Fallacies are common errors in your argument that make it weaker. A fallacy (meaning a false idea or belief) is usually a claim without evidence.
Slippery slope
A series of small steps that start with the first step. It means something terrible will happen, but its not really logical because all of the in between steps are missing.
Example: If the government bans Hummers because they are bad for the environment, then eventually all cars will be illegal. Therefore, we should not ban Hummers.
Banning Hummers is not the same as banning all cars.
Hasty Generalization
This is a conclusion made without enough evidence.
Example: Even though it’s the first day, I can tell that this is going to be a boring class.
The person needs to go to more classes than just one to have a complete opinion.
Circular Argument
This is an argument that is just re-stated, and not actually proven
Example: President Obama is a good leader because he governs well.
Govern and lead are very similar, and almost the same idea. There is no specific evidence as to why he is a good leader.
Either/or This is an argument based on two results. There may be more.
Example: Americans can either completely stop eating fast food or continue to get fatter.
In this example, there are only two choices, but the writer ignores a lot of options. Americans could eat fast food occasionally, or exercise more.
Personal Attack: This attacks a person instead of his/her argument or opinion.
Example: Fat people are unhealthy because they are lazy and don’t want to exercise.
Some people are naturally large, and do exercise, but still can’t lose weight. Instead of examining weight-loss strategies, the author simply attacks fat people for being lazy.