In the last few years, the concept of denialism has gained currency among science writers. It first came to my attention with Michael Specter’s book of the same title, and shortly thereafter, in the Hoofnagles’ blog on My concern is whether denialism is a useful and coherent concept. Should defenders of critical thinking and science add the fledgling term “denialism” to their vocabulary to help clarify talk about a particular class of unwelcome attitudes towards scientific progress and the scientific method? My judgment is negative on the question; we would do well to abandon the term “denialism,” just as we should abandon the use of any term that obscures valid distinctions while creating more confusion than it removes.

It pains me to come to this conclusion, because there are many things written by the Denialism Blog and other “anti-denialists” that I agree with. But to model critical thinking, I need to go wherever reason takes me, no matter how much I dislike the destination. The truth doesn’t care about our feelings.

Before I present the case for rejecting the concept of denialism, let me begin by applauding some of what these critics say, and acknowledge where they are on pretty solid ground. For example, I share the Denialism bloggers’ disdain for

… rhetorical tactics [that] give the appearance of argument or legitimate debate, when in actuality there is none. These false arguments are used when one has few or no facts to support one’s viewpoint against a scientific consensus or against overwhelming evidence to the contrary. They are effective in distracting from actual useful debate using emotionally appealing, but ultimately empty and illogical assertions.

These tactics include “conspiracy, selectivity (cherry-picking), fake experts, impossible expectations (also known as moving goalposts), and general fallacies of logic.”

And I applaud the “anti-denialists” goals:

We’re trying to inform people about denialism and how to recognize denialist arguments so that ultimately they will be less effective in swaying those that may not be fully informed about science. Hopefully, by creating awareness of the ground rules of legitimate scientific debate, citizens, policy makers, and the media may better distinguish between sound and unsound scientific debate.

The so-called “denialists” have an intellectual demeanor that I too find odious, characterized by their ability to “make things up” such that

it takes forever to knock down each argument as they’re only limited by their imagination while we’re limited by things like logic and data. … Denialists are not honest brokers in … debate … . They aren’t interested in truth, data, or informative discussion; they’re interested in their world view being the only one, and they’ll say anything to try to bring this about.

Many years ago, the late Martin Gardner wrote a wonderful book called Science: Good, Bad and Bogus in which he catalogued a wide variety of pseudoscience and crackpot theories. Garnder didn’t much press the distinction in the book’s title. Nevertheless, there is a difference in kind between conscientious scientific research that is ultimately shown to be flawed (the “bad” science) and pseudoscience or junk science (the “bogus”) which steadfastly evades the issue of what would constitute empirical disconfirmation for its theories. Keep this distinction in mind when you think about the following claims:

  • The Earth is flat
  • The Earth is less than 6,000 years old
  • Extraterrestrial beings have visited the Earth in UFOs
  • The Nazis did not conduct a program of genocide against the Jews in World War II
  • The sun and the other planets orbit the Earth
  • DTP vaccines cause autism in children
  • Fossil-fuel combustion has a small-to-negligible impact on global climate change
  • HIV is not the primary cause of AIDS

There are a couple of things to point out here. First, for each of these statements, there exists a scientific consensus that they are false. That is, there is now a consensus that they are false. A geocentric solar system used to be the scientific consensus; that shifted to a heliocentric consensus over four hundred years ago. (Always slow to embrace scientific progress, the Catholic Church didn’t remove heliocentric texts from its List of Forbidden Books until 1758.) The point is that we know what science was initially bad (or good) only in retrospect, as confirmatory or disconfirmatory evidence accumulates. While geocentricists might well be extinct, there are still plenty of young-Earthers around! So the second point is that “wackiness” can cover a wide range of plausibilities, from views held by deluded or pathologically confirmation-biased eccentrics to minority viewpoints among well-credentialed members of the scientific establishment.

Is everyone who hews to some statement on the “wacky list” automatically a “denialist?” No, because not everyone holding a “denialist thesis” has the wherewithal to defend it with “denialist arguments.” The anti-denialists admit that “just because some people believe in stupid things, doesn’t make them denialists… . We aren’t suggesting everybody who has a few wacky ideas is a crank… .” If that’s the case, before you brand someone a “denialist,” you need to expose their fallacious reasoning and their intellectual dishonesty. This is a burden of proof concern: it would be invalid to jump to the conclusion that someone is a “denialist” just because they happen to  be a skeptic about a claim for which some degree of scientific consensus exists. Laymen (the “uninitiated masses”) are to be given the benefit of the doubt.

On the other hand, it is not so clear that trained scientists are supposed to receive the same charity. After all, they are neither ignorant nor stupid; they should know better, right? So here is the main problem I have with the “anti-denialists:” the presumption that maverick scientists who dissent from the majority viewpoint are more likely to be “denialists” is nothing more than bias.  Given that bias, the “denialism” label is apt to be used as a rhetorical tactic to lump both real crackpots and serious skeptics together, thereby smearing the latter.

There clearly is a distinction to be made between a skeptic who does not think the available empirical evidence is sufficient to establish the acceptability of a hypothesis, regardless of how generally accepted it is, and pseudoscientist, i.e., someone who can’t imagine what evidence would be sufficient to change his mind. The styles of argumentation that they use will be entirely different. Ignoring this critical distinction between skeptical science and junk science  makes it easy to suggest that flat-Earthers and anthropogenic global warming skeptics are generally cut from the same epistemological cloth. The bloggers’ characterization of Richard Lindzen as a “denialist” (and not merely a skeptic) doesn’t do much to dispel the suggestion. So much for upholding the burden of proof.

Another concern with “denialism” is that it does not encourage constructive debate. On the contrary, it is a conversation-killer. If your beliefs align with current scientific consensus on some issue, it is understandably tempting to write off as a crank someone who disagrees, and forgo ever talking to them ― on the principle that “we don’t argue with cranks.” But if anti-denialism really is about the defense of critical thinking in science, then it can not be about the suppression and ridicule of intellectually honest skeptics raising questions that challenge scientific orthodoxy.

Showing that a concept conflates and confuses distinct types of things is enough to invalidate it. I think I’ve done that. Showing that it gives rise to anti-social antics further warrants rejecting its use. I’ll just ask one further question: what do we gain by recharacterizing some of the well-known irrationalities of junk science as “denialist arguments?” Sophistry and fraud have been the stock-in-trade of junk science for decades, at least. Insofar as our Denialism bloggers are on solid ground as critics of junk science,  there is nothing particularly novel in their approach. Have they really said anything that has not already been said (and continues to be said) under the rubric of “critical thinking” or within the context of debate concerning the soundness of specific scientific claims? Even if the concept of denialism were coherent, would we even need it?

Despite my sympathies with some of the work that science writers are doing in opposition to “denialism,” the concept behind it is highly problematic: it is redundant, licenses bias and skirting the burden of proof, and encourages labeling to excuse intellectual disengagement. Ultimately the concept is incoherent, since it permits a conflation of some forms of legitimate skepticism with the pseudoscientific rantings of bona fide crackpots and charlatans. Those of us concerned with promoting critical thinking and the public understanding of science can have more constructive conversations among ourselves and be more effective public advocates for science when we keep the distinctions between skepticism, junk science, and related notions clear. “Denialism” doesn’t help us achieve that goal.