Scientists Can Agree on Things that Aren’t So

Whenever you hear “all scientists agree” or “we now know,” it’s no guarantee a finding won’t be disputed years later.  In the following examples, CEH focuses not so much on the content of the disputed subjects as the implications for philosophy of science.

The big warmup:  One very strong consensus among establishment scientists right now is that humans are causing global warming.  Science Daily reported a survey of 4,000 abstracts of scientific papers that indicated an “overwhelming consensus among scientists,” as high as 97%, “that recent warming is human-caused” (cf. fallacy of statistics).  Yet contrary data still arise from time to time.  For instance, New Scientist reported that re-analysis of global temperatures over the last decade shows that “Earth will warm more slowly over this century than we thought it would” – diminishing some of the frantic appeals for immediate action of past years.  Apparently the rate of heating hit a plateau even with more greenhouse gases being pumped into the atmosphere.  It doesn’t change the consensus; the new data are just “buying us a little more time to cut our greenhouse gas emissions and prevent dangerous climate change,” the article continued.  Likewise, PhysOrg spun the new data to mean that we still face a “Dire outlook despite global warming ‘pause’,” according to the study published in Nature Geoscience.  Skeptics of global warming like to point out that a few decades ago, the consensus warned that Earth was approaching a period of global cooling that would have drastic effects on human life.

What will the consensus believe about climate change in a few years or decades?  Nobody knows.  It’s instructive, though, to look at other examples of shifting consensus in science.

Salt is good:  Jesus once said “Salt it good” (intending a spiritual application, Luke 14:34), but dietary salt has been a bogeyman for many years according to the scientific community.  That’s why it was shocking to find a report in Science Magazine that “smashes the paradigm that lower [salt intake] is better.”  It’s a serious overturn, too: “an expert panel … says that there is little evidence that dropping below 2300 mg of salt lowers the risk of cardiovascular disease—and some hints it might actually do harm.”  Some scientists, to be sure, are complaining that the report is flawed, but the problem is that science may never be able to figure out what advice is sound:

Radically reducing your salt intake is good for your health. Or is it? That question is at the center of a passionate debate once again after an Institute of Medicine (IOM) report last week called into question official recommendations advising people to consume less sodium. The high-profile study is the latest in a controversy that has raged for decades—and some researchers say the science of salt is so complex that they may never find solid answers.

Those already at risk of cardiovascular problems might benefit from lower sodium intake, but what about the majority of healthy people?  Scientists still agree that American consumption is too high; it’s mainly the advice for radical reduction that is being questioned.  But who knows?  Evidence linking high salt intake to disease for healthy people is spotty.  Philosophically, there’s also a risk of confusing cause and effect:

The evidence is far from clear-cut. It mainly comes from studies on patients treated for serious diseases, which means there is a danger of confusing cause and effect, Antman warns. For instance, patients with heart failure or metastatic cancer might have a low sodium intake simply because they eat less. “This is not solid evidence,” he says.

The article goes on to give physiological reasons why reduced sodium might cause harm in some people.  There may be political and rhetorical reasons behind the low-salt craze, too: “Sodium is just easier to measure and make public policy around,” one remarked.  Another said, “If you are going to ask people to change something, you need to have at least a clue that there will be a benefit.”

Consensus is the business of politics. Science, on the contrary, requires only one investigator who happens to be right.

Fat is not all bad:  Here’s another surprise.  Obesity has been a large topic for discussion in the news.  Fat certainly doesn’t improve one’s looks, but does it shorten life?  Possibly not, reported Nature. In “The big fat truth,” Virginia Hughes revealed a kind of scientific conspiracy: “More and more studies show that being overweight does not always shorten life — but some public-health researchers would rather not talk about them.”  And it’s not just that being a little overweight is less harmful than thought.  Look at this: a recent study published in the Journal of the American Medical Association provided evidence that “people deemed ‘overweight’ by international standards were 6% less likely to die than were those of ‘normal’ weight over the same time period.”  This caused an outrage at Harvard, where organizers of a packed-out event wanted to explain “why [the] new study about weight and death was absolutely wrong.”  It’s a “pile of rubbish,” one scientist said, worried about how the fast-food industry might spin the story.  Nevertheless, Nature sided with the need to remain objective about the “obesity paradox” a string of findings showing that, while obesity is clearly bad, having a few extra pounds is not necessarily unhealthy—and might actually be beneficial.

The story illustrates how the political and sociological influences on scientific consensus cannot be ignored.  The article tied into our first discussion about climate change:

Willett says that he is also concerned that obesity-paradox studies could undermine people’s trust in science. “You hear it so often, people say: ‘I read something one month and then a couple of months later I hear the opposite. Scientists just can’t get it right‘,” he says. “We see that time and time again being exploited, by the soda industry, in the case of obesity, or by the oil industry, in the case of global warming.”

But isn’t it science’s job to “get the world right,” not to worry about policy?  Can they blame individuals and industries for taking advantage of findings that contradict the consensus?  That’s how the lead author of the JAMA paper feels.  “Our job is not to make policy, it’s to provide accurate information to guide policy-makers and other people who are interested in these topics,” Katherine Flegal said.

Ethicists act ethically, right?  Readers might be disturbed to find out that experts whose business it is to judge ethics do not necessarily act any more ethically than the rest of us.  Science Daily wonders who is watching the watchers:

Do ethicists engage in better moral behavior than other professors? The answer is no. Nor are they more likely than nonethicists to act according to values they espouse, according to researchers from the University of California, Riverside and Stetson University in Florida.

Volcano winter, not:  It made for a good story.  A super-eruption of Indonesian supervolcano Mt. Toba 70,000 years ago—the largest eruption of the past 2.5 million years—changed the course of human evolution, driving our ancestors nearly extinct in a kind of “nuclear winter” scenario as ash blocked the sun and made early man shiver to death.  Maybe not; Live Science reported, based on a paper in PNAS, that new evidence shows little if any effect on humans in Africa or India, even though ash has been found twice as far away as previously thought.  Even though Mt. Toba put out over 200 times as much ash as Krakatoa, there was no evidence of cooling in lake sediments in Africa, and artifacts from India show that people got along fairly well.

Who’s crazy?  As reported before (5/10/13, 5/18/12), psychiatry is embroiled in controversy with the release of its new bible of psychiatric diseases, DSM-5, this month.  Are we to believe one article in New Scientist that 1 in 5 children develops a mental disorder each year?  Or is Live Science more correct to question the controversial diagnoses in the field’s bible?  Maybe the authors of the manual need a serious diagnosis themselves if they think 20% of the population is abnormal.  Evolution News & Views considered this an example of how a “science” can collapse, comparing 14 of psychiatry’s faults with those of Darwinian evolution.

Bye-bye, instinctual attachment theory:  It was all the rage in the post-World War II era: “instinctual attachment theory.”  Have you seen those black-and-white photos of Harry Harlow getting a monkey baby to cuddle up to a fake mother made of wire and cloth?  The conclusion drawn from such experiments by Konrad Lorentz and John Bowlby was that infant humans are like baby ducks, imprinting on their mother at a critical period of “instinctual attachment.”  Without it, they develop psychological problems.  The researchers apparently ignored other factors, like peer influence, on maturation.  Writing for Science Magazine, Ben Harris did not have much good to say about this flawed theory in hindsight as he reviewed a new book on it by historian of science Marga Vicedo, titled The Nature and Nurture of Love From Imprinting to Attachment in Cold War America (U of Chicago Press).   The take-home message is larger than one story about how a few scientists fooled themselves and the public:

As the reader learns, animal research was not the only discipline misrepresented by the radical instinctivists. Anna Freud, for example, complained that Bowlby excised the subjective, psychological essence of psychoanalysis in his fervor to biologize the infant-mother bond. In her chronicles of such disagreements between Bowlby and his critics, Vicedo’s analysis of scientific evidence is thorough enough to be used in a course on research methodology.

As a historian of science, however, she is after bigger game. She asks how a scientific theory can endure when its evidence and logic are persuasively refuted by experts. Her answer is that Bowlby’s attachment theory brought the authority of biology to the seemingly less rigorous field of developmental psychology. It also borrowed from enough scientific and social-scientific specialties to outflank critics who only knew one discipline. And compared to their opponents, Bowlby and Lorenz presented a united front that persisted for decades—while others moved to new research questions.

Caveat emptor:  When evaluating “What science says” or “What scientists believe,” we should remember H. L. Mencken’s proverb, “For every complex problem there is an answer that is clear, simple, and wrong.”  Politicians and special-interest groups are all too hasty to cite the consensus in support of their agendas, charging their opponents with being “deniers” or worse if they dispute what “science says.”  Mario Livio, writing for Nature in the aftermath of some recent high-profile retractions and frauds, called on scientists to embrace their mistakes.  There’s a human tendency to want to cover up research mistakes, but in actuality, even the mistake can trigger scientific progress in other directions.

In the “Science and Culture Update” on talk-show host Michael Medved’s radio program this week (hear it on ID the Future), Discovery Institute fellows Stephen Meyer and Jay Richards chatted with Medved about the problems with scientific consensus.  When should an individual doubt a concensus?  Richards explains that “the consensus says” can be a catch-phrase that signals an appeal to authority – else the debater would simply cite the evidence to support his claim.  Meyer emphasized that good science thrives on open debate, not just about the evidence, but about the interpretation of the evidence.  “Saying there’s a consensus means we don’t have to argue.  That’s what’s unscientific,” he said.

In 2003, the late novelist Michael Crichton gave a devastating critique of consensus to an audience of scientists at Caltech, where he said, “Consensus is the business of politics. Science, on the contrary, requires only one investigator who happens to be right, which means that he or she has results that are verifiable by reference to the real world.  In science consensus is irrelevant.”  For more of his comments, see the 12/27/2003 entry or the entire speech here.

As we consider these lessons for their application to the creation-evolution debate, we offer a quote by William Patten of Dartmouth from 1930: “Evolution itself has long since passed out of the field of scientific controversy.  There is no other subject on which scientific opinion is so completely unanimous.  It is the one great truth we most surely know.”  In 1943, Edwin Grant Conklin said, “The fact of evolution is no longer questioned by men of science.”  Yet evolution remains controversial to the present, a majority of the public disagreeing with the scientific consensus.  The Darwinians continue using their consensus as a bandwagon fallacy to try to keep their critics at bay.  We think scientific conclusions should be determined by the evidence, not the consensus.  If one Darwin skeptic were right, and a million scientists disagreed, who would you believe?

This entry is primarily about scientific consensus, but the flip side is that non-scientists can also hang onto notions that aren’t true.  To that problem, we would like to show that gullibility is part of human nature, something we all need to address.  While scientists are “supposed to” have more rigorous standards of evidence, we wrongly assume that the category “scientist” is different in kind from that of “people” in general.  Here’s a quote by C. S. Lewis that ties us all together: “Experimental verification is not a new kind of assurance coming in to supply the deficiencies of mere logic.  We should therefore abandon the distinction between scientific and non-scientific thought. The proper distinction is between logical and non-logical thought.”