Denialism is a thing. What I mean is that denialism is a definable intellectual strategy, with consistent features that tend to cluster together. I first wrote about denialism 12 years ago, before global warming denial made the term more widespread. I pointed out that certain beliefs tend to follow the same fallacious arguments – HIV denial, creationism (evolution denial), holocaust denial, and mental illness denial. I would add now global warming denial and germ theory/vaccine science denial.

I characterized denialism as a subset of pseudoscience, one that tries to cloak itself in the language of skepticism while eschewing the actual process of scientific skepticism. But further, denialism exists on a spectrum with skepticism, without a clear demarcation in between (similar to science and pseudoscience). People also tend to use themselves for calibration – anyone more skeptical than you is a denier, and anyone less skeptical than you is a true believer.

Geneticist Sean B. Carroll (not to be confused with the physicist Sean M. Carroll) in his 2007 book, The Making of the Fittest: DNA and the Ultimate Forensic Record of Evolution, lists what he identified as the six core features of denialism. I think they make an excellent list, and would like to expand on them:

1) Cast doubt on the science.

2) Question the scientists’ motives and integrity.

3) Magnify any disagreements among the scientists; cite gadflies as authorities.

4) Exaggerate the potential for harm from the science.

5) Appeal to the importance of personal freedom.

6) Object that acceptance of the science would repudiate some key philosophy.

As you will see, all of these strategies are insidious because they are extreme versions of reasonable positions. Their underlying principles are sound, it is their specific application that is the problem.

Doubt, for example, is key to skepticism and science. The absence of doubt is gullibility. This feature, most of all, is what makes denialism pseudo-skepticism. The problem with the denialist approach is that doubt is not used as a tool of honest questioning, but rather of undermining a belief one does not like. As with pseudoscience in general, they start with the conclusion then work backwards.

This strategy can also be called, “just asking questions” or “JAQing off.” You can often tell the difference because, when a true scientist asks a question they want an answer, and will give due consideration to any possibilities. Deniers, however, will ask the same undermining questions over and over, long after they have been definitively answered. The questions, used to cast doubt, are all they are interested in, not the process of discovery they are meant to inspire.

Questioning motives is extremely common among the opponents of science, in my experience. Just read the comments to any article on GMO and count how long it takes for anyone defending the science of GMO to be labeled a Monsanto Shill. Any critic of pseudoscience in medicine is automatically a Pharma shill. Climate scientists are just trying to use hysteria to get grants, and evolutionary biologists are secretly promoting atheism (even, apparently, when they are not atheists).

At the reasonable end of the spectrum is the sensible requirement for the full disclosure of potential conflicts of interest, so readers can judge for themselves the integrity of the source. This can easily slide into a witch hunt, however, with even the thinnest and past tenuous connection used to argue that a scientist is actually a paid shill and should be completely discounted.

Magnifying disagreements among scientists is easy to do, because such disagreements are always present. This can take two basic forms: The first is to magnify the implication of the disagreement – in other words, present a disagreement over small details as if they call into question much more fundamental aspects of the science. This feature was on my list as well, “Confusing internal debate over details with negation of the whole.” Creationists, for example, will use debate over the exact sequence of evolutionary branchings to argue that no evolution occurred at all.

The second aspect of this strategy, as Carroll implies with his reference to gadflies, is to present a small minority dissent as if it is a mainstream controversy. You can almost always find some scientists somewhere to disagree with even the most solid scientific consensus. I have argued that this is a good thing. Complacency can lead to stagnation in science, and it’s always good to have someone shaking the tree. But we have to put such dissent into context. Sometimes it’s a genuine controversy, and the science can go either way. Other times the science is solid and the dissent is insignificant.

Exaggerating the potential for harm also suffers from the demarcation problem. A reasonable application of the precautionary principle means that we anticipate potential harm and err on the side of avoiding it. Denialists, however, can take rare or insignificant risks and magnify them, even arguing that the slightest potential for harm is unacceptable. Vaccine deniers, for example, demand zero risk from vaccines. HIV deniers exaggerate the side effects of anti-HIV drugs, while minimizing their efficacy.

Personal freedom is highly valued in US culture (and elsewhere), so the appeal to personal freedom is especially effective. This is why appealing to freedom is so common. Laws meant to shield charlatans from the standard of care in medicine are sold as “healthcare freedom” laws. Creationist attempts to undermine the teaching of evolution are framed as “academic freedom.” Anti-vaccinationists, of course, are constantly advocating for the parents right to choose.

Finally, I agree that noting that accepting a particular science would be inconvenient for a particular political or religious ideology is also extremely common. Creationists argue that accepting evolution will undermine belief in God, and even result in moral decay. Global warming deniers argue that accepting the “alarmist” claims about climate change will result in a government take over of private industry. I characterized this strategy as an argument from final consequences logical fallacy – evolution is wrong because if it were true society would suffer moral decay.

This feature also often provides a clue as to the true motivation of the denial. The science is secondary – it is the moral hazard they are truly concerned about.

I have also pointed out that this is an inherently flawed strategy. If you truly wish to advocate for a particular moral or ethical position, the worst thing you can to is tie that position to a false scientific position. Doing so allows opponents to attack your moral position by attacking the pseudoscience to which you have anchored it. You are far better off acknowledging legitimate science, and advocating for your moral position on moral grounds.

If you ideologically favor free markets, then don’t deny global warming, rather offer free-market solutions.

In my 2012 discussion of denialism I also pointed out several other common features, although they are related to the list above. For example, in order to manufacture doubt about a particular science or scientific conclusion, deniers use several specific strategies. They often use semantic arguments in place of substantive arguments, sometimes playing on the difference between colloquial and technical definitions of terms. Mental illness deniers, for example, try to define mental illness out of existence by defining “illness” in a narrow way that is meant to exclude anything cognitive or behavioral.

Evolution deniers do the same thing, defining science in a deliberately narrow way in order to exclude all historical sciences, including evolution.

Deniers also use some generic strategies of pseudoscience, such as making selective use of evidence or cherry picking. Global warming deniers, for example, point to the pause in warming of global surface temperatures, while ignoring ocean temperatures. Or they point to the recent increase in arctic ice, while ignoring the longer term decreasing trend, or the increase in antarctic sea ice, ignoring the decrease in antarctic land ice, or the global decrease in all ice.

Deniers further like to move the goalpost. No matter how much evidence you can produce to support the science they dislike, it isn’t enough. Fill in one gap, and they will point to the smaller gaps. At times they move the goalposts forever out of reach – “show me one study that proves, by itself, that HIV and only HIV causes AIDS .” That sort of conclusion requires dozens of studies. This is similar to the challenge to “show me one fossil that proves evolution.”

Vaccine deniers ask for evidence of vaccine safety, but no amount of evidence is enough. Thimerosal is mostly removed from vaccines, and they just move onto the the next “toxin.” They demand the one kind of study that will never happen, a randomized vaccinated vs unvaccinated study (because you ethically cannot randomize children to not receive standard medical care). This is identical to the strategy of denial used by the tobacco industry, demanding a randomized controlled study of smoking vs non-smoking.

Related to this is the abuse of the caution not to assume causation from correlation. It is true that correlation is not necessarily causation, but it might be. Multiple independent correlations can be used to arrive at a high probability of a specific causation, such as smoking causing lung cancer.

Finally, deniers are fond of claiming that there is emerging skepticism towards the science they are denying. Creationists argue that evolution is a “theory in crisis” that is on the verge of being rejected by the mainstream. Global warming is a hoax that is being exposed. The public is starting to wise up about vaccines and will soon reject them. Just you wait – we will be vindicated in the near future.

Conclusion

Denialism is essentially a form of pseudoscience. It begins with the conclusion and then works backward to fill in arguments that support the desired conclusion, which in the case of denialism is opposition to a scientific conclusion (rather than support for an unscientific one).

Denialism is common because this appears to be the default mode of human psychology. People tend to cling to their beliefs (even when those beliefs are arbitrary, or have been assigned to them), and then will jealously defend those beliefs. The more intelligent and even informed someone is, the better they are able to marshal arguments in support of their belief and rationalize away inconvenient data. This behavior seems to be directly proportional to the emotional investment in the belief.

The only solution I can see is to make a conscious effort to become emotionally uninvested in any particular belief. This is easier said than done, but it is a worthy goal. Instead we should be invested in using a valid process, and then accept whatever conclusion that process leads to. This is a high energy path to follow as it seems to go upstream against our inherent human nature. It is a path worth taking, however.