Fallacies

What is Fallacy? Fallacies are defects that weaken arguments. You can find dozens of examples of fallacious reasoning in newspapers, advertisements, and other sources.

Hasty Generalization Definition: Making assumptions about a whole group or range of cases based on a sample that is inadequate (usually because it is atypical or just too small). Example: "My roommate said her philosophy class was hard, and the one I'm in is hard, too. All philosophy classes must be hard!"

Slippery Slope Definition: The arguer claims that a sort of chain reaction, usually ending in some dire consequence, will take place, but there's really not enough evidence for that assumption. Example: Animal experimentation reduces our respect for life. If we don't respect life, we are likely to be more and more tolerant of violent acts like war and murder. Soon our society will become a battlefield in which everyone constantly fears for their lives. It will be the end of civilization. To prevent this terrible consequence, we should make animal experimentation illegal right now.

Non Sequitur Definition: An attempt to relate two or more ideas which are not related; one idea does not logically lead to the other Example: Disarmament weakened the United States after WW1 and the Vietnam War. For this reason, the city’s attempts to limit gun sales will weaken the United States.

Doubtful Authority Definition: Arguments can be strengthened with references to experts or famous people. This becomes a fallacy when the person being referenced is not an expert on the issue being argued. Example: According to Diane Sawyer, interest rates will remain low during the next year.

Can you name this Fallacy? I know three redheads who have terrible tempers, and since Annabel has red hair, I’ll bet she has a terrible temper too. HASTY GENERALIZATION

Can you name this Fallacy? The meteorologist predicted the wrong amount of rain for May. Obviously the meteorologist is unreliable. HASTY GENERALIZATION

Can you name this Fallacy? We have to stop the tuition increase! The next thing you know, they'll be charging $40,000 a semester! SLIPPERY SLOPE

Can you name this Fallacy? Supreme Court Justice Byron White was an All-American football player while in college, so how can you say that athletes are dumb? HASTY GENERALIZATION

Can you name this Fallacy? According to LeBron James, Crest toothpaste is the best for ensuring good teeth. Doubtful Authority

Can you name this Fallacy? Crimes of theft and robbery have been increasing at an alarming rate lately. The conclusion is obvious, we must reinstate the death penalty immediately. NON SEQUITUR