THE NATURE AND KINDS OF FALLACIESThe 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. • 5. • 2. • 3.The unique ability to call a fallacy by name will give a person a greater advantage over an opponent in debate and argumentation. • 4. The valid forms of inference can best be shown and explained by contrasting them with invalid ones.ADVANTAGES IN KNOWING FALLACIES • 1. Familiarity with these errors in logic can assist us from being deceived by them. Mastery in the recognition of fallacies will enable one to apply the principles of logic to everything one reads or hears. the study of fallacies will provide the occasion for a review of much of the lessons concerning rudiments of logic. Fallacies serve as danger signals to warn us of injudicious reasoning. . – B. Fallacy of accent. Incorrect conversion. – C. – E. and Fallacy of amphiboly . Rhetorical fallacies. Incorrect obversion. Incorrect contrapositions. Rhetorical Fallacies: – A.errors in reasoning. – D. • 2. Logical fallacies.errors of understanding or of interpretation due to the use of language.KINDS OF FALLACIES • 1. I. • II. Fallacy of simple accident. Formal Fallacies: • 1. Fallacy of converse accident. B. Formal Fallacies in disjunctive syllogisms. and 2. 3. The fallacy of equivocation a. Fallacy of composition. The fallacy of quantity 1. . The fallacy of quality 1. • 2. 2. Fallacy of specific accident. b. Material Fallacies: 1. Formal Fallacies in hypothetical syllogisms. and • 3. Formal Fallacies in categorical syllogisms. Fallacy of division. Logical Fallacies: – A. • 6. • 3. • 2. • 7. The Fallacy of presumption – A.• 2. Argumentum ad captandum vulgus . • 1. Argumentum ad ignorantiam. Circulus in probando – B. • 5. • 10. • 4. Argumentum ad misericordiam. Argumentum ad judicium. Argumentum ad crumenam. • 9. Assumptio non probata • 2. Argumentum ex concessio. Argumentum ad verecundiam. Ignoration elenchi • 1. Argumentum ad populum. Argumentum ad baculum. Begging the question or petitio principii. Argumentum ad hominem. • 8. Incorrect obversion arises when in changing the original proposition from affirmative to negative or from negative to affirmative. propter hoc. – Example : All members of this class are Filipinos. . – 1. Complex question • D.• C. Non Sequitor – 1. the meaning of the original proposition is changed. Simple non sequitor. – Rhetorical fallacies are also called hermeneutic fallacies. ergo. and – 2. False cause-post hoc. No members of this class are Filipinos. without changing the meaning of the original proposition. • Example: All cats are animals. If a term is not distributed in the original proposition but it is distributed in the second proposition. No members of this class are aliens. Example: All members of this class are Filipinos. • 2. (Logical conversion) . (Incorrect conversion) – All cats are animals.Logical obversion is the changing of the riginal proposition from affirmative to negative or viceversa. – Some animals are cats. the fallacy arises. • All animals are cats. Incorrect conversion-arises when in the transposition of the subject and the predicate the meaning of the original proposition is changed. Type 1. • Example: All men are immortal. No men are immortal.Logical contraposition in the formation of new proposition without changing the meaning of the original proposition. Incorrect contraposition. Any of the rules of contraposition is violated in the fallacy.• 3.All immortal beings are nonmen. Type II. .No immortal beings are men. ” .4. • Examples: • “Post no bills” “ No parking on both sides.” • “We should be neighbors. 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. The notorious criminal had been arrested by the policeman who robbed the bank. The fallacy of amphiboly. an accident befell the priest. • Example: 1. While crossing the bridge. . The use of ambiguous pronouns or of dangling participial phrases often gives rise to this fallacy. • 2.• 5.arises on account of faulty grammatical construction of the sentence which gives rise to miscomprehension. • b. Fallacy of negative premise. Fallacy of 4 terms. Fallacy of illicit minor. • A. Formal fallacies-those that arise from the violations of the rules of syllogism. They are not merely errors of interpretation. Fallacy of undistributed middle. Fallacy of illicit major. Fallacy of particular premise. • f. Formal fallacy in categorical syllogisms: • a. • c. . • 1. • e.Logical fallacies are errors in inferring. • d. Any violation of these rules gives rise to a mistake in inference. A noun eats meat. Filipinos are Europeans. A dog eats meat. Frenchmen are Europeans.• A. Dog is a noun. . Fallacy of 4 terms: • Examples: Filipinos are oriental. Fallacy of undistributed middle term. Hence. • Japanese are orientals.the rule of syllogism requires that the middle term must be distributed at least once. • Example: • Filipinos are orientals. • Filipinos are Japanese. the middle term orientals is not distributed either in the major premise or in the minor premise. . • In the example. A term is distributed when it is used universally.• B. the fallacy. • C. the major term “heroic people” is not distributed in the major premise. the fallacy. • Example: Filipinos are heroic people. . • Americans are not Filipinos. The major premise is distributed in the conclusion because it used negatively. Hence. 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. • Americans are not heroic people. • In the example. • Example: All representatives are at least 25 years of age. All representatives are voters.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. The minor term voters is distributed in the conclusion when it was not distributed in the minor premise. . All voters are at least 25 years of age. The fallacy of illicit minor term.• d. Horses are not dogs. – Example: Cows are not dogs.• e. The fallacy of negative premises occurs when the premises are both negative. . (no conclusion). • Example (A). • B. The possibilities are not exhaustive. Juan may be both dishonest and stupid at the same time. • Juan is not stupid. • Juan is dishonest.• 2. The alternatives are not mutually exclusive. Formal Fallacies in disjunctive syllogisms arises when: • A. The mention of one of the qualifying adjectives does not preclude the mention of the other.Juan is either dishonest or stupid. . • Example: Senator X is either an LDP or Liberal. Senator X is not an LDP. NP PDPLaban. ETC.• B. .LP. Partido ng Bayan LAKAS – NUCD. In the Philippines at present Senators belong to either LDP. Senator X is a Liberal. The fallacy of possibilities not exhaustive arises when the posssiblities used in the predicate of the disjunctive major premise are not exhaustive. Fallacy of denying the antecedent.” it does not necessarily follow that “Juana will not be happy.) • Example: If Pedro marries Juana.” On the other hand. Pedro will not marry Juana. When the antecedent is denied in “Pedro will not marry Juana.” follows logically. Juana will not be happy. . if the antecedent is affirmed. “Juana will be happy.Formal Fallacies in hypothetical syllogisms: • A. the conclusion. (Antecedent is one which states the condition or limitation. she will be happy.committed when the minor premise denies the antecedent of the major premise. B. .” it does not necessarily follow that “David graduated with honors. Fallacy affirming the consequent arises when the minor premise affirms the consequent.” The major premise does not say that David would not be appointed unless he graduated with honors. • When the consequent is affirmed. “David has been appointed to the faculty. he will be appointed to the faculty. • Example: • If David graduated with honors. • David has been appointed to the faculty. • David graduated with honors. • 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. Fallacy of equivocation • 2. • Kinds: • 1. Fallacy of presumption. .B. but from the confusion in the connotation or denotation of the terms used or from a faulty assumption of facts. MATERIAL FALLACIES • Material fallacies are those that arise not from the violations of the rules of syllogism. in the former. • (I ) All members of this class weigh less than 50 kilos. the error lies in the mistaken interpretation of the connotation or denotation of the terms while in the latter. all.000 kilos. . • The word.• The fallacy of equivocation differs from the fallacy of amphiboly in that. 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. • Two kinds of fallacy of equivocation: • 1. • (C ) All members of this class weigh 1. the error lies in the faulty grammatical structure of the sentences. is sometimes used collectively and sometimes used individually. B. • ( I) the word.D.• ( C ) the word. B.D. 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. refers to each and every individual member. • A. • Example: • All members of this class weigh less that 150lbs.G. & H weigh less than 150 lbs.F. & H are all members of this class. all.E.E. refers to the aggregate of the members of the class. • Classes of fallacy of quantity: • A. • A.G. all.C.F.C. . 500 lbs. The Philippines is a rich country.• B. • .500 lbs. Juan de la Cruz lives in the Philippines. Juan de la Cruz is a rich man. • Example: All members of this class weigh 1. A is a member of this class. Fallacy of division arises when we assert that what is true of the whole collectively is true of a part taken singly. A weighs 1. »This envelope is good for binding books. Words are sometimes used in different senses.Fallacies of quality. in its broader sense. • 3 types of fallacy of quality: • 1. . and in its minor premise. that is. • Example: Paper is good for binding books. »This envelope is made of paper. simple accident is committed when in the major premise we use a term in its generic sense. we use the same term in its specific term.arise from the confusion in the attributes connoted by terms used in the proposition. . • The word man in the major premise is used in its generic sense. • Example: • Man invented the atomic bomb. • David invented the atomic bomb. • David is a man.• 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. while the word man in the minor premise is used in its specific sense. X poisons his patients.• 2. in the minor premise. X prescribes opium for her patients. we use the same term in its generic sense. that is. • Example: • Opium acts as poison in the human body. in its narrowest connotation. and. . • Dr. • Dr. Fallacy of converse accident arise when in the major premise we use a term in its specific sense. • • • • Example: All criminals must be sent to prison. X is a criminal lawyer. X must be sent to prison. . Atty. 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.• 3. Atty. without presenting evidence or argument.FALLACIES OF PRESUMPTION • This arises when the disputant assumes. the truth of the conclusion which it is his duty to prove it. –2 types: 1. Assumptio non-probata 2. circulus in probando . • 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. Circulus in probando-arises when the arguer uses two unproved propositions. 2. “X” has killed another person.• 1. It arises when the arguer uses the conclusion to be proved as the means of proving it. . Assumptio non-probata-means the assumption of the truth of an unproved premise. each to establish the validity of the other. Example: Your answer is correct. because it is the same as my answer. Example: All persons who have killed other persons must be electrocuted. “X” must be electrocuted. ”.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.B) The fallacy of ignoratio elenchi called “irrelevant conclusion. 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. . • C.