Logical Fallacies

AUTHOR'S NOTE:

These are the basic logical fallacies, informal and formal. They are

drawn from several sources. The informal fallacies are more likely

to be useful, especially when you are debating with someone else.

If you learn the fallacies and become fluent in them you will be

able to quickly spot the use of logical fallacies in someone elseUs

reasoning, or even your own! Note: A fallacy is a deceptive, false,

or misleading argument, notion, belief, etc.

The fallacies listed here are from a hypercard shareware stack that

I have put together.

The basic format of this list (and of the stack), is (1) the formal name

of the fallacy (usually its Latin name), followed by (2) a description of

the fallacy.

John W. Eshleman, Ed.D.

143 Blakeford Dr.

Dublin, OH 43017

CIS: 73767,1466

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UPLOADER'S NOTE:

The temptation among all of us is to chalk up the value of the enclosed

fallacies of logic, to purely academic exercises. However, to do so would

be a grievous error.

Logic is not just the "rules" of validity and soundness, but it is also

the straightest and most conducive path to practical communication.

Meaning, the enclosed should *not* be exclusively viewed as a weapon

against your dialogue opponent, but rather also as a tool for the

examination of your own assertions.

When I first started in Philosophy my Professor of Logic said to our

class --

"Learn the fallacies and learn them well. So well that immediately

when you hear one, a red flag goes up, sirens sound, and lights

flash. Then stop. Examine what is being said, and you will know

how to reply. And if it is you saying it, ask yourself if you must

say it that way. And still further yet, if your answer is in the

affirmative, stop your argument there. For the argument is yet to be

conceived that is more important than honesty and integrity."

Words to live by.

Kevin W. Walker, B.A.(Phil.),

M.A. Candidate

CPO 4492

Wheaton College Graduate School

Wheaton, IL 60187

CI$: 72070,3436

GEnie: K.WALKER12

 

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LIST OF LOGICAL FALLACIES:

ACCENTUS

Description: A Fallacy of Ambiguity, where the ambiguity arises from

the emphasis (accent) placed on a word or phrase.

 

AFFIRMATION OF THE CONSEQUENT

Description: An argument from the truth of a hypothetical statement,

and the truth of the consequent to the truth of the antecedent. In

the syllogism below, P is the antecedent and Q is the consequent:

P implies Q

Q is true <-- Affirming the consequent

______________

Therefore: P is true

 

AMBIGUITY

Description: An argument in the course of which at least one term is

used in different senses. Also known as equivocation. There are

several types of "fallacies of ambiguity," including REIFICATION,

EQUIVOCATION, AMPHIBOLY, COMPOSITION, DIVISION, and

ACCENTUS.

 

AMPHIBOLY

Description: A type of Fallacy of Ambiguity where the ambiguity

involved is of an "amphibolous" (equivocal, uncertain) nature.

Amphiboly is a syntactic error. The fallacy is caused by faulty

sentence structure, and can result in a meaning not intended by

the author. "The department store now has pants for men with

32 waists." (How many waists do you have? I have only one!)

 

ARGUMENTUM AD ANTIQUITAM

Description: A fallacy of asserting that something is right or good

simply because it is old; that is, because "that's the way it's always

been."

 

ARGUMENTUM AD BACULUM

Description: An argument that resorts to the threat of force to cause

the acceptance of the conclusion. Ad baculum arguments also

include threats of fear to cause acceptance (e.g., "Do this or you'll

go to Hades when you die!" or "Might makes right.").

 

ARGUMENTUM AD CRUMENAM

Description: Fallacy of believing that money is a criterion of

correctness; that those with more money are more likely to be

right.

 

ARGUMENTUM AD HOMINEM

Description: An argument that attempts to disprove the truth of what

is asserted by attacking the speaker rather than the speaker's

argument. Another way of putting it: Fallacy where you attack

someone's character instead of dealing with salient issues. There

are two basic types of ad hominem arguments: (1) abusive, and

(2) circumstantial.

 

ARGUMENTUM AD IGNORANTIAM

Description: An argument that a proposition is true because it has

not been shown to be false, or vice versa. Ad ignorantium arguments

are also known as "appeals to ignorance." This fallacy has two forms:

1. P is true, because it has not been proven false.

2. P is false, because it has not been proven true.

 

ARGUMENTUM AD LAZARUM

Description: A fallacy of assuming that because someone is poor he

or she is sounder or more virtuous than one who is wealthier. This

fallacy is the opposite of the informal fallacy "argumentum ad

crumenam."

 

ARGUMENTUM AD MISERICORDIAM

Description: An argument that appeals to pity for the sake of getting

a conclusion accepted.

 

ARGUMENTUM AD NAUSEUM

Description: The incorrect belief that an assertion is more likely to

be true the more often it is heard. An "argumentum ad nauseum"

is one that employs constant repitition in asserting a truth.

 

ARGUMENTUM AD NOVITAM

Description: A fallacy of asserting that something is more correct

simply because it is new or newer than something else. Or that

something is better because it is newer. This type of fallacy is the

opposite of the "argumentum ad antiquitam" fallacy.

 

ARGUMENTUM AD NUMERAM

Description: A fallacy that asserts that the more people who support

or believe a proposition then the more likely that that proposition is correct; it equates mass support with correctness.

 

ARGUMENTUM AD POPULUM

Description: An argument that appeals to the beliefs of the multitude

(i.e., the "populace"). Another way of putting it: Speaker deals

with passions of audience rather than with salient issues. This

fallacy is also known as "Appeal to Tradition" Ad populum arguments

often occur in (1) propaganda, (2) demagoguery, and (3) advertising.

 

ARGUMENTUM AD VERECUNDIAM

Description: An argument in which an authority is appealed to on

matters outside his/her field of authority. "Ad verecundiam" also

refers to a fallacy of simply resorting to appeals to authority.

 

BEGGING THE QUESTION (CIRCULAR REASONING)

Description: An argument that assumes as part of its premises the

very conclusion that is supposed to be true. Another way of saying

this is: Fallacy of assuming at the onset of an argument the very point

you are trying to prove. The fallacy is also sometimes referred to

as "Circulus in Probando." This Fallacy is also known by the Latin

"PETITIO PRINCIPII".

 

BIFURCATION

Description: Also referred to as the "black and white" fallacy,

bifurcation is the presentation of a situation or condition with

only two alternatives, whereas in fact other alternatives exist or

can exist.

 

COMPOSITION

Description: An argument in which one assumes that a whole has

a property solely because its various parts have that property.

Composition is a type of Fallacy of Ambiguity.

 

CONVERTING A CONDITIONAL

Description: If P then Q, therefore, if Q then P.

 

CUM HOC ERGO PROPTER HOC

Description: A fallacy of correlation that links events because they

occur simultaneously; one asserts that because two events occur

together they are causally related, and leaves no room for other

factors that may be the cause(s) of the events. This fallacy is similar

to the "post hoc" fallacy.

 

DENIAL OF THE ANTECEDENT

Description: An argument in which one infers the falsity of the

consequent from the truth of a hypothetical proposition, and the

falsity of its antecedent.

P implies Q

Not-P

____________

Therefore: Not-Q

 

DIVISION

Description: An argument in which one assumes that various parts

have a property solely because the whole has that same property.

Division is a type of Fallacy of Ambiguity.

 

EQUIVOCATION

Description: An argument in which an equivocal expression is used in

one sense in one premise and in a different sense in another premise,

or in the conclusion. Equivocal means (1) of uncertain significance;

not determined, and (2) having different meanings equally possible.

Equivocation is a type of Fallacy of Ambiguity. The opposite of

equivocation is "unovocation," in which a word always carries the

same meaning through a given context.

 

FALLACY OF INTERROGATION

Description: The question asked has a presuppostion which the

answerer may wish to deny, but which he/she would be accepting

if he/she gave anything that would count as an answer. Any answer

to the question "Why does such-and-such happen?" presupposes that

such-and-such does indeed happen.

 

FALSE ANALOGY

Description: An analogy is a partial similarity between the like features

of two things or events on which a comparison can be made. A

false analogy involves comparing two things that are NOT similar.

Note that the two things may be similar in superficial ways, but

not with respect to what is being argued.

 

HASTY GENERALIZATION (SECUNDUM QUID)

Description: An argument in which a proposition is used as a

premise without attention given to some obvious condition that

would affect the proposition's application. This fallacy is also known

as the "hasty generalization." It is a fallacy that takes evidence

from several, possibly unrepresentative, cases to a general rule;

generalizing from few to many. Note the relation to statistics: Much

of statistics concerns whether or not a sample is representative of a

larger population. The larger the sample size, the better the

representativeness. Note also that the opposite of a hasty generalization

is a sweeping generalization.

 

IGNORATIO ELENCHI

Description: An argument that is supposed to prove one proposition

but succeeds only in proving a different one. Ignoratio elenchi stands

for "pure and simple irrelevance."

 

ILLICIT PROCESS

Description: A syllogistic argument in which a term is distributed in

the conclusion, but not in the premises. One of the rules for a valid

categorical syllogism is that if either term is distributed in the

conclusion, then it must be distributed in the premises. There are

two types of Illicit Process: Illicit Process of the Major Term and

Illicit Process of the Minor Term.

 

PLURIUM INTERROGATIONUM-MANY QUESTIONS

Description: A demand for a simple answer to a complex question.

 

NON CAUSA PRO CAUSA

Description: An argument to reject a proposition because of the falsity

of some other proposition that seems to be a consequence of the first,

but really is not.

 

NON-SEQUITUR

Description: An argument in which the conclusion is not a necessary

consequence of the premises. Another way of putting this is: A

conclusion drawn from premises that provide no logical connection

to it.

 

PETITIO PRINCIPII

Description: Same as "Begging the Question" The argument assumes

its conclusion is true but DOES NOT SHOW it to be true. Petitio principii

has two forms:

1. P is true, because P is true.

2. P is true, because A is true. And A is true because B is true.

And B is true because P is true.

 

POST HOC, ERGO PROPTER HOC

Description: An argument from a premise of the form "A preceded B" to

a conclusion of the form "A caused B." Simply because one event

precedes another event in time does not mean that the first event is

the cause of the second event. This argument resembles a fallacy known

as a Hasty Generalization.

 

QUATERNIO TERMINORUM

Description: An argument of the syllogistic form in which there occur

four or more terms. In a standard categorical syllogism there are

only three terms: a subject, a predicate, and a middle term.

 

RED HERRING

Description: A fallacy when irrelevant material is introduced to the

issue being discussed, such that everyone's attention is diverted

away from the points being made, and toward a different conclusion.

It is not logically valid to divert a chain of reasoning with

extraneous points.

 

REIFICATION

Description: To reify something is to convert an abstract concept into

a concrete thing. Reification is a Fallacy of Ambiguity. Reification is

also sometimes known as a fallacy of "hypostatization".

 

SHIFTING THE BURDEN OF PROOF

Description: The burden of proof is always on the person making

the assertion or proposition. Shifting the burden of proof, a special

case of "argumentum ad ignorantium," is a fallacy of putting the

burden of proof on the person who denies or questions the assertion

being made. The source of the fallacy is the assumption that something

is true unless proven otherwise.

 

SPECIAL PLEADING

Description: Special pleading is a logical fallacy wherein a double

standard is employed by the person making the assertion.

Special pleading typically happens when one insists upon less

strict treatment for the argument he/she is making than he or

she would make when evaluating someone else's arguments.

 

STRAW MAN

Description: It is a fallacy to misrepresent someone else's position

for the purposes of more easily attacking it, then to knock down

that misrepresented position, and then to conclude that the

original position has been demolished. It is a fallacy because it

fails to deal with the actual arguments that one has made.

 

SWEEPING GENERALIZATION

Description: Also known by the Latin term "DICTO SIMPLICITER",

a Sweeping Generalization occurs when a general rule is applied to

a particular situation in which the features of that particular

situation render the rule inapplicable. A sweeping generalization

is the opposite of a hasty generalization.

 

TWO WRONGS MAKE A RIGHT (TU QUOQUE)

Description: Two wrongs never add up to a right; you cannot right

a wrong by applying yet another wrong. Such a fallacy is a

misplaced appeal to consistency. It is a fallacy because it makes

no attempt to deal with the subject under discussion.

 

UNDISTRIBUTED MIDDLE

Description: A syllogistic argument in which the middle term of

a categorical syllogism is not distributed in at least one of the

premises.

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