Cesar Gulang's Blog

FALLACIES
The term “fallacy” is taken from the Latin word fallere which means to deceive or to lead astray, or from the Latin fallo meaning “I deceive.” From this etymological definition, a fallacy is an argument designed to deceive an opponent in order to lead him astray from the issue. Strictly speaking, fallacies are violations of the rules on inference.

I.Rhetorical fallacies
1.Incorrect obversion arises when, in changing the original proposition from affirmative to negative or from negative to affirmative, the meaning of the original proposition is changed.
Example:
All men are mortal beings.
No men are mortal beings.


2.Incorrect conversion arises from the mistake in the distribution of terms such that a term which is not distributed in the original proposition is distributed in the second proposition.
Example:
All mothers are females.
All females are mothers.

3.The fallacy of accent can be committed when there is a faulty emphasis of word. This may come in three variations: emphasis on punctuation, wrong interpretation of words, and word lifting.
Examples:
Emphasis on punctuation
Ruffa says Gretchen is cheating.
Ruffa, says Gretchen is cheating.
Ruffa says, Gretchen is cheating.

In the second statement, the one guilty of cheating is Ruffa according to Gretchen. While in the third statement, the one guilty of cheating is Gretchen according to Ruffa.

Wrong interpretation of words

No parking on both sides.

A driver reads this literally and parks his car only on the left side rationalizing that what he is doing is legitimate inasmuch as he is not parking his car on both sides of the road or lane.

Jesus said: “Love your neighbor.” Well, I should not love Mary for she is not my neighbour.

The word “neighbor” does not represent only those persons living near your dwelling places or homes. In the Christian sense, it refers to all persons other than yourself.

Word lifting

I said, do not kill her.
I said... kill her.

Word lifting is a manner of abridging a certain statement to the extent of taking out words out of the context without noticing that those words once taken may alter the meaning of the statement.


4.The fallacy of amphiboly is committed when the arguer misinterprets a statement that is ambiguous owing to some structural defect and proceeds to draw a conclusion based on this faulty interpretation.
Example:
A reckless motorist Friday struck and injured a student who was jogging through the campus in his pick-up truck. Therefore, it is unsafe to jog in your pick-up truck.

II.Logical fallacies
A.Formal fallacies

1.Formal fallacies in categorical syllogisms are committed when the rules of the syllogism are violated.
(a)Fallacy of four terms – there must only be three terms in the entire syllogism, each of which must occur twice and must be used exactly in the same meaning throughout the argument. This fallacy is committed when more than three terms are used in the syllogism.
Example:
All men are handsome beings.
Juan is a man.
Therefore, Pedro is a handsome being.

(b)Fallacy of undistributed middle – the middle term must be universal in at least one of the premises. Violation of this rule gives rise to the fallacy of undistributed middle.

Example:

All monkeys are banana-eaters.
Juan is a banana-eater.
Therefore, Juan is a monkey.

(c)Fallacy of illicit major – is committed when the major term in the conclusion is universal but particular in the major premise.

Example:

All judges are lawyers.
Some professionals are not judges.
Therefore some professionals are not lawyers.

(d)Fallacy of illicit minor – is committed when the minor term in the conclusion is universal but particular in the minor premise.

Example:

All communists are subversive elements.
All communists are critics of the present administration.
Therefore, all critics of the present administration are subversive elements.

(e)Fallacy of negative premises – there must be at least one affirmative premise, as a rule. Violation of this rule constitutes a fallacy of negative premises.


Example:

Major Premise: No dogs are cats.
Minor Premise: No dogs are mice.
(No conclusion)

(f)Fallacy of particular premises – One of the premises must be universal. Violation of this rule gives rise to this fallacy.

Example:

Some politicians are Filipinos.
Some Cebuanos are not politicians.
Therefore, some Cebuanos are not Filipinos.


2.Formal fallacies in disjunctive syllogisms
3.Formal fallacies in hypothetical syllogisms

B.Material fallacies
1.The fallacy of equivocation
(a)The fallacy of quantity
(1)Fallacy of composition is committed when an attribute of a specific part is applied to the collective whole.
Example:
Jose is an intelligent boy.
Jose studies in Ateneo de Manila University.
Therefore, all who study in Ateneo are intelligent.

(2)Fallacy of division is committed when an attribute of a collective whole is applied to a specific part.
Example:
Logic students are good debaters.
John is a logic student.
Therefore, John is a good debater.

(b)The fallacy of quality
(1)Fallacy of simple accident
(2)Fallacy of converse accident proceeds from forming a general rule out of an insufficient amount of data or an incorrect interpretation of data.
Example:
Peter, my neighbor, won in the Bingo Pilipino.
James, my neighbour, also won in the Bingo Pilipino.
Therefore, we should play the Bingo Pilipino.

(3)Fallacy of specific accident is often called the “fallacy of ambiguous middle.”
Example:
Traffic is heavy every day.
Garry is a traffic policeman.
So, Garry is heavy.

2.The fallacy of presumption
(a)Begging the question
(1)Assumptio non- probata means the assumption of the truth of an unproved premise.
Example:
Everyone who cheats must be expelled.
Kim has cheated.
Hence, Kim must be expelled.

(2)Circulus in probando arises when the arguer uses two unproved propositions, each to establish the validity of the other.
Example:
The Bible is written by God because the Bible says so.

(b)Ignorantio elenchi
(1)Argumentum ad hominem can be committed when the listener attempts to disprove the truth of what is asserted by attacking the person or the character of the speaker rather than the content of his argument.
Example:
The speaker (who was a haunch back) on stage was delivering a speech in support of a certain political candidate.
A certain person from the audience shouted saying, “How can you expect a straight reasoning from a crooked man?”
(2)Argumentum ad populum is committed when the claim being advanced by the speaker is emotionally convincing and eventually accommodated by the people or the audience.
Example:
Filipinos are lovers of peace and development.
Therefore, Filipinos would support the RP-US Visiting Forces Agreement (VFA) for joint military exercises.

(3)Argumentum ad ignorantiam
Example:
No one has proven it true that God wrote the bible.
Therefore, God is not the author of the bible.


No one has conclusively proven that there is no life on the moons of Jupiter.
Therefore, there is life on the moons of Jupiter.

(4)Argumentum ad verecundiam is committed when a speaker cites a claim grounded on a premise being made by an expert in an unrelated field.
Example:
The warrantless arrest of Sen. Honasan, Enrile, and Santiago is legal because Cardinal Sin said so.
(5)Argumentum ad baculum is committed when an arguer poses a conclusion to another person and tells that person either implicitly or explicitly that some harm will come to him if he does not accept the conclusion.
Example:
I believed that Carlos P. Romulo was the most intelligent UN Secretary General. And if you do not agree with this political belief, you will receive a grade of 5.0 in Forensics.
Therefore, Carlos P. Romulo is the most intelligent UN Secretary General.

(6)Argumentum ex concessio is an argument from a previous admission. This fallacy arises when the disputant ignores the real question and asserts that his contention is valid because his opponent has previously admitted it to be so.
Example:
(c)Complex question involves a question that presumes another hidden question that makes it complex.
Example:
Question: Have you stopped visiting my wife?
Answer: Yes or No.
If the respondent answers the question with “yes,” then a conclusion can be presumed that, “The respondent had visited my wife, and now he stops.” And if the respondent answers the question with “no,” then a conclusion can be presumed that, “The respondent has been visiting my wife up to the present.”
(d)Non sequitor
(1)Simple non sequitor – arises when the arguer draws a conclusion from a premise, without having a valid connection between the assumed or known truth in the premise and the alleged truth in the conclusion.
Example:
John is the most behave student in the class; therefore, he should be given the most tasks.

(2)False cause – post hoc, ergo propter hoc occurs when there is confusion in inferring cause-effect correlations.
Example:
Yesterday, I received a letter obliging me to write the same for fifty pieces. Days had passed and I failed to do so. I met an accident. Therefore, this letter must be mysterious.