In practical meaning the term “burden of proof” is actually a little strong because it implies the need to prove beyond a doubt. In practice it is really the burden of evidence. The side that has the burden of proof is obligated to provide evidence to back up their view point.
Determining the burden of proof is not always easy to do because it varies in different circumstances and changes in the course of the discussion.
Criteria for Finding the Burden of Proof
In general the burden of proof goes to the party making the claim. An American criminal trial is a good example of this since the prosecution has the burden of proof since the defendant is assumed innocent until proven guilty. This however is not an absolute rule since some circumstance can change the burden of proof to some one denying a claim. A party making the new claim about an accepted idea has the burden of proof. For example those claiming that the Apollo Moon landings did not really happen have the Burden of proof.
Burden of Proof fallacy
Burden of Proof fallacy is the process of wrongfully trying to switch the burden of proof to your opponent. For example proponents of abiogenesis need to prove that it is possible because we already know that intelligence can produce complex organized systems because we already do it, though not to the degree of life. On the other hand no real evidence for abiogenesis has been produced just unproven stories about how it could have happened.
Real Burden of Proof switching.
The Burden of Proof can legitimately switch sides when new arguments have been made or evidence presented. If the opposition wishes to dispute the new evidence or argument, they have the burden of proof in doing so. Hence the burden of proof has switched.