Fallacies 3

7/30/2019 Fallacies 3

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Brian A. Ray Abraham Baldwin Agricultural College

Fallacies of Presumption, Ambiguity,and Grammatical Analogy


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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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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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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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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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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.



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.



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.



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.



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.



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.



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.



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



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.



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.



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.



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.



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).



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

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