What’s the difference between skeptics and denialists?

Crumpled colorful paper notes with words "Wrong", "Right" and question marks.

Why are those who battle pseudoscience called skeptics?

It’s not because they are skeptical in the colloquial sense. Rather, the term refers to the philosophy of skepticism. It’s an approach to knowledge that requires that claims be well supported by evidence.

According to Wikipedia:

[pullquote align=”right” cite=”” link=”” color=”” class=”” size=””]Skeptics won’t believe without evidence; denialists won’t believe evidence.[/pullquote]

In philosophy, skepticism refers more specifically to any one of several propositions. These include propositions about:

(a) an inquiry,
(b) a method of obtaining knowledge through systematic doubt and continual testing,
(c) the arbitrariness, relativity, or subjectivity of moral values,
(d) the limitations of knowledge,
(e) a method of intellectual caution and suspended judgment.

Are people who are skeptical of scientific consensus on issues like vaccines and evolution entitled to be called skeptics? No, they’re denialists as Andrew Dart explains in an chapter from Building your Skeptical Toolkit:

… [T]here are a lot of people who like to call themselves skeptics but who it can be strongly argued are anything but. There’s HIV/AIDS skeptics, global warming skeptics, moon landing skeptics, evolution skeptics, holocaust skeptics, 9/11 skeptics and vaccination skeptics, to name but a few. But while there may be some people who would use these labels who could legitimately be described as skeptics the vast majority of them are not practicing skepticism at all, but rather skepticism’s evil twin, denialism.

What’s the difference between skeptics and denialists?

Denialism … is driven by ideology rather than evidence. Now denialists may claim they care about the evidence and will happily display any that supports their point of view, but in most cases they reject far more evidence than they accept. Furthermore, denialists will cling to evidence no matter how many times they have been shown that it is flawed, incorrect or that it does not support their conclusions; the same old arguments just come up again and again. Denialism also tends to focus on trying to generate a controversy surrounding the subject at hand, often in the public rather than scientific arena, and does so more often than not by denying that a scientific consensus on the matter even exists.

It’s easy to see how anti-vaccine parents and creationists are denialists. Though it isn’t as obvious, natural childbirth and homebirth advocates are denialists, too. They deny the scientific consensus of modern obstetrics. And natural childbirth and homebirth advocates share key attitudes with anti-vaxxers, creationists and other denialists.

1. Denialists love of conspiracy theories.

As Dart explains:

So the vast majority of the scientific community and an overwhelming mountain of evidence is aligned against you, what are you going to do? Well you could always claim that there is a conspiracy to supress the truth and that the scientists working in the field are engaged in a complex cover up for some bizarre and often undefined reason…

Anti-vaxxers are blunt about their favorite conspiracy: Big Pharma is in cahoots with Big Medicine to make money from useless and/or harmful vaccines.

Natural childbirth and homebirth advocates do include some blunt conspiracy theories like the idea that C-sections occur because obstetricians want to get to their golf games, but professional natural childbirth and homebirth advocates are more subtle. They assert an acculturation conspiracy, whereby doctors are “socialized” to participate in the conspiracy to foist harmful/scientifically unsubstantiated practices on women.

Most scientists are viewed as simply towing the party line and it is assumed that none of them ever comes to their own conclusions based upon the evidence; they just believe what they are told to believe. As for the peer review process, well that is just a tool of the conspiracy to make sure that only those papers that agree with the conspirator’s message get published.

Conspiracy theories, whether blunt or subtle are nothing more than evasions.

These conspiracy theories never attempt to actually address the evidence; rather they seek to dismiss it entirely as a fabrication of unseen forces. Furthermore no explanation as to how a conspiracy so vast that it encompasses every scientist in a given field, as well as every student studying to become a scientist in that field, can maintain itself without someone blowing the whistle is ever given, and reasons why the conspiracies exist in the first place are equally rare and incoherent.

2. Denialists love fake experts.

Fake experts are defined as people who claim to be experts in a given field but whose opinions differ greatly from the consensus of scientists working in that field and from established knowledge…

Only in the world of anti-vax and alternative health can actresses and other public figures without medical training be considered experts.

3. Denialists love cherry-picking.

Cherry picking is the act of selecting papers and evidence that seem to support your point of view, whilst at the same time ignoring the far greater body of evidence that goes against
your position.

Anti-vaxxers, like most advocates of alternative health, make cherry-picking even easier than usual since they don’t even bother to read the articles they cite.

4. Denialists love impossible expectations

Hence the insistence by anti-vaxxers that we don’t know if vaccines are effective if we don’t have a randomized controlled trial of vaccines vs. placebo, an experiment that would be unethical.

5. Denialists love logical fallacies.

I’ve written extensively about the logical fallacies favored by natural childbirth and homebirth advocates including the argument from ignorance, and the fallacy of the lonely fact.

Dart’s conclusion is one that anyone who cares about scientific integrity should keep in mind:

It is not the topic that makes someone a skeptic or a denier, it is how they handle evidence that contradicts their pre-existing beliefs. Do they resort to claiming there is a conspiracy to suppress the truth in order to explain why the evidence is against them? Are the people presenting the argument actually experts in the topic at hand? Do they cherry pick the data and only present those findings that agree with them? And do they constantly move the goalposts and make use of logical fallacies in defense of their claims? If you keep a look out for these five things then you should have a good idea whether you are dealing with a genuine skeptic or a closed minded denier.

How can lay people tell the difference between skeptics and denialists? The best way is to master the scientific literature of the topic under discussion. Then you will understand what the preponderance of the scientific evidence shows and you will recognize cherry picking. You can also read up about logical fallacies since those are often employed in defense of pseudoscience.

But there’s an easier way. As Dart notes, denialists can’t handle evidence that contradicts their pre-existing beliefs. That’s why denialist websites, message board and Facebook pages delete scientific evidence that does not support their claims and ban anyone who posts such evidence. They create echo chambers where they will never be forced to address dissent. They resort to elaborate and nonsensical conspiracy theories to promote claims that have been repeatedly disproven. If you find yourself on such a website, message board or Facebook page, you can be sure they are peddling pseudoscience.

Simply put:

Skeptics won’t believe without evidence; denialists won’t believe evidence.