The Argument from Incredulity is a pretty little fallacy that arises whenever someone states a statement is false because they personally believe it to be false or are unwilling to deal with a fact being true. The Argument from Incredulity is frequently ventured forth by the dumb so tends to be bundled with other fallacies. This fallacy often tends to be obvious unlike some more subtle fallacies but tends to take some heavy lifting to overcome.

The Argument from Personal Incredulity comes in two different forms
1) One is unwilling to consider something true so it must be false

Example: I got into a heated argument with my brother over anthropogenic climate change and the scientific consensus behind it. He stated that humanity couldn’t affect climate because of how insignificant we are in the grand scheme of things (here disputed). He’s unwilling to believe humanity’s at least partial responsibility because he’s unwilling to believe that our actions are significant.

2) A belief that “the masses” agree with oneself and therefore oneself must be right.

Example: A co-worker and I got into a spat over Mother Theresa and some of the allegations laid against her by Christopher Hitchens. She stated Hitchens was full of garbage because everyone knows how great of a person she was. This is also called argumentum ad populum.

Overcoming and Avoiding this Fallacy
Personal incredulity can be tough/annoying to overcome as the person in question has decided fact based on one thing (conscious or not) based on some other belief. One could tackle the underlying belief system but one often sounds arrogant. Instead, the best tactic is to be narrow and specific. An offended opponent will simply gainsay to a standstill.

Pursue the fact- Many Arguments from Personal Incredulity are based on some fact or idea that’s held to be central and far more important than it actually is. An anecdote becomes the rule or a single exception disproves a broad class despite this exception being taken into account. This is a war of evidence, good luck.

Realizing the belief – Many Arguments from Incredulity arise from unprovable beliefs. Try to identify the underlying belief and whether or not it really applies. Some people can do amazing contortions of logic to justify an idea. Rather than disproving the underlying belief, disconnecting the two can be much easier and doesn’t nearly hurt as many people’s feelings. The Catholic Church has done this a number of times in recognizing science from heliocentrism to evolution while preserving core beliefs. If the Catholics can do it then anyone can.

Example: Some faiths prohibit blood transfusions on the grounds that there is a Biblical ban on consuming (“eating” in the translation) blood. Some non-theistic organizations attack the belief in Biblical inerrancy to save lives where attacking the translation would be far more reasonable. I’d venture that there are adherents to the faith that don’t understand the origin of the belief and full understanding would make pointing out that eating blood is not the same as a blood transfusion. Attacking someone’s faith wholesale simply makes many people your enemy rather than a single person.

Avoiding this fallacy –Whenever I stumble upon something I find unappetizing, I try to figure out why. I go through a simple tool box of “is it logical?” “Does it fit with what I know to be logical?” and most importantly “What ideas or facts would prove or disprove this idea?” Generally if poking around for 20 minutes doesn’t give me a good idea I try to talk to an expert. This quickly reduces one’s chances of being hit by an urban legend or erroneous conventional wisdom. If I find an idea questionable, I try to see who agrees with that idea and then check their sources and logic for exceptions and so on. I’m lazy, chances are someone who cares more about the point has do their homework so I don’t have to.

Some arguments from incredulity try to use numbers to justify a belief as somehow a large number of believers makes something true. There are also times when numbers do make right, or at least help. The first is democracy, where the implicit assumption is that the group is trying to pursue what’s right, but values egalitarianism above perfect truth. The second is in dealing with experts which happens when the incredulity comes from disagreeing with something in the sciences. Experts are by definition more learned and in the sciences subject to peer review which helps to root out falseness. This is also an excuse to bring up the 2001 Ig Nobel prize winning Dunning-Kruger effect whereby the dumb don’t realize they’re dumb and it takes a good bit of work to even get there. For a long time I didn’t embrace macro-evolution because I didn’t fully understand the mechanisms in genetic drift and divergent speciation and mistook my understanding for the body of understanding.

Sadly, arguments from incredulity often start when someone is young and makes a genuine objection to a belief and is poorly rebuffed, ignored, or falsely agreed with. Don’t feel bad if you’ve succumbed to this in some way as I’m confident we all have. The goal is to have the presence of mind to discard erroneous belief as they are found rather than excising it after it’s festered.

If you’ve encountered any arguments from incredulity, share it!