The Marlinspike Thinker

There is a story about Henry Kissinger visiting the CIA Saigon station during the Vietnam war. It is said that a CIA officer asked Kissinger if he was satisfied with the information the CIA had been providing to him, and it is said that Kissinger replied "As long as it supports my policy, I am satisfied." (David Corn The Blond Ghost) If this story is correct, Kissinger here demonstrated the absolute opposite of critical thinking. He did not want good information. He did not want to hear the truth. He wanted "information" that supported his previously chosen plan of action. It is arguable that this attitude was typical of American policymakers at that time, and that their habit of accepting only information they wanted to hear led to the continuation of a war that caused tens of thousands of American deaths, and hundreds of thousands of deaths among the indigenous people of the region. (Later on in American history, the same kind of thinking led us into the Iraq War, with similar consequences.)

"Defensive thinking" is my name for the attitude displayed by Kissinger and many, many, many other people throughout history. A defensive thinker has a fixed belief that he likes, and he bends all his mental efforts to defending that belief. A defensive thinker does not stop to seriously consider the possibility that his belief might be wrong. Instead, he firmly holds to the conviction that he is right, and casts about for ways to "prove" his belief to others. The result of this is that if he started out wrong, he will stay wrong because he is actually devoting all his efforts to avoiding the evidence that would enable him to come to the truth. This is bad. This is something you should never do.

At least some English teachers seem to encourage defensive thinking, and one or two might even exert themselves to discourage critical thinking. If you've ever had a teacher who told you to choose your paper's thesis before you did your research, you've had someone set you up for defensive thinking. If you've ever had a teacher tell you you are not allowed to change your thesis, you've had someone tell you you're not allowed to think critically. Teachers who tell students to make up their minds before they know all the facts are training them to think defensively (which means training them not to think critically). Teachers who do not allow students to change their minds when they realize they're wrong are preventing them them from thinking independently (which again means training them not to think critically). Hopefully I am wrong about this, and no actual English teachers act this way. Even one would be too many.

Critical thinking, which is the only kind of thinking that tends to lead towards truth, demands that you make your best efforts to never, ever think defensively. To avoid defensive thinking, you have to be able set aside fixed beliefs and instead do your best to apply rigorous logic to all available evidence.

Critical thinking absolutely requires you to be able to change your mind.

To be able to understand and apply logic, there's some things you really need to understand. I'm going to remind you of these concepts from time to time, but it is very important that you get these crucial concepts and definitions straight in your own mind as soon as you can.

Critical Thinking

When I say that I want you to "think", what I mean is that I want you to think critically (not defensively), which means I want you to do some specific things:

1. Think independently. When you think independently, you don't care what other people think. This means that when you see that some other people believe something, you completely ignore the fact that those people believe whatever it is. Suppose someone you know believes something very passionately, so passionately that you find yourself really wanting to agree with that person. If you're an independent thinker, you ignore those feelings and make up your own mind. Suppose that person forcefully insists to you that, say, ducks are mammals. Suppose he insists so forcefully that you are afraid to disagree. If you're an independent thinker, you ignore your fears and refuse to agree. An independent thinker recognizes that how believers feel and act has nothing whatsoever to do with whether or not their beliefs are true. To an independent thinker, the mere beliefs of other people don't matter at all.

2. Ignore the confidence of others. Sometimes people will say things very confidently. Sometimes people will say things in a tone of voice that implies that what they say is clearly true, and that anyone who doesn't believe the same thing is an idiot. Such people will often say that they "know" these things, or that you should "know" this. This has nothing to do with logic. People who speak with complete confidence often have absolutely no logical basis for what they say. People who are unshakably convinced that they are absolutely correct are often completely and utterly wrong. In fact, people who speak with complete confidence are often completely stupid. Mere confidence is meaningless, and you should pay no attention to it.

3. Ignore your own feelings. In addition to ignoring how other people feel about things, you also need to ignore your own feelings about things. If you feel very passionately that something has to be true, you need to remember that that absolutely does not mean that it is true. No matter how passionate you are about your belief, you have to remember that your feelings can't make things true or false. If you're going to be a critical thinker, and you do have to be a critical thinker for this class, you have to be able to set your own feelings aside when you think about any issue.

4. Ignore your own preexisting beliefs. It's not just your feelings you have to ignore, you also have to be able to set aside whatever it is you happen to believe before you start thinking critically about the issue. If you think something is true, and I ask you to think critically about that thing, what you have to do is forget whatever it was that you thought was true up to that point, and start thinking from that point as if you had never previously thought about the issue. Remember that beliefs are not evidence. Just as other people believing things does not give you any reason to think that those things are true, you believing things does not, by itself, mean that those things are true.

5. Do all the work of thinking yourself. When you listen to what other people say, or read what they write, you don't ignore their arguments, but you don't let them determine what you think. No matter what people say about things, no matter how convincing their words feel to you, you have to step back and look at all the available facts and think through the whole issue all by yourself. If someone tries to get you to believe something, you can ask them to explain their reasons for believing this thing that they so confidently believe. (If  they can't give you any actual reasons, you should laugh at them.) If they give you what they think are "reasons" for believing what they believe, you should carefully note down everything they say, but you should also work out entirely for yourself what you think about the matter, taking into account everything everybody says about all sides of the issue, plus whatever else you might know about it, and about logic in general.

6. Be willing to be wrong. Your most important cognitive capacity is your ability to change your mind. This means that, at any point in any reasoning process, you should be willing to admit that, based on your present thinking, everything you thought before was wrong. Some people find it hard to admit that they were wrong about something. Some people find it impossible to admit they were ever wrong about anything. Critical thinkers are people who are capable of admitting that things they previously thought were wrong. Critical thinkers change their minds quite frequently. People who never change their minds are not critical thinkers. This class requires critical thinking, so this class requires you to change your mind whenever new evidence or new understanding shows that what you previously thought was wrong.

7. Try to think logically. Right now, you probably have very little idea what the word "logic" means. That's okay. Many people have absolutely no idea what logic is. Even worse, there are people who use the word "logic" and the term "critical thinking" to mean just about the opposite of what they actually mean. So what I want you to know right now is that you're supposed to think logically, even though you really don't yet know what "thinking logically" means. The whole rest of this class is all about explaining what logic is and how to think logically, so hopefully by the time the semester is over you will have a pretty good idea of what "think logically" means.

Rhetoric is Not Logic

"Rhetoric" is the ancient art of effective and elegant verbal communication. The student of rhetoric learns how to speak confidently, clearly, precisely, entertainingly and persuasively. She does not learn anything about logic, nor does rhetoric concern itself with the difference between logically good and logically bad arguments. If you want to learn to speak better, a good course in rhetoric will help you with that, but it will not help you with logic. The student of logic basically learns to ignore rhetoric. This means that you will try very hard not to be swayed by pretty speeches. Pretty speeches have talked many, many people into believing some very, very stupid things, and a logical thinker learns how to not be talked into things. No matter how good a speaker or writer makes you feel about a certain claim, you will do your absolute best to set your feelings aside and just think about the available facts.

Badgering is Not Logic

"Badgering" is when someone keeps talking at you to make you agree with him. It is a form of bullying, and obviously has nothing to do with logic. The best thing to do with someone who tries to badger you into agreeing with him is to pretend to get a phone call, fake a heart attack, or, ideally, kick him very hard in the groin and run away.

Logic Means Thinking About Arguments

The most basic fact about logical thinking is that it is thinking about arguments. You may not fully understand the idea of thinking logically right now, but if you get the point that thinking logically means thinking about arguments, you will have understood the most basic and important thing about logical thinking. A person who doesn't think about arguments isn't thinking logically. No ifs, ands, or buts, if you're not considering and carefully evaluating arguments, you're not thinking logically.

Technically, an "argument" is the set of reasons given by someone to get other people to believe something. In this class, for simplicity's sake, we will often use the word "argument" to refer to any attempt to persuade anyone to believe anything, but technically the "argument" for a belief is the set of reasons given in support of a claim. If someone just says something, he's not arguing. If he backs up what he says with reasons, then he is giving an argument. Thus an argument is a verbal attempt to get you to believe something. Anytime anyone tries to get you to change your mind about something, that person is giving you an argument. What you need to do is try to figure out is whether or not it is a good argument, or a bad argument.

At this point, I want to remind you that thinking about arguments does not mean choosing a thesis and then coming up with "arguments" to support that thesis. This is defensive thinking and it is fundamentally dishonest. When you think critically about arguments you don't think "how can I make this thesis look true?" When you think critically about arguments you take each present argument and think about whether or not the given reasons really do provide logical support for the claim the arguer wants you to accept.

Fact, Opinion, Judgement

Here's a story. A few hundred years ago, the word "comet" meant "a bright light that appears in the sky for a relatively short period of time, that moves relative to the background of fixed stars, and which has one or two glowing "tails" that stretch from the light away across the sky. Back in ancient days, nobody knew what or where comets really were, although many people had opinions. Some ancient people thought they were signs of bad news erected by gods. Others may have thought they were falling stars. Aristotle thought they were burning gasses in the Earth's upper atmosphere. (Seneca the Younger thought that they were objects moving through empty space outside of Earth's atmosphere, but very few people paid attention to him.)

 Halley's Comet    Comet Hyutake     

A "fact" is something that can be easily verified by any person who cares to look carefully at the situation. (Facts are also sometimes called "evidence.") Here are some facts about comets that were available to people through ancient times, before there were telescopes:

The reasons these claims are facts is because they were observed and reported by many, many reliable people, and when comets were visible, anyone who cared to look would be able to tell that it wasn't there before, that its brightness changed, that it had a halo, or a tail, or two tails, and so on. Another way to put this is to say that anyone who disputed any one of these claims could easily be proved wrong.

Also, look at that list of facts and notice that none of them contradict any others. Each of these claims is consistent with every one of the other claims on this list. If two of these claims disagreed with each other, we'd have to take at least one of them off the list. If we couldn't easily tell which one was correct, we'd have to take both of them off the list.

In this class, the word "fact" shall be used to denote any claim that is obviously true, or which no-one seriously disputes. In real life, it is often very difficult to ascertain the actual facts of a case, and people often argue about what the facts are. Even worse, sometimes people use the word "fact" to mean "something I passionately believe." I hope you never do that.

Opinions

"Opinion" is just whatever people happen to think. If you believe something, then that is your opinion. If another person believes something else, then that is her opinion. Some opinions are supported by the available evidence, some opinions are contradicted by the available evidence, and some are neither supported nor contradicted by the evidence.

Here are some opinions about comets:

The reason that these claims are opinions rather than facts is that, if someone disputes one of them, that person is not easily proved wrong. In fact, it might be impossible to prove the dissenter wrong. In fact, he might even turn out to be right. If an ancient person claimed that comets were not actually bad omens, and that bad stuff happened pretty continuously whether there were funny lights in the sky or not, there was no clear and obvious way to prove him wrong. The same applies to all the other opinions here.

Also notice that some of these opinions contradict others. This is because opinions are freely chosen by people. They have no necessary connection to any piece of evidence, and different people can have different opinions. Thus "opinion" is just whatever people happen to think. If you believe something, then that is your opinion. If another person believes something else, then that is her opinion. Some opinions are supported by the available evidence, some opinions are contradicted by the available evidence, and some are neither supported nor contradicted by the evidence.

Judgements

Some people form their opinions simply based on whatever they happen to feel about a topic, but other people form their opinions after and on the basis of a careful consideration of all the available evidence. A "judgement" is an opinion that is based on critical thinking. It's important to remember that judgement is not a process of defending whatever it is that you happen to happen to want to believe. Here's a story:

Sophia and Fido are both enrolled in Lucifer DeMorte's critical thinking class for which they are required to demonstrate critical thinking in an essay assignment. They both choose the topic of "paddling" by preschool teachers. "Paddling" is defined as the practice of swatting a child on the bottom with sufficient force to cause a mild but sharp pain. Sophia, being a good student, decides to go to the library and look for scientific research before she starts to think about the issue. Fido, being unclear on the concept of critical thinking, decides that paddling must be harmful to children, and starts thinking about how he is going to "prove" this. He decides to go to the library to try to find evidence to support this view. Meanwhile, Sophia has found several research papers studying the long-term effects of paddling. None of these papers found evidence of long-term harm from paddling, and several gave evidence that paddling did not have any bad effects of any kind. Sophia decides to base her paper on this research, and goes away to start organizing her thoughts. Fido finds exactly the same set of papers, and decides to ignore all of them because they do not support his belief that paddling causes long term harm. He then searches the magazine archive looking for articles that say paddling causes harm. While he's looking, Sophia finishes deciding what she will say, and starts typing out her paper. Fido does not find any magazine articles supporting his thesis that paddling causes harm, so instead he collects some articles concerning parents who slapped, punched and kicked their own children. While he's photocopying these articles, Sophia finishes her first draft. While she is looking over and thinking about what she's written, Fido goes home and thinks about how he's going to prove that paddling is harmful. He decides to do two things in his paper. First, he will describe instances of serious child abuse that go far, far, faaaaar beyond anything involved in paddling, and second, he will describe an imaginary scenario in which paddling causes an imaginary child imaginary serious long-term imaginary harm. While he's planning all this, Sophia decides she's not happy with her first draft and writes out a whole new version of her paper, using all the same facts and reasoning, but better organized and more elegantly expressed. Fido then writes a paper that spends two pages describing the horrors of child abuse and three pages explaining a story he made up in which paddling managed to cause imaginary serious, long-term psychological harm. While he's doing this, Sophia has a Stella Artois and watches several episodes of Dr. Who. The next day, they both turn in their papers. A week later, Sophia gets her paper back with an A, and Fido gets his paper back with an F and several comments from the instructor asking him things like "can you prove that beating a child with a hockey stick is the same as paddling?" and "can you prove that paddling ever actually causes harms like these?" Fido ignores these questions, and decides that he got an F because the professor didn't want to believe that paddling was harmful.

While Fido actually did more physical work in this story, he deserved his F because he made no judgements at any point in the process. While he did "work" on his paper in terms of coming up with things to say, he actually did no work whatsoever in terms of figuring out what the real answer actually was. Because Sophia made up her mind on the basis of the best available evidence, her thesis was her judgement while Fido's was just his unsupported opinion

It's important to remember that, while judgements can be right or wrong, they are worth considering, whereas mere opinions are not really worth talking about.

Mindlessness

There's one important point about this story that I want to emphasize, and that is that Fido really did not think at any point in the story. I know that people often use the word "think" to mean whatever ideas someone has in their head, but that's not the way I use the word "think" in this class. When I say I want you to think about something, I mean I want you to set aside whatever beliefs you might already have, ignore everyone else's opinions, review all the known facts, analyze all the relevant arguments and anything else you can think of, and come to a conclusion based entirely on the logical implications of those known facts. If this means completely changing your mind about the issue, that's what you should do. Your ability to change you mind is your most important cognitive faculty. If you can't change your mind, if you make up your mind and then refuse to ever change it no matter what evidence is presented to you, then you really can't be said to be thinking at all.

Mindlessness is not the same as being wrong. Thoughtful people are often wrong, and a mindless one might accidentally happen to occasionally defend a true claim. What characterizes mindlessness is a lack of thought. This can often be detected when people substitute unsupported conclusions for argument. When someone writes, as their whole analysis, something like "Pat is wrong because he is only stating his opinion while Mike has the facts," they are at least doing a very poor job of expressing their thoughts, and might even be being completely mindless. Remember, you can only say that something is mere "opinion" when it comes with no reasoning. When someone supports their claim with reasons, they're not just stating an opinion, they're making a judgement. They might be wrong, but as long as they're trying to present real reasons, they're not being mindless.

Evidence

A collection of facts (like the one given above regarding comets) is sometimes referred to as "evidence." The word means "that which is evident." So when someone talks about the evidence in a case, they are talking about all the evident facts. If a "fact" isn't something anybody can see for herself, then it isn't evident, and can't be called evidence. Scientific studies and other forms of reputable research can be evidence. Personal opinions and unsupported statements are not evidence. Suppose Sophia and Fido are given a follow-on assignment in which they are supposed to discuss an article by Dr. Wackem Harder, a famous doctor who insists that paddling causes serious long-term physical and psychological harm. Initially, both Sophia and Fido are convinced by Dr. Harder's paper, and each writes a paper saying, in essence, "paddling is bad because Wackem Harder says so." Both of them take their papers to their professor for feedback. To both of them, Professor DeMorte says "you need to think about evidence here. Ask yourselves if Dr. Harder gives any actual evidence to support his claim that paddling is harmful. If he does, rewrite your paper to include a section that thoroughly describes all this evidence. If he doesn't, change your thesis accordingly, and rewrite your paper to support this new thesis." Both students go home to work on their papers. Sophia interprets her instructions to include the possibility that Harder has no evidence, and takes another, more careful look at his article. Fido misinterprets the professor's instructions. He ignores the possibility that Harder is wrong, and decides that what he has to do is prove that Harder does give evidence. Both students look into Dr. Harder and his article. They both find that his doctorate is in communication studies, and that he has absolutely no training or experience in child psychology, physiology or any other field that might be relevant. They both find that he is famous because he has a popular radio show in which he makes wild statements that usually turn out to be false. Finally, they both find that, although his article repeatedly and vehemently insists that paddling is terrible for children, he actually does not include any scientific research of any kind. (His article is actually a lot like Fido's first paper) Sophia realizes that Harder actually provides no evidence whatsoever, and she writes a whole new paper describing what Harder says, saying how it is different from giving evidence, and arguing that he is wrong because, despite his vehemence, he gives no evidence, and all the actual evidence is against him. Fido assumes that Dr. Harder is right, and that Harder's article must therefore contain evidence. Fido doesn't think about looking for studies. Instead, he decides that whatever Harder says is "evidence," and adds a sentence near the end of his paper that says "Dr. Harder gives evidence that paddling is harmful." Sophia gets her paper back with an A. Fido gets his paper back with an F. When he looks at his paper, he sees that the word "evidence" is circled in red with a note that says "what is this evidence? If you can't say what the evidence is, then there isn't any, and you should change your mind." Fido feels that this is very unfair. Fido feels that since he feels that Dr. Harder is right, that means Harder has evidence. The idea of looking for evidence before deciding who is right or wrong does not occur to Fido.

It's important to remember that when an instructor asks you if there is evidence supporting a claim, you have to look at what is said in support of a claim, and whether that includes reference to eyewitness testimony, scientific studies, academic articles or other concrete ways of supporting a claim. If you can't come up with something like that, you can't say there's evidence.

Empirical Truth

A statement is "empirical" if it is about the real world. If you say that something does or does not exist, you are making an empirical statement. If you say that some existing thing has or doesn't have a certain feature, you are making an empirical statement. If you claim that fairies and elves exist, you are making an empirical statement. If you claim that Mars has an atmosphere, you are making an empirical statement. If you say that electrons exist, or that moving electrons create magnetic fields, you are making an empirical statement. All the statements of science, from physics through history and everything in between, all those statements are empirical statements. All statements about what's happening or has happened in the world are empirical statements. Just about any issue that any ordinary person will ever worry about will be an empirical question. Empirical statements are only ever proved true or false by compelling evidence, and it follows that whether an empirical statement is true or false depends entirely on the evidence available. Thus, in this class, just as in real life, the word "true" basically means "completely supported by absolutely all the evidence." If a statement about the world isn't supported by evidence, you logically and morally should not say that it is true.

Support and Proof

A fact "supports" a claim if the fact cannot easily be explained without assuming that the claim is true. In other words, a fact supports a claim if you must assume that the claim is true in order to reasonably explain the fact. If you can reasonably explain the fact without assuming the claim is true, the fact does not support the claim. For instance, a line of white paw-prints running over your dining-room carpet cannot easily be explained without assuming that your cat knocked over the flour in the kitchen, thus the paw-prints support the claim that the cat was on the kitchen counter. (Assuming that you only have one cat, and that there are no raccoons in your house, and so on.)

A claim is "proved" when all of the relevant evidence, taken together makes it extremely unlikely that the claim is false. If everything we know about the spilled flour is consistent with the cat knocking the flour over, and every other possible explanation is somehow ruled out, then we have proved that the cat did it.

There are different levels of support that can exist for a claim, depending on how much evidence is available, and so on. It is often very difficult to tell exactly where a particular case falls on this spectrum, and reasonable people can reasonably disagree about how strong a case is, so this scale is just here to give you a general idea about standards of proof and support.

1. Absolute Support. Here the claim is proved to such a high standard that it cannot logically be false. No empirical claim is ever proved absolutely, so if absolute proof is your standard, nothing empirical will ever be proved for you.

2. Virtually Absolute Support. Here the claim is proved to such a high standard that it is almost inconceivable for it to be false. It's logically possible for it to be false, but that's about it. When a claim is supported by compelling proof, all the evidence in the world says it's true, and we have absolutely no reason to believe anything else. Very few claims are supported by virtually absolute proof, so I will generally not be worrying about it in this class.

3. Compelling Support, or "proof."  Here the claim is proved to at least the same high standard as is commonly used for other kinds of claims that we accept as true. One way to say that a claim is "proved" is to say that it is supported by a "compelling argument." The proof given may not be absolutely certain, but as far as we know right now, all the evidence we have says it's true, and we have no real reason to believe anything else. Another way to look at it is that the evidence we have says that we can rely on this claim, and that it's a good idea to treat it as true until we have reason not to. Claims with compelling support sometimes turn out to be false, but this very rarely happens, so it's good enough for us to go on with our lives. When science is working correctly, this is the standard of proof that is used. No other field uses higher standards than science for empirical claims, so this is the best standard for anyone to use. In this class, when I use the word "proof," I will generally mean that it has "compelling support" or it has a "compelling argument" behind it.

4. Well supported. We say a claim is "well supported" when we think that the evidence for it is strong enough that it's probably true, but not strong enough to say that it's proved to be true. It may not be easy to come up with a reasonable alternative explanation for the facts, but we think it can be done. Obviously, there's a degree of subjectivity here, and reasonable people can reasonably disagree about whether a claim is proved or just well-supported. I'm not going to give quiz or exam questions on the difference between "proved" and "well-supported." I just want you to be aware that it can be hard to tell if a claim is proved or just almost proved.

5. Supported. A claim is "supported" when the available evidence makes that claim more likely to be true than it would be if that evidence didn't exist. Thus a claim is supported when the available evidence gives us some reason to think the claim is true.

6. Unsupported. A claim is "unsupported" when the available evidence makes that claim just as likely to be false as it would be if that evidence didn't exist. Thus a claim is unsupported when the available evidence gives us no reason to think it is true.

Proven, Disproven, Unproven

At any given time, any given purely factual claim can have one of three logical statuses. It could have been proven true ("proven" or "proved"), it could have been proven false ("disproven" or "disproved"), or it could have been neither proved nor disproved, in which case it is "unproven.

When a claim is "proven," we have compelling reason to believe that it is true.

When a claim is "disproved," we have compelling reason to believe that it is false.

When a claim is "unproven," we have we don't have compelling reason to believe that it is true, and we have we don't have compelling reason to believe that it is false either.

Generally speaking, if you want to say that a claim is true, you have to be able to come up with compelling evidence that it is true. If you want to say that a claim is false, you have to be able to come up with compelling reasons that it is false. And if you want to say it is unproven, you have to be able to show that the arguments on both sides are no good.

The Right To Believe What You Want To Believe

It is important to remember that people have a right to believe whatever they want to believe. Just as long as they don't try to force or fool others into believing things. A person can believe anything that he wishes to believe, but if he is honest he will not assert his beliefs as true unless he has good, logical reason to believe them. (It is not honest to assert a belief as true unless you have good reason to believe it is true.)

The basic point of this class is not to indoctrinate you into any particular set of opinions. Rather it is to train you to be able to decide whether or not a given opinion is logically supported by the evidence offered to support it.  I should warn you that in this class you are going to hear my opinions. (Although I'll try to keep the ranting to a minimum.) You should also know that you are not supposed to agree with me on everything. If you think I'm wrong, you can, and should, say so. (At least think so.) Even if you can't quite figure out exactly why I'm wrong, you can still say I'm wrong. You will be graded on your demonstrated ability to determine whether or not particular conclusions are adequately supported by the reasons offered in support of those conclusions. That is all. Your personal opinions are your own business, and you have a perfect right to express your personal opinions whenever appropriate.

Finally, in this class, I define a "rational" person as one who doesn't engage in any bad reasoning to support her beliefs. That doesn't mean that every one of her beliefs has to be supported by reason, it just means that she's not fooling herself about the basis of her beliefs. An irrational person is one who holds unsupported beliefs and pretends that logic supports those beliefs. Consider the following short dialog.

Zebulon. I believe in dragons because it gives me joy to think that they exist. I don't expect anyone else to believe in them.
Yalie. But you don't have any evidence that they do exist!
Zebulon. None whatsoever.
Yalie. So then you should be like me, and believe that they don't exist.

In this dialog, Zebulon is being perfectly rational. He believes something without foundation, but he admits this, and doesn't pretend that his unfounded belief has a foundation, or that anyone else has any reason to agree with him. If anyone here is irrational, it's Yalie, who is disrespecting Zebulon's right to believe what he wants.

The problem here is that while you don't have to have a logical basis for your personal beliefs, you have no right to insist that other people should share your beliefs. You have a right to believe whatever you want to believe, and no-one has a right to insist that you change your mind, but by the same token, you have to recognize that other people have a right to their particular beliefs as well, especially if their beliefs are actually supported by logic.

Speaking Logically

In this class, I want you to be more than simply rational (in the sense of not being irrational). I want you to be logical, and to pay very careful attention to the details of every situation. I will often ask you if a particular claim is logically supported, or if a certain statement is logically correct. Given the unfortunate lack of evidence for the existence of dragons, it would not be logically okay for Zebulon to say "it's true that dragons exist" or even to seriously say "dragons exist." While it is perfectly okay, and rational, to say "I believe in . . . " whatever you like, it is definitely not logical to state your belief as if it is true when you know of no facts supporting that belief.

 

Analysis of Atomic Arguments

The word "analysis" literally means "breaking apart" in Ancient Greek. Nowadays it means to break down a complicated topic into smaller ideas and issues so that it is easier to understand. Analysis makes complicated, confusing issues simpler and easier to understand, and the more analysis you do, the simpler and easier the issue gets. As you get better at analysis, you will find that things that look incomprehensible to others start to look more and more understandable to you.

Usually, when one person attempts to persuade another, they will actually give a bunch of arguments all lumped together to support their point. This can get very complicated, and to keep things as simple as possible I'm going to ignore this complication for a long as I can. Unfortunately, a bunch of little arguments lumped together is also called an "argument," so whenever I need to make things clear I'm going to use the term "extended argument" to mean a bunch of arguments arranged to support a thesis, and the term "atomic argument" to mean one of those little arguments. (Since I'm mainly going to be talking about atomic arguments, I will generally use the term "argument" to mean "atomic argument.")

Any given (atomic) argument can be broken down into a "conclusion" and one or more "premises."

A "conclusion" is basically some thing that someone is trying to get you to believe by offering reasons that may or may not logically support his point. It is the main point of any argument. If you can figure out what claim an arguer is trying to get you to believe, then you've figured out what his conclusion is.

A "premise" is a reason someone gives you to change your mind about something. In any argument, the premises are all the reasons given in support of the conclusion. If a "conclusion" comes without premises, then it's just an unsupported claim, and you don't have to take it seriously.

Standardization

The first step in analyzing arguments is always to separate conclusions from premises in a process called "standardization." The way I would like you to do this is to start by making two lists; one of conclusions, and another of premises, arranged like this:

 

Conclusion                                                    

  Premises                                                                    

Notice that I wrote "conclusion," which is singular, and "premises," which is plural. I did this because an atomic argument can have many premises, but it can have only one conclusion. (If there's more than one conclusion, it's not an atomic argument.)

Here is a very simple argument to analyze

Look, the most intelligent among us are also always the worst among us. That Mensa member threatened the people next door with death, poisoned them with thallium, which actually killed one of them, and used thallium poisoning as the plot of a "Mensa Murder Weekend." So all smart people are evil.

First, we divide the argument up into separate sentences:

Since one sentence can make several points, we try to divide the argument up into individual points.

Trying to make sure we understand the argument correctly, we try to put each point into our own words. (You can also look up words you don't know, or other facts, if you like.) Notice that this time I split the second point into three separate points. Sometimes it helps to do that.

Next, we identify possible conclusion statements. If it's not immediately here's a couple of different ways to do this.

One way to do this is to figure out which of his claims is most controversial. A claim is "controversial" claim is one that we would expect a lot of people to disagree with. So in the following list, I've bolded the most controversial claims, dimmed the others, and (explained why I did what I did.)

Another way to identify conclusions is to (temporarily) cross out every point that isn't apparantly supported by some other point in this list. Remember that one point is supported by another point if the second point makes the first point more likely to be true. So a point is "apparantly supported" by another if the second point at least appears to make the first more likely to be true. Since at this point we're just analyzing the argument, we won't worry about whether or it really does support the other point right now. (We can think about that later.)

Okay, now you may have noticed that I got different results with the second method. This is fine. Analysis can go different ways and still come out right. Besides, looking at things from different angles can tell us stuff that we wouldn't otherwise notice.

The next thing to do is make sure that none of the points are repetitions of other points. Look at the first and last points in the above list. Is there any real difference between what they're saying? In point of fact, although they use different words, they actually say exactly the same thing ("smart people are bad people"), so I'm deleting the second repetition of that claim. So now our list of claims (rearranged a little, and with conclusions in bold) looks like this:

Okay, let's finish up this phase by filling in those two lists I told you about before, at least as far as I can at this point.

 

Conclusion                                                    
If someone is very clever, he or she will also be a bad person.
This murderer was a smart person.





  Premises                                                                  
Some guy threatened to kill his neighbors.
He poisoned them.
Thallium was the poison used. 
It killed one of the victims.
He was a member of Mensa.
He used thallium poisoning as the plot of a "Mensa Murder Weekend."

 

Okay, now I have a problem. I have two items in the "conclusion" list, and I'm only supposed to have one there. There's two ways to handle this, the easy way and the hard way. We'll do it the easy way right now, (to illustrate standarization) and worry about the hard way later in the semester (when you'll be more used to logic.)

Standardization: The Easy Way

The easy way to sort out the "multiple conclusions" problem is simply pick the least controversial claim in the conclusion list, and move it to the premise list. Since the idea of a smart murderer is less controversial than the idea that all smart people are bad, the "smart murderer" claim gets moved over, like so:

 

Conclusion                                                    
If someone is very clever, he or she will also be a bad person.







  Premises                                                                  
Some guy threatened to kill his neighbors.
He poisoned them.
Thallium was the poison used. 
It killed one of the victims.
He was a member of Mensa.
He used thallium poisoning as the plot of a "Mensa Murder Weekend."
He was a smart person.

 

Okay, there is a lot more analytic work we could do on this argument, but this is enough for right now. The important thing is to get the basic idea of standardization, which is to list all the premises, draw a thick line under those premises, and then write the conclusion under that line, like so.

 

Some guy threatened to kill his neighbors.
He poisoned them.
Thallium was the poison used. 
It killed one of the victims.
He was a member of Mensa.
He used thallium poisoning as the plot of a "Mensa Murder Weekend."
He was a smart person.

If someone is very clever, he or she will also be a bad person.

 

 

Another Example

Here's another example, which we shall do a little differently.

A lot of Muslims live in my neighborhood. There's a mosque just up the street from my house, and Muslim people visit here from all over the world. So I meet many, many Muslims from all different countries as neighbors and friends. None of them want to forcibly convert anyone to Islam. None of them know anyone who wants to forcibly convert people to Islam. In fact, no Muslim I know or know of knows of anyone who wants to forcibly convert people to Islam. So I don't think it's true that a majority of Muslims want to forcibly convert people to Islam.

First, we list all the claims in this argument.

I don't see any duplications, so I'm not going to cross anything out. I'm going to take the boldest claim as the conclusion here, and enter it in the "conclusion" list.

 

Conclusion                                                    
It's not true that a majority of Muslims want to forcibly convert anyone to Islam.

  Premises                                                                  

 

And then add all the other claims under the "premises" heading.

 

Conclusion                                                    
It's not true that a majority of Muslims want to forcibly convert anyone to Islam.






  Premises                                                                  
Many Muslims live in the arguer's neighborhood.
There's a mosque near where the arguer lives.
Muslim people visit this mosque from all over the world.
The arguer has met Muslims from all over the world.
None of the Muslims the arguer has met want to forcibly convert anyone to Islam.
None of them know any Muslims who want to forcibly convert anyone to Islam.
 

And then I push the conclusion down the page:

 








It's not true that a majority of Muslims want to forcibly convert anyone to Islam.

  Premises                                                                  
Many Muslims live in the arguer's neighborhood.
There's a mosque near where the arguer lives.
Muslim people visit this mosque from all over the world.
The arguer has met Muslims from all over the world.
None of the Muslims the arguer has met want to forcibly convert anyone to Islam.
None of them know any Muslims who want to forcibly convert anyone to Islam.


 

And move the premises over to standardize the argument:

 

Many Muslims live in the arguer's neighborhood.
There's a mosque near where the arguer lives.
Muslim people visit this mosque from all over the world.
The arguer has met Muslims from all over the world.
None of the Muslims the arguer has met want to forcibly convert anyone to Islam.
None of them know any Muslims who want to forcibly convert anyone to Islam.

It's not true that a majority of Muslims want to forcibly convert anyone to Islam.

 


 

 

Breakown Boxing

Another way to do this is to use what I call a "breakdown box." this involves drawing a double box like so:

 

The top part is called the "premise hole" and the bottom part is called the "conclusion hole."

"Premise Hole"
"Conclusion Hole"

When you have an argument with a lot of premises, make the premise hole good and big.










 

Then put the conclusion of the argument into the conclusion hole.










It's not true that a majority of Muslims want to forcibly convert anyone to Islam.

Then put the premises of the argument into the premise hole.

Many Muslims live in the arguer's neighborhood.
There's a mosque near where the arguer lives.
Muslim people visit this mosque from all over the world.
The arguer has met Muslims from all over the world.
None of the Muslims the arguer has met want to forcibly convert anyone to Islam.
None of them know any Muslims who want to forcibly convert anyone to Islam.



It's not true that a majority of Muslims want to forcibly convert anyone to Islam.

Then, erase the outer wall of the box . . .

Many Muslims live in the arguer's neighborhood.
There's a mosque near where the arguer lives.
Muslim people visit this mosque from all over the world.
The arguer has met Muslims from all over the world.
None of the Muslims the arguer has met want to forcibly convert anyone to Islam.
None of them know any Muslims who want to forcibly convert anyone to Islam.                         

It's not true that a majority of Muslims want to forcibly convert anyone to Islam.

. . . and you're done!

Needs Work

What is the implied conclusion of this particular argument: "It's clear that the only possible explanation for the sudden collapse of the Horrible Eyesore Tower is that Flatulous, the Wind-God must have struck it down. It's true that leading engineers have generally agreed that the collapse was caused by the use of sub-standard steel and an incorrect calculation of wind-loading, but I don't accept that explanation, so it follows that Flatulous is the only logical explanation."

Flatulous, the Wind-God exists and destroyed the Horrible Eyesore Tower.

The Horrible Eyesore Tower collapsed because of sub-standard steel and an incorrect calculation of wind-loading.

Flatulous, the Wind-God lives in the Horrible Eyesore Tower.

Flatulous, the Wind-God is a leading engineer who studies building disasters.

Opposing Arguments

An argument that supports a conclusion that in any way contradicts the conclusion of another argument is an "opposing" argument to that argument.

Two arguments that support conclusions that contradict each other are "opposing" arguments to each other.

Challenging Conclusions and Challenging Premises

When two arguments oppose each other, there's two ways they can do it.

1. They could do it without referring to each other's premises.

2. They could do it in such a way that one argument refers to the premises of the other argument.

For instance, consider the following three arguments:

Many Muslims live in the arguer's neighborhood.
There's a mosque near where the arguer lives.
Muslim people visit this mosque from all over the world.
The arguer has met Muslims from all over the world.
None of the Muslims the arguer has met want to forcibly convert anyone to Islam.
None of them know any Muslims who want to forcibly convert anyone to Islam.                         

It's not true that a majority of Muslims want to forcibly convert anyone to Islam.


Al Queda are Muslims who want to forcibly convert people to Islam.
ISIS are Muslims who want to forcibly convert people to Islam.
Islamic Jihad are Muslims who want to forcibly convert people to Islam.                       

It is true that a majority of Muslims want to forcibly convert anyone to Islam.


The arguer's neighborhood is in a well-to-do American neighborhood.
That nearby mosque is the most liberal mosque in the Islamic world.
Only liberal muslims visit this mosque.
The arguer has only met liberal muslims.
The muslims the arguer has met might have lied about wanting to forcibly convert anyone to Islam.
The muslims he's met might have lied about Muslims who want to forcibly convert people to Islam.

It might still be true that a majority of Muslims want to forcibly convert anyone to Islam.

We will talk more about this later.

Thoughtfullness versus Mindlessness

One of the problems with teaching logic is that people who are not being logical tend not to notice (or admit) that they are not being logical. Personally, I think that at least some people who are "thinking" emotionally will also falsely insist that they are thinking critically when they're not, and will scornfully proclaim that they are being logical when in fact they are obstinately being the exact opposite of logical. This difference is embodied in two fictional characters I call "Thoughtful Thelma" and "Mindless Mikey." Thoughtful Thelma tries very hard to think logically, which means that she always tries to figure out what the facts actually are, what evidence actually exists and, most importantly, starts with the available evidence and reasons her way to the conclusion that honestly appears to her to be best supported by that evidence. Mindless Mikey, however, never stops to think about whether his ideas actually are true or false. He believes that they're true, and that, for him, is enough. When discussing his ideas, Mikey deploys all the language of logic and critical thinking in his defense of his ideas. He uses the words "fact," "evidence," "logic" and so on, while simultaneously lying about the facts, ignoring evidence and not being logical at all. He also tends to get angry when people disagree with him. Instead of carefully working through the opposing arguments, he denigrates his opponents, implies they don't understand things, and asserts that they disagree with him for dishonest reasons. Where Thelma reasons from the known facts to whatever conclusion actually best explains those facts, Mikey sticks to whatever conclusion he happens to like, and says whatever he can think of to get other people to agree with him.

It's important to remember that the crucial difference between Mindless Mikey and Thoughtful Thelma is one of behavior.  Mindless Mikey may be a highly educated, widely known, even highly respected figure. There may be millions of people who think Mikey is the smartest person alive. (I don't say that these are smart people.) It doesn't matter. What matters is how a person deals with evidence and logic. Here are some examples of Mindless Mikey in action.

Mikey is assigned to write a paper critically analyzing a dispute between two thinkers, Dr. Smith and Professor Jones. Mikey reads both there papers, and finds that Smith defends a thesis that Mikey already agrees with, so Mindless Mikey writes a paper stating that Smith is right because "Smith has the facts while Jones is only giving his opinion," without even beginning to look at the evidence. (The phrase "X has the facts while Y only has his opinion" is pretty much meaningless. It appears to be something some people write when they feel one side is right, but absolutely cannot think of anything to say that would even begin to support that claim. The last time I saw this phrase in a student paper, writer that the student said "had the facts" in fact gave no evidence whatsoever in support of his claims while the writer who, according to the student "was only giving his opinion" actually provided a long list of citations to scientific papers and other forms of evidence, so the student was basically lying about who had the facts in this particular dispute.)

Mikey is assigned to write a paper investigating the scientific question of "Thermal Discombobulation." Mikey finds that all the top scientists in relevant area of science all assert that Thermal Discombobulation is true, while the idea that Thermal Discombobulation. is false is only supported by a few much, much less qualified scientists, a few scientists in other areas of science, business leaders, politicians and television commentators. Despite the weight of scientific authority in favor of Thermal Discombobulation, Mikey thinks it isn't true, and so he mindlessly writes that Thermal Discombobulation is false, and that all the reputable scientists who support Thermal Discombobulation.only do so because they are in the grip of a vast conspiracy (for which Mikey gives no evidence) that steers grant money and university appointments only to people willing to pretend that Thermal Discombobulation is true.

Like Fido in the earlier section on judgment, Mindless Mikey gets a paper back from his professor asking "is this claim supported by any evidence?" Being mindless, Mikey makes no effort to ask himself if there is or is not any actual evidence that actually supports the claim. Instead, he (mindlessly) says to himself "this claim is true. True claims are supported by evidence, therefore this claim is supported by evidence." Then he adds a line to his paper saying "this claim is supported by evidence," (without saying at all about what he thinks this evidence actually is) and thinks he has answered the question. (Of course, Mikey is surprised and resentful when his paper receives an "F.")

In another assignment, Mikey is assigned to write a paper critically analyzing a dispute between two thinkers, Mrs. A and Mr. B. Mikey is given links to websites containing the evidence he needs to settle the dispute, but Mikey ignores these links. Instead, Mikey is swayed by the vehemence of Mrs. A's rhetoric, and thinks that because Mrs. A is sooooooooo angry at Mr. B, and says such horrible things about Mr. B, that Mr. B must be a terrible person. And so, without bothering to look at any of the avaiable evidence, he writes a paper saying that Mr. B is wrong because "he does not provide support for his claims." This is mindless because, firstly, there was evidence there for Mikey to look at and think about, and secondly because Mikey was specifically told to think critically, and therefore to ignore his feelings about the issue, Mikey allowed Mrs. A's angry language to turn him against Mr. B without ever stopping to think about the evidence.

Whereas Thoughtful Thelma is always willing to change her mind when it turns out that the evidence doesn't support her views, Mindless Mikey always assumes that whatever he happens to believe is true, and that because he thinks it's true, it must be a fact, and it must be supported by evidence. This is mindlessness because there is never any effort to look for facts, to examine evidence, or to spend any time at all thinking about what the facts might actually mean.

Don't be like Mindless Mikey. Reason only from the facts, and always, always, always, always, always, always, always, always be willing to change your mind.

Possibly irrelevant videos

The following videos might be helpful, but I made them a long time ago, and I've reorganized the class since then, so some of what I say in these videos may fail to match this chapter.

First half of basics lecture

basics 02 140205

Exercises

1. What is the meaning of the term "independent thinking?"
        a. "Independent thinking" means figuring out what your professor wants you to say and then putting your professor's opinion into your own words.
        b. "Independent thinking" means remembering what your parents, priests or other authority figures want you to think and thinking that thing.
        c. "Independent thinking" means ignoring what other people say and just applying your best understanding of logic to all the available evidence.
        d. "Independent thinking"means looking into your heart to work out what you personally feel is the truth.

2. True or False: When someone makes a claim with complete confidence that it is true, her confidence by itself gives you a good reason to think that the claim is true.

3. True or False: When you feel very strongly that something is true, and you believe it with all your heart, that gives you a good reason to think that it is true.

4. True or False: When you are asked to think about a particular question, you should always start by thinking about what you already believe about the issue.

5. True or False: If someone else has already logically analyzed an issue, you can give your own logical analysis simply by describing everything this other person said.

6. True or False: If something you previously stated to be true turns out to be contradicted by all the available evidence, you can logically still go on saying that it is true.

7. True or False: Smart people tend to be people who never change their minds about anything.

8. True or False: It is possible to think logically without thinking about arguments.

9. True or False: It is possible to think critically about the world without thinking about evidence.

10. True or False: If you already believe something is true then you can logically assume it's supported by evidence.

11. True or False: If someone can write an emotionally persuasive speech in support of a claim, then that claim is true.

12. True or False: The logical thinker ignores rhetoric and looks for the facts.

13. True or False: You can know that something is true without knowing of any reason to think that it is true.

14. True or False: People who try to pressure you into agreeing with them are not being logical.

15. Select the one and only true statement:
    a. A "fact" is something you believe to be true.
    b. A "fact" is something everyone believes to be true.
    c. A "fact" is something that anyone can independently verify to be true.
    d. A "fact" is something that may or may not be true.

16. Select the one and only statement that is a fact about comets:
    a. Comets are omens of doom.
    b. Comets sometimes have glowing tails.
    c. Comets are an atmospheric phenomenon.
    d. Comets are made by gasses burning in the upper air.

17. Select the one and only true statement:
    a. An "opinion" is something someone believes to be true.
    b. An "opinion" is something someone else believes that is not a fact.
    c. An "opinion" is something someone else believes that you don't believe.
    d. An "opinion"is something that has been proved to be true.

18. Select the one and only true statement:
    a. A "judgment" is just someone's opinion.
    b. A "judgment" is whatever you personally happen to think.
    c. A "judgment" is an opinion formed by applying logic to the available facts.
    d. A "judgment" is when you decide whether something is good or bad.

19. True or False: Critical thinking is when you think up reasons to support things you believe.

20. When you've looked everywhere, but can't find evidence to support your beliefs, if you're being logical, you should:
    a. Keep looking, the evidence has to be out there somewhere.
    b. Make up a plausible story that supports your beliefs.
    c. Say that evidence exists, without saying what it is.
    d. Change your mind and give up the belief you had before.

21. True or False: It's logically okay to ignore evidence that contradicts your beliefs.

22. True or False: Once you've chosen a point of view you can't ever change your thesis.

23. True or False: If you can't prove something, you shouldn't say it's true in a paper.

24. You fulfill a critical thinking assignment by:
    a. Writing a paper that explains what you feel to be true about the subject.
    b. Explaining what you think is logically implied by the available evidence.
    c. Explaining what one or more other people think about the subject.
    d. Writing a paper that gives all your personal beliefs about the topic.

25. True or False: "Evidence" is basically the same as "facts."

26. Select the one and only true statement:
    a. Vehemently expressed opinions count as evidence.
    b. Scientific papers and other academic journal articles count as evidence.
    c. The opinions of untrained people count as evidence.
    d. A strong feeling that something must be true counts as evidence.

27. True or False: If you can't describe the evidence, you have no evidence.

28. When a professor asks "can you prove X," she wants you to:
        a. Ignore the question.
        b. Think about whether you can prove X, and change your mind if and only if you can't prove X.
        c. Assume that X is not true, and go on from there.
        d. Do your very, very best to prove that X is true.

29. True or False: If you believe X, that means that there is evidence for X.

30. True or False: You should look at all the available relevant evidence before you decide what the truth is.

31. Select the one and only true statement:
        a. "Empirical" reasoning is only used by scientists.
        b. "Empirical" statements are statements about the meanings of words.
        c. Things exist that are not supported by empirical reasoning.
        d. "Empirical" statements are statements about the real world.

32. Select the one and only true statement:
        a. A statement is empirically true if it is passionately believed by someone.
        b. A statement is empirically true if it is what everyone believes.
        c. A statement is empirically true if it is completely supported by all the evidence.
        d. A statement is empirically true if you strongly believe it is true.

33. Select the one and only true definition of logical support:
        a. A fact supports a conclusion if it makes you feel that the conclusion is true.
        b. A fact supports a conclusion if it cannot be easily explained without assuming the conclusion is true.
        c. A fact supports a conclusion if you write it in the same paragraph as the conclusion.
        d. A fact supports a conclusion if somebody says it does.

34. True or False: Some empirical claims can be supported absolutely

35. Select the one and only true statement:
        a. A claim is only proved if it is absolutely supported.
        b. A claim is only proved if it is absolutely or virtually absolutely supported.
        c. A claim is only proved if it is at least compellingly supported.
        d. A claim is proved if it is at least well supported.

36. True or False: If a claim is unsupported, it's still logically okay to say that it's true.

37. Select the one and only true statement:
        a. When a claim is not proven, that means it's disproved.
        b. When a claim is not disproved, that means it's proven.
        c. When a claim is not proven, that doesn't mean it's disproved.
        d. When a claim is proven to be not proven, that does mean it's disproved.

38. True or False: You can logically say a claim is true without compelling reason to believe it.

39. True or False: You can logically say a claim is false without compelling reason to disbelieve it.

40. True or False: You can logically say a claim is unproven even if you have compelling reason to believe it.

41. True or False: You can logically say a claim has not been disproved even if you have compelling reason to disbelieve that claim. (Read this carefully before answering)

42. Select the one and only true statement:
        a. You don't have a right to believe things that have been disproved.
        b. You don't have a right to believe things that have not been proven.
        c. You don't have a right to believe things other people don't believe.
        d. You have a right to believe anythings you want to believe.

Say which of the following are arguments, and which are just claims:

1. Rasputin had to be poisoned, shot, bludgeoned and drowned, so Russian monks are sure hard to kill.
2. All guitarists are high-ranking academics.
3. Swaggart and Bakker had affairs, which shows that televangelists are all hypocrites.
4. The lead guitarist from Queen is chancellor of a university.
5. The Russian monk Rasputin had to be poisoned, shot, bludgeoned and drowned before he would die.
6. All televangelists are all hypocrites.
7. Russian monks are hard to kill.
8. The lead guitarist from Queen is chancellor of a university, proving that all guitarists are high-ranking academics.
9. Russian monks are routinely equipped with antitoxins, kevlar and snorkels, so they are very hard to kill.
10. Guitar shredding requires graduate work in astrophysics.

Write out the conclusion of each of the following arguments:

11. Composite body aircraft will never be commercially successful, they just cost too much!
12. The failure of the Beechcraft Starship proves that composite body aircraft will never be commercially successful.
13. Bert Rutan says that composite body aircraft will be commercially successful within the decade!
14. Rasputin had to be poisoned, shot, bludgeoned and drowned, so Russian monks are sure hard to kill.
15. Rasputin was just one Russian monk, so you can't say Russian monks are always hard to kill.
16. Russian monks are very hard to kill because they are routinely equipped with antitoxins, kevlar and snorkels.
17. Guitar shredding is just like Nobel Prize winning, so all guitarists are high-ranking academics.
18. All guitarists are high-ranking academics. After all, the lead guitarist from Queen is chancellor of a university!
19. Guitar shredding requires graduate work in astrophysics, so all guitarists are high-ranking academics.
20. That's just one guitarist from just one band, so not all guitarists are high-ranking academics.

Write out the premises of each of the following arguments:

21. Composite body aircraft will never be commercially successful, they just cost too much!
22. The failure of the Beechcraft Starship proves that composite body aircraft will never be commercially successful.
23. Bert Rutan says that composite body aircraft will be commercially successful within the decade!
24. Rasputin had to be poisoned, shot, bludgeoned and drowned, so Russian monks are sure hard to kill.
25. Rasputin was just one Russian monk, so you can't say Russian monks are always hard to kill.
26. Russian monks are very hard to kill because they are routinely equipped with antitoxins, kevlar and snorkels.
27. Guitar shredding is just like Nobel Prize winning, so all guitarists are high-ranking academics.
28. All guitarists are high-ranking academics. After all, the lead guitarist from Queen is chancellor of a university!
29. Guitar shredding requires graduate work in astrophysics, so all guitarists are high-ranking academics.
30. That's just one guitarist from just one band, so not all guitarists are high-ranking academics.

Do a basic breakdown of each of the following arguments:

31. Composite body aircraft will never be commercially successful, they just cost too much!
32. The failure of the Beechcraft Starship proves that composite body aircraft will never be commercially successful.
33. Bert Rutan says that composite body aircraft will be commercially successful within the decade!
34. Rasputin had to be poisoned, shot, bludgeoned and drowned, so Russian monks are sure hard to kill.
35. Rasputin was just one Russian monk, so you can't say Russian monks are always hard to kill.
36. Russian monks are very hard to kill because they are routinely equipped with antitoxins, kevlar and snorkels.
37. Guitar shredding is just like Nobel Prize winning, so all guitarists are high-ranking academics.
38. All guitarists are high-ranking academics. after all, the lead guitarist from Queen is chancellor of a university!
39. Guitar shredding requires graduate work in astrophysics, so all guitarists are high-ranking academics.
40. That's just one guitarist from just one band, so not all guitarists are high-ranking academics.

 

 

Answers to the Above Exerecises

1. c. "Independent thinking" means ignoring what other people say and just applying your best understanding of logic to all the available evidence.
2. False: A feeling or attitude of confidence is logically meaningless.
3. False: Things people feel very strongly to be true, and believe with all their hearts are often false.
4. False: You should always start by ignoring what you already believe about the issue.
5. False: You can only give your own logical analysis by doing the work for yourself.
6. False: You should not assert things that are contradicted by the available evidence.
7. False: Smart people tend to change their minds a lot. It's dumb people who don't change their minds.
8. False: It is not possible to think logically without thinking about arguments.
9. False: It is not possible to think critically without thinking about evidence.
10. False: Believing something doesn't mean it's supported by evidence.
11. False: Emotionally persuasion is very different from proof.
12. True: The logical thinker does ignore rhetoric and does look for the facts.
13. False: If you don't have a reason to think something is true, then you can't know it, because it might very well not be true at all.
14. True: Emotional pressure isn't logic. (And people who do it are bad people.)
15. c. A "fact" is something that anyone can independently verify to be true.
16. b. Comets sometimes have glowing tails.
17. a. An "opinion" is something someone believes to be true. Even if the "someone" is you.
18. c.  A "judgment" is an opinion formed by applying logic to the available facts.
19. False: Thinking up reasons to support things you believe is a form of dishonesty.
20. d. If you can't find evidence to support your beliefs, that gives you a logical reason to change your beliefs.
21. False: It is not logically okay to ignore evidence that contradicts your beliefs.
22. False: You can always change your thesis. If the evidence supports a different thesis, you should change your thesis.
23. True: If you can't prove something, then it's unproven, and you shouldn't say it's true.
24. b. Critical thinking is thinking about what is logically implied by the available evidence.
25. True: "Evidence" is the same as "facts." I can't think of any meaningful difference.
26. b.  Scientific papers and journal articles are usually the best available evidence.
27. True: If you actually had actual evidence, you would be able to give a description of that evidence.
28. b. Think about whether you can prove X, and change your mind if and only if you can't prove X. When a professor asks you a question, she generally means you to answer the question she actually asks. If I ask you if you can prove something, you are supposed to think seriously about whether you can prove that thing. You're not supposed to assume you can prove it, and you're not supposed to assume you can't prove it. You're supposed to think about whether you can prove it or not. If you can come up with a compelling argument for X, you should describe that argument clearly and completely on your paper. If you can't come up with an argument that you can describe, you should then and only then assume that X is not true, and rewrite your whole project, from the beginning, on that assumption.
29. False: If you believe something, that doesn't mean there is evidence for it. People believe lots of things that are not true.
30. True: You should look at all the evidence before you decide what the truth is. If you don't, you're not being honest.
31. d.  "Empirical" statements are statements about the real world. If you say something exists or doesn't, you are making an empirical statement.
32. c. There is no empirical truth without compelling evidence.
33. b. A fact only supports a conclusion if it cannot be easily explained without assuming the conclusion is true.
34. False: No empirical claims can be supported absolutely. Absolute support never exists for such claims.
35. c. A claim is only proved if it is at least compellingly supported. "Compelling support" is basically another term for "prook."
36. False: If a claim is unsupported, you can still believe it, but it's not logically okay to say it's true.
37. c. When a claim is not proven, that doesn't mean it's disproved. Logically, unproven things can still be true.
38. False: You can not logically say a claim is true without compelling reason to believe it.
39. False: You can not logically say a claim is false without compelling reason to disbelieve it.
40. False: You can not logically say a claim is unproven when you have compelling reason to believe it.
41. False: You can not logically say a claim has not been disproven when you have compelling reason to disbelieve it.
42. d. You have a right to believe anythings you want to believe. You can't tell other people they have to believe what you believe, but you can hold and express any beliefs you like.

Copyright © 2014 by Martin C. Young

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