Denialism is a person’s choice to deny certain particular facts.  It is an essentially irrational belief where the person substitutes his or her personal opinion for established knowledge. Indeed, one of the hallmarks of denialism is a failure to recognise the distinction between opinions and facts.

Denialism should not be confused with modern scientific skepticism, which is the challenging of beliefs that are unscientific, irrational or based on insufficient evidence.  Instead of denying facts, modern skeptics test claims by analysing whether they are supported by adequate empirical evidence. Denialism is the a priori rejection of ideas without objective consideration.

The philosophical skepticism of the Academic Skeptics and Pyrrhonists in Classical Greece (which was quite different to modern skepticism) consisted of doubting whether there can be any knowledge or facts at all, rather than denying particular facts.

Science denialism is the rejection of basic facts and concepts that are undisputed, well-supported parts of the scientific consensus on a subject, in favour of radical and controversial opinions of an unscientific nature. For example, the term climate change denialist is applied to people who argue against the scientific consensus that the global warming of planet Earth is a real and occurring event primarily caused by human activity. 

The term evolution denialist or ‘creationist’ is applied to people who argue against the fact that life on Earth has evolved from earlier forms, instead of having been created by a supernatural being in its current form.

Other instances include Holocaust denialism, AIDS denialism, vaccination denialism, and Flat-Earthism. The various forms of denialism present the common feature of the person rejecting overwhelming evidence, often with attempts to deny the existence of a scientific consensus or alternatively to allege a conspiracy theory to fake or conceal the evidence. Denialism is commonly one of the foundations of quackery and other varieties of woo.

The motivations and causes of denialism include irrationality, religion and self-interest (political, economic or financial), beliefs in conspiracy theories or even defence mechanisms meant to protect the psyche of the denialist against mentally disturbing facts and ideas.


Filed under Logical fallacies

12 responses to “Denialism

  1. Pingback: Fallacy | The Logical Place

  2. When I show climate alarmists graphs like this, which prove that CO2 does not drive sea-level, almost all of them deny that fact, despite the proof. That obviously fits Tim’s definition of “denialism.”

    However, contrary to Tim’s definition, calling someone a “denier” is actually a reference to Holocaust denial, an especially odious and hateful form of irrationality. That’s why calling people “climate deniers,” “science deniers,” etc. is disreputable.

    Most people who deny the proof that CO2 has no significant effect on sea-level are merely garden-variety irrational, they are not the moral equivalent of Holocaust deniers.


  3. “You can tell a genuine sceptic from a denier (as I discuss in The Knowledge Wars) because the sceptic will want to look at new data and conclusions and, like any real scientist, will modify their conclusions accordingly. The denier remains ‘locked in’ to a sort of ‘decerebrate rigidity’.” – Prof. Peter Doherty, 1996 Nobel Prize in Medicine.


  4. I don’t think it is relevant what some people mistakenly think about facts. Whether a given proposition is or is not a fact is not merely a matter of opinion.


  5. I’d encourage further analysis. Anti-vaxxers, Holocaust deniers, global warming deniers, and evolution deniers are very different groups with different motivations (although the last two, in the US, do overlap), and the concept of “woo”, as described at your link, is too broad and fluid to be enlightening.


    • But one thing all deniers have in common is the denial of facts – whatever type of facts they might be.


      • They would, of course, denies this. They are disputing what the rest of us regard as established facts. I don’t see this (except in some extreme pathological cases, like Ham’s kind of creationism) as challenging the authority of facts, but rather as applying extreme bias in deciding what is or is not factual.

        Liked by 1 person

      • Steve jenkins

        This seems to suggest that scientific consensus is regarded as fact. The question to consider when it comes to evolution for example is “is science in denial?”. As a huge science buff, I see no parallel in evolutionary biology with the scientific method. Chemistry and physics have laws and method arriving at fact through observable and repeatable experimentation. Not so with evolutionary science. I’m with Dr David Berlinski on this. There isnt robust enough evidence. The common DNA ancestor has been debunked, the absence of any transitional forms anywhere in the history of life on our planet – a startling absence of evidence, and the unlocking of the genome which tells us that there is not one single example of an increase of information in the dna blueprint vital to evolve from simple to more complex life. It’s staggering. There is a huge amount of assumption, and presupposition when it comes to evolution, a lack of robust evidence and an ignorance of the scientific method so it appears I would have to take a huge leap of faith to believe one type of life evolved into another more complex form and ignore the evidence to the contrary. So which set of facts reflect truth? So I go back to my original question, is science biased and in denial over the evolutionary process?


      • Most of what you say is simple assertion contrary to fact. For example,you deplore and their alleged lack of transitional forms, when such forms abound. In fact, if you check out “transitional fossil” in Wikipedia you will have numerous examples, and we had a beautiful transitional form between a dinosaur’s toothed jaws and a bird’s beak announced only last week:

        But you do make one positive assertion, for which I would like to see the evidence. “The common DNA ancestor has been debunked”. This is a definite claim, and it is up to you as the maker of the claim to justify it.

        There is a difference between rule-seeking science and historical science, but that arises purely from the difference in their subject matter. Even Answers in Genesis does not deny the reality, on historical evidence, of the Ice Ages. Do you? If so, how do you explain away the evidence for them? If not, how are you able to dismiss evolution as “not science”?

        Liked by 1 person

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s