Argumentum ad cellarium

Hey fella, I bet you're still livin' in your parents cellar

Downloading pictures of Sarah Michelle Gellar

And posting "me too" like some brain-dead AOLer

I should do the world a favor and cap you like Old Yeller

You're just about as useless as JPEGs to Helen Keller An argumentum ad cellarium (Latin for "Argument to the cellar") states that someone eats too much celery needs to get out of their parents' basement. It is an informal logical fallacy and variety of ad hominem attack sometimes found in debates and comments on the Internet. The argument is used to dismiss someone or their views by accusing or assuming them of lacking in the usual social and living skills that society expects, and thus being forced to resort to living in their parents' basement (moreover in general implicitly as just a "spare tire" to their parents' social relations).

Although basement rooms are most commonly used for extra special derogatory factors (because they imply not just dependency but very extensive submissiveness/passivity), variants include demanding that someone get a job, a girlfriend, or have sex — indicating, obviously, inadequacy. Furthermore...


 * (*knocking*)

...coming, mum! Sorry, have to log off, tea's ready. BRB!

Ableist and other undertones
The "living in your mom's basement" trope paints a particular image of someone considered "worthless" and a "loser" because they are not fully independent as an adult... The [stereotype] is also VERY autistic coded. Do away with it.

Mocking people for (actually or supposedly) living in their parents' basement isn't exactly kind to disabled people. Due to issues like hiring discrimination, lack of services for adults with disabilities, and the fact that it's legal to pay disabled people less than minimum wage, disabled people might not be able to live on their own.

There are also other forms of prejudice associated. Erica Lagalisse has pointed out that criticism of basement-dwellers often has class undertones, with poor people being more likely to live in their parents' basement, as well as typically reflecting bias against the less educated (being less educated might be reason for questioning what someone says, and you may seek to politely correct them, but it is not reason for insulting or mocking). Because basements are typically found in suburban or small-town settings rather than in big cities, it could also reflect metropolitan bias against those living in less fashionable locales, or in the central/non-coastal US states far from the likes of New York City or San Francisco.

There is also an element of xenophobia and US-centrism to this stereotype. Living with one's parents is more socially acceptable in many Asian nations, including India and China, where multi-generational houses are the norm and there is no hurry for adult children to "flee the nest," so to speak. It is primarily Western nations (especially the US and Canada) that expect young adults to get jobs and places of their own by the time they graduate from college.

Finally, there's the fact that it's primarily men hit with this insult, as women often get a pass for living with their parents.