Common Sense and Prosecutor’s Fallacy(s)

Guest post by John Pittman.  It was supposed to go up last Friday, but in my haste to buy everything on Earth for Christmas, I didn’t have time to do the editing and it slipped my mind this weekend when so much Copenhagen news happened (News always happens on the weekend).  Anyway, John responds to Mann’s WP article in the first link below.  Take a few moments to read the comments to Mann’s article, Mann is not terribly popular with the internet public.

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In this Washington Post Article, Dr. Mann makes a demonstrably weak effort to continue the meme that the scandal from the alleged email leak do not matter. There are several reasons why this response is weak. The first argument:

When I was on a jury one time, we were instructed not to give up our “common sense.” Despite what the defense, prosecution, or even the judge instructed, we were not to forgo common sense. This was an instruction from the judge. The trial proceeded until the judge made the mistake of instructing the prosecution how to proceed with their case. The defendant immediately called for a mistrial. The jury was removed to wait the outcome. We were dismissed and a mistrial declared. GHG and temperature can’t speak, but data can. Persons such as JeffID and Steve McIntyre, among others, are getting the data to speak. Dr. Mann is asking readers to suspend common sense. The fact that not all the emails have been released, per the hacker, does not mean they were taken out of context. It means we don’t know. He asks us to come to a judgment without data. In other words, do something that defies common sense. He asks that we ignore what JeffID, Steve McIntyre, I and others have found that do question the results. So he asks us to both prejudge and to ignore what has been found. Does this mean that the problems discovered are real? No. ABSOLUTELY NOT. However, it does mean they need explanation.

From http://en.wikipedia.org/wiki/Prosecutor’s_fallacy misunderstanding conditional probability or misunderstanding the idea of multiple testing.

As I stated here,

“”The real argument concerns present temperature, past temperature, climate sensitivity and climate predictions (projections). To understand what the furor is about one has to go back to the SAR.””

I also stated there would be a long line of apologists trying to minimize what the emails state. This post I want to address and expand a point by Dr. Lindzen. Dr. Lindzen makes a good point in the video linked by Steve. It is about the Prosecutor’s Fallacy(s) seen in the CRU Climategate emails. Dr. Lindzen’s comments alone show the weakness of Dr. Mann’s claim. I would like to take it a couple of steps further.

https://noconsensus.wordpress.com/2009/12/16/2744/ JeffID has a post relevant to this discussion, as does Steve McIntyre here climategatekeeping and climategatekeeping2. Where these go into technical details, this post is about procedure and methodology.

Two of the greatest achievements derived from philosophy have been Law and Science. We commonly speak of the rule of law and the scientific procedure. These common methodologies are similar and have been used to take mankind from hovels to exploring space. Their similarities speak of our common experience and their success. We will look at fallacies, procedural errors, and methodological errors. One thing they do not require is the suspension of common sense. It may take a lot of education and math, but it does not require suspension of common sense.

Many are claiming that the emails did not show that the process of peer review was stopped. That statement has been shown to be doubtful by Steve’s post. Further the emails in climategatekeeping-2 indicate that there is something worse than a fallacy going on. We will come back to this in a bit.

Another excuse has been that there are so many other papers that did make it supporting the consensus. This fails as Calvin ball at CA notes:

Stop and think about that statement. What he’s rather directly saying is that scientific issues can and should be settled with a scale. Stack the papers on one side of the issue on one side of the scale, and stack the papers on the other side of the issue on the other side of the scale. The truth is the heaver stack.

Expressed like this, the hacked emails do not show they have been mined for words or phrases, but for violations of procedure and methodology, besides the fallacy that Calvin notes. It is interesting that Dr. Mann should challenge Sarah Pallin on an unsubstantive issue rather than a substantive issue. Such as, release of code for MBH 98 as his cohorts are clamoring for at RC. Perhaps he should address the substantive issue raised when 3rd parties were asked to look into his work by explaining the email here . Or perhaps he can explain how this email of his with this comment is somehow taken out of context by explaining how the potential problems with temperature constructions could change his claims and conclusions. Perhaps he should just address how substantive are his claims of “best physical understanding” could be effected by the emails with a substantive release of MBH code. Perhaps address whether or not Dr. Wegman was correct about the independent nature of Jones, Mann, Briffa, Crowley. Now that would be a substantive issue to explore. And related to the emails.

In a recent “Perspectives” opinion piece, W. Broecker suggests that the “hockey stick” reconstruction of climate change over the past 1000 years – with extreme warming only in the late 20th century – is incorrect, and that the so-called “Medieval Warm Period” was at least as warm as the 20th century and due to oscillations in the thermohaline circulation. To reach this conclusion, Dr. Broecker rejects traditional empirical “proxy” climate indicators of past climate (e.g. tree ring, ice core, coral, and long historical documentary records) that are the foundation of a number of hemispheric reconstructions, as well as our current best physical understanding of the factors controlling climate at century-to-millennial timescales. We disagree with Broecker on several major points: (1) It cannot reasonably be argued that the Middle Ages were as warm as the 20th century at global or hemispheric scales. Although regional warmth during the Middle Ages may have sometimes been significantly greater than present, four different hemispheric-scale reconstructions (Jones, Mann, Briffa, Crowley) have been completed for the last 1000 years — all of them showing warmth in the Middle Ages that is either no warmer or significantly less than mid-20th century warmth. This is because it has been known for a quarter of a century that the timing of warmth during the Middle Ages was significantly different in different regions (Lamb, Dansgaard, Hughes). Failure to take this observation into account can lead to serious errors in the inference of hemispheric temperature trends

Returning to our contentions, the emails are full of prosecutor’s fallacies. But worse they are full of procedural problems. In emails that so many have discussed, there are continual procedure violations of the sort from my story. Remember these are not just any scientists. They are writing the IPCC’s reports that are supposed to be all sorts of things, like fair and independent, that the emails indicate that the reports are not. In particular, we read of those who should be independent, are actually spoon feeding the answers to one side and not the other. Even worse, they seem to be engaged in a conspiracy not only to deny revealing what should be revealed, as a matter of course, they are trying to throw out the others’ works even when they know that the other side has made an effort to do it themselves, and as were argued in the emails to be presenting something that was different and hung together. Since this email was addressed to these scientists including Dr. Mann, I find it disingenuous for Dr. Mann to now claim that emails are somehow taken out of context. See this link for a detailed falsification of Dr. Mann’s simplistic claims.

Before we conclude a point about “what if” the temperature does not swing upwards so sharply? Not only does Mann’s quote in the WaPo “Past Few Decades Warmest on Record, Study Confirms,” become questionable, there is a more salient point. JeffID, Steve McIntyre and Zorita have shown the mechanism of the hockey stick. What JeffID showed, in particular, is that with a lesser uptick, there will most probably be a lesser deflation of the MWP. In that these studies quoted by Mann show MWP almost as large as CWP, using a smaller uptick for 1950 onwards may make the MWP as warm as CWP. If that happens, just read the Context post linked above and realize that this decrease in the magnitude of the uptick could by itself invalidate AR3 and AR4, and that the Yamal problems will “make it worse than we thought”; then read Dr. Mann’s weak arguments. You should feel your common sense has been dragged through the sewer. If you appreciate the law or the scientific method, words may fail to express your opinion of the weakness of Dr. Mann’s arguments.

To conclude, we leave it with the Mann:

Dr. Mann claims

As world leaders work in Copenhagen to try to combat this problem, some critics are seeking to cloud the debate and confuse the public.

No, Dr. Mann, what we are seeking is open and transparent science, and if you would do your part such as release the code for your works such that they were reproducible, then you wouldn’t have to be holding up Sarah Pallin as a worthy opponent. You could be addressing McIntyre and McKitrick, and a growing number, instead.