Argumentum ad Lapidem

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© 2011-2019 by Zack Smith. All rights reserved.

Argumentum ad Lapidem

A claim is proclaimed to be false because, the arguer says, it is absurd. Because they reject a claim as absurd, they signalling that discussion of it is off the table. You may as well be talking to a stone.

A variant of this is to assert that the claim is outrageous, insulting, disgraceful, disrespectful, slanderous, racist, anti-Semitic etc. Any word will be used if it stops the discussion and denies the claim.

  • I shall label your claim as absurd.
  • Therefore your claim is false. ]]


The claim that anyone in the Catholic Church molested any children is absurd and slanderous, and therefore false.

The idea that my wife/husband/priest/boss embezzled millions of dollars is absurd and slanderous, therefore false.

The idea that our country doesn't need to have any debt whatsoever because we can print money is simply offensive [to bankers who own the Federal Reserve], therefore false.

Circa 2000 BC: The claim that the Earth is round is utterly absurd, therefore false.


Labeling a concept as absurd is an attempt at avoiding any discussion of it, which shows the weakness of the arguer's ability to argue the issue and/or their fear of any such discussion.

You may discover that the reason for the avoidance is due to any of many factors:

  • A conflict of interest.
  • A lack of confidence about reasoning and research.
  • A lack of willingness to question assumptions.
  • A laziness about doing a real investigation.
  • A lack of expertise and a refusal to gain expertise.
  • A fear of breaking away from easy, conformist thinking and making waves.

It is frequently the case that people avoid a discussion while rejecting a claim because of cognitive dissonance, meaning the implications of the claim being true has logical consequences for their other beliefs e.g. negating them, but they want to retain those beliefs. An example of two beliefs that cause cognitive dissonance are:

  • If the government had foreknowledge about 9/11 and they intentionally failed to warn people then 3000 people were murdered for a purpose but that purpose must have been truly sinister.
  • I want to believe the government and the people who run it are good.

As a result, any suggestion that someone has committed a serious crime is handily rejected as absurd, even if crimes done by people outside of government are readily accept.

It may be that the arguer lacks any expertise in the specific topic matter. For example, they may have a PhD in psychology, but if the topic matter is physics and their last exposure to physics was in an 8th grade class that they slept through, then no wonder that they want to avoid a debate. However if they have no expertise, they have no business rejecting the claim. But their pride can intrude, and they will pretend to have expertise that they do not have.