.

    http://newmonetarism.blogspot.com/2015/05/dont-get-mathy-with-me-or-ill-give-you.html

    This image expresses the idea that science helps us converge toward truth. It represents perfectly what Pr. Romer assumes, so you can’t use that image against Williamson unless you’re willing to throw Romer under the bus too. This image also adds an important bit that rationalist perspectives such as Pr. Romer’s (there are lots of evidence for that: citing Leibniz, assuming rules within human consciousness, requiring a “universal pragmatic” for science, bitching against some “adversarial” system, etc.) underestimate: that we are all in a fog, and that we need one another to progress. In a word, Williamson is a pragmatist.

    If we’re all in it together, then we don’t act as if we alone stand on the top of the mountain and present to our fellow men the truth tables upon which we all ought to calculate. We accept that while we try to coordinate our efforts, it’s hard, and we try to establish communication channels as we try to move into the snow. We don’t join force with otters by telling them: abide by my scriptures or else I will castigate you as a sub-human. That kind of behavior is obnoxious to no end, and most importantly runs the risk to lose all the members of the expedition.

    If you’re to question the INTEGRITY ™ of your peers publicly on the basis of some norms of science, you’re not into any kind of “substance” that the question I’m trying to answer presumes. Even if Pr. Romer is right on every technical points he raises — perhaps even more so if he actually does — he loses them all on style in my book. Strategically speaking, it just sucks, unless you’re an entrepreneur fishing for controversy as a publicity stunt or something.

    It’s not like I never said that before:

    http://initforthegold.blogspot.com/2010/10/willard-on-curry.html

    Being right and truthful doesn’t legitimize INTEGRITY ™ crusades.

    ***

    There are other links too. Perhaps you’ll like this one:

    https://growthecon.wordpress.com/2015/05/29/more-on-mathiness/

    ADD. The latter one’s good for mathiness, but not for the substance. Here’s the one I meant:

    https://growthecon.wordpress.com/2015/06/05/market-power-versus-price-taking-in-economic-growth/

  71. >> Even a risk with a very low probability becomes unacceptable when it affects all of us – there is no reversing mistakes of that magnitude.

    >In a basic sense, I think this is correct

    Actually, it makes no sense at all. A risk isn’t unacceptable just because it is of low probability. It has to be of high consequence, or magnitude, as well. “no reversing mistakes of that magnitude” simply presumes what it is trying to demonstrate, and is essentially circular, and certainly doesn’t follow from what came before. Is your “Nassim Taleb” capable of constructing a coherent argument? because what you’ve quoted certainly isn’t one.

  72. WMC,
    Are you imaging that he’s discussing a risk of of minimal consequence? I had assumed that he was referring to the risk of something that had extremely severe consequence (possibly based on the comment about having only one planet), but maybe I’m mistaken; maybe he was just considering the possibility that everyone on the planet would simply stub their toes a little more often in a warmer world.

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