Burden of proof (philosophy)

The burden of proof (Latin: onus probandi) is the job of a person who is involved in a debate to show proof for their claim. 
When people are in a discussion and one makes a claim that the other one does not agree with, the one who makes the claim has the burden "of proof". It means he must show proof of that claim, especially when it is controversial. 
Carl Sagan said that: "extraordinary claims require extraordinary evidence" – which is known as the Sagan standard.
Often these philosophical debates moved from what the claim was to debating who has the "burden of proof" or the best proof for their claim.
The burden of proof also exclaims when the accuser makes an accusation, they have the burden of proof to prove that what they said is true with evidence.