Examples Of Fallacy

Fallacy

• Fallacies are defects in an argument.

• Fallacies cause an argument to be invalid, unsound, or weak.

Formal Fallacies

• Identified through discrepancies in syllogistic patterns and terms.

• Only found in deductive arguments.

• For a deductive argument to be valid, it must be absolutely impossible for both its premises to be true and its conclusion to be false. With a good deductive argument, that simply cannot happen; the truth of the premises entails the truth of the conclusion.

The classic example of a deductively valid argument is:

– 1. All men are mortal. (premise)

– 2. Socrates is a man. (premise)

– 3. Therefore Socrates is mortal. (guaranteed conclusion)

– It is simply not possible that both (1) and (2) are true and

Informal Fallacies

Fallacy: Burden of Proof

Appeal to Ignorance ("Ad Ignorantiam")

Description of Burden of Proof

Burden of Proof is a fallacy in which the burden of proof is placed on the wrong side. Another version occurs when a lack of evidence for side A is taken to be evidence for side B in cases in which the burden of proof actually rests on side B. A common name for this is an Appeal to Ignorance. This sort of reasoning typically has the following form:

1. Claim X is presented by side A and the burden of proof actually rests on side B.

2. Side B claims that X is false because there is no proof for X.

A very common example of this would be: “God exists because there is no proof that He does not.”

Fallacy: Appeal to Authority

Also Known as: Ad Verecundiam

Description of Appeal to Authority

An Appeal to Authority is a fallacy with the following form:

1. Person A is (claimed to be) an authority on subject

P is presented, with the intent to create pity.

2. Therefore claim C is true.

This line of "reasoning" is fallacious because pity does not serve as evidence for a claim. This is extremely clear in the following case: "You must accept that 1+1=46, after all I'm dying..." While you may pity me because I am dying, it would hardly make my claim true.

Fallacy: Hasty Generalization

Also Known as: Fallacy of Insufficient Statistics, Fallacy of Insufficient Sample, Leaping to A Conclusion, Hasty Induction.

Description of Hasty Generalization

This fallacy is committed when a person draws a conclusion about a population based on a sample that is not large enough. It has the following form:

1. Sample S, which is too small, is taken from population P.

2. Conclusion C is drawn about Population P based on S.

The person committing the fallacy is misusing the following type of reasoning, which is known variously as Inductive Generalization, Generalization, and Statistical Generalization:

1. X% of all observed A's are B''s.

2. Therefore X% of all A's are Bs.

The fallacy is committed when not enough A's are observed to warrant the conclusion. If enough A's are observed then the reasoning is not