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Fallacies 1. arguments. One of our main critical thinking questions was: Does the evidence support the conclusion ? How do we evaluate whether specific evidence supports a specific conclusion? How do we answer this question?. Arguments.
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One of our main critical thinking questions was: Does the evidence support the conclusion? How do we evaluate whether specific evidence supports a specific conclusion? How do we answer this question?
Arguments The word ‘argument’ as it is used normally in English, means something like this: “An exchange of diverging or opposite views, typically a heated or angry one: ‘I've had an argument with my father’.”
Arguments In philosophy, we use the word ‘argument’ differently. A philosophical argument: • Is not an exchange of views • Doesn’t need to present opposing or contrary views • Is not typically heated or angry.
Arguments Instead, a philosophical argument consists of two parts: the premises and the conclusion. The premises are statements of the evidence that are given in support of the conclusion. The conclusion is the claim that the premises are supposed to support.
Example Premise 1: Either the butler is the murderer, or the gardener is the murderer. Premise 2: The butler is not the murderer. Therefore, Conclusion: The gardener is the murderer.
Relevance There is no requirement that the premises of an argument have anything to do with the consequent. For example, this is an argument: Premise: There are exactly 117 hairs on my hand. Conclusion: It’s half past three o’clock.
Misleading Arguments An argument is misleading when the person making it: • Knowingly presents unreliable evidence; or • Knowingly presents irrelevant evidence designed to trick you; or • Knowingly hides relevant evidence that goes against their claim.
Misleading Arguments (The person making a misleading argument doesn’t always have to do bad things knowingly. Sometimes it is enough that they should have known not to do those things.)
Critical Thinking Is there any evidence to support the claim? Is the evidence reliable and trustworthy? How reliable is it? Should you accept it? Does the evidence actually support the claim? Is there other evidence you should consider?
Critical Thinking Critical thinking involves asking these questions at the right times, knowing how to answer them, and knowing how to use those answers to accept or reject a claim.
Determining If Something Is Misleading Is there any evidence to support the claim? No The claim is unsupported, but not misleading. Yes Go investigate the evidence!
No (Unsupported) Many of our beliefs are opinions that are not supported by any evidence. These beliefs might be wrong and we might disagree. But as long as the person presenting them is clear that they have no evidence and are simply stating an opinion, this is not misleading anyone.
No (Unsupported) Be careful! Sometimes people’s opinions are stated in a way that suggests there is evidence when there really is not. “Dr.” suggests the opinion of an expert. “Author of [book on the subject]” suggests the opinion of an expert.
Yes, There Is Evidence Presented Is the evidence reliable and trustworthy? No Unreliable and untrustworthy evidence can be misleading. Yes Keep critically thinking!
No, The Evidence Is Not Reliable Reasons evidence might not be reliable: • It’s made up (lies). • It’s just an opinion. • It’s based on false authority. • It’s misinterpreted.
Lies From “Ancient Aliens”: http://www.youtube.com/watch?v=lIkbvNcl58U
Lying for What You Think Is Good “What harm would it do, if a man told a good strong lie for the sake of the good and for the Christian church ... a lie out of necessity, a useful lie, a helpful lie, such lies would not be against God, he would accept them.”
Lying for Profit In 1998, Dr. Andrew Wakefield published a paper linking vaccines to a new bowel disease which caused autism. Later it was discovered that Wakefield faked the results of his experiments. He thought that if he could show a connection, he could get $43 million USD ($333 million HKD) from selling tests for the made-up disease.
Mere Opinions Sometimes the premise strongly supports the conclusion, but the premise is just someone’s opinion.
Appeal to Authority It’s OK to find out what to believe from experts in many cases. However, this is not true when: • The expert is not an expert about what you want to know. • Experts in general disagree about the question. • The expert has a history of lying or misleading about the question.
Expert #1: Dr. AlgundEenboom Dr. AlgundEenboom is a doctor. A doctor of dentistry. He is not a scientist or a historian.
Google Search http://www-user.rhrk.uni-kl.de/~aws/seta/Eenboom.htm Dr. Algund Eeenboom (Leer, Deutschland) geb. 1946 in Leer (Deutschland) studierte Zahnmedizin an der Universitat Munster und promovierte in diesem Fach an der Universitat Tubingen. Als Zahnarzt ist er seit 1979 in eigner Praxis tatig.
Google Translate: German to English Dr. LagundoEeenboom (Leer, Germany) born 1946 in Leer (Germany) studied dentistry at the University Munster and a PhD in the subject at the University Tubingen. As a dentist he is TTIG since 1979 in his own practice.
Yes, Let’s Keep Thinking Critically Does the evidence (supposing that it’s true) actually support the claim? No Irrelevant evidence usually is misleading. Yes Keep critically thinking!
Irrelevant Evidence There are many ways that evidence can seem to support a conclusion, without actually doing so: • No connection with the claim. • Circular reasoning. • Better alternative explanations. • Special circumstances.
No Connection with the Claim • Clustering illusion: it looked like there was a pattern there, but there wasn’t. • Regression fallacy: going back to normal seemed to be for a reason, when it wasn’t. • Base rate neglect fallacy: a reliable test said the claim was true, but since the base rate of the condition is very low, it is still unlikely that the claim is true.
Circular Reasoning Circular reasoning involves trying to show that a claim is true by assuming that it is true in the premises. It has the form: X is true. Why? Because X.
Example: “It says in the Bible that God exists. Since the Bible is God's word, and God never speaks falsely, then everything in the Bible must be true. So, God must exist.”
Example Premise 1: The bible is God’s word. Premise 2: God never speaks falsely. Conclusion: Everything in the bible is true. Premise 1: Everything in the bible is true. Premise 2: The bible says that it is God’s word. Conclusion: The bible is God’s word.
Experiment • Researchers created a list of facts that about 50% of people knew. • Subjects in this experiment read the list of facts and had to say which ones they knew. • They then had to judge what percentage of other people would know those facts.
Example • Hong Kong has twice as many skyscrapers (> 14 stories) as New York. • More tourists from China come to Hong Kong than tourists from all other countries combined. • Hong Kong has the highest average IQ, 107. • Sarah Lee WaiSze won a bronze medal at the London summer olympics.
The Curse of Knowledge Researchers found that the subjects responded differently about other people’s knowledge of a fact when the subjects themselves knew that fact. If the subjects did know a fact, they said that an inaccurately large percentage of others would know it, too. The researchers call this finding “the curse of knowledge.”
Circular Reasoning The researchers claim that this “curse” happensbecause subjects make more mistakes whenthey have to judge the knowledge of others.People are much better at judging what theythemselves know.
Good Reasoning The researchers claim that this “curse” happensbecause subjects have trouble switching theirpoint of view to consider what someone elsemight know, mistakenly projecting their ownknowledge onto others.
Circular Reasoning + Brains Brain scans indicate that this “curse” happensbecause of the frontal lobe brain circuitryknown to be involved in self-knowledge.Subjects make more mistakes when they haveto judge the knowledge of others. People aremuch better at judging what they themselvesknow.
Straw Man Fallacy The Straw Man Fallacy (sometimes in the UK called “Aunt Sally Fallacy”) is when you misrepresent your opponent, and argue against the misrepresentation, rather than against your opponents claim.
Example: Evolution According to the theory of evolution, any two living things have a common ancestor. You and I are related. We are family. We are also related to monkeys, and rats, and pandas. We are also related to bugs, and bananas, and bacteria.
