Shifting the Burden of Proof
A logical fallacy where the arguer improperly places the burden of proving a claim on the opponent, arguing that because the opponent cannot disprove the claim, it must be true. It is a form of argumentum ad ignorantiam.
THE IDEA
2.4 SHIFTING THE BURDEN OF PROOF
Shifting the burden of proof is a fallacy in which the person making a claim demands that someone else disprove it, rather than providing evidence to support the claim. It is a type of argumentum ad ignorantiam, maintaining that a claim must be true (or false) simply because it has not been proven otherwise. In rational argumentation, the burden of proof lies with the person making an assertion; this fallacy attempts to reverse that obligation.
Consider these examples:
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Lawyer: “My client did not rob the bank last Friday. Prove that he did!” In the criminal-prosecution setting described in the use cases, this is a counterexample: the prosecution bears the burden of proving guilt. Asking it to do so does not improperly shift that burden.
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Brian: “The CIA is in charge of cocaine distribution in the United States.” Alex: “That is crazy!” Brian: “Prove that it isn’t so!” Brian makes an extraordinary claim and demands that Alex disprove it, rather than providing supporting evidence.
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Preacher: “God wants everyone to donate money to my ministry.” Congregant: “I don’t think that’s what God wants.” Preacher: “Well, provide evidence that God doesn’t want it.” Here again, the preacher insists that the congregant disprove a claim, when the preacher is the one obliged to offer proof.
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Amelia declares that a teapot is, at this very moment, in orbit around the Sun between Earth and Mars, and insists that because no one can prove her wrong, her claim is valid. This classic illustration (often attributed to Bertrand Russell) underscores that the inability to disprove an extraordinary claim does not make it true; the responsibility to provide positive evidence always falls on the person making the assertion.
The CIA, preacher, and teapot examples ask the listener to disprove an unsupported claim. A failure to disprove it supplies no evidence that it is true. The lawyer example shows why the context and existing burden matter.
When to use it
In a courtroom, the prosecutor must provide evidence beyond reasonable doubt; the defense does not have to prove innocence.
In scientific debates, the person making a new claim is responsible for providing experimental evidence.
In everyday discussions, avoid demanding proof of a negative (e.g., 'Prove that it isn’t so').
When evaluating arguments, check who is making the claim and whether they have evidence to support it.
A pseudoscientist claiming that psychic powers exist because no one has proven they don't.
In a legal trial, the prosecution incorrectly arguing that the defendant must prove innocence.
A conspiracy theorist asserting that a theory is true because skeptics cannot disprove every aspect.
FROM THEORY TO EVERYDAY LIFE
In practice
A Counterexample: Lawyer’s Defense
Lawyer: My client did not rob the bank last Friday. Prove that he did!
In the criminal-prosecution setting described here, the prosecution bears the burden of proving guilt. This demand is therefore a counterexample to the fallacy.
CIA Conspiracy
Brian: The CIA is in charge of cocaine distribution in the United States. Alex: That is crazy! Brian: Prove that it isn’t so!
Preacher’s Demand
Preacher: God wants everyone to donate money to my ministry. Congregant: I don’t think that’s what God wants. Preacher: Well, provide evidence that God doesn’t want it.
Amelia's Teapot
Amelia declares that a teapot is, at this very moment, in orbit around the Sun between Earth and Mars. She insists that because no one can prove her wrong, her claim is valid. The inability to disprove it does not establish that the teapot exists.
A MOMENT TO REFLECT
Put it to work.
How can you recognize when someone is shifting the burden of proof in a debate?
What is the proper way to respond when someone asks you to disprove their unsupported claim?
Why is it important for the arguer to provide evidence rather than the opponent to disprove?
When have you assumed something was true simply because others couldn't disprove it?
In a debate, how can you ensure that the proper burden of proof is maintained?
What are the dangers of shifting the burden of proof in scientific or legal contexts?
CONTINUE THE CONVERSATION
Source texts
- Wisdom Theory 100 Mental Models (2020) (Wisdom Theory)
- Informal Logical Fallacies A Brief Guide