Friday, October 12, 2007

Mona Charen on Fat and Global Warming: Not all Consensuses are Created Equal

Rich in irony, as Al Gore receives a Nobel Prize for his work on global warming, Mona Charen adds to the denialist list, with an argument that, boiled down to the essentials, amounts to "science has been wrong before, so we should assume it is wrong now." This is an argument that is horribly flawed logically. The premise is poorly defined, and the conclusion doesn't follow anyway. Yet this is heard so often in so many ways I thought it worth tackling in detail. This is not about global warming per se. It could apply to any finding of science that finds itself under attack with this argument.

The premise is poorly defined because saying "science was wrong" is too imprecise. Perfection is rarely attained, or required, in any field. Quantum physics sees to that. So the relevant measure of a theory is not whether it is wrong: for most theories we know that already. The relevant question is "How wrong is it?". Consider Newtonian physics. It says if I am travelling in a car going 40 mph, and throw a baseball another 70 mph, the ball will travel 110 mph relative to the earth. Believe it or not, this is wrong. Einstein showed with his theory of relativity that the ball would actually travel 109.99... mph. Too picky you say? Exactly. The question isn't "was Newton wrong?" The question is "How wrong was Newton?", and the answer is hardly wrong at all, and hardly wrong at all is a far better view than most any other.

So when someone says "science was wrong", the question is how wrong was it?. Right and wrong are relative. And for the most part, science is rarely substantively wrong, and it's errors tend to decrease in severity within a subject over time. Take the scientific consensus of opinion on the shape of the earth. It was, roughly: flat, spherical, oblately spherical, and slightly on the pear side of oblately spherical with a northern top. Notice that each error was smaller than the previous one (think in terms of average curvature per straight line distance), and that there is a pattern of sorts as it zooms in on reality. It does not oscillate wildly, as if one day we might discover that the earth is cube shaped. This, history clearly shows, is the pattern of science. Note also the historical pattern that while science makes errors, it is almost always science that corrects them. Creationists might trumpet the Piltdown hoax, but it was evolutionary scientists, not creationist hacks, that exposed it with evidence. Science, with apologies to Churchill, is the worst form of epistemology, except for all the others that have been tried.

Second, the conclusion of this horrid argument doesn't even follow if you grant the premise. So science has been wrong before? So what? Whether it is right or not now has to do with the evidence, not history. If LeBron James has missed 10 shots in a row, may we then conclude he will miss the next one as well (with a nod to Bayes), even in the face of evidence that he made it? Of course not.

So if Mona, or anyone else, is going to challenge the scientific consensus of anthropocentric global warming, she needs to do it with evidence, in the scientific literature, not in pop-science op-eds, with cries of persecution and logically poor rhetoric. Whatever science's track record of accuracy on science, it beats the track record of political hacks tenfold. What do you want to bet Mona is an evolution denier too? The two seem to run together. Funny coincidence that.

Charon's article focuses on an article in the New York Times which discusses the changing opinions of scientists regarding the supposed damaging effects of fat in our diet. As it is, the really sad thing about Mona's article is even if we dismissed all of the above, the case she tries to make still doesn't hold up. The situations between the current consensus on AGW and the former consensus on fatty foods (which I have not researched but will accept as stated for the sake of argument) are dissimilar in crucial ways her argument cannot survive.

The New York Times article focuses on a comment by then-Surgeon General C. Everett Koop:

"He introduced his report with these words: “The depth of the science base underlying its findings is even more impressive than that for tobacco and health in 1964.”

That was a ludicrous statement, as Gary Taubes demonstrates in his new book meticulously debunking diet myths, “Good Calories, Bad Calories” (Knopf, 2007). The notion that fatty foods shorten your life began as a hypothesis based on dubious assumptions and data; when scientists tried to confirm it they failed repeatedly. The evidence against Häagen-Dazs was nothing like the evidence against Marlboros.

It may seem bizarre that a surgeon general could go so wrong. After all, wasn’t it his job to express the scientific consensus? But that was the problem. Dr. Koop was expressing the consensus."

Right away there are glaring differences between this and AGW. AGW is not failing to be confirmed by scientists. The findings are being confirmed repeatedly, and in multiple disciplines. Second, on what was the supposed scientific consensus on fatty foods based if scientists were unable to confirm it experimentally? If it was simply an unconfirmed hypothesis lacking peer-reviewed evidence, then it doesn't qualify as science. That some scientists may have held this to be so as a personal belief is entirely irrelevant to a judgement of the scientific process, as their opinions on politics and sports teams are. No peer-reviewed articles supporting the hypothesis, no scientific consensus, period.

So it was a popular consensus they had, and that is simply a case of group think, or as the article calls it, cascading:

"He was caught in what social scientists call a cascade.

We like to think that people improve their judgment by putting their minds together, and sometimes they do. The studio audience at “Who Wants to Be a Millionaire” usually votes for the right answer. But suppose, instead of the audience members voting silently in unison, they voted out loud one after another. And suppose the first person gets it wrong.

If the second person isn’t sure of the answer, he’s liable to go along with the first person’s guess. By then, even if the third person suspects another answer is right, she’s more liable to go along just because she assumes the first two together know more than she does. Thus begins an “informational cascade” as one person after another assumes that the rest can’t all be wrong.

Because of this effect, groups are surprisingly prone to reach mistaken conclusions even when most of the people started out knowing better..."

OK, point taken. But this is not how the scientific process works, and in fact, far from a condemnation of the scientific method, this is an affirmation of the importance of replicable experimentation. It is also worth nothing again, that the truth about a fatty diet was ultimately determined by scientists, not the cynics. It certainly wasn't, and rarely is, found by skeptics working outside their field, as science critics almost always are. And finally, this is not in any way a parallel to AGW, which was not something promoted by a single individual in a position of political power, as the fatty food theory apparently was, but has grown little by battled little from experimentation all over the world.

In a final confirmation of Charon's crankiness, she ends her criticism of scientists supposedly accepting something without sufficient science by, well, accepting hypotheses promoted by Bjorn Lomborg, non-climatologist (denialists are almost universally from fields other than the ones they criticize), and favorite son of the AGW denialists. And of course, he makes his case, just as the HIV denialists and evolution denialists do, in popular books, while avoiding the scientific literature. Charon ends with:

"The consensus is wrong on global warming. Wonder when The New York Times will figure it out? In the meanwhile, Lomborg points the way toward clear analysis."

Really Mona? And your basis for trusting a single individual over the worldwide scientific community is what exactly? Simple: he is telling her what she wants to hear, and her conservative sycophants will no doubt repeat his and her claims, sans understanding, as they have to this point, which creates in that little political subculture the illusion that they have science to back their views. Now THAT'S a cascade.

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