Guest post: Denialism as Pseudoscientific Thinking.

In pseudoscience there’s a subtype called Denialism. Denialism seeks to deny an established science and violate multiple principles of logic, and scientific methodology, this is mostly because of a priori beliefs and preconceptions. Typically the same cognitive and logical errors are committed in denialism reasoning.

The whole process starts with a desired conclusion, that a generally accepted scientific or historical claim is not true. Denialists have ideological reasons, and engage in motivated reasoning, rationalizing away the undesired claim.

In essence and practical terms, they work backward from their desired conclusion, filling in justifications.

1. Moving the goalposts

In moving the goalposts, they always demand more evidence for a claim, even if currently available. However when that burden of evidence is met, the goalposts are moved and more evidence is demanded.

They may use vagueness in defining a certain term to move the goalpost away from any possible dis-confirming evidence.

2. Unreasonable demand for evidence

Because science has gaps, they explore them as if it the specific scientific theory being discussed is invalid or not well established.

Let’s take the example of HIV denial. Deniers often demand a single study or scientific paper establishing HIV as the cause of AIDS. However, it is not established by a single study but rather by a large body of evidence.

In scientific reasoning we must see if the gaps are slowly being filled, and if predictions are met, and if it fits together with other lines of evidence, observational or experimental.

If a theory has been going around in circles and not progressing, that is a strong indication of pseudoscience.

3. Pointing out disagreements

Disagreements within a discipline are explored, often small details, as if the science in question is not solid.

4. Denying entire categories of evidence

Another strategy the narrowing of evidence that may count as “scientific”. The most common is using the logical fallacy of confusing correlation with causation.

Correlation is not the same as causation, not necessarily anyway. Correlations need to be used properly, and multiple correlations can triangulate a specific causal relationship observed in a correlation. Epidemiology is based on correlations and observational evidence, if they were invalid the entire field simply would vanish.

They can even deny all historical sciences such as astronomy, geology, or even forensics.

5. False dichotomy

This is an argument from ignorance. If a version of events is not true then the alternate claim or version must be. However, they rarely provide positive evidence for their alternate claim.

6. Campaign of Doubt

Little factoids can be gathered and taken out of context. The goal is to sow doubt, uncertainty, and distrust, focusing on apparent inconsistencies, or gaps. However in healthy skepticism we consider all the evidence in the proper perspective, and even though knowledge is incomplete, reliable conclusions can be achieved.

7. Conspiracy theory

As a last resort comes the conspiracy theory, claiming that the scientific evidence itself is fraudulent, a grand conspiracy. This tactic allows them to dismiss all the evidence and rationalize it away.



Grant, John. Denying Science. Amherst: Prometheus Books, 2011.

Novella, Steven. “More on God of the Gaps.” NeuroLogica Blog. http://theness.com/neurologicablog/index.php/more-on-god-of-the-gaps

Novella, Steven. “Skepticism and Denial.” The NESS. http://www.theness.com/index.php/skepticism-and-denial

Specter, Michael. Denialism: How Irrational Thinking Hinders Scientific Progress, Harms the Planet, and Threatens Our Lives. London: Penguin Press, 2009

Tokuno, Hajime. “Holocaust Denial.” The NESS. http://www.theness.com/index.php/holocaust-denial


For more information on Sérgio Fontinhas, see Big Fitness Project.

Guest post: Science versus Pseudoscience.

Pseudoscience is so flawed that it cannot be considered legitimate science. Of course it is common to claim that one’s beliefs are scientific, but mostly they are not.

Pseudoscience lacks the true method of science and goes way beyond just a few errors, the methods themselves are so flawed that makes the theory suspicious.

Between the two extremes of science and pseudoscience there is a gray zone, but legitimate science and pseudosciences can still be identified. The denial of this two extremes in the continuum, is a false continuum logical fallacy, or philosophically called the demarcation problem.

Features of Pseudoscience

1. Motivated reasoning

The most prominent feature of this pathological science is working backward from desired results, or motivated reasoning. The result is that they make evidence fit into preconceived notions. They use biased logic and cherry-picked evidence in order to defend a desired conclusion. There’s no concern and effort to prove their own theories wrong.

This relates to the congruence bias, testing one’s own theory by looking for positive evidence and cherry-picked evidence.

2. Burden of proof and confirmation bias

They will only look for confirming evidence, avoid dis-confirming evidence, and may engage in special pleading and shifting the burden of proof.

In confirmation bias, they look for supportive evidence for their own desired conclusions, choosing only the evidence that supports their own theory, irrespective of quality, negative evidence.

3. Anecdotal evidence

Anecdotes are uncontrolled, or ad-hoc observations, and they are not systematic. They rely on confirmation bias and recall bias.

Low-grade evidence is often favored no matter how implausible it may be.

Emotional appeal is another typical tactic among pseudoscientists who try to defend their statements, claiming what people say is more important than actual numbers on paper.

Pseudoscientific belief may even be based upon a single case or observation, preliminary evidence, or even a single anecdote. This is the hasty generalization logical fallacy.

Pseudoscientific principles may also be based upon a philosophical idea, not been empirically tested or developed as a scientific theory.

4. Grandiose claims (Galileo syndrome)

This involves grandiose claims based upon preliminary evidence. Far-reaching claims overturn entire portions of well-established science, using very little research or tiny bits of evidence.

5. Alternative science

In extreme cases, pseudoscience leads to alternative science, all of science is replaced with an alternative version.

6. Absolute claims

Pseudoscientists make bold claims that are often absolute and go way beyond the evidence. Pseudoscientists offer simple answers to complex questions, a theory of everything where one tiny casual source is used to explain the entire universe, if it comes to that.

7. Hostility

Pseudoscientists generally cannot accept criticism and avoid the scientific community. They claim being victim of a conspiracy and stay away from mainstream science and community.

8. Vagueness

Pseudoscientists use vague terms and words to obfuscate, so they can shift the definition around, use it in different ways at different times when it suits them, to confuse others and avoid explaining their point. Vague terms such as “information” or “energy” are often used with no specificity as in a scientific discussion.

9. Stagnation

Pseudosciences fail to progress, and tend to be stagnant. They are ad nauseam trying to establish their theory rather than build a body of evidence for it.

10. Anomaly hunting

Anomaly hunting is yet another common feature in which they search for anomalies trying to establish a conclusion, which does not seek to refute or explore other alternatives.



Nickerson, Raymond. “Confirmation Bias: A Ubiquitous Phenomenon in Many Guises.” Review of General Psychology 2, no. 2 (1998): 175–220.

Novella, Steven. “Anomaly Hunting.” NeuroLogica Blog. http://theness.com/neurologicablog/index.php/anomaly-hunting

Pigliucci, Massimo. Nonsense on Stilts: How to Tell Science from Bunk. Chicago: University of Chicago Press, 2010

Shermer, Michael, The Borderlands of Science: Where Sense Meets Nonsense. New York: Oxford University Press, 2001.

Gardner, Martin. Fads and Fallacies in the Name of Science. Mineola: Dover Publications, 1957
Shermer, Michael. Why People Believe Weird Things. New York: Henry Holt/Times Books, 1997.


For more information on Sérgio Fontinhas, see Big Fitness Project.