A Priori

The a priori fallacy exists when the arguer decides on what he wants to believe, and then asserts that reality matches that belief.

It often takes the form of an assumption that something is true, and a choice to make no inquiry to check facts.

Often the arguer, when faced with reality that differs from the belief, deploys other fallacies and strategies to support a priori.

• He seeks out evidence to support his belief, which may be flimsy or suspect or mere rumors.
• She reinterprets her experiences to support the belief.
• He flatly rejects counter-evidence and contrary arguments without analysis.
• She praises or rewards people who have spoken in accord with her belief.
• He mocks or punishes people who have spoken contrarily e.g. calling them conspriacy theorists or subversives.

A priori is the basis for much prejudice, discrimination, unscientific thinking, and propaganda. Because this fallacy is all about escaping from reality, it can be the basis for collective psychosis.

A priori is found in everything from official propaganda to just casual lazy thinking. The motivation for it can be very personal in nature, or it may be maximization of profits.

Examples

We in the Church know the Earth is the center of the universe, and we don't need a conspiracy theorist like Galileo going around contradicting us, saying we're all lying.

I know that Fred is a thief, therefore he is. I don't need to try to disprove what I know.

South Korea is going to launch a vicious attack at any moment in coordination with the USA, because we the North Korean military simply know it.

I have come to a detailed understanding of how the world is in fact ruled by God or aliens or Reptilians, therefore it must be.

I believe genetically-modified products are safe, therefore they are. Don't you know that the corporate-funded scientists say so, as do politicians? Appeal to Authority.

That government agency we don't like has to be that way because it's infiltrated by Commies, therefore it is. Time for another witch-hunt.

Weaknesses

The arguer wants to believe X, so he claims that reality matches his belief. That by itself is silly. You need only point out that wishing something to be true does not make it true.

But then the problem is compounded and made more conspicuous with the piling on of additional faulty logic and useless strategies:

• Seeking out confirming evidence: Ask why he is ignoring contradictory evidence.
• Misrepresenting flimsy evidence or logic as being strong: Point out the weakness of the logic.
• Reinterpreting her experiences: Ask whether she has not molded her belief after the fact.
• Rejecting contrary views without analysis: Point out the lack of commitment to truth exhibited.
• Etc.

Sometimes a lazy a priori thinker with put on an air of intellectualism, and proclaim that Occam's Razor<i> supports his evidence-free belief. My belief is the simplest explanation. Therefore it is more likely to be true than any more complicated belief.

If a belief requires evidence, you must demand evidence.

Sometimes a thuggish a priori arguer will attempt to use force to beat confessions out of people, then call that evidence, or even use humiliation to get people to confess, as Joe McCarthy did to suspected Communists in the 1950's. But only a liar thinks that facts can change because force is applied. The truth is bullet-proof.

A thug who cannot win an argument will often use force to achieve a bogus victory.

Increasingly one see that an arguer will rely on a narrow set of dishonest sources, like oft-debunked corporate scientists who insist that toxic products are safe, or politically-appointed scientists who deny physical evidence of government corruption, to confirm his a prior belief.

The arguer may have a vested interest, or his associates may have, which can expose his appearance of ignorant assuming or wishing to believe as being a sham,

concealing a concrete motivation. It may take work to identify that vested interest, but you are not alone:

• SHAME project
• Open Secrets
• Wikileaks