The Fallacy of 'Moving the Goalposts', Explained

Here at Snopes, we encounter our fair share of logical fallacies, or errors in reasoning that tend to be more persuasive than they really are, and are based on poor or faulty logic. 

In previous coverage, we've looked at a range of fallacies including ad hominem attacks, the black sheep effect, confirmation biases, and more. Now, we're unpacking the concept of "changing the goalposts" — or reworking "the terms of a debate or conflict after its started," according to journalist and editor Peter Stothard, speaking to The New York Times in 1990, to gain an advantage over others.

Indeed, changing the rules in the middle...