informal fallacies

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Informal Fallacies Fallacy An Error in Reasoning To find out a fallacy is to identify the ways (recognizable patterns) in which one is tempted to reason incorrectly. Incorrect Reasoning: Premises of an argument fail to support its Conclusion. E.g., all sciences are materialistic, Karl Marx was a materialist, therefore Karl Marx was scientific.

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Page 1: Informal Fallacies

Informal Fallacies

FallacyAn Error in Reasoning

To find out a fallacy is to identify the ways (recognizable patterns) in which one is tempted to reason incorrectly.

Incorrect Reasoning: Premises of an argument fail to support its Conclusion.

E.g., all sciences are materialistic, Karl Marx was a materialist, therefore Karl Marx was scientific.

Page 2: Informal Fallacies

Formal Fallacies & Informal Fallacies

Type of Incorrect Argument

Formal Fallacy: Defect recognized in the form/structure of a deductive argument

Informal Fallacy: Defect due to the content of the language used

“the pitfalls laid by language in the way of a thinker”

Page 3: Informal Fallacies

Classification of Fallacies

Identifiable Common Features

No indubitable Taxonomy of FallaciesTherefore, working classification (somewhat

arbitrary)

1. Fallacies of Relevance2. Fallacies of Defective Induction3. Fallacies of Presumption4. Fallacies of Ambiguity

Page 4: Informal Fallacies

Fallacies of Relevance/Irrelevance

1. The Appeal to the Populace (Argument ad Populum)

2. The Appeal to Emotion3. The Red Herring4. The Straw Man5. The Attack on the Person

(Abusive/Circumstantial)6. The Appeal to Force7. Missing the Point

Page 5: Informal Fallacies

The Appeal to the Populace (Argument ad Populum)

Attempt to win popular assent to a conclusion by arousing the feeling of the people—mobilizing public sentiment—to excite enthusiasm/stir emotions (Appeal to emotion)

Instead of providing convincing evidence and

rational justification if one resorts to unduly invoking emotions, one commits a fallacy of this kind.

Page 6: Informal Fallacies

Patriotism & Advertisement

Many emotions are invoked and demands are pressed in the name of Nation and most of them in some sense seem justified. However, if the emotions are incited to garner support on illogical grounds, then the appeal becomes fallacious. For example, if a party demands vote in the name of religion, caste and region etc., it is not logically justified because the voters are supposed to vote on the merits of the candidate and the accidental facts like belonging to a religion or caste etc. do not constitute any merits which show the integrity and honesty of a candidate.

Page 7: Informal Fallacies

P&A cont…

Page 8: Informal Fallacies

ad Populum cont…

My party candidate is an accused person only, others have given tickets to criminals.

There is a fallacy of bandwagon in the given example, because instead of providing any rational justification for why the party ticket is given to an accused person, the spoke person is pointing out that others are also doing the same. His reason is logically irrelevant to support his claim that giving ticket to a tainted person is necessary. Though it is psychologically appealing that a vicious person can very well overcome another vicious, but it is not necessary. A virtuous person can be a more potential candidate against the vicious ones.

Page 9: Informal Fallacies

Argument ad Misericordiam (appeal to pity)

Latin misericordiam means “merciful heart”. Mercy is a noble emotion and there is nothing wrong to appeal to this virtue. But if an undue appeal is made, then it becomes a fallacy.

For example, a law officer commits this fallacy if he pleads for the leniency to his client, who killed his parents, on the grounds that he is an orphan.

Page 10: Informal Fallacies

The Red Herring

Some distraction is deliberately introduced to mislead or confuse to win the argument

Children are abused in New Delhi because there is a paucity of affordable child-care facilities.

Here the scarcity of child-care facility (creche) is brought in to take away the attention from the deteriorating law and order situation in the national capital.

Page 11: Informal Fallacies

The Straw Man Fallacy

Presenting an opponent’s position in a way easy to refute (may be a variety of red herring)

Assumption: opponent’s position is understood in its extremity

(a) Remarks by Mr. Mohan Bhagwat on reservation

(b) Taking any remark too literally (donkey/dog)

Page 12: Informal Fallacies

Argument Against the person (ad hominem)

• Argument Against the Person (abusive)Mr. Lalu Yadav’s concern for corruption is not

acceptable since he himself is convicted on corruption charges.

• Argument Against the Person (circumstantial)Non-NET qualified students’ demand is not

legitimate because those protesting belong to this category itself

Page 13: Informal Fallacies

Appeal to Force (Argument ad Baculum)

Force or threat of force is pressed into service instead of any rational justification

E.g. if you do not agree with my view, you have to face the consequences—fundamentalists

Page 14: Informal Fallacies

Missing the Point (Ignoratio Elenchi)

Such mistake is likely to be made when one seeks to refute another’s argument. Ignoratio elenchi is a “mistaken refutation”…the refutation goes haywire when the arguer fails to understand the position in dispute.

E.g. Opposition says that the economic situation is worsening because the prices of everything are rising. Govt. says that economy is improving and we are conducting raids on the hoarders to keep the prices low… non sequitur

Page 15: Informal Fallacies

Fallacies of Defective Induction

• The Argument from Ignorance (ad ignorantiam): x is true because it is not proven to be false…apprehension towards any new thing is likely to involve this fallacy.

• Appeal to Inappropriate Authority (argument ad verecundiam): a conclusion is accepted to be true when an expert endorses. Obvious fallacy is seen where a non-experts advice is used to accept a conclusion.

Page 16: Informal Fallacies

FDI cont…

• False Cause (argument non causa pro causa)when a non-cause is accepted as the cause of

something, such fallacy is committed (WMD issue for UK)

post hoc ergo propter hoc: after this, therefore because of this

Fallacy of the slippery slope: change in one will lead to necessary change in the other…likely (Collegium System Vs. NJAC)

Page 17: Informal Fallacies

FDI cont…

• Hasty Generalization:moving carelessly from short sample size to a general

claim (converse accident)

Varun, Vipin, Vikas, Vaibhav, Vishakha are the students of SMVDU.

Their name begins with a letter which is in the centre of SMVDU.

Therefore, SMVDU admits only those whose name begin with V.

Page 18: Informal Fallacies

Fallacies of Presumption

Fallacy due to tacit assumption which is unwarranted, dubious or false

Fallacy of Accident:Mistaken application of the general to special

cases

Complex Question:Deceitful device: have you stopped beating your

wife?

Page 19: Informal Fallacies

FP cont…

• Begging the Question: (petitio principi)When the conclusion of an argument is assumed

in any one of the premisesE.g. there is no such thing as knowledge which

cannot be practiced, for such knowledge is no knowledge.

Religious texts contain the message of God, they say that God exists, therefore we must accept that God exists.

Page 20: Informal Fallacies

Fallacies of Ambiguity

• Fallacy of Equivocation (due to more than one literal meaning) MMS

• Fallacy of Amphiboly (fallacious due to grammatical construction) X, along with his wife, Y, donated his house for charity

• Fallacy of Accent (shift in the emphasis) We should not speak ill of our friends…terms and conditions apply

• Fallacy of Composition (features of parts to the whole)

• Fallacy of Division (reverse of the fallacy of composition)

Page 21: Informal Fallacies

Mill’s Method

Cause and Effect Relationship

The Method of AgreementThe Method of Disagreement/DifferenceThe Joint Method of Agreement and DifferenceThe Method of ResiduesThe Method of Concomitant Variation