LOGICAL FALLACIES

False Dilemma

when someone is asked to choose between two options when there is at least one other option available.

You’re either with us or against us.

Arguing from Ignorance

Arguments from ignorance infer that a proposition is true from the fact that it is not known to be false.

No one has been able to disprove the existence of God.

Therefore:God exists.

Complex Cause

The effect is caused by a number of objects or events, of which the cause identified is only a part

The Challenger explosion was caused by the cold weather. (True, however, it would not have occurred had the O-rings been properly constructed.)

Circular definition

The definition includes the term being defined as a part of the definition.

An animal is human if and only if it has human parents.

Questionable Analogy

Arguments by analogy rest on a comparison.(1) A and B are similar.

(2) A has a certain characteristic.Therefore:(3) B must have that characteristic too.

a watch and the universe are similar (both display order and complexity), and therefore watches are the product of intelligent design that the universe must be a product of intelligent design too.

Slippery Slope

Slippery slope argues that one thing leads to another, so we shouldn’t do the first thing.

(1) If you buy a Green Day album, then next you’ll be buying Buzzcocks albums, and before

you know it you’ll be a punk with green hair and everything.

(2) You don’t want to become a punk.Therefore:

(3) You shouldn’t buy a Green Day album.

begging the question

The truth of the conclusion is assumed by the premises. Often, the conclusion is simply restated in the premises in a slightly different form."The belief in God is universal. After all, everyone believes in God."

post hoc ergo propter hoc

it is assumed that because one thing occurred after another, it must have occurred as a result of it

(1) Most people who are read the last rites die shortly afterwards.Therefore:(2) Priests are going around killing people with magic words!

Argument of Popularity

if a large number of people engage in some activity, then it must be the right thing to do.

Everybody likes/does/thinks/agree on A. Therefore A must be right.

Denying the antecedent

If A is true then B is true. A is not true, therefore B is not true.

If you work hard, you will get a good job. If you do not work hard you will not get a good job.

Hasty Generalization

when a person draws a conclusion about a population based on a sample that is not large enough35% of Iowans are corn farmers, so all Iowans must be corn farmers.

Confusing cause and effect

when a person assumes that one event must cause another just because the events occur together

video games causes teen violence