LOGICAL FALLACIES

• A logical fallacy is an error of reasoning.

• When someone adopts a position based on a bad piece of reasoning, they commit a fallacy.

• Fallacies can generally be classified as:

• Informal: premises fail to support the proposed conclusion.

• Formal: logical structure is flawed.

WHAT ARE LOGICAL FALLACIES?

The attack is on the person involved with the issue rather than the issue itself.

Example:• Because the

President is in office, that is why there was a tornado that destroyed my house.

AD HOMINEM

The authority in question is not identified.

Example:

* 2 out of 3 doctors agree that Dia-fu-rati-rhea will eliminate bloating and constipation.

ANONYMOUS AUTHORITY

The authority is not an expert in the field.

Example:

* I’m an NBA player and I eat Wheaties as part of a healthy breakfast.

APPEAL TO AUTHORITY

The sample is too small to support a generalization about the population.

Example:

Danica is a brunette who is in my math class and is whiz at Calculus. All brunette girls must be good at Calculus.

HASTY GENERALIZATION

Because one thing follows another, it is held to cause the other.

Example:

Since the President has got elected, the economy has gone to hell!

POST HOC

The two objects being compared are relevantly dissimilar.

Example:

* “Clogged arteries require surgery to clear them; our clogged highways require equally drastic measures.”

FALSE ANALOGY

An unrelated issue is introduced to divert attention from the real issue.

Example:

“How can I be failing if I’m never absent?”

RED HERRING

A series of increasingly unacceptable consequences is drawn.

Example:

"We've got to stop them from banning pornography. Once they start banning one form of literature, they will never stop. Next thing you know, they will be burning books like the Nazis.”

SLIPPERY SLOPE

Statements that are so general that they oversimplify reality.

Example:

A patriot pontificates: “In times of crisis, every American supports his President.”

A little kid might say: “All birds can fly.”

OVERGENERALIZATION

The truth of the conclusion is assumed by the premise.

Example:

1) The Air Force studied UFOs in the 50s in New Mexico.

2) Area 51 is an Air Force base in New Mexico and has been open since the 50s.

3) Therefore, there are UFOs housed in Area 51.

BEGGING THE QUESTION