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Fallacies Minds & Machines. Fallacies Bad arguments are called fallacies. Fallacies tend to exploit common psychological aspects of our mind: many people.

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Presentation on theme: "Fallacies Minds & Machines. Fallacies Bad arguments are called fallacies. Fallacies tend to exploit common psychological aspects of our mind: many people."— Presentation transcript:

1 Fallacies Minds & Machines

2 Fallacies Bad arguments are called fallacies. Fallacies tend to exploit common psychological aspects of our mind: many people think that they are good arguments. Fallacies usually follow certain patterns, so there are several categories of common fallacies. You can see fallacies around you all the time once you recognize these patterns.

3 Truth-Seeking vs Persuading One reason why there are so many fallacies is that many people use arguments to persuade other people, and to win debates, rather than to find the truth. As someone said: “Arguments are to people as what lampposts are for drunks: they are used for support rather than illumination”. There is probably a good evolutionary reason for why people want to persuade, rather than find the truth: it is much easier to persuade, and there are immediate pay-offs to persuading others, while finding the truth is hard, and even if you find it, there may not be an immediate pay-off. Since we are doing philosophy in this course, our goal of arguments is to find the truth, not to win or persuade. Accordingly, in this course a good argument is understood as an argument that gets us closer to the truth, i.e. an argument that is sound. Of course, lawyers, politicians, car sales people, and basically everyone else (!) defines a good argument as one that is persuasive, sound or not.

4 Fallacies of Relevance Fallacies that violate the first criterion of good arguments (the premises should support the conclusion) are fallacies of relevance. In other words, any time the conclusion cannot reasonably be drawn from the premises, we are dealing with a fallacy of relevance. –Ad Hominem –Appeal to Authority –Red Herring –Appeal to Fear, Force, Pity, Vanity, etc. –Appeal to Ignorance

5 Ad Hominem The Ad Hominem Fallacy is committed when someone rejects a belief or argument based on its source. Examples: –Bill Clinton’s proposal is bad, because he had sex in the White House (abusive ad hominem) –Of course he opposes rent control. He owns two apartment buildings himself! (circumstantial ad hominem) –John Kerry criticizes George Bush’s military record? Wait, didn’t Kerry get those 3 purple hearts by blowing up some innocent Vietnamese? (inconsistency ad hominem, pseudorefutation or ‘tu quoque’)

6 Appeal to Authority Inappropriate Authority: –According to my dad … –Einstein said … [something about evolution] Unidentified Authority: –Studies show … –Experts agree … –Science says … Appeal to the Masses: –Everybody knows …

7 Red Herring Sometimes the premises seem related to the conclusion, but they really aren’t: you are being led down the wrong path. Example: –I can't believe you thought that latest Disney movie was ok for children to watch. Disney pays 12-year old girls 31 cents an hour to sow their products together.

8 Appeal to Emotions (Fear, Pity, Vanity, etc) Fear: –If you don’t believe in God, God sure won’t be happy about that! Pity: –I deserve an A in the class because my mom was really sick and so I couldn’t concentrate Vanity: –Intelligent people like yourself deserve [fill in any product here]

9 Appeal to Ignorance An appeal to ignorance is made when one argues that something is the case since no one has shown that it is not the case: –Smoking is ok, since no one has proven that it is bad for your health. –Our factory output shouldn’t be restricted for environmental reasons, since no one has shown that the green house effect really exists.

10 Fallacies of Assumption A fallacy of assumption violates the second criterion of a good argument (the premises should be plausible). Thus, a fallacy of assumption is an argument that makes a dubious assumption. –False Dilemma Perfectionist Fallacy Line-Drawing Fallacy –Straw Man –Slippery Slope –Begging the Question

11 False Dilemma An argument assumes a false dilemma when it assumes that one of two cases must be true, where in fact there are other options as well. Examples: –Since you’re not a capitalist, you must be a communist! –You’re either with us, or against us. –Are you a Democrat or a Republican? –Nature or nurture?

12 Perfectionist Fallacy The perfectionist fallacy presents us with a kind of ‘all or nothing’ false dilemma: –We shouldn’t give aid to countries where people are starving, because we can’t eradicate hunger completely. –Since no one has proven with absolute certainty that God exists, it is just as rational to believe that God does not exist as it is to believe that God does exist.

13 Line-Drawing Fallacy Another kind of false dilemma: Either we can draw a line between two things, or there is no difference between the two at all: –Abortion is murder from the moment of conception, since we can’t draw the line before which the fetus is not a person, and after which the fetus is.

14 Straw Man A Straw Man argument attacks something by attacking a helpless caricature of that something: it often distorts the original by exaggeration. Example: –The movement to allow prayer in public school classrooms is a major threat to our freedom. The advocates of prayer in school want to require every school child to participate in a Christian religious program prior to every school day.

15 Slippery Slope A slippery slope fallacy makes a dubious assumption that one thing will lead to another –If the “experts” decide today that we should have fluorides in our tea, coffee, frozen orange juice, lemonade, and every cell of our bodies, what’s next? Tranquilizers to avoid civil disorders? What about birth-control chemicals to be routed to the water in certain ethnic neighborhoods?

16 Begging the Question Circular reasoning: –God exists because the bible says so. … What, why we can trust what the Bible says? Easy, the Bible is the word of God. –Of course my salary is higher than yours, because my work is more important. …You’re asking me why it is more important? Well, my salary is higher, isn’t it? The “True Scotsman” Fallacy: –All Germans like sauerkraut. … Oh, your brother-in-law is German and he doesn’t like sauerkraut? Well, he is not a true German then, is he?

17 Other Fallacies Rhetorical Fallacies The One Big Ethical Fallacy

18 Rhetorical Fallacies Simply by using certain words to ‘frame’ an issue, question, or position, you can sway people one way or the other. –Technical Note: Maybe these are not so much ‘fallacies’, as they don’t constitute any argument, but simply ploys to persuade people. Examples: –Yay and Boo words –Exaggerating and Minimizing –Proof Surrogates –And many more!!!! Take my Methods of Reasoning course in the spring!

19 Euphemisms and Dysphemisms Are we fighting “terrorists” or are we helping “freedom fighters”? Are you “pro-life” or “pro-choice”? Do you have a “rendez-vous in the back of a Limosine” or an “affair in the back of a Buick”? “Feminist” or “feminazi”? Etc.

20 Hyperbole and Downplayers “That was the biggest … ever!!” “I was just trying to …” So, he got his “degree” from …, did he?” Etc.

21 Proof Surrogates “Obviously, …” “Clearly …” “As everyone knows, …” “Anyone with half a brain would agree that …” Etc.

22 And the One Big Ethical Fallacy Ought from Is! “Well, that’s how we should behave, because everyone behaves that way!” Subclasses: –Naturalistic Fallacy: “It’s natural, so it’s good” –Normalistic Fallacy: “It’s normal, so it’s good” –Traditionalistic Fallacy: “It’s always been that way, so it’s good”

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