Logical fallacy summary

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Latest revision as of 09:46, 2 October 2011

A logical fallacy is a statement that is made appearing or claiming to be truthful or accurate, but due to an error in the structure of the claim, is not necessarily truthful nor accurate.

Unfortunately, logical fallacies are rampant in mainstream media. Being aware of the various types of fallacies and how they are structured, can help you identify misleading statements and recognize what is and isn't legitimate information.

Contents 1 Fallacies of Distraction 1.1 False Dilemma 1.2 From Ignorance 1.3 Slippery Slope 1.4 Complex Question 2 Appeals to Motives in Place of Support 2.1 Appeal to Force 2.2 Appeal to Pity 2.3 Consequences 2.4 Prejudicial Language 2.5 Popularity 3 Changing the Subject 3.1 Attacking the Person (Ad Hominem) 3.2 Appeal to Authority 3.3 Anonymous Authority 3.4 Style Over Substance 3.5 Moving the Bar 4 Inductive Fallacies 4.1 Hasty Generalization 4.2 Unrepresentative Sample 4.3 False Analogy 4.4 Slothful Induction 4.5 Fallacy of Exclusion 5 Fallacies Involving Statistical Syllogisms 5.1 Accident 5.2 Converse Accident 6 Causal Fallacies 6.1 Post Hoc Ergo Propter Hoc 6.2 Joint effect 6.3 Insignificant 6.4 Wrong Direction 6.5 Complex Cause 7 Missing the Point, Distraction 7.1 Begging the Question 7.2 Irrelevant Conclusion 7.3 Red Herring 7.4 Straw Man 8 Fallacies of Ambiguity 8.1 Equivocation 8.2 Amphiboly 8.3 Accent 9 Category Errors 9.1 Composition 9.2 Division 10 Non Sequitur 10.1 Affirming the Consequent 10.2 Argument By Question 10.3 Denying the Antecedent 10.4 Inconsistency 11 Syllogistic Errors 11.1 Fallacy of Four Terms 11.2 Undistributed Middle 11.3 Illicit Major 11.4 Illicit Minor 11.5 Fallacy of Exclusive Premises 11.6 Fallacy of Drawing an Affirmative Conclusion From a Negative Premise 11.7 Existential Fallacy 12 Fallacies of Explanation 12.1 Subverted Support 12.2 Non-support 12.3 Untestability 12.4 Limited Scope 12.5 Limited Depth 13 Fallacies of Definition 13.1 Too Broad 13.2 Too Narrow 13.3 Failure to Elucidate 13.4 Circular Definition 13.5 Conflicting Conditions 14 See Also

Fallacies of Distraction

These fallacies depend upon distracting or confusing the person.

False Dilemma

two choices are given when in fact there are three or more options.

If you're not with us, then you're with the terrorists

From Ignorance

because something is not known to be true, it is assumed to be false

Have you ever seen a zombie?

'There is no such thing as a black swan because none has ever been observed.'

Slippery Slope

a series of increasingly unacceptable consequences is drawn

If we allow cannabis to be decriminalized, they'll be legalizing heroin next!

Complex Question

two unrelated points are conjoined as a single proposition

Appeals to Motives in Place of Support

These fallacies prey upon peoples' emotions.

Appeal to Force

the reader is persuaded to agree by force

Appeal to Pity

the reader is persuaded to agree by sympathy

"How can you say that ball was out of bounds? It was so close, and I'm down ten games to two"

"You always win these arguments. Can you just let me win once?"

Consequences

the reader is warned of unacceptable consequences. This is pretty much a constant logical fallacy upon which most religion is based.

This can include concepts such as "they'll move on to much bigger targets than just the twin towers at 9/11 if they're not stopped" to persuade viewers.

Prejudicial Language

value or moral goodness is attached to believing the author

Popularity

a proposition is argued to be true because it is widely held to be true

If God wasn't real, why would the vast majority of people believe in God?

Changing the Subject

These fallacies also distract the person by bringing up something not necessarily related to the subject at hand.

Attacking the Person (Ad Hominem)

the person's character is attacked, the person's circumstances are noted, the person does not practise what is preached

Appeal to Authority

the authority is not an expert in the field, experts in the field disagree, the authority was joking, drunk, or in some other way not being serious

Anonymous Authority

the authority in question is not named

Style Over Substance

the manner in which an argument (or arguer) is presented is felt to affect the truth of the conclusion

Moving the Bar

once a question has been answered or an argument made, the criteria for answering is suddenly changed

Inductive Fallacies

A claim is made that is not fully-justified.

Hasty Generalization

the sample is too small to support an inductive generalization about a population

Unrepresentative Sample

the sample is unrepresentative of the sample as a whole

False Analogy

the two objects or events being compared are relevantly dissimilar

Slothful Induction

the conclusion of a strong inductive argument is denied despite the evidence to the contrary

Hugo has had twelve car accidents in the last six months, yet he insists that it is just a coincidence and not his fault. (Inductively, the evidence is overwhelming that it is his fault.)

Fallacy of Exclusion

evidence which would change the outcome of an inductive argument is excluded from consideration

Fallacies Involving Statistical Syllogisms

A Syllogism is a claim that is based on the combination of two prior claims. Using statistics, one can easily manipulate data to make erroneous claims.

Accident

a generalization is applied when circumstances suggest that there should be an exception

Converse Accident

an exception is applied in circumstances where a generalization should apply

Causal Fallacies

A dubious/erroneous cause-and-effect relationship is claimed.

Post Hoc Ergo Propter Hoc

because one thing follows another, it is held to be caused by the other

Joint effect

one thing is held to cause another when in fact they are both the joint effects of an underlying cause

Insignificant

one thing is held to cause another, and it does, but it is insignificant compared to other causes of the effect

Wrong Direction

the direction between cause and effect is reversed

Complex Cause

the cause identified is only a part of the entire cause of the effect

Missing the Point, Distraction

Someone goes off topic, partially as a distraction and partially to cover up the fact that they're injecting something not directly related to the subject at hand, using it as phony "evidence."

Begging the Question

the truth of the conclusion is assumed by the premises

Irrelevant Conclusion

an argument in defense of one conclusion instead proves a different conclusion

Red Herring

the introduction of additional, often unrelated information or commentary as a means of avoiding the principal argument

Straw Man

the author attacks an argument different from (and weaker than) the opposition's best argument

Fallacies of Ambiguity

These are methods of presenting claims which, due to the nature of their delivery, are misleading or erroneous.

Equivocation

the same term is used with two different meanings

Amphiboly

the structure of a sentence allows two different interpretations

Accent

the emphasis on a word or phrase suggests a meaning contrary to what the sentence actually says

Category Errors

These are false claims.

Composition

because the attributes of the parts of a whole have a certain property, it is argued that the whole has that property

Division

because the whole has a certain property, it is argued that the parts have that property

Non Sequitur

These are unsupported and presumptuous conclusions.

Affirming the Consequent

any argument of the form: If A, then B. B; therefore A

All Italians eat spaghetti, so anyone who eats spaghetti is Italian.

Argument By Question

a false assumption is introduced in the form of an interrogative

Have you stopped beating your wife?

(this assumption can't be denied by answering simply "yes" or "no".)

Denying the Antecedent

any argument of the form: If A then B, Not A, thus Not B

Inconsistency

asserting that contrary or contradictory statements are both true

Syllogistic Errors

Errors in deductive reasoning. Improve use of major and minor premises when trying to make a conclusion.

Fallacy of Four Terms

a syllogism has four terms

Undistributed Middle

two separate categories are said to be connected because they share a common property

Illicit Major

the predicate of the conclusion talks about all of something, but the premises only mention some cases of the term in the predicate

Illicit Minor

the subject of the conclusion talks about all of something, but the premises only mention some cases of the term in the subject

Fallacy of Exclusive Premises

a syllogism has two negative premises

Fallacy of Drawing an Affirmative Conclusion From a Negative Premise

as the name implies

Existential Fallacy

a particular conclusion is drawn from universal premises

Fallacies of Explanation

These are clearly subjective and dubious methods of making claims.

Subverted Support

The phenomenon being explained doesn't exist

Non-support

Evidence for the phenomenon being explained is biased

Untestability

The theory which explains cannot be tested

Limited Scope

The theory which explains can only explain one thing

Limited Depth

The theory which explains does not appeal to underlying causes

Fallacies of Definition

Using improper technique or evidence in justifying a claim.

Too Broad

The definition includes items which should not be included

Too Narrow

The definition does not include all the items which should be included

Failure to Elucidate

The definition is more difficult to understand than the word or concept being defined

Circular Definition

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

Conflicting Conditions

The definition is self-contradictory

See Also

• Master list of logical fallacies
• Logical_Fallacies_by_Todangst
• Logical fallacies

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