Logical fallacy

A group of commonly used tactics that have no place in legitimate debate.

Evidence Fallacies

Slippery Slope- Extrapolating progressively larger effects from one cause (i.e. A to B, B to C, C to D, therefore A to D). Only a valid fallacy if you cannot show A causes B, B causes C, etc. Example: "A slice of pizza contains fat. Fat can lad to cholesterol. Cholesterol can lead to clogged arteries. Clogged arteries can lead to a heart attack. Heart attacks can be a cause of death. Thus, a single slice of pizza can kill you."

Confusing fact with opinion- Asserting opinions as fact, or discounting facts as opinions.

Red Herring- Distracting readers with irrelevant material

Myth of the Mean- Using averages to cover up problems, or to skew perception.

Flawed statistical comparisons- Using inappropriate statistics to skew perception, distort a reader's view of reality. Example: There were less car accidents per year in the 1920's than there are now, therefore drivers must have been better than today.

Defective testimony- Quoting out of context, or omitting a speaker's credentials.

Flawed Proofs

Ad hominem- Attempting to tie the validity of your opponent's argument to his personal credibility rather than its intrinsic merits

Begging the question- The argument fails to prove anything because it applies what it is supposed to prove as fact. (circular logic)

Defective Arguments

Shaky principle- Basing a line of argument on an unsound assumption.

Omitted qualifiers- Confusing probability with certainty by asserting a conclusion without qualification.

Post Hoc- A occurred before B, thus A caused B

Non sequitur- Reasoning in which principles and observations are unrelated to each other or to the conclusion drawn.

Hasty generalization- Drawing a conclusion from a limited observational pool, or conclusion based on insufficient or non representative observations.

Faulty analogy- An analogy which does not apply to the situation in question

Persuasive Design Fallacies

False Dilemma- Forcing your opponent to choose between two artificially designed choices. "How can you say the attempt at rehabilitation of criminals has merit when so many participants return to prison later?" The choice is between "The rehabilitation of criminals is 100% effective" and "the attempt at rehabilitation of criminals is worthless".

Strawman- A distortion of your enemy's position so you can knock it down more easily --- Most of the information for this page was obtained at Logic Fallacies in Debating on the SD.net forum.