Posts Tagged ‘consensus science’

Low-salt pseudo science

August 19, 2014

For almost 100 years, some scientists have been warning about the harmful effects of salt in our diets. For the last 40 years or so that has also been the “consensus” view of the medical/regulatory establishment. It was “settled science” we were told. There was complete “consensus” within the medical world it was proclaimed.

Salt was evil.

But apparently the “settled” science was not quite so settled after all. The “consensus” was nothing more than “group think”. In the words of the Wall Street Journal:

Yet the latest USDA food pyramid, which was updated as recently as 2011, clings to simplistic low-salt pseudo-science. The FDA is pressuring food manufacturers and restaurants to remove salt from their recipes and menus, while the public health lobby is still urging the agency to go further and regulate NaCl as if it were a poison.

The larger point is that no scientific enterprise is static, and political claims that some line of inquiry is over and “settled” are usually good indications that real debate and uncertainty are aboil. In medicine in particular, the illusion that science can provide some objective answer that applies to everyone—how much salt to eat, how and how often to screen for cancer, even whom to treat with cholesterol-lowering drugs, and so on—is a special danger.

It is not so easy now to retrace exactly how the salt scare developed and became part of the establishment view. Certainly Lewis Dahl of the Brookhaven National Laboratory was one of the key actors who spread the alarm. He was well placed within US Government circles and soon rather dubious and alarmist conclusions became part of the “establishment view”. Pseudo science became “settled science”:

Scientific American:

In 1904 French doctors reported that six of their subjects who had high blood pressure—a known risk factor for heart disease—were salt fiends. Worries escalated in the 1970s when Brookhaven National Laboratory’s Lewis Dahl claimed that he had  “unequivocal” evidence that salt causes hypertension: he induced high blood pressure in rats by feeding them the human equivalent of 500 grams of sodium a day. (Today the average American consumes 3.4 grams of sodium, or 8.5 grams of salt, a day.)

Dahl also discovered population trends that continue to be cited as strong evidence of a link between salt intake and high blood pressure. People living in countries with a high salt consumption—such as Japan—also tend to have high blood pressure and more strokes. But as a paper pointed out several years later in the American Journal of Hypertension, scientists had little luck finding such associations when they compared sodium intakes within populations, which suggested that genetics or other cultural factors might be the culprit. Nevertheless, in 1977 the U.S. Senate’s Select Committee on Nutrition and Human Needs released a report recommending that Americans cut their salt intake by 50 to 85 percent, based largely on Dahl’s work.

Thereafter “group think” took over. Consensus opinion – and not objective science – ruled. Now we are finding out that there is no clear evidence that salt is harmful and there is some evidence that too little salt is dangerous and can increase the risk of heart disease.

Scientific American:

In April 2010 the Institute of Medicine urged the U.S. Food and Drug Administration to regulate the amount of salt that food manufacturers put into products; New York City Mayor Michael Bloomberg has already convinced 16 companies to do so voluntarily. But if the U.S. does conquer salt, what will we gain? Bland french fries, for sure. But a healthy nation? Not necessarily.

This week a meta-analysis of seven studies involving a total of 6,250 subjects in the American Journal of Hypertension found no strong evidence that cutting salt intake reduces the risk for heart attacks, strokes or death in people with normal or high blood pressure. In May European researchers publishing in the Journal of the American Medical Association reported that the less sodium that study subjects excreted in their urine—an excellent measure of prior consumption—the greater their risk was of dying from heart disease. These findings call into question the common wisdom that excess salt is bad for you, but the evidence linking salt to heart disease has always been tenuous.

It has taken 40 years for this alarmist meme that salt is harmful to be brought down to earth. Group-think and “consensus science” has its own inertia which makes it difficult to overturn what becomes matters of faith rather than of evidence.

And just a few days ago another establishment paper created headlines when it stated that salt “causes 1.65 million deaths every year across the globe. A published study in New England Journal of Medicine on Thursday, found that an average consumed salt (sodium) per day is twice the amount recommended by the World Health Organization. A 3.95 gm consumption per day beyond the recommended amount of 2 gm”. But all they actually did was measure/estimate salt consumption and then multiplied that by an assumed death rate.  By the time the headlines were written a simple measurement of salt consumption became evidence of the dangers of salt! That’s consensus science!

The 1970s and 80s saw many such alarmist memes – based on little and dubious science – become the “consensus view” and the “politically correct” faith to be followed. It was the time when the nonsensical “Limits to Growth” became the bible of the day. It was the time of the DDT scare where the disadvantages were blown out of all proportion and the subsequent ban has been a case of “throwing the baby out with the bath water. Natural variations of the ozone hole were taken to be due to the human use of fluorocarbons. Acid rain was going to kill all the forests.

Whenever I now hear that some science is “settled” or that there is a consensus around some “belief” – as with climate science today – I am inclined to view the claims with a very large bushel of salt.

“Consensus science” – by definition – is not “science” and is a dangerous thing

April 30, 2013

The internet is full of polls that I generally find irritating. How many believe that “A” will happen? or that “B will win? or that “C” is better than “D”? Whatever the result of the poll may be, they show nothing more than where the preponderance of belief  lies. The polls are evidence only of what people believe; they are not evidence of the subject being voted upon.

Either something is or it is not.

If we don’t know whether it is or is not, we can formulate it as a hypothesis and address it by the scientific method. The formulation is then as a falsifiable hypothesis and we then predict what data might be collectable if the hypothesis was false. We then collect data and where data is not available we design and carry out experiments to provide such data. These data and their analysis should be tested – for the classical scientific method – to see if the hypothesis is false (not – it should be noted – to show that the hypothesis is true). Where the data cannot show the hypothesis to be false it means only that the hypothesis is still unproven but the data set adds to the body of evidence in favour of the hypothesis in the particular circumstances in which that data-set was collected.

When we don’t know we can still suppose the hypothesis to be true or false. But that is just a supposition and lies in the realms of belief and religion. We can take a vote within some group and see how many believe it to be true or to be false. Commercial and other interests may be vested in the supposition. Lobbying and persuasion can be applied in favour of or against the supposition. Voters can be influenced and cajoled and persuaded to vote for or against. A completely democratic and transparent system of voting may be applied. And  the result may be overwhelmingly in favour or against the supposition. But even where a majority – even an overwhelming majority of say 97% – of some group believes the proposed hypothesis to be true, the vote adds not one iota of evidence in favour of or against the hypothesis. An overwhelming vote that a hypothesis is true when it is actually false makes it no less false. All the vote can show is the preponderance of belief (and belief – by definition – comes into play when and because evidence is lacking).

And all that democratic process to establish what people believe brings us no closer to answering the question of whether the supposition is true.

But it gets worse.

Once a “democratic” majority has confirmed its belief in a supposed “truth” of a supposition, then there is a immense societal pressure against proving the supposition to be false. Falsifiable hypotheses are reformulated to be no longer falsifiable. The scientific method is perverted – for reasons of the vested interests – to now produce anecdotal evidence trying to “prove the hypothesis” rather than trying to collect data to try and show the hypothesis to be false. Evidence against the majority belief is not collected because it is no longer expedient to do so. Not only is it not collected, it is ignored even when it is plain and obvious. The moment a scientific hypothesis invokes or has to invoke a majority vote or a consensus in its support it leaves the scientific arena and enters the  political universe. Truth becomes whatever the majority believes. Proper scientific effort directed to falsifying the supposition is not just discouraged, it is penalised and attracts sanctions in the form of reduced funding and rejection of publications. It becomes heresy. Even where the believed supposition is actually true, the supposition remains as belief and cannot easily be brought back into the rational world.

As Judith Curry wrote recently:

With genuinely well-established scientific theories, ‘consensus’ is not discussed and the concept of consensus is arguably irrelevant.  For example, there is no point to discussing a consensus that the Earth orbits the sun, or that the hydrogen molecule has less mass than the nitrogen molecule.  While a consensus may arise surrounding a specific scientific hypothesis or theory, the existence of a consensus is not itself the evidence. ……. 

Given the complexity of the climate problem, ‘expert judgments’ about uncertainty and confidence levels are made by the IPCC on issues that are dominated by unquantifiable uncertainties. It is difficult to avoid concluding that the IPCC consensus is manufactured and that the existence of this consensus does not lend intellectual substance to their conclusions.

“Consensus science” has no option but to become science by majority vote. Polls replace evidence. And where the belief is false, the belief itself prevents a return to the truth. “Consensus science” as belief cannot be “science”. The simple fact is that whenever a “scientific hypothesis” invokes a consensus in its support it is – per force – just a belief. It becomes religion and not science. And that is a dangerous thing.

Related: Climate change: no consensus on consensus

Horror! Science cuts

September 25, 2010

science and funding

It is perfectly understandable, predictable and expected that the Science Establishment should find the idea of budget cuts unpalatable. Through the various recent financial crises Universities and Scientific establishments globally have come through relatively unscathed. But like all bubbles that have burst and are bursting it is perhaps time that the protected science funding bubbles took their share of the hit. It is also perhaps time for a return to the quest for scientific knowledge rather than the quest for science funding.

They cannot, on the one hand, use the excuse of “consensus science” to pour money down rotten drains and on the other demand a privileged position protected from the ills being suffered by the majority of society.

Democracy in Science to determine priorities and funding for paths of investigation is both inevitable and correct. But the science itself is indifferent to what the majority vote might think it should be.

In business and management it is almost a cliche that the greatest strides in productivity and effectiveness come at the time of budget and manpower cuts. I see no reason why this should not also apply to science and scientists. The weeping and the tearing of hair would be a little more convincing if it came from third parties and not the Scientific Establishment.

Martin Rees, the president of the Royal Society and all University Vice Chancellors are most perturbed at the spending cuts that might be implemented by the new UK government.

The New Scientist’s Roger Highfield bemoans the damage that could be done to SCIENCE.

Rees was speaking with five university vice chancellors as scientists steel themselves for deep cuts at the Department of Business, Innovation and Skills.

The gory details will be laid bare in October’s Comprehensive Spending Review, in which all government departments have been asked to prepare for budgets to fall by up to 25 per cent, perhaps even more.

In their submission to the Treasury, the Royal Society has described the potential effects of the cuts, where “an X per cent cut would lead to a much more than X per cent decrease in output, because we would lose the most talented people”. They outline three scenarios:

  • 20 per cent cuts are the “game over” scenario, which would cause irreversible destruction and be “very tragic”, said Rees.
  • 10 per cent is the “slash and burn” option with “serious consequences”.
  • Constant cash, a reduction in real terms, “could be accommodated”.

At the Royal Institution, during an event organised by the Campaign for Science and Engineering and the Science Media Centre, Rees also made the point that the UK will be less attractive to mobile talent and young people as other countries invest more in research.

Just to make sure that the Treasury gets the point, the Vice Chancellors also weighed in:

  • Glynis Breakwell of the University of Bath warned about “short termism” and the perils of stop-go funding, which would be “fatal”.
  • Malcolm Grant of University College London described how the cuts will damage research that “touches people’s lives”, squander the investment of the past two decades and damage an asset of great national importance.
  • Andy Haines of the London School of Hygiene and Tropical Medicine outlined how the cuts would harm health research as competitors, such as the US and China, are investing more in these areas.
  • Rick Trainor of King’s College London talked of the damage to long-term research capacity, and Simon Gaskell of Queen Mary, University of London once again underlined the harm to the pool of national talent.

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