Consensus Beats Evidence

John Cook of Oz has an interesting study:

Conservatives are less likely to accept the reality of human-caused climate science when presented with supporting scientific evidence. But tell them that 99 out of 100 climate scientists agree on the subject, and conservatives will be more likely to accept that humans are altering the climate, according to a new pilot study.

The findings, presented today (Dec. 7) at the annual meeting of the American Geophysical Union, suggest that scientists shouldn’t break out the graphs and tables when talking climate with conservatives. Instead, climate advocates should emphasize how much of the scientific community agrees on the subject.

I find this result as expected – people already disposed to disbelieve the climate consensus will not be swayed by evidence any more than people already disposed to believe will be swayed by cherry-picked evidence. The point is that nobody but a professional has the time to really examine the balance of the evidence.

Anyone who doesn’t have the time resorts to “fast thinking” which is to look for proxy evidence. The most important such evidence is the balance of opinion of those who do have the time and motivation to examine the evidence.

As I quoted some years ago:

A Slashdot reader summarizes neatly: “when deep quality metrics are unavailable, customers will base their decisions on shallow metrics instead.”

As a proxy, consensus of expert opinion is really more than a shallow metric, actually. Though it is not as deep a measure as the real balance of evidence, it is a sensible way to proceed on matters on which one is inexpert.

I think that various cynical political groups understood this long ago.

The existence or otherwise of a consensus is therefore far more important in this debate (and others where science impinges on policy) than a presentation of evidence. This isn’t exactly rational, but it’s the next best thing when we don’t have the resources to examine a matter rationally. That’s why direct attacks on the consensus measures are crucial.

And if you look at all the other attacks on climate science, they are not substantive at all. It is a key weakness of science in these debates that it is obligated to look at every potentially serious challenge. But the challenges are not challenges to science or the authority of science. The challenges are directed specifically at muddling the public perception of consensus.


  1. Disregard empirical evidence and instead rely on appeals to authority ("consensus"). No wonder we "deniers" are whipping you with one hand tied behind our backs. You have faith, we have actual, real, science. Check with Galileo and the Catholic church to see how relying on faith in the face of emprical evidence works out in the end. Good luck with that...

  2. That position is illogical. How do you explain that for forty years the consensus was that stomach ulcers were caused by stress and excess acidity. In fact the science - discovered by two Australians - was that a bacterium was responsible. They were right and the consensus was totally and absolutely wrong.

  3. No claim is made here that consensus is infallible.

    The claim is that nobody has time and skill to investigate everything, and few even have time to investigate anything in great detail. Therefore we defer to a consensus when it exists. Consequently, those who wish to oppose the consensus politically only pretend to examine the evidence. Rather they attempt to undermine the existence of consensus, or its legitimacy as you are doing here.

    This all said, it seems a very long time since classical physical science got anything terribly wrong at mundane time and space scales, which is what you are implying.

  4. We are not disregarding empirical evidence in general. We are disregarding cherry-picked empirical evidence. It is difficult for a non-expert to get a good sense of the balance of evidence. This is why we tend to defer to expertise. And this in turn is why those who dislike the opinion of the experts, like yourself, try to raise doubts about the legitimacy of that expertise ("disregard emiprical evidence") and of the public's acceptance thereof ("whipping you with one hand tied").

  5. Carbonicus got it backwards. The real science is almost all on the other side. Hence the plain English word, "consensus". Galileo (and all your other heroes) would certainly have followed nature, reality, and truth rather than your snark, insults as argument, PR, and other fluff guided by huge amounts of money and effort in the service of short-term profits.

    Not rocking the boat has become the ultimate boat-rocker as nature heats up.

  6. From the article, "Anyone who doesn't have the time resorts to 'fast thinking' which is to look for proxy evidence. The most important such evidence is the balance of opinion of those who do have the time and motivation to examine the evidence."

    Ah... check with the experts. Great idea! Unfortunately, for many Americans this will turn out to be their uncle the the engineer at Exxon, or their brother the computer programmer at that start-up in town. Or maybe just that list of self-anointed experts BA put together by the guys with the post office box and an official sounding name.

    Anyway, I believe the web address for Logical Science has been taken over by a different set of people, but I have the lists, some quotes and updated links from the Google cache a while back:

    Feel free to use as you wish or suggest additions if you like.

    As for the nature of scientific consensus, this could use a little work:

    ... but its a start.

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