The Nature and Kinds of Fallacies

THE NATURE AND KINDS OF FALLACIES

The antithesis of truth is called error. Truth is the aim and goal of both science and philosophy, and truth can be achieved only through accurate thinking. It is the ultimate goal of logic to supply the mind with knowledge of the laws of thought and the rules of correct inferential thinking, so that the mind can proceed with ease, order and precision in its pursuit of truth.

Error in logic is called FALLACY.

• The term “fallacy” is derived from the Latin word “fallo”. It means, etymologically “I deceive.”

• A fallacy is a deceptive argument. It is an argument that seems to be conclusive but it is actually not conclusive. Its sequence seems to be valid but it is actually invalid. Also, its premises may seem to be true but are actually false.

ADVANTAGES IN KNOWING FALLACIES• 1- The unique ability to call a fallacy by name will give a

person a greater advantage over an opponent in debate and argumentation.

• 2. The valid forms of inference can best be shown and explained by contrasting them with invalid ones.

• 3. Mastery in the recognition of fallacies will enable one to apply the principles of logic to everything one reads or hears.

• 4. the study of fallacies will provide the occasion for a review of much of the lessons concerning rudiments of logic.

• 5. Fallacies serve as danger signals to warn us of injudicious reasoning. Familiarity with these errors in logic can assist us from being deceived by them.

KINDS OF FALLACIES• 1. Rhetorical fallacies- errors of understanding

or of interpretation due to the use of language.

• 2. Logical fallacies- errors in reasoning.I. Rhetorical Fallacies:– A. Incorrect obversion;– B. Incorrect conversion;– C. Incorrect contrapositions;– D. Fallacy of accent; and– E. Fallacy of amphiboly

• II. Logical Fallacies:–A. Formal Fallacies:• 1. Formal Fallacies in categorical syllogisms;

• 2. Formal Fallacies in disjunctive syllogisms; and• 3. Formal Fallacies in hypothetical syllogisms.

B. Material Fallacies:1. The fallacy of equivocation

a. The fallacy of quantity

1. Fallacy of composition; and2. Fallacy of division.b. The fallacy of quality

1. Fallacy of simple accident;2. Fallacy of converse accident;

3. Fallacy of specific accident.

• 2. The Fallacy of presumption– A. Begging the question or petitio principii.

• 1. Assumptio non probata• 2. Circulus in probando

– B. Ignoration elenchi • 1. Argumentum ad hominem;• 2. Argumentum ad populum;• 3. Argumentum ad ignorantiam;• 4. Argumentum ad verecundiam;• 5. Argumentum ad judicium;• 6. Argumentum ad baculum;• 7. Argumentum ex concessio; • 8. Argumentum ad misericordiam;• 9. Argumentum ad crumenam;• 10. Argumentum ad captandum vulgus

• C. Complex question• D. Non Sequitor– 1. Simple non sequitor; and– 2. False cause-post hoc; ergo; propter hoc.

– Rhetorical fallacies are also called hermeneutic 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 members of this class are Filipinos.No members of this class are Filipinos.

Logical obversion is the changing of the riginal proposition from affirmative to negative or vice-versa, without changing the meaning of the original proposition.Example: All members of this class are Filipinos.

No members of this class are aliens.• 2. Incorrect conversion-arises when in the

transposition of the subject and the predicate the meaning of the original proposition is changed. If a term is not distributed in the original proposition but it is distributed in the second proposition, the fallacy arises.

• Example: All cats are animals. • All animals are cats. (Incorrect conversion)

– All cats are animals.– Some animals are cats. (Logical conversion)

• 3. Incorrect contraposition- Logical contraposition in the formation of new proposition without changing the meaning of the original proposition. Any of the rules of contraposition is violated in the fallacy.

• Example: All men are immortal. No men are immortal.

Type 1- No immortal beings are men.Type II- All immortal beings are non-

men.

4. The fallacy of accent is committed when the meaning of a proposition is misinterpreted on account of a misplaced accent or emphasis on a term.

• Examples:• “Post no bills” “ No parking on both

sides.”• “We should be neighbors.”

• 5. The fallacy of amphiboly- arises on account of faulty grammatical construction of the sentence which gives rise to miscomprehension. The use of ambiguous pronouns or of dangling participial phrases often gives rise to this fallacy.

• Example: 1. The notorious criminal had been arrested by the policeman who robbed the bank.

• 2. While crossing the bridge, an accident befell the priest.

Logical fallacies are errors in inferring. They are not merely errors of interpretation.

• A. Formal fallacies-those that arise from the violations of the rules of syllogism. Any violation of these rules gives rise to a mistake in inference.

• 1. Formal fallacy in categorical syllogisms:• a. Fallacy of 4 terms;• b. Fallacy of undistributed middle;• c. Fallacy of illicit major; • d. Fallacy of illicit minor;• e. Fallacy of negative premise;• f. Fallacy of particular premise.

• A. Fallacy of 4 terms:

• Examples: Filipinos are oriental; Frenchmen are Europeans;

Filipinos are Europeans.

Dog is a noun; A dog eats meat; A noun eats meat.

• B. Fallacy of undistributed middle term- the rule of syllogism requires that the middle term must be distributed at least once. A term is distributed when it is used universally.

• Example: • Filipinos are orientals;• Japanese are orientals;• Filipinos are Japanese.

• In the example, the middle term orientals is not distributed either in the major premise or in the minor premise. Hence, the fallacy.

• C. The fallacy of illicit major term arises when the major term is distributed in the conclusion but it was not distributed in the major premise.

• Example: Filipinos are heroic people.• Americans are not Filipinos;• Americans are not heroic people.

• In the example, the major term “heroic people” is not distributed in the major premise. The major premise is distributed in the conclusion because it used negatively. Hence, the fallacy.

• d. The fallacy of illicit minor term- a violation of the rule that the minor term should not be distributed in the conclusion when it was not distributed in the minor premise.

• Example: All representatives are at least 25 years of age;

All representatives are voters;All voters are at least 25 years of age.

The minor term voters is distributed in the conclusion when it was not distributed in the minor premise.

• e. The fallacy of negative premises occurs when the premises are both negative.

– Example: Cows are not dogs.Horses are not dogs.(no conclusion).

• 2. Formal Fallacies in disjunctive syllogisms arises when:

• A. The alternatives are not mutually exclusive;• B. The possibilities are not exhaustive.

• Example (A)- Juan is either dishonest or stupid;

• Juan is not stupid;• Juan is dishonest.

Juan may be both dishonest and stupid at the same time. The mention of one of the qualifying adjectives does not preclude the mention of the other.

• B. The fallacy of possibilities not exhaustive arises when the posssiblities used in the predicate of the disjunctive major premise are not exhaustive.

• Example: Senator X is either an LDP or Liberal;

Senator X is not an LDP; Senator X is a Liberal.

In the Philippines at present Senators belong to either LDP,LP, NP PDP-Laban, Partido ng Bayan LAKAS –NUCD, ETC.

Formal Fallacies in hypothetical syllogisms:

• A. Fallacy of denying the antecedent- committed when the minor premise denies the antecedent of the major premise. (Antecedent is one which states the condition or limitation.)

• Example: If Pedro marries Juana, she will be happy;

Pedro will not marry Juana;Juana will not be happy.

When the antecedent is denied in “Pedro will not marry Juana,” it does not necessarily follow that “Juana will not be happy.” On the other hand, if the antecedent is affirmed, the conclusion, “Juana will be happy,” follows logically.

B. Fallacy affirming the consequent arises when the minor premise affirms the consequent.

• Example:• If David graduated with honors, he will be

appointed to the faculty;• David has been appointed to the faculty;• David graduated with honors.

• When the consequent is affirmed, “David has been appointed to the faculty,” it does not necessarily follow that “David graduated with honors.” The major premise does not say that David would not be appointed unless he graduated with honors.

B. MATERIAL FALLACIES• Material fallacies are those that arise not from

the violations of the rules of syllogism, but from the confusion in the connotation or denotation of the terms used or from a faulty assumption of facts.

• Kinds: • 1. Fallacy of equivocation• 2. Fallacy of presumption.

• Fallacy of equivocation arise from the assumption that what is true of a term used in one sense is also true of the same term used in another sense.

• The fallacy of equivocation differs from the fallacy of amphiboly in that, in the former, the error lies in the mistaken interpretation of the connotation or denotation of the terms while in the latter, the error lies in the faulty grammatical structure of the sentences.

• Two kinds of fallacy of equivocation:• 1. Fallacy of quantity –arise when we assert that

what is true of a whole taken collectively is true of a part taken individually or that what is true of a part taken singly is true of the whole taken collectively.

• The word, all, is sometimes used collectively and sometimes used individually.

• (C ) All members of this class weigh 1,000 kilos.• (I ) All members of this class weigh less than 50 kilos.

• ( C ) the word, all, refers to the aggregate of the members of the class.

• ( I) the word, all, refers to each and every individual member.

• Classes of fallacy of quantity:• A. Fallacy of composition (false synthesis) is a

fallacy of quantity in which we assert that what is true of a part taken singly is true of the whole taken collectively.

• Example: • All members of this class weigh less that 150lbs. • A,B,C,D,E,F,G, & H are all members of this class;• A, B,C,D,E,F,G, & H weigh less than 150 lbs.

• B. Fallacy of division arises when we assert that what is true of the whole collectively is true of a part taken singly.

• Example: All members of this class weigh 1,500 lbs;

A is a member of this class; A weighs 1,500 lbs.

The Philippines is a rich country;Juan de la Cruz lives in the Philippines;Juan de la Cruz is a rich man.

•

Fallacies of quality- arise from the confusion in the attributes connoted by terms used in the proposition.

Words are sometimes used in different senses.

• 3 types of fallacy of quality:• 1. simple accident is committed when in the

major premise we use a term in its generic sense, that is, in its broader sense, and in its minor premise, we use the same term in its specific term.

• Example: Paper is good for binding books;»This envelope is made of paper;»This envelope is good for binding

books.

• Paper in the major premise refers to the material of which the envelope is made while paper in the minor premise refers to the form in which the envelope is found.

• Example:• Man invented the atomic bomb;• David is a man;• David invented the atomic bomb.• The word man in the major premise is used in

its generic sense, while the word man in the minor premise is used in its specific sense.

• 2. Fallacy of converse accident arise when in the major premise we use a term in its specific sense, that is, in its narrowest connotation, and, in the minor premise, we use the same term in its generic sense.

• Example:• Opium acts as poison in the human body;• Dr. X prescribes opium for her patients;• Dr. X poisons his patients.

• 3. Fallacy of specific accident arise when the middle term is used to connote one thing in the major premise and another thing in the minor premise.

• Example:• All criminals must be sent to prison;• Atty. X is a criminal lawyer;• Atty. X must be sent to prison.

FALLACIES OF PRESUMPTION• This arises when the disputant assumes,

without presenting evidence or argument, the truth of the conclusion which it is his duty to prove it.

• Kinds:• A) Begging the question arises when the

arguer assumes the truth of the proposition which is in the essence the same as the conclusion which he seeks to establish.

–2 types: 1. Assumptio non-probata 2. circulus in probando

• 1. Assumptio non-probata-means the assumption of the truth of an unproved premise. It arises when the arguer uses the conclusion to be proved as the means of proving it.Example: All persons who have killed other persons must

be electrocuted.“X” has killed another person;“X” must be electrocuted.

2. Circulus in probando-arises when the arguer uses two unproved propositions, each to establish the validity of the other.

Example: Your answer is correct, because it is the same as my answer.

B) The fallacy of ignoratio elenchi called “irrelevant conclusion,”- committed when the disputant brushes aside or ignore the real question at issue and attempts to prove something which has no bearing on the question under discussion.• C. Fallacy of complex question (fallacious question)

arises when a debater asks a question that implies the truth of an assumption.

• Example: Are you a man with feminine traits?

• D. Fallacy of non-sequitor (“it does not follow”) arises when a debater draws a conclusion from a premise without showing a valid connection between the assumed or know truth in the premise and the alleged truth in the conclusion.