Judith Curry: Born Beyond the Shark?

Judith Curry leaves only one possible argument for doubt that she has jumped the shark.

You’ll need some context for this one:

Lets frame belief, disbelief, and doubt in the context of the Italian flag, that was introduced previously on the hurricane thread in which evidence for a hypothesis is represented as green, evidence against is represented as red, and the white area reflecting uncommitted belief that can be associated with uncertainty in evidence or unknowns.

Let’s look at an example in the above-linked article:

Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.

This statement is often used as a litmus test for belief regarding global warming, i.e. you believe this statement (consensus) or you don’t (skeptic). Very likely denotes a probability of anthropogenic influence between 90 and 99% (lets pick 95%) and I interpret most to mean between 51 and 90% (lets pick 70%), with the remainder (30%) associated with natural variability. Hence, the Italian flag analysis could represent this in the following way:

5% assigned to uncommitted belief (white),
67% assigned to anthropogenic forcing (green),
28% assigned to natural variability (red).

my personal weights for the Italian flag are:

white 40%,
green 30%,
red 30%.

My assignment allows the anthropogenic influence to be as large as 70% and as small as 30%

As I have pointed out previously, that last sentence is immensely sloppy, conflating a hypothesis (a proposition that must be either true or false) with a weighting.

Now, I believe (and haven’t really made the case) that weightings are much more useful in decision making under uncertainty than are hypotheses. But that’s not the issue here. The issue is that Judith Curry, in unveiling her new intellectual tool with great fanfare and off-key notes of false modesty, conflates confidence in a hypothesis with weighting.

This leads to an unambiguous contradiction.
Suppose we eliminate the white altogether, and consider only the yes and the no. I must do this because I don’t understand the “uncommitted belief” idea at all. But let;s simplify. Suppose I had a measurement with a very well-characterized uncertainty of the quantity. My belief that the majority of the warming is attributable to anthropogenic influence, say, is in line with IPCC:
  • p (f < 50%) : 0.02
  • p (f > 50%) : 0.98
Suppose, to be more specific, I believed (consistent with the above) as follows:
  • p (f < 50%) : 0.02
  • p (50 % <= f < 60%) : 0.02
  • p (60 % <= f < 70%) : 0.1
  • p (70 % <= f < 80%) : 0.72
  • p (80 % <= f < 90%) : 0.1
  • p (90 % <= f <= 100%) : 0.02
Then I would be quite confident that the percentage would be in the range 60% … 90 %. But according to Curry’s mangling “My assignment allows the anthropogenic influence to be as large as 98% and as small as 98%”
In other words, a well defined uncertainty yields an inconsistent certainty.
This leaves aside how to deal with the third value in a two valued logic.
In addressing that, consider that if one believes that the odds of a proposition A is P, then according to ordinary rules the odds of not-A is assigned a value of (1oo% – P).
The desire to separate out uncertainty from “uncommitted belief” requires a good deal more serious thought than Curry has put into it. (It turns out, in fact, that a lot of people have already thought about it. Read up on frequentists vs Bayesians.)
Curry’s muddle effectively demonstrates the problems with using frequentist logic in situations where an estimate is required, rather than a hypothesis tested. Suppose, to return to a favorite example, one has in view a creature and wishes to estimate whether it is a duck.
The evidence may be sufficient for a frequentist to state with confidence that the probability of the present observations in the case of a duck is P, and the probability of the present observations in the case of a not-duck is Q. In most cases (lacking a huge observational set), the sum of P and Q will be less than 1. Indeed, once there is enough evidence to make P and Q add to 1, it would be very pathologically strange not to be able to state with certainty the duckiness of the creature in question; either P will be one and Q zero or the other way round. That’s essentially at the core of frequentist analysis.
I think this gap is what Curry may be trying to grapple with in her white zone, given that in earth science we often lack enough data for a compelling frequentist analysis of important questions.
Neither P nor Q is an estimate of the probability that, given the observations, one sees a duck. This depends, it turns out, on the expected rarity of ducks! Assuming you are willing to quantify your prior belief in ducks, you can make a consistent argument for the propbability space being partitioned into duck and not-duck with none of that peculiar middle ground. Now, all of this should be very old hat to people who think about uncertainty. But it appears completely unfamiliar to Curry.
Yet she unveils her muddle with great fanfare, and in doing so, presents two inconsistent views of what it means right off the bat! In the light of all this, let’s consider her most recent contribution to Currian probabilistics, which begins
Historical surface temperature observations over the 20th century show a clear signal of increasing surface temperatures. Italian flag: Green 70%, White 30%, Red 0%. (Note: nobody is claiming that the temperatures have NOT increased.)

OK, is it fair to say that “Note: nobody is claiming that the temperatures have NOT increased” means that nobody claims that “Historical surface temperature observations over the 20th century show a clear signal of increasing surface temperatures”? I mean, if nobody can claim the contrary, then the signal must be clear, right? So what does that white 30% represent? Does it represent 70% “it has warmed and I can deal with it” and 30% “it has warmed and I am in denial”? Or does it represent “although nobody claims it hasn’t warmed, and there is a 0% chance that it hasn’t warmed, there is still a 30% chance that it hasn’t NOT warmed?”

Now consider the adulation that this muddle obtains from the peanut gallery. (Note, there’s plenty more where this came from, but this is from another essay in the series. Thanks to bluegrue in comments.)

Oliver Manuel: Thank you, Dr. Curry, for having the courage to question the way uncertainty has been characterized in climate assessment reports.

Gordon Ford: Excellent post. When we were young we all feared “the monster under the bed”. Many have not learned to live with monster. In the real world (such as gold mining) one learns to live with the error in the estimate exceeding the estimate.

Paskvacs, eggcorning fiercely: I’m personally in favor of letting science guys work this out all by themselves. If they end up committing suicide, so be it. Say “La V”. But, as soon as you try to ‘reasonably’ let the legal system (with any new tweaks you want add) get their greedy little hands on anything like this fiasco, you –and not the scientists– are the one committing suicide.

hunter: Very interesting. I like this concept very much.

MaxL: Thank you, Dr. Curry, for introducing the discussion of uncertainty and questioning the way it has been used in climate science.

Baa Humbug: Would it be fair to say, if the true uncertainties in the climate models were enunciated clearly, Kyoto would not have happened and Copenhagen would have been a side show attended by a handfull of people?

and finally I will quote the entire comment of one Danley Wolfe along with Curry’s response

Danley Wolfe: Judith,
this is a great post. I think the phrase “(t)here can also be epistemic uncertainty about how a physical, chemical or biological process works is extremely important. Scientists suffer from “completeness fallacy” meaning they need to carry through work to some meaningful level of completion (for reasons such as need to mark progress, need to publish, need for peer recognition, need to meet deadlines for IPCC assessments, etc.). A model which lack sufficient treatment of all suspected independent variables – and their interaction is – under- ie., mis-specified. Result is that the model will tend to over-emphasize or under-emphasize attribution for the variables that are fully treated. I have long suspected this to be the case in climate modeling for global warming. There are many forcings and
some are known to be underrepresented in the modeling such as aerosols / clouds and black soot.

curryja: Danley, very true, same goes for solar also.

Um, what?

OK. I am stretched to the limit. Somebody has to call “horseshit” here, and it might as well be me.

We have reached a point where it is impossible to judge that Curry is in touch with the science that she is supposed to be a prominent participant in. So has she lost touch, or has she never had much scientific insight to begin with? That’s the only question any of this burbling raises.

Admittedly, she is very highly published. I know a couple of her students and think highly of them. On the other hand, to be honest no paper of hers has ever come across my radar in anything I’ve investigated. (As a dilettante, I don’t contribute much to the primary literature myself, but I do read a whole lot of stuff.) I mean, could this be the stuff of some subtle neurological decay, where a formerly competent scientist starts making no more sense than the peanut gallery? After all, dedicated naysayers are still highly intelligent and scientifically competent by comparison to the lay public (that’s the whole problem) even though they are actually quite ignorant and confused about the actual science. So a decline to that level of functionality would not be obvious, and if a person already had tenure, it would ordinarily go uncommented upon.

Or alternatively, is the peer review system so shabby that a person of modest intellectual accomplishments, one who, despite years of connection to the scientific community, numerous publications and promotion to a position of responsibility, is capable of such vapid, illogical, pointlessly contentious writing.

Either way it’s sadly amusing to see this nonsense treated by the fan base as the breakthrough in reasoning about uncertainty that it obviously isn’t.

But as far as I can see, the uncertain hypothesis raised here is

“Did Judith Curry jump the shark (green), or was she born and raised on the far side of the shark in the first place (red)?”
I think that covers all the possibilities, unfortunately, and it’s either awkward or really really awkward, depending on which way it comes out.
(Note: all emphases in quotes added by me.)

Update: This post has generated some interest on a thread at Kloor’s (starting with AMac lighting into me at #49) Judith Curry herself responded rather graciously, given how harsh the above was.
Well this is entertaining. MT and others seem annoyed because they think I invented uncertainty or am taking claim for it or something? Hardly. Its the Emperor’s New Clothes thing. And the fact that MT and others don’t get it (i.e. that uncertainty and allegations of overconfidence of IPCC are important things to talk about, its the naked emperor, really) just tells me how clueless some members of the community actually are.

I give MT credit for at least discussing what i say in the blog, rather than rehashing old drive by comments that I’ve made at other blogs. But i suggest he try out his arguments over at my blog, where they would receive some real dissection from some serious experts in logic, bayesian reasoning, etc. Nobody ever burns their bridges with me in terms of meaning i wouldn’t pay attention to their argument.

I replied:

I have to admit this is a surprisingly gracious response to my less-than-gracious posting. I am, in that regard at least, impressed and grateful.

I still can extract no sense from the Italian Flag arguments to date; it seems to me that there is no unifying method at all, just a sort of fig leaf for various commingled classes of rough intuitive guess.

Now, arguably that is all that IPCC is providing, and all we’re discussing is whose intuition is more reliable. If that is the case, though, that is how it should be discussed. Devices intended to illuminate should not obfuscate.

If you want to discuss uncertainty, and decision-making under uncertainty, by all means, let’s do that. (I’ve been trying to close that loop for decades, myself.)

As for the critique of models which so exercises Tom Fuller, let me withdraw it for the sake of more productive argument. If Dr. Curry wants to throw red meat to the inactivists on occasion, she should be held to account. But that only a secondary cause of my disappointment with her contributions to date.

Let’s focus on where the focus belongs, on how to think about uncertainty.

If Dr. Curry will continue to allow me to post on her site I will actually be grateful but I will nevertheless behave as an ingrate. If Dr. Curry is to make a genuinely positive contribution to the problem of how to deal with uncertainty in the high-stakes field of climate policy, she will need to proceed at least with considerably greater clarity than she has managed to date. It’s my impression that considerably greater care is needed as well.

I will continue to be an advocate for clarity and precision of thought. I hope others with some interest in uncertainty will stop yielding Dr. Curry a free pass on these matters, where she is an obvious novice.

If she actually wants to participate in a discussion of uncertainty, then it is important to do so carefully. One aspect of the problem is separating out one’s own biases from the various other sources of error, and another is careful thought along lines that are unfamiliar to most physical scientists. The casually appealing ideal of “separating politics from science” may turn out to be more subtle of a matter than it might at first appear.

I guess I was in a dreadful mood, too. The world is looking particularly messed up to me these days. (Willard has taken to calling me Doctor Doom, but I assured him that I am Victor to him.)

None of that means the Italian flag stuff made any sense, nor that Curry should continue to get a free ride. Science, in the end, is not about centrism or extremism or purity or pragmatism. Science is about reason, logic, and honest contention of ideas. I am at least provisionally convinced by this exchange that whatever else is going on, Curry honestly believes in that.
I think we should take her up on it, next time she waves that flag. I suppose we should ignore what the press or the peanut gallery thinks of her and focus on her reasoning or lack thereof.
Update: Would this posting have gotten any attention at all without the “snarky” bit at the end?

I really do think Judith Curry either jumped the shark or was never on this side of the shark. This flag stuff really looks very amateurish.

It might have been more prudent on my part not to ask the question in that way. But I did want the whole issue to get some attention, and in that I succeeded. I certainly wont apologize for this flavor of criticism to anyone who doesn’t hold McIntyre to a comparable standard.

I’m impressed by the constructive spirit in which she receives this criticism. I will be more impressed if she actually addresses it. Indeed, sharks of this breed can be unjumped, as it appears Claude Allegre has just demonstrated. I’m willing to grovel on the substance if somebody can make a coherent case for it.

Anyway, if someone can’t bear the sight of this sort of criticism, PDA has provided a redacted version of those parts of this article that address the uncertainty “flag”.

Update: Pleased to see James in agreement.

: Fuller raises the interesting question as to whether I posted this out of scientific or political motivation (or, for that matter, out of sheer self-destructive stupidity, which I’ve been wondering from the start).

Here’s my defense.

While there is no room for ad hominem arguments in science, what Curry is doing is apparently very far from science. Then the question of what she is doing and why becomes relevant as a political question, yes. I present a case that IFA as we have seen to date is not science.

Is she doing not-science because a) she knows it is not science and wants to fool others b) she is no longer capable of doing science or c) she was never capable of doing science?

Now, I can assure you on the basis of experience that this conversation is going on behind the scenes among actual, real scientists. The question is only whether I was right or wrong to raise it publicly, to bring it into the open.

There is no doubt I was rude within the norms of science. I stipulate that.

The credulity and adulation associated with the transparent nonsense has been a matter of some political importance. There has never been much risk that this nonsense would percolate up through scientific discussions, but there is an increasing risk that it will be forced down to science from the congressional level. So arguably it’s important to raise the question, and I did so.

In this case, the contradictions are elementary enough to be accessible to a diligent political staffer. So making the case in such a way that such a staffer would be likely to come across it and work through it may be important. It’s not hard to imagine this cluster of half-baked ideas making its way into the national discussion via too much credulity at the top.

Therefore, for a change Tom Fuller is right. My motivation is indeed political. I wish to defend science from an injection of nonsense from the political level. Lysenkoism never works out very well. And Lysenkoism is exactly the central risk of politicization of science.


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