3.4b: Fallacies of Ambiguity

Ambiguous

An expression is considered this if it is susceptible to different interpretations in a given context. - ex: "Tuna are biting off the Washington coast."

Fallacies of Ambiguity

These fallacies arise from the occurrence of some form of ambiguity [uncertainty or inexactness of meaning in language] in either the premises or the conclusion (or both). - when the conclusion of an argument depends on a shift in meaning of an ambiguous word or phrase or on the wrong interpretation of an ambiguous statement, the argument commits a ___ _ ___. - two of these: Equivocation & Amphiboly

Amphiboly

This fallacy occurs when the arguer misinterprets an ambiguous statement and then draws a conclusion based on this faulty interpretation. The original statement is usually asserted by someone other than the arguer, and the ambiguity usually arises from a mistake in grammar or punctuation (missing comma, or some other careless arrangement of words). - ex: "The tour guide said that standing in Greenwich Village, the Empire State Building could easily be seen. It follow that the Empire State Building is in Greenwich Village." Does "standing in" mean the empire state building's location, or a person's location? - Equivocation involves the meaning of the sentence, whereas ___ involves the structure of the sentence. - causes lots of problems in contracts and wills. Ex: "Mr. James signed a contract that reads, 'In exchange for painting my house, I promise to pay David 5,000 and give him my new Cadillac only if he finishes the job by May 1.' Therefore, since David did not finish until May 10, it follows that he gets neither the 5,000 nor the Cadillac." In this argument, David will argue that the condition that he finish by May 1 affected only the Cadillac and that he therefore is entitled to 5,000. This dispute could have been resolved by simply adding a comma. - ex: "James said that he saw a picture of a beautiful girl stashed in Stephen's locker. We can only conclude that Stephen has broken the rules, because girls are not allowed in the locker room." This is a misunderstanding as to what was meant by "no girls in locker room." - ex: "Professor Johnson said that he will give a lecture about heart failure in the biology lecture hall. It must be the case that a number of heart failures have occurred there recently." Here the ambiguity concerns what takes place in the biology lecture hall; is it the lecture or the heart failures? This ambiguity can be eliminated by inserting commas ("Professor Johnson said that he will give a lecture, about heart failure, in the biology lecture hall") or by moving the ambiguous modifier ("Professor Johnson said that he will give a lecture in the biology lecture hall about heart failure"). - is a Fallacy of Ambiguity

Equivocation

This fallacy occurs when the conclusion of an argument depends on the fact that word or phrase is used, either explicitly or implicitly, in two different senses in the argument. Such arguments are either invalid or have a false premise, and in either case they are unsound. - ___ involves the meaning of the sentence, whereas Amphiboly involves the structure of the sentence. - ex: "We have a duty to do what is right. We have a right to speak out in defense of the innocent. Therefore, we have a duty to speak out in defense of the innocent." This argument uses "right" in two senses. In the first premise "right" means morally correct, but in the second it means a just claim or power. - ex: "A mouse is an animal. Therefore, a large mouse is a large animal." This argument uses a relative word ambiguously. The word "large" means different things depending on the context. Large relevant to mouse, and then large in context of the animal population as a whole. - ex: "Any law can be repealed by the legislative authority. But the law of gravity is a law. Therefore, the law of gravity can be repealed by the legislative authority." - ex: "Stacy is a terrible poker player. But every poker player is a person. Therefore, Stacy is a terrible person." - is a Fallacy of Ambiguity