Who must show it

The burden of proof sits with the person making the claim, especially a claim that asks you to set aside a reviewed body of work. One expert can be right against a consensus. The weight then comes from the evidence they bring, not from fame. A blog that says 'research shows' and links only to another blog has not yet carried anything. Trace the chain to the study, or say that the chain stopped. You do not have to prove the claim is false.

Fallacy

Shifting the burden of proof

The person who asserts a claim carries the burden of giving a reason. Shifting the burden tells the sceptic to disprove it instead. Scepticism is not itself a positive theory that needs the same kind of proof.

Open the full card

Mini check

A doctor with a large online following rejects a medical consensus. How should you weigh their view?

Ask what evidence they offer that the consensus missed; one expert counts for less than the reviewed body of evidence.Follow them, because a doctor who is qualified and has a large audience cannot be wrong about the medicine.Dismiss them at once, because a person who disagrees with a medical consensus has already proved their view wrong.Follow whichever side has more followers online, because the larger audience is the stronger medical evidence.

A blog says "research shows" and links to another blog, which links to a press release. What is the right move?

Trace the chain to the original research and read what it actually found.Count the blogs: two sources agreeing makes it twice as likely.Trust the press release, because it is the most official-looking.Assume the research does not exist, because blogs are unreliable.

Try it today

When a post says research shows something, open the link and see whether a study is actually there.

Next step