As skeptics we apply various labels to certain kinds of intellectual behavior. Perhaps the big three are pseudoscience, conspiracy theory, and denialism. There are many specific subtypes of these three big categories, however. Quackery, for example, is medical pseudoscience. Tooth Fairy science, a term coined by Harriet Hall on SBM, refers to a certain type of crank pseudoscience in which many studies are done but they never challenge the core assumption of a claim.

These terms are useful because they have operational definitions. One of my first major pieces of skeptical writing was a dissection of exactly what makes a pseudoscience, and I have spent the last 20 years refining my understanding of this definition. I have done the same for denialism and conspiracy thinking. These are actual phenomena that need to be understood by any critical thinker. They are, I would argue, legitimate philosophical concepts.

Like all philosophical concepts, they often get abused when translated into the popular culture. What I have found is that these terms are mostly properly understood and used by those trying to be genuinely skeptical. There are varying levels of nuance, and all of these concepts are fuzzy around the edges, but in general people get what a conspiracy theory is, and when someone is denying established science.

Problems arise mainly with those who are the target of these labels – with those who believe in a particular pseudoscience or conspiracy theory or engage in denialism. They bristle at the application of these concepts to their beliefs, and often push back.

Their pushback takes a few forms. They of course can simply deny the specific accusation, and argue that creationism is legitimate science, or that global warming denial is just proper skepticism. Conspiracy theorists are fond of arguing that some conspiracies are demonstrably real, and therefore all conspiracy theories are somehow legitimate or at least plausible. This argument misses the point that it is the necessary size of an alleged conspiracy that makes it implausible.

Another strategy, however, is to go at the root concept, to deny that pseudoscience, conspiracy theories, or denialism even exist. They argue that these terms were invented by skeptics as pejorative labels to dismiss ideas they don’t like out of hand. In order to defend this position, however, they have to invent and attack skeptical straw men. If you read popular skeptical writing you will find that most thoughtful skeptics do not reject ideas out of hand, but go into great detail about exactly why a particular claim is not backed by credible science.

It is, in fact, often ironic that proponents of pseudoscience are often dismissive of skeptical arguments when they claim that skeptics are being dismissive. They often fail to address the details and meat of our analysis and the basis for our position.

For longer discussions of why these concepts are valid read the articles linked above, but here is a quick summary:

Pseudoscience is a process of supporting a particular claim that pretends to be scientific but is not being true to a valid scientific process. The core feature of pseudoscience is that it begins with a desired conclusion, and then works backwards to seek any supporting evidence. It relies upon poor scientific methodology, special pleading, cherry picking only supportive evidence, and making claims that go far beyond the evidence.

Conspiracy thinking uses the alleged existence of a conspiracy to explain the absence of evidence for a claim, and the existence of apparently contradictory evidence. In the extreme there is nothing that can, even in theory, disprove the conspiracy theory. In order to accomplish this, the conspiracy has to become larger and deeper with each new bit of contrary evidence that has to be explained away. Further, the conspirators need to be given incredible power, influence, and foresight in order to pull off the conspiracy, but also blatant stupidity to allow the conspiracy theorists to see through their machinations. Everyone who does not agree with them is dismissed as naive, or part of the conspiracy.

Denialism is the flip side of pseudoscience, where similar techniques are used to deny established science rather than promote a specific claim. They also begin with their conclusion, and engage in cherry picking, post-hoc reasoning, and special pleading. They rely heavily on the fallacy of moving the goalposts – no evidence is sufficient to convince them of the scientific claim they deny, so they keep moving the bar for what constitutes sufficient evidence.

When skeptics and scientists spend their time examining a belief, concluding that it is a pseudoscience of some sort, and then carefully arguing why they came to this conclusion, believers will often claim that they are being mean-spirited and closed-minded. They use as evidence for this characterization the mere fact that the skeptic applied some pseudoscience label to the belief, as if using such concepts is inherently biased.

Believers argue that by applying the label “conspiracy theory,” for example, people will be immediately prejudiced against it. Even if this were true, I find that argument irrelevant. You should be skeptical of something that can be legitimately labeled a pseudoscience or denialism, as long as that label is justified by detailed arguments. The label helps understand what is happening as part of a recurring phenomenon. There are commonalities among pseudosciences or conspiracy theories that justify lumping them under one conceptual label.

Further, the claim of prejudice may not even be true. A recent study looked at the effect of labeling a claim a “conspiracy theory” vs just calling it an “idea” or a “corruption allegation.” They found no difference is acceptance of the claim regardless of the label. The “conspiracy theory” label had no negative effect on the attitude of the participants toward the claims.

The authors speculate that this may be due to the fact that the conspiracy theory label has been used so much that its effect is diluted. The label itself is applied to even mundane accusations of corruption, and not reserved for the grand conspiracy theories that skeptics mean.

It also may be that enough people read the details of the claims and decide for themselves if they constitute a conspiracy theory or not. That may be overly optimistic, but I don’t think so. People are used to reading all sorts of claims on the internet, and most people do treat such claims as they would those of a used-car salesman. Yes, some people are just credulous, but I think most people are suspicious of claims they read on the internet.

That is – unless those claims are in line with their existing beliefs and ideology. That is what the psychological research shows – people are generally skeptical of claims unless those claims support their existing beliefs. The more emotionally invested they are in those beliefs, the more they engage in motivated reasoning to support them, to deny evidence, to accept pseudoscience, and to engage in conspiracy thinking.

What is perhaps even more interesting, is that there are subsets of people for whom each of these phenomena are their belief system. People tend to accept conspiracy theories whey they are in line with their political ideology, for example. If you are conservative you are much more likely to accept that global warming is a hoax. If you have an anti-corporate or anti-government ideology, you are more likely to deny the science of GM foods and believe that scientists are part of a conspiracy.

But if you are a conspiracy theorist, if the existence of conspiracies is your ideology, then you believe all conspiracies.

Likewise there seem to be those who like to deny all conventional science. They fancy themselves skeptics but they are really contrarians engaged in denialism.

There are also those whose ideology is anti-scientific, who reject that science can distinguish among claims that are likely to be true or not be true, and so routinely accept any pseudoscience.

Most people, however, are opportunistic pseudoscientists, deniers, and conspiracy theorists. They engage in such thinking when convenient in order to maintain their ideological belief systems.

And of course, being a true skeptic means understanding the nature of pseudoscience, of denialism and of conspiracy thinking. It means being vigilant for these cognitive pitfalls in your own thinking, and weeding them out as much as possible. It means trying really hard to accept what the science says, regardless of the implications for your existing beliefs.

Skepticism is a real thing also. It is a valid philosophical concept, and it is the antidote to pseudoscience, denialism, and conspiracy thinking.