LOGICAL FALLACIES/ERRORS OF ARGUMENT Deduction Fallacies Term Definition Example(s) 1 Equivocation Ambiguity 2 types: The word or phrase may be ambiguous, in which case it has more than one distinct meaning OR The word or phrase may be vague, in which case it has no distinct meaning President Clinton should ve been impeached only if he had improper relations with Monica Lewinsky. He didn t have relations with Lewinsky. Therefore, he shouldn t have been impeached. Marriage is a subject of great gravity, so getting married will make us gain weight. I don t know why you think Clinton has sober judgment when you admit that he s a heavy drinker. The sign said, Fine for parking here. Since it was fine, I parked there.
2 Undistributed Middle Two separate categories are said to be connected because they share a common property All arguments with undistributed middle terms are bad arguments. This is a bad argument. Therefore, this argument has an undistributed middle. All students carry backpacks. My grandfather carries a backpack. Therefore, my grandfather is a student. grandfather is someone who carries a backpack; student is someone who carries a backpack 3 Illicit Process 2 types: Major & Minor 4 Conclusion from Two Negative Premises Fallacy of Exclusive Premises 5 Affirmative Conclusion from a Negative Premise The subject/predicate of the conclusion talks about all of something, but the premises only mention some cases of the term in the subject/predicate Major = predicate Minor = subject Two negative premises can t establish a relationship in a chain of reasoning; therefore, a conclusion can t be drawn One negative premise excludes relationship between two terms; therefore, conclusion has to exclude this relationship All students carry backpacks. My grandfather is a student. Therefore, my grandfather carries a backpack. All dogs are animals. No cats are dogs. Therefore, no cats are animals. All terrorists are extremists. All extremists are radicals. Therefore, all radicals are terrorists. No reptiles are mammals. No dogs are reptiles. Therefore, no dogs are mammals. We don't read that trash. People who read that trash don t appreciate real literature. Therefore, we appreciate real literature.
6 Either-Or Fallacy False Dilemma An oversimplification that reduces alternatives to only two choices when more may actually exist Either we ban boxing or hundreds of young men will be senselessly killed. Patients either get better or they don t. America: Love it or leave it. 7 Affirming the Consequent 8 Denying the Antecedent Induction Fallacies 1 Faulty Generalization Hasty Generalization Stereotyping If A then B. B. Therefore, A. Though the premises are true, the conclusion could be false If A then B. Not A. Therefore, not B. Though the premises are true, the conclusion may be false. Conclusion is unjustified due to insufficient/biased evidence If the mill were polluting the river, then we would see an increase in fish deaths. Fish deaths have increased. Thus, the mill is polluting the river. If you get hit by a car when you are 6 then you will die young. But you were not hit by a car when you were six. Thus, you will not die young. Professor Brugger is a hard grader because he gave my roommate a D- last year.
The majority of people in the United States die in hospitals, so stay out of them. I got bitten by a bunny once. I think they should all be slaughtered. What biological purpose do they serve? 2 Faulty Causal Generalizations False Cause Causation Fallacy Post Hoc Arguing that because Event B occurred after Event A, Event A caused Event B There was an increase of births during the full moon. Therefore, full moons cause birth rates to rise. I drank a Coldbuster Jamba Juice and three days later my cold disappeared!
3 Faulty Analogy False Analogy Faulty Comparison Basing an argument on a poor comparison of two things, ideas, events or situations; comparing apples and oranges Teaching kids about sex education is like letting them loose in a candy store. The American Indian had to make way for Western civilization; after all, you can't make an omelette without breaking a few eggs. Since the mind is essentially a wet computer, our task is to figure out how we can best program it!
Miscellaneous Fallacies 1 Begging the Question Loading the conclusion in the claim; assuming that something is true before it s proven 2 Ad Hominem Personal Attack An attack on the character of the individual rather than his/her actual arguments or qualifications The antiwar demonstrators of the 1970s should be remembered as the cowards that they were. Your arguments against Freud are due to your unresolved unconscious conflicts. Rudy Giuliani divorced his loving wife of many years. How could he possibly be qualified to be mayor? How can you trust Freud he himself was bipolar!
3 Ad Populum Bandwagon Appealing to prejudices or inclinations. If a majority of people believe or do something, everyone else should, too. Over 70 percent of Americans favor the adoption of a national sky marshal program; what s your problem? 4 Red Herring Avoiding countering an opposing argument directly by introducing a new or non-issue to the argument Equal pay for women is an important issue, but I wonder whether women really want to take the responsibility that comes with higher-paying jobs.
http://videocafe.crooksandliars.com/heather/michele-bachmann-announces-her-presidentia 5 Complex Question Loaded Question An unanswerable, biased question sometimes allowing only two possible answers: yes or no. Hey, Frank, have you quit hanging around crack addicts yet? More Miscellaneous Fallacies 6 Appeal to False Auth. Association Fallacy Ideas or actions are (un)acceptable because of people associated with them The hijackers were Egyptian; obviously Egyptians support terrorism. All those who can afford it prefer Freudian therapy.
7 Non Sequitur Any illogical conclusion (usually reached from faulty premises or poor evidence) Japanese children spend 40% more time in the classroom than U.S. children. American parents should take more interest in the kids education.
8 Shifting Burden of Proof Whatever has not been proven false must There is no compelling evidence that UFOs are Appeal to Ignorance necessarily be true; whatever has not been not visiting the Earth; therefore, UFOs exist. proven true must necessarily be false. Absence of evidence is evidence. In its 30+ years, SETI hasn t ever detected signals from an ET, so neither aliens nor their UFOs exist. 9 Contradiction Simultaneous acceptance and denial of a proposition or statement; two contradictory inferences can be drawn from the premise 10 Fallacy of Composition A property shared by a number of individual items, is also shared by a collection of those items; a property of the parts of an object, must also be a property of the whole Intelligent people have open minds. Politicians are supposed to be intelligent. But anyone who says that recreational drugs shouldn t be legalized has a closed mind. Therefore, politicians are not intelligent people. Every course I took in college was wellorganized; therefore, my college education was well-organized. This new truck is made entirely of lightweight aluminum components, and is therefore very lightweight.
11 Fallacy of Division Assuming that a property of some object must apply to its parts; a property of a collection of items is shared by each item. 12 Circular Argument A sentence or argument that restates rather than proves http://www.youtube.com/watch?v=8-qnawudhuq 13 Genetic Fallacy Arguing that the origins of a person, object, or institution determine its worth Ocelots are now dying out. Sparky is an ocelot. Therefore, Sparky is now dying out. Humans are conscious and are made of cells; therefore, each cell has consciousness. President Reagan was a great communicator because he had that knack of talking effectively to the people. Plagiarism is dishonest because it is deceitful. He speaks with a German accent. He must be a Nazi. Can there any good thing come out of Nazareth? (John 1:46). 14 Oversimplification Ignores an issue s complexities, variations, or exceptions The influx of foreign cars almost destroyed the American auto industry.