Fallacy Friday!

Today's Logical Fallacy is... Half Truth!

(Cherry-Picking, Card Stacking, Incomplete Information, Texas Sharpshooter, suppressed evidence, fallacy of incomplete evidence, argument ...

Friday, April 4, 2014

Don't claim without evidence: Shifting the Burden of Proof

Shifting the burden of proof fallacies occur when the burden of proof is placed on the wrong side of an argument. In a logical argument, the “burden of proof” lies with the individual making the claim; in other words, if you claim something, you need to provide the evidence for that claim. When you “shift the burden of proof,” instead of providing evidence to support their claim, you challenge your opponent to disprove it, and just because your claim can’t be disproven does not mean that it is then credible (it is also fallacious to require absolute proof of something as well as there are no absolutes). What we don’t know cannot be used as evidence for or against anything. Absence of knowledge is not knowledge. In the American legal system, the burden of proof lies with the prosecution, and the accused is “innocent until proven guilty.” If you claim that Bigfoot exists, psychic powers are real, or telekinesis is possible, then you have the burden of proof and must provide the evidence to support it.

How it applies: This fallacy is committed anytime someone claims that God must exist because you cannot disprove it. It’s also committed when someone claims that the lack of evidence for God is then proof that He does not exist (note: this not the same thing as saying that not enough evidence suggests that there is no God). This fallacy is also committed when someone claims that the laws of nature have changed (the historical vs observational science argument). The individual making the claim would need to provide evidence that the laws of nature have changed; as it turns out, there is none.


  • “Space-aliens are everywhere among us, even here on campus, masquerading as true humans! I dare you prove it isn't so! See? You can't! That means you have to accept that what I say is true."
  • Bertrand declares that a teapot is, at this very moment, in orbit around the Sun between the Earth and Mars, and that because no one can prove him wrong, his claim is therefore a valid one.
  • Hundreds of years ago, scientists made the same claim against bacteria – “I don’t see it, so it must not exist.” After the microscope allowed us to see smaller objects, the existence of bacteria was finally proved. These early skeptics fell into the trap of appealing to their own ignorance – another type of fallacy.
  • “Aliens don’t exist because no one has ever proven that they do.” (This doesn’t mean that people shouldn’t be skeptical about extraterrestrials because of the lack of evidence. This is a fallacy because the author is claiming that the lack of evidence is proof that they do not exist.)
  • Of course leprechauns/ghosts/aliens/pink elephants/mermaids exist. Has anyone ever proven otherwise?
  • Prove there’s no global conspiracy!
  • Prove that aliens couldn’t have built the pyramids!

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