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Errors in Reasoning. Fallacies A Fallacy is “any error in reasoning that makes an argument fail to establish its conclusion.” There are two kinds of fallacies.

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Presentation on theme: "Errors in Reasoning. Fallacies A Fallacy is “any error in reasoning that makes an argument fail to establish its conclusion.” There are two kinds of fallacies."— Presentation transcript:

1 Errors in Reasoning

2 Fallacies A Fallacy is “any error in reasoning that makes an argument fail to establish its conclusion.” There are two kinds of fallacies Formal and Informal This chapter focuses on informal fallacies. Informal fallacies have recognizable errors in content

3 The Fallacies begin Appeal to ignorance – claiming something is true (or false) just because we cannot prove it is false (or true). For example: “you cannot prove that God does not exist. Therefore God does exist.” Or, “you cannot prove the defendant is innocent, therefore he is guilty.” The Problem is that lack of evidence often does not prove anything, although sometimes it does.

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5 Appeal to false authority This fallacy claims that “so-and-so” says “X is true” or “X is false” and rests the argument on “so-and- so's” authority; but, in fact, “so-and-so” is not really an expert on the matter they speak for. For example: Jenny McCarthy and Jim Carey are public proponents for the view that some vaccines cause autism. But, of course, McCarthy and Carey have absolutely no expertise in this area.

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7 Appeal to Popular opinion This fallacy holds that because the majority of people think something is true, it is, therefore, true. This kind of thinking is often behind opinion polls where we learn that, say, 57% of Americans think X or y. The problem is that the majority of people have often believed in terrible things, like thinking women should not be allowed to vote, or that slavery was a good thing. Nothing is right just because most people think it is so.

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9 Appeal to tradition Quite similar to the appeal to popularity, but here the argument is that “we have always done it this way, so it is the right way to do things.” This argument suffers from the same flaw, just because something has always been done a certain way, does not mean it is right. For example: someone might claim that marriage must be between “one man and one woman” simply on the grounds that “it has always been so.” Nothing follows from this

10 Against the Person This argument attacks a person's character rather then their argument. For example: “Rush Limbaugh says global warming is not real. Limbaugh, however, is a big fat idiot! We must conclude therefore that Rush is wrong about Global warming. There are some other versions of this fallacy: you can attack someone's circumstances rather than their argument, you can poison the well, or use what is called the tu quoque (you too) fallacy.

11 Against the person in action You can't believe anyone who looks like this:

12 Emotion based fallacies Appeal to pity – takes an emotional response to an unfortunate situation as a reason to believe or act in a certain way Appeal to Emotion – Believe that something is true because it makes me feel good, or that it is false because it makes me feel bad. Appeal to Force – This fallacy basically says “do this or something bad will happen to you!”

13 Irrelevant Conclusion This is an argument in which premises are given but the conclusion really has nothing to do with them. For example: If you vote you participate in democracy. If you participate in democracy you count as a citizen. Therefore, Democracy is better than all other types of governments The most common types of arguments given here are the red herring and the straw man

14 Red Herring http://www.youtube.com/watch?v=exdK7Lirngg

15 Straw Man http://www.youtube.com/watch?v=v5vzCmURh7o &feature=related

16 Loaded Question & Loaded Language Loaded language is language that creates bias before a point is even made For instance: “my opponent, that dishonest jerk over there, wants to....” A loaded question is designed to trap the view into answering against themselves For instance: “have you stopped cheating on your taxes yet?” Or “what were you doing there at that time on that night?”

17 False Cause There are several versions of this fallacy. We will focus, however, on one particular version: the so- called post hoc fallacy The post hoc fallacy states that because one event follows shortly after another event, the first event caused the other. This is a fallacy because merely preceding something in time does not make an event the cause of another For instance, suppose I come home from a trip and my wife gets over a case of the flu: my coming home did not cause her recovery

18 A few other fallacies Begging the question – assuming what you are trying to prove Hasty Generalization – making a conclusion about an entire group based on a small selection of samples. This is often a worry when opinion polls are taken False Dilemma- claiming that someone only has two options when they actually have at least three. Equivocation – using the same word but changing the meaning of it, while, at the same time, acting as if you did not do so.

19 Fallacies in our daily decisions http://movies.netflix.com/WiMovie/Frontline_The_ Vaccine_War/70138090?trkid=2361637#height1 917


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