Protect science! – The lack of intellectual integrity exemplified by a recent public discussion in Germany

The recent debate in Germany about the health consequences of air pollution, particulate matter and nitrogen oxides has shown how scientific research results can suddenly becomethe center of a heated political discussion. It was triggered by the publication of a position paper by Dieter Köhler, a pneumologist (lung researcher), and Thomas Koch, an engineer who has been active in the automotive industry for many years, on 22 January 2019.

In their two-page paper, which takes more the form of a press release rather than that a scientific research study, the authors boldly claim that the views shared by various health organizations (including the World Health Organization, WHO) on the health risks posed by air pollution, particulate matter and nitrogen oxides lack a solid scientific basis. According to the authors, the many studies on the dangers of air pollution have great weaknesses, the data used has been interpreted one-sidedly, and in general the researchers have been biased. Hard stuff. Is someone finally calling the scientific community to order and explaining to us what the world really is like? The assertions made weigh so heavily that one would expect them to be supported by valid and strong arguments, at best hard scientific evidence. In this case, such an opinion would be desirable and would greatly help the scientific and social debate on this important issue, as the issue of the health hazards associated with traffic is particularly explosive in Germany with its large car industry and the recent manipulation scandals by VW and other car makers. Instead of the expected scientific evidence, however, the authors are embarking on an embarrassing sham debate with sometimes hair-raising arguments that are very reminiscent of the argumentation patterns of climate change deniers and tobacco lobbyists. Let us take a look at them in detail.

First, Köhler and Koch use the commonplace argument that correlations are not causalities. We know this statement from other science skeptical circles. What makes it so seductive for many people is that it is true, even if it is not at allapplicable. Of course, from a data study that shows us correlations, we can never be sure about causalities. Anyone who claims this (or cites it as a criticism of an existing view) has not grasped the essence of science. Just as a scientific theory can never claim ultimate truth, observations and data are never ultimatefor making final causal connections. However, a causality, or the correctness of a scientific theory,can be assumedtrue (even if this is not 100% certain), if 1. the effects have been observed in many different, independent studies carried out with various methods, and 2. there exists a probable mechanism or a plausible theory. Both conditions are easily met here: There are tens of thousands of studies on air pollutants and their influence on our health, and the combination of particulate matter or nitrogen oxides and lung inflammation is very plausible (nitrogen dioxide is a corrosive irritant gas). And even if, despite all the studies, this finding should at some point turn out to be wrong (there is always a certain – albeit very small – probability that this will happen, as well as that climate change is actually not caused by humans), until then risk ethics requires attention to be paid to the possibility of very harmful (in the case of climate change even apocalyptic) developments.

A very similar (actually the same) point is the one that the authors cite as the second „argument“: There are many other factors that influence disease frequency and life expectancy. This, too, is quite banal, but can hardly be a suitable ground to refute an existing consensus on the harmfulness of air pollution for our health. In view of what has been said above concerning the first argument, there is no need for any further reply on this point.

Next, the authors discuss thresholds and the question about the exact mechanisms by which air pollution affects the human body („toxicity patterns“). In fact, it is difficult to isolate the effects of nitrogen oxides on our health. There are countless epidemiological studies on this subject, often with thousands of participants and many hundreds of variables and correspondingly complex statistical models. The risk of biases in the studies is reduced as much as possible by researchers excluding the influence of other known factors. Absolute certainty, however, never exists. Nevertheless, the harmful effect of particulate matter is clearly proven, while the uncertainties are somewhat greater for nitrogen oxides. However, it is almost impossible to get to a single threshold value, which summarizes everything and above which concentration of fine dust particles and nitrogen oxides are definitely harmful. But to conclude from this that „all these studies measure a constant disturbance variable (bias)“ is downright insane. With the same reasoning one could say that we do not understand exactly how the increasing CO2 content in the atmosphere affects the global (and local) climate, so we have to conclude that it does not do so at all. Using such an argument to declare the scientific work behind thousands of studies as flawed or even interest driven is deeply deceitful.

However, the authors keep the most outrageous argumentation, ironically listed in the paper as „the strongest argument against the extremely one-sided evaluation of the studies“, for a final climax. Here the smokers are drawn in, who „quasi voluntarily participate in a huge exposure study“. From the well-known fact that smoking shortens life expectancy by about ten years, Köhler and Koch conclude daringly that smokers, who with each cigarette inhale one hundred to 1000 times as much nitrogen oxides and particulate matter, „would all have to die after a few months“. Since they obviously do not do that, the studies must be wrong. That is of course complete nonsense, as experts have already called the authors on that conclusion. It is based on a variation of the very logical error of reasoning that the authors coined towards with such polemical intent in their first argument. For it is of course also true that a lack of correlation in one context cannot be used to infer a lack of causality in another (possibly related) context. Most smokers simply do not smoke for 24 hours and neither do pregnant women, babies and children. In contrast all are inhaling pollution.

Finally, the authors point out that all current information on pollution „essentially comes from the same source“. This is a grossly false statement, in clearer words a plain lie, which comes close to the standards of Donald Trump. Countless independent research studies have contributed to the scientific consensus on this issue that has emerged over many years. By the way, neither of the two authors has ever participated in this research: In his career, Köhler has not published a single peer-reviewed study on nitrogen oxides or on the health hazards of particulate matter in a scientific journal. He published only one article in the non-peer-reviewed “Ärzteblatt”, which is more of an official communication organ of the German chamber of doctors than an accepted science journal. And Koch has is an engineer far away from any medical research.

Instead of presenting their doubts and criticisms in scientific circles and discussing them with experts and thus contributing to a constructive scientific exchange, the authors chose the path via the public. Obviously they are more interested in showmanship, self-affirmation, lobbyism or the spread of ideologies than in „objectifying the discussion“. It is about the biased sowing of doubts about scientific statements, which deliberately creates uncertainty, which can then be politically exploited.On a subject as important as air pollution and the threat to our health, arguing with false facts and lies is, however, not only inappropriate but lacks intellectual integrity. Science is still the most effective method against alternative facts. That is why populists like Köhler and Koch discredit and fight itsfindings with such vehement words. The fact that they are partly successful is all the worse. An unholy alliance of politicians from the CSU, FDP and AfD as well as the German Federation for Motor Trades and Repairs welcomed their statements swiftly demanding respective legislative changes.

At the latest when the German Minister for Transport and Infrastructure,Andreas Scheuer (CSU),states that the initiative will bring „objectivity and facts into the diesel debate“, civil society will have to stand up and defend itself against the denigration of science by unscrupulous populists. This is also the task of the liberal press, which in some cases frighteningly uncritically reiterated the statements of the critics and thus ensured that this populist polemic against established scientific findings received media attention in the first place. This is ultimately a question of intellectual integrity. And the latter is, after all, the foundation of our open society.


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