What is the fallacy in which a person adheres to an original idea, even after it has been proven wrong?

In other words, it is the inverse of hindsight bias. In hindsight bias, the person imagines themself to predict an outcome, and says "I knew it all along" even though they did not actually predict it.

I am looking for the term that is sort of the inverse of this: the person makes an incorrect prediction, and then keeps pretending that it was right even after it is proven wrong.

For example: let's say an auto mechanic is brought a car with a braking problem. The mechanic says, "It's probably the master cylinder." So, he replaces the master cylinder, but the problem persists. Next, the mechanic thinks maybe the new master cylinder was bad, so he replaces it again, but at the same time he tightens all the brake line fittings. The problem is fixed and he reports to the owner: "it was the master cylinder", even though logic suggests it was actually his secondary action that fixed the problem. He sticks to his original diagnosis, even though there is every indication it was wrong.

  • 1
    Maybe Stupidity ? Dec 22, 2019 at 14:00
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    – J D
    Dec 22, 2019 at 15:27
  • 1
    This is called confirmation bias, but it isn't a fallacy.
    – Conifold
    Dec 22, 2019 at 17:58
  • Like Mauro I'd call it stupidity.
    – user20253
    Dec 23, 2019 at 13:06

2 Answers 2


The question as asked looks for a fallacy, so let us clarify the question by defining. For the sake of discussion, I'd propose:

A fallacy is a persuasive, but illogical form of reasoning that leads us from a set of premises to an incorrect conclusion.

You want the fallacy where:

...a person adheres to an original idea, even after it has been proven wrong

But the choice of a person to adhere to a false conclusion (presumably because they reject your proof and reasoning) isn't a 'persuasive, illogical form of reasoning'. That is to say, there can be no fallacy to describe what you are after, because your situation as described isn't itself an argument, it is a choice. What you are interested in is how people stick to ideas even though (and let us presume when you say "proven wrong", you mean it in some very narrow and technical sense that should be obvious to all parties such as a simple deductive fallacy) it borders on baffling to continue to refuse to accept. Let's exemplify.

You argue Socrates is mortal, and your opponent, after hearing the argument "Socrates is a man, all men are mortal, therefore Socrates is mortal" looks you in the eyes and strenuously and earnestly objects. Now, the question of Socrates' mortality has for many hundreds of years been settled logically (and empirically given his untimely end). Your question is, what is the fallacy at play with your opponent? The answer isn't one of fallacy (logical) anymore, but one of cognitive bias (psychological). This phenomenon of rejecting obvious evidence and proof is fascinating, particularly in the extreme with cranks and crackpots who will spend their lifetimes arguing they've found perpetual motion machines, violations of accepted laws of physics, and insisting on bizarre forms of reality.

A classic example when a person might stick with an obviously wrong claim about evidence (from which arguments are built and affect inference) is Asch's experiment with lines which shows that people make decisions other than self-evident experience. In this class study, people will often vote to claim a line is of the wrong length to conform to social pressure.

Of course, this happens in much more subtle ways, when a person who has strong emotional ties to a subject matter, for instance, and in all other matters demonstrating profound reasonableness, parts in some small way with truth as in the related concept of cognitive distortion. Biases and distortions, unfortunately, are the rule rather than the exception, and this is idea is so powerful it won Daniel Kahneman a Nobel Prize in 2002. To cite one specific bias that predisposes a person to stick with a bad argument doesn't seem possible, as the context is highly relevant to the choice. Wikipedia maintains a list, and anyone of these biases might result in a person, in your words, to adhere "to an original idea, even after it has been proven wrong".

  • 1
    Perhaps fallacy was too strong a word. The sense is a "bias" and I did give a bias as an example in my question. Dec 22, 2019 at 19:03
  • I did recognize it. But as a rule of thumb when answering questions, I try to use the same words asked. Either way, I think the safe bet is no one bias leads to people stubbornly adhering to bad argumentation. Evidence and reason are largely normative activities, since the nature of truth is normative to a certain extent.
    – J D
    Dec 22, 2019 at 19:38

The term I was looking for was confirmation bias, as was mentioned in one of the comments. The Wikipedia defines it as:

Confirmation bias is the tendency to search for, interpret, favor, and recall information in a way that affirms one's prior beliefs or hypotheses.

  • 1
    Hello: Not sure that confirmation bias is the answer. Under conditions of confirmation bias one looks purely for confirmatory evidence without knowing or believing that the idea, hypothesis or whatever that one maintains is wrong. But the case you describe is one of 'pretending that' the idea, hypothesis or whatever is 'right even after it is proven wrong'. 'Pretending' that something is right, where 'pretending' implies feigning, isn't the same as looking purely for confirmatory evidence. J D's answer strikes me as spot on.
    – Geoffrey Thomas
    Dec 23, 2019 at 9:53
  • @TylerDurden I'm glad you found an answer you were looking for. Obviously some of us here are partial to precision in adherence to conventional semantic definition. :) To that end, just be mindful that a bias in evidential selection and bias in rejecting superior conclusions aren't equivalent. To suggest that evidence of confirmation bias in an argument implies a bad conclusion would be the essence of the fallacy fallacy. Good luck!
    – J D
    Dec 23, 2019 at 11:31

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