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  • 1.LOGICFallacies

2. Fallacies A fallacy is derived from the Latin word fallo,which means I deceive. It is a deceptiveargument that seems to be conclusive but is actuallynot conclusive. Either its sequence seems to bevalid but is actually invalid, or else its premiseseems to be true but is actually false. Anappearance of validity and truth is essential to afallacy, for it would deceive no one unless it at leastseemed to be valid or true.An intended fallacy is called Sophism. It gets thisname because it was a favorite device of the ancientGreek sophists, who claimed to be able to proveeither side of any question. 3. The term fallacy is sometimes applied to ambiguous statements thatare not actually parts of an argument. The reason for this is that theymight be understood in a sense in which they are not true and thus bean occasion of deception.Cause of Fallacies Many fallacies arise from the matter of inference rather from defective form and might consequently seem to lie outside the scope of logic. Since the time of Aristotle, treatises on logic have always included a discussion of fallacies. 4. Effects/Importance to Knowledge of Fallacies1.) Correct forms of interference are often best illustrated and explainedby contrasting them with incorrect forms. You cannot know the correctforms of thought without simultaneously knowing the incorrect form.You cannot think correctly unless you avoid thinking incorrectly; andyou can neither avoid incorrect thinking nor detect incorrect thinkingunless you are skilled in recognizing incorrect thinking.2.) The study of fallacies will serve as a review of much of what wehave already seen. You should not consider fallacies in isolation fromthe other parts of logic, but intimately connected with them.3.) Readiness in recognizing fallacies will help you apply the principlesof logic to everything you read or hear and put you on your guardagainst the more common sources of deception.4.) Finally, the ability to call a fallacy by name will give you a greatadvantage over an opponent in discussion and debate. 5. 1. Fallacies of Language Aristotle lists six fallacies of language. The first five are various kinds of ambiguity and consist of using an expression in different senses in different parts of an argument but proceeding as though it were used in the same sense.A. Equivocationconsists in using a word that has the same spelling or sound, but a different meaning, in different parts of an argument. The word need not be an equivocal term in the strict sense the ambiguous use of an analogous term or a change in the way a term is used (that is, an illegitimate shift of supposition) can suffice. 6. Example (the equivocal use of the word naturalWhat is natural is good;but to make mistakes is natural;therefore to make mistakes is goodIn its first occurrence, the word natural means constituting or perfecting anature; in its second occurrence, it means due to the limitations of nature.Only in the first sense of the word is it true that what is natural is good. (thissyllogism also incurs the fallacy of four terms). 7. Example: the equivocal use of violate of law and of man He who violates the law should be punished;but when we illustrate fallacies we violate many laws; therefore when we illustrate fallacies we should be punished.He who violates a moral law perhaps should be punished but hardlyone who violates a law of logic.Man can be predicted of many; but you are a man;therefore you can predicted by many.The concept man can be predicted of many; however, you are notthe concept man but a real man. 8. B. Amphiboly is syntactical ambiguity. It consists in using a phrase whose individual words are univocal but whose meaning is ambiguous because the grammatical construction can be interpreted in various ways.When king Pyrrhus asked the oracle whether he would conquerthe Romans, the oracle answered in the following Latinhexameter:Aio te, Aeacide, Romanosvincer posse. (Pyrrhus the Romans can, I say, subdue.)Who was to conquer whom? King Pyrrus made the disastrousmistake of thinking that he was to conquer the Romans ratherthan the Romans were to conquer him. 9. Similar to this is the response that the oracle gave to KingCroesus when he was planning a war against the Persians.If Croesus wages war against the Persians, he will destroy a mighty kingdomWhose kingdom? His own? Or the Persians? The oracle did notsay, but the event proved that it was to be his own. 10. c. Composition consists in taking words or phrases as a unit when they should be taken separately.Cajus falls into this fallacy when he admits that thieves andmurderers are excluded from the kingdom of heaven, but thendenies that he himself is excluded since he is only a thief but nota murderer. 11. d. Divisionis the converse of the fallacy of composition and consists in taking separately what should be taken together as a unit.You fall into this fallacy when you argue;All in this room weigh about two tons;but Mary Alice in in this room;therefore Mary Alice weighs about two tons. All in this room is to be understood collectively in the majorpremise; but in the conclusion you proceed as though it had beentaken distributively; you divide, or separate, what is true onlywhen taken together as a unit. 12. e. Accent consists in the ambiguous use of a word that has differentmeanings when it is accented differently. This fallacy isthe same as equivocation except that, strictly speaking,words having different accents are not the same words. Example:John is not a depraved murderer - emphasizing depraved, you deny that john is depraved without stating whether or not ha is a murderer; if you emphasized murderer, you deny that he is a murderer without, however, stating whether or not he is depraved.Thou shall not bear false witness against thy neighbor If you emphasized shall not bear, you suggest the one should not tolerate false witness; if you emphasized false you hint that it is all right to say evil things about your neighbor. 13. f. Figures of Speech is a special type of false analogy that consists in wrongly inferring similarity of meaning from similarity of word structure.Example: Note the words immaterial, insoluble and inflammableWhat is immaterial is not material and what is insoluble is not soluble; therefore what is inflammable is not flammable.In immaterial and insoluble the prefix im- or in is a negativeparticle; but in inflammable it is an intensive particle. 14. Famous example of fallacy in Mills Utilitarianism:The only proof capable of being given that an object is visible isthat people actually see it. The only proof that a sound isaudible is because people hear it,; and so of the other sources ofour experience. In like manner, I apprehend, the sole evidence itis possible to produce that anything is desirable, is that peopledo actually desire it.This fallacy rests on the false assumption that, in the word desirable,that suffix ible (or -able) must mean capable being since ithas this meaning in visible and Audible 15. 2. Fallacies not of Language Aristotle lists seven fallacies not of language. They have this in common, that all of them arise from some kind of confusion about the things that are spoken of. Either what is essential to a thing is confused with what is merely accidental.a. Accident consists in affirming or denying of a thing what has beenaffirmed or denied only of some accidental modification orcondition of the thing, or vice versa. The sophists dialogue with the acquaintance of Coriscus illustrates this fallacy.Do you know Coriscus?YesDo you Know the man who is approaching with his face muffled?No.But he is Coriscus; you have both affirmed and denied that you know Coriscus. 16. To have his face muffled is an accident in Coriscus; it is possible to knowCoriscus without knowing him according to this particular accidentalcondition. ( you can know him without always recognizing him.) youillustrate the same fallacy when you argue: You say that you ate what you brought; but you brought raw meat; therefore you must have eaten raw meat.You did not intended to assert a complete identity between what you ate andwhat you brought. All you wanted to say is that they were substantially thesame; you did not intend to deny that the accidental condition of the meatwas change by cooking. 17. A conditional form of this fallacy consist in arguing that a thing itself should beforbidden or destroyed because its use sometimes leads to abuse. The abuseshould be eliminated, of course; but it does not fallow from this that the useshould also be eliminated. Alcoholic drinks lead to drunkennessand should therefore be forbidden.You can construct a parallel argument which is obviously absurd. Good food leads to overeating and should therefore be forbiddenYou might have a valid argument, through, if you show that the use of a thing isinseparable from its abuse and that the abuse always has serious evilconsequences. 18. b. Confusion of Absolute and Qualified Statement Under this heading we shall treat of two distinct but closely related fallacies. The first of these consist in using a principle that is restricted in its applicability as thought it were an absolutely universal principle, and thus applying it to cases for which it was not intended. What is true only with qualification or limitation is taken to be true absolutely or without any qualification or limitation. We illustrate this fallacy when we argue:Water boils at 212 Fahrenheit;therefore water boils at 212 Fahrenheit on the top of mount Everest. The premise is not true absolutely but only with the limitations under an atmospheric pressure corresponding to 760 mm.of mercury. hence, when we use this premise to infer that water boils at 212 Fahrenheit on the top of mount Everest, we are applying a principle to a case that nit was not intended to cover. We do the same when we argues 19. Germans are good musicians; therefore thisGermans is a good musician.The premise is true