Shifting burden of persuasion is when one person or group has to provide proof that something is true or correct, while another person or group doesn't have to provide proof. It is like a race. The first team to reach the finish line wins, but one team (the one with the shifting burden) has to run faster than the other in order to win. For example, if you have a debate about whether or not a certain law is fair, the person who believes the law is unfair has the burden of persuasion, meaning they have to provide proof that the law is wrong or unfair. The other person doesn't have to prove anything. If the person with the shifting burden can't provide proof that the law is wrong, then the other person wins the argument!