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Consilience and Consensus: Or why climate skeptics are wrong

At some point in the history of all scientific theories, only a minority of scientists—or even just one—supported them, before evidence accumulated to the point of general acceptance. The Copernican model, germ theory, the vaccination principle, evolutionary theory, plate tectonics and the big bang theory were all once heretical ideas that became consensus science. How did this happen?

Scientific American (cover)

An answer may be found in what 19th-century philosopher of science William Whewell called a “consilience of inductions.” For a theory to be accepted, Whewell argued, it must be based on more than one induction—or a single generalization drawn from specific facts. It must have multiple inductions that converge on one another, independently but in conjunction. “Accordingly the cases in which inductions from classes of facts altogether different have thus jumped together,” he wrote in his 1840 book The Philosophy of the Inductive Sciences, “belong only to the best established theories which the history of science contains.” Call it a “convergence of evidence.”

Consensus science is a phrase often heard today in conjunction with anthropogenic global warming (AGW). Is there a consensus on AGW? There is. The tens of thousands of scientists who belong to the American Association for the Advancement of Science, the American Chemical Society, the American Geophysical Union, the American Medical Association, the American Meteorological Society, the American Physical Society, the Geological Society of America, the U.S. National Academy of Sciences and, most notably, the Intergovernmental Panel on Climate Change all concur that AGW is in fact real. Why? …

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About this week’s eSkeptic

In this week’s eSkeptic, David Priess reviews Red Team: How To Succeed by Thinking Like the Enemy by Micah Zenko.

Advocatus Diaboli—the Devil’s Advocate

by David Priess

Recognize your assumptions. Question them regularly. Don’t fall prey to mirror-imaging and related mindsets. Avoid cherry-picking to support your preferred hypothesis. Value evidence over belief.

Skeptics in diverse fields ranging from the hard sciences to intelligence analysis know these maxims well. But plenty of research has made it clear that only exceptional effort keeps us all from falling prey to the same troublesome mental traits; it’s just plain hard to move beyond mere recognition of critical thinking best practices to actually practicing them best.

This becomes even more daunting when it comes to collective decision-making. After all, companies and government offices alike suffer not only from lapses of critical thinking by individual members of the group, including its leaders, but also from various biases inherent in hierarchical structures. The same organizational processes and cultural characteristics that facilitate smooth corporate operations tend to inhibit original and contrarian thinking.

Micah Zenko’s Red Team explores a promising corrective technique: challenging established views through dedicated “red teams” that run simulations, conduct vulnerability probes, and analyze alternatives. Zenko—a Senior Fellow at the Council on Foreign Relations, columnist on, and frequent author on national security topics—suggests that adequately constructed and empowered red teams deliver fresh perspectives to decision-makers that can make the difference between success and failure…

Read the full review

Yvette d'Entremont
Don’t Mess With Her Pumpkin Spice Lattes

In this episode of Skepticality, Derek presents another interview from his trip to The Amazing Meeting 13, an interview with Yvette d’Entremont, a.k.a. SciBabe, an analytical chemist with a background in forensics and toxicology. Before working full-time as a science writer and public speaker, Yvette worked as a chemistry professor and a toxicology chemist researching pesticides for safety. She now runs her own blog/website, SciBabe, dedicated to debunking pseudoscience. Find out how SciBabe came to be and why she ended up focusing on clearing up misinformation about science, food and nutrition.

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Mr. Deity turns his all-knowingness back on.


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  1. Dawit Tesfazghi Ghebrmedhin says:

    “Every recursive change has its own continual leap. “

  2. Tzindaro says:

    “Climate change is real”and “climate change is caused by humans” are two different statements. “Climate change is caused by greenhouse gases” is a third statement that does not necessarily follow from the first two. It is entirely possible for the first two statements to be true and not the third one. The efforts cited are mostly devoted to establishing the first two statements, for which there is a great deal of evidence, but there is very little for the third, actually none at all.

    The acceptance of the third statement is not based on evidence, but on a lack of a competing theory to explain the other two. There is, in principle, no reason why the first two statements could not be correct and the third one wrong. But so far, very little effort has been made to identify or rule out any possible alternate theory of the MECHANISM by which humans are changing the climate. The greenhouse gases theory is accepted by default, for lack of any other explanation that the scientists can think of, not because there is evidence for it. In other words, it is based on ignorance, not evidence.

    And that is poor science.

  3. Dr. Sidethink says:

    It seems that you are suggesting that climate change would not exist if there were no humans.

    If there WAS climate change before these were humans, the logical implications are somewhere between humerus (pun intended) and astounding.


  4. Antoine A H Wonders says:

    There was climate change before humans. World climate is, and has always been, the result of plate tectonics, insolation, the dynamics of ice cap waxing and waning, the carbon cycle (as driven by vegetation, oceans and volcanism), and local factors. The current global warming has a significant component not related to those. Scientists cannot think of any other plausible explanation than greenhouse gases, because they have come to that conclusion after testing and rejecting alternatives. The bad science has already been done, based on the assumption that extra greenhouse gas wouldn’t effect climate.

  5. Tzindaro says:

    ” Scientists cannot think of any other plausible explanation than greenhouse gases, because they have come to that conclusion after testing and rejecting alternatives. ”

    Which alternatives did they test, please? Did they calculate the change in albedo caused by particulates from forest or bush fires or other destructive land-use practices such as ploughing, cattle-grazing, or urbanization? Did they calculate the impact of over-fishing on the plankton in the oceans that remove CO2 from the atmosphere? Did they look into the effects of radioactive Krypton 85 released by reprocessing of nuclear reactor fuel rods in altering the electrical characteristics of the atmosphere in the light of numerous findings that many storm systems are controlled by geo-electrical factors? Please tell me the citations for these possibilities that you say were tested before being ruled out.

    The inability to think of an alternative possibility is not evidence for the single possibility one can think of. It is evidence for an inability to think.

  6. Leo says:

    Even the broadest consensus can be wrong – truth is no quantitative (or democratic) feature, but that isn’t the point. The point is that the ‘scientific’ consensus is translatet into a moral statement, i.e. that climate (or any other) CHANGE IS BAD! That is a classical conservative assumption. There are losers and winners like in any other transformation – bad for Polar Bears, good for tropical insects. Bad for Florida (and some tropical islands) good for Portland (presumably). It is the moral implication that is to be challenged not the predictive models (even if they are questionable as well). But that woud be anti-dogmatic mainstream.

  7. klima says:

    is er een engels versie van deze site?

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