Hasty Generalization

An argument is constructed where because one thing is such a way, therefore all members of its group are such a way. The group is often described as people, but in truth can be anything: Things, actions, situations et cetera.

In a Hasty Generalization, the arguer fails to assess or even consider the full data set, because he wants to argue the validity of the second claim, that all X are C.

Example

Hey coworker, you made a mistake in that project, therefore you always make mistakes. (This is sometimes known as dickhead logic.)

I once heard about an atheist who was mean, so they're all mean.

The team lost their first game. Therefore they will lose all of the games.

I heard a plane crashed once, so I'm afraid air travel is very dangerous.

You forgot a fact in the interview. Therefore you don't know anything at all.

You got an answer wrong on your test. Therefore all of your answers are wrong.

Weaknesses

Any data other than the limited set the arguer is focusing on will disprove his claim. He knows this so tell anyone he is trying to influence that he's fixating on a narrow set of evidence. He is blowing it out of proportion.

The arguer is making a mountain out of a molehill means accentuating the importance of something trivial.

If the arguer does not have bad intentions but for instance is motivated by fear, kindly point out that he is making an inductive error (specific to general), and demand that the arguer consider all data.

An arguer may use evasive tactics such as:

 *  Preventing you from presenting other evidence.
 *  Making it tedious to present other evidence.
 *  Acting cagey to prevent you from identifying a motive for the logical fallacy.
 *  If the error is about you he may talk behind your back so you cannot make your case.

If the fallacy is directed at a group of people, counterexamples are usually easy to find that disprove that all members of a group are a given way.