This fallacy, also called argument to the point of disgust, happens when a person thinks simply repeating a statement (whether fact or fiction) makes it true.
This one is easy to spot, but apparently not so easy to stop. Creationists will say things like, “Evolution is only a theory” over and over. Anyone educated enough understands that the word theory has different implications in science when compared to its everyday use. However, someone dependent on argumentum ad nauseam won’t stop once this is conveyed. In fact, that person may simply keep repeating his argument over your argument. It can be annoying and very frustrating.
A person may also use this fallacy when she is trying to hide from the truth of something or keep from admitting a mistake. For example, let’s say Billy’s mother (let’s call her Jane) finds out that Billy, who’s about fourteen, is doing illegal drugs. She may not want to admit that her sweet boy is doing anything along those lines. Jane may keep telling herself that Billy’s drug use is not possible; he could never do that, etc. This isn’t a fallacy like we see in a debate. This is more of a personal application. However, just like in a debate, no matter how many times Jane repeats it to herself, that repetition doesn’t change the facts of the situation.
Repeating like this is usually easy to detect, but you’d be surprised how many people fall for it. Politicians and news pundits have a bad habit of repeating a statement or catch phrase over and over again without adding any substance to it. It can seep into peoples’ brains and convince them that a fact is fiction. Humans like repetition. It’s safe and gives us a secure feeling. It seems simple, but that may be why this fallacy works so often.