Don’t you hate it when a friend agrees to a set of rules in a game and then complains about them? They try to claim they actually won by weaseling their way out of the contractually agreed-upon rules?

This is a logical fallacy in argument known as moving the goalposts. This fallacy is commonly considered a version of the special pleading fallacy. After a claim is shown to be false, an attempt at making a special exception is made.

As in the case of a player trying to move the goalposts in order to render his loss a win, those who commit this fallacy are unwilling to admit failure, but instead wish to alter a set of criteria after it has already been decided upon and the process has already started.

In 2009 a Swedish soccer goalkeeper was actually caught on camera trying to move the goalposts in order to gain an advantage. While this measure was meant to be done out of sight, the logical fallacy is done openly and before an audience. Sadly, he wasn’t even suspended.

Here are some other examples:

• Suppose an alleged psychic agreed to be put under a test which demonstrated that his powers were fraudulent, only for him to argue that the test was unfair and that one had to have faith in his powers for them to work.
• Suppose in a boss tells an employee that if they do X they will be promoted. Employee does X, and the boss decides to add criteria Y to the table, etc. to save the company money by not giving the employee a promotion.
• Suppose a parent was against vaccines because she was told they contain mercury, which she was told causes autism. When it is revealed to her that vaccines no longer have mercury, nor did the removal of mercury from vaccines ever affect the rate of children who have autism, she will then say that, well, okay, it’s not the mercury, but it is…different toxins and stuff.
• Suppose a newly elected President with no experience in politics or military agrees to introduce 10 pieces of legislation in his first 100 days. At that 100 day mark, when only one of those 10 pieces of legislation has been introduced (and not even voted on yet), he complains that it is an unrealistic standard. It probably is unrealistic, but he’d already made the promise himself using that standard. He has committed the fallacy by moving the very goalpost he himself has set.

That concludes today’s study on fallacies.