Fallacies 3

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    Brian A. Ray Abraham Baldwin Agricultural College

    Fallacies of Presumption, Ambiguity,and Grammatical Analogy

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    Brian A. Ray Abraham Baldwin Agricultural College

    Fallacies of Presumption:

    Overview

    Begging the Question

    Complex Question

    Non SequiturDoes Not Follow

    False Dichotomy

    Suppressed Evidence

    Equivocation

    Amphiboly

    Composition

    Division

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    Brian A. Ray Abraham Baldwin Agricultural College

    Begging the Question: Definition

    This fallacy occurs when an arguer uses

    some form of phraseology to conceal a keypremise that may be unsupported by

    argument.

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    Brian A. Ray Abraham Baldwin Agricultural College

    Begging the Question: Examples

    Murder is morally wrong. This being the

    case, it follows that abortion is morally wrong.

    Comment :Ignores the fact that the argument

    doesnt prove that abortion is murder, which is thereal point of controversy.

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    Brian A. Ray Abraham Baldwin Agricultural College

    Complex Question: Definition

    This fallacy occurs when a single question

    that is really two (or more) questions is asked

    and a single answer is then applied to both

    questions

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    Brian A. Ray Abraham Baldwin Agricultural College

    Complex Question: Examples

    Do you still beat your wife?

    Comment :However you answer this question, itcommits you to saying that you engaged in this

    behavior in the past.

    Have you stopped cheating on exams?

    Comment :Supposes that you have cheated in

    the past.

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    Non SequiturDoes Not Follow:

    Definition

    This fallacy occurs when the arguer attempts

    to link two or more ideas that are not logicallyrelated as if they are connected or causative.

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    Non SequiturDoes Not Follow:

    Examples

    If Americans can send a man to the moon,

    then we can cure cancer and defeat AIDS.

    Comment: The technology and knowledge

    required to send men to the moon is distinctly

    different from that needed to cure cancer andAIDS.

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    False Dichotomy: Definition

    This fallacy occurs when the arguer assumes

    there are only two alternatives when in fact

    there are more than two.

    This is often referred to as the either or

    fallacy.

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    False Dichotomy: Example

    Either you buy only American-made products

    or you dont deserve to be called a loyalAmerica. Yesterday you bought a new

    Toyota. Its clear you dont deserve to be

    called a loyal American.

    Comment :The person may still be a very loyal

    citizen.

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    Suppressed Evidence: Definition

    Occurs in inductive arguments that ignore

    some important piece of evidence thatoutweighs the presented evidence and

    entails a very different conclusion.

    Difficult to detect because you must know

    about the details of the case.

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    Suppressed Evidence: Example

    Used car salesman: This car is a great

    value. Its clean and has low mileage.

    Comment :The salesman may not be telling you

    that the car had been in a serious crash.

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    Equivocation: Definition

    Occurs when the conclusion of an argument

    depends on the fact that a word or phrase isused, either explicitly or implicitly, in two

    different senses in the argument. Such

    arguments are either invalid or have a false

    premise.

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    Equivocation: Example

    Some triangles are obtuse. Whatever is

    obtuse is ignorant, so some triangles areignorant.

    Comment :Obtuse is used in two ways:

    Greater than 90 degrees

    Not smart

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    Amphiboly: Definition

    Occurs when the arguer misinterprets a

    statement that is syntactically orgrammatically ambiguous and proceeds to

    draw a conclusion based on this faulty

    interpretation.

    Its important to keep in mind that it is thefaulty conclusion that is the fallacy, not the

    misplaced/ambiguous statement.

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    Amphiboly: Example

    Professor Johnson said that he will give alecture about heart failure in the biologylecture hall. It must be the case that anumber of heart failures have occurred thererecently.

    Comment :The phrase in the biology lecturehall should be placed immediately after lectureinstead of heart failure.

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    Composition: Definition

    This fallacy occurs when the conclusion of an

    argument depends on the erroneoustransference of an attribute from the part of

    something to the whole.

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    Composition: Example

    Each sentence in this composition is well-

    written. Therefore, the whole essay is well-written.

    Comment :It doesnt follow from the fact that

    each individual sentence is well written that thewhole essay is well written.

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    Division: Definition

    Occurs when the conclusion of an argument

    depends on the erroneous transference of anattribute from a whole (or a class) onto its

    parts (or members).

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    Division: Example

    America is a wealthy country. Bill Smith is an

    American; therefore, he is wealthy.

    Comment :Even though it is true that the country

    as a whole is wealthy, it doesnt follow that each

    individual in the country is a wealthy individual.

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    Fallacies of Presumption: Review

    Begging the Question

    Complex Question

    Non SequiturDoes Not Follow

    False Dichotomy

    Suppressed Evidence

    Equivocation

    Amphiboly

    Composition

    Division