Logical fallacy

Begging the Question

assumes in the premise what the arguer should be trying to prove in the conclusion.  Essentially, the rhetor assumes the audience agrees with an unstated premise with which the audience may not, in fact, agree.

Argument from analogy

explains something unfamiliar by comparing it to something more familiar.  Analogies are useful strategies to use when explaining something, but they do not constitute proof. 

Argument from analogy

For example, one might say that students are stuffed into rooms and made to move about in masses and according to bells, like cattle.  Therefore, like cattle, students will eventually be slaughtered.  See how this doesn’t work?  ignore important differences between the items being compared.  

Personal Attack ad hominem

tries to divert attention from the facts of an argument by attacking the motives or character of the person making the argument.

Personal attack

For example, it would be a fallacy to say that we shouldn’t follow the ruling of a judge because he cheated on his wife is a

Hasty or Sweeping Generalization

when a conclusion is reached on the basis of too little evidence. 

Hasty generalization

For example, one might say that, because your best friend got an A an AP Calculus, every student will get an A in the class.

False Dilemma either/or

When you suggest that only two alternatives exist even though there may be others. 

False dilemma

For example, saying that, if you can’t get an A in the class, you might as well fail, is a fallacy because there are lots of grades in between!

Equivocation

the meaning of a key term changes at some point in the argument.  It may seem as if a conclusion follows from a premise when it actually does not. 

Equivocation

Example: Computers are remarkable human accomplishments, but how human can we be if we rely on computers to make our decisions for us?  In this example, the use of human in the first sentence refers to the entire human race.  In the second sentence, human means “civilized” or “intelligent.”

Red Herring

when the focus of an argument is changed to divert the audience from the actual issue. 

Red herring

For example, telling a teacher that you shouldn’t be reprimanded at for talking in class because another student was talking in class is a .   This is different from Personal Attack, which focuses on the ethical qualities of an individual.

You also

Asserting that an opponent’s argument has no value because the opponent does not follow his or her own advice.  While that person might be a hypocrite, you will be a poor rhetor! 

You also

For example, saying that Ms. Hohman shouldn’t expect her students to get an A in English when she herself received a C in English in college is a fallacy

Appeal to Doubtful Authority

Bolstering an argument with references to people who are not experts on the topic. 

Appeal to doubtful authority

For example, arguing that interest rates will remain low next year because Ted Koppel, a respected journalist, says they will, is an appeal to doubtful authority because, although Koppel is a great journalist, he is not an economist.  This is why I always tell you that a person who is employed by a newspaper is not necessarily an expert source on a topic!

Misleading Statistics

Using statistics that have been distorted or misrepresented, only using pieces of statistics, or taking them out of context. 

Misleading statistics

For example, saying that women can never be firefighters because 50% of the women in the training program failed, and you fail to mention that there were only two females in the training program is a fallacy.  This is because it’s not based on a large enough sample.  

Post Hoc After This, Therefore Because of This

assuming that because two events occur close together in time, the first must be the cause of the second. 

Post hoc

For example, assuming that Frodo chewed my shoe because I forgot to pet him shortly before is a fallacy.  Two events happening close together does not necessarily equate causation.

Non Sequitur

When a statement does not logically follow from a previous statement. 

Non sequitur

For example, stating that, because many accidents happened when people drove the Ford Model T, no one should drive a car in today’s society.  The Ford Model T is very different from today’s vehicles, so it is not logical to assume that we shouldn’t drive any cars.