Burden of Proof
Demanding that someone disprove your claim, rather than proving it yourself.
Also known as: shifting the burden of proof, argument from ignorance, Russell's teapot
What it means
The burden of proof is the obligation to provide evidence for a claim. In logic, science, and law, this burden rests with the person making the assertion. If you claim something is true, it’s your job to show why. It is not your opponent’s job to prove you wrong.
Shifting the burden of proof is the fallacy of reversing this - making a claim and then demanding that others disprove it rather than providing evidence yourself. “You can’t prove God doesn’t exist.” “You can’t prove the vaccine is safe.” “You can’t prove there’s no conspiracy.” Each of these takes an unproven assertion and treats the inability to disprove it as evidence that it’s true.
The philosopher Bertrand Russell illustrated this beautifully with his teapot: if someone claims there’s a china teapot orbiting the Sun between Earth and Mars, too small to be detected by any telescope, the burden of proof doesn’t fall on everyone else to prove the teapot doesn’t exist. The claim is unfalsifiable by design, which is precisely why the person making it must provide the evidence.
In the real world
In conspiracy theory culture, the burden of proof is almost always reversed. “The moon landing was faked - prove me wrong.” The person making the extraordinary claim offers no evidence that meets normal standards, but demands that sceptics prove a negative. Since proving a negative is often impossible, the conspiracy theory survives not because it’s supported but because it can’t be definitively killed.
In health and wellness discourse, this fallacy is everywhere. “This crystal heals anxiety - prove it doesn’t.” “Detox teas cleanse your body - show me evidence they don’t work.” The burden should be on the person selling the product to demonstrate that it works, not on the buyer to prove it doesn’t. But shifting the burden sounds like open-mindedness: “Keep an open mind - you can’t prove it’s not real.”
In everyday arguments, it’s the person who makes an accusation and then says “prove you didn’t.” “I think you’ve been lying to me.” “I haven’t - what makes you think that?” “Prove it.” The burden has quietly shifted from the accuser to the accused, and the accused is now stuck trying to prove a negative - which is almost always impossible.
How to spot it
When someone makes a claim and then challenges you to disprove it, they've shifted the burden. The person making the claim is responsible for providing evidence. 'You can't prove it's NOT true' is never a valid argument.
The thought to hold onto
The person who makes the claim carries the evidence. If they hand you the burden instead, they've handed you an empty bag.