Burden of proof

Shifting the burden of proof is when you treat the other side as if they have to prove their claim while you don't have to prove yours—or you say something is true until someone proves it false (or the other way round). Who has to give evidence depends on the claim and the context; shifting the burden unfairly is a trick to avoid giving reasons. The person making a positive claim usually has to back it up; you can't place the full burden on the person who is sceptical.

Examples

• No one has ever shown that this supplement doesn't work, so it must work.

• You can't prove there's no afterlife, so there must be one.

• Nobody has proved the document is a forgery, so it's genuine.

• You haven't shown that the policy is harmful, so it's fine.

• There's no evidence that he's guilty, so we should assume he's innocent.