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8/30/16

Arguments 2

INFORMAL FALLACIES AND OTHER MUNDANE

POINTS ABOUT LOGIC

INTRODUCTION

• Before introducing and discussing informal fallacies (the main subject of this lecture), we’ll need a definition of fallacies more generally.

• First, let’s start with a basic definition: A fallacy is an error in reasoning that tends to be psychologically persuasive.

• As we learned last time, once we have determined that there is an argument, and then determined what the conclusion is and what the premises are, then we can evaluate the argument. This can sometimes be quite easy like in Ex. 1 and 2 below:

INTRODUCTION

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• Ex 1. Two plus two equals four. So, the Miami Heat will win the NBA Championship.

• Or

• Ex 2. Denver was the last dinosaur. John likes dinosaurs. So, John must have destroyed all the unicorns.

•But when an argument is not so easy to evaluate then it is important (and helpful, generally) to know that arguments can go wrong in one of two ways:

• Logical form is bad

• Premises are false (something about the content not the structure)

• Informal fallacies are instances of both these problems!

INTRODUCTION

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• Indeed! Even if the logic is perfect, if the premises are false – any of them – then we are not rationally compelled to think that the conclusion is true. This need not force the person who constructs the argument to give up. It might be possible (and likely it is entirely plausible) to reconstruct the argument in such a way as to not need the faulty premise. It will be an important tool for you when you evaluate arguments to be able to determine if any given premise of an argument is false. It is very common to encounter arguments that make errors (logical or substantive). Many such faulty arguments look powerful, though, and we need to be very careful about them.

• First, some points about Formal fallacies.

• You remember that fallacies are _________(?)

• For the most part, we are going to be interested in informal fallacies but I would quickly like to look at Formal Fallacies.

• Ex 3. If nepotism is wrong, then it is destructive. And it is destructive. So, nepotism is wrong. • This is an instance of the formal fallacy called “Affirming the

Consequent”. • Bowel movement example.

FORMAL FALLACIES

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FORMAL FALLACIES

• Ex 4. If good intentions make good sermons, then Reverend McGuire is a good preacher. Unfortunately, they don’t, so he’s not.

• This is an instance of the formal fallacy called “Denying the Antecedent”.

• Ex 5. All cantaloupes are melons. All watermelons are melons. So, all watermelons are cantaloupes.

• This is an instance of the formal fallacy called “The Undistributed Middle”.

• These will be as much as you need to know for the course. If you care to know more then head over to RationalWiki or about.com’s page on arguments.

A METHODOLOGICAL AND TERMINOLOGICAL ASIDE

• It is important to get some basics about arguments out of the way before moving forward with informal fallacies. The first thing I’d like to discuss is some not so far-fetched rules of engagement (THE PRINCIPLES, bro!):

• Principle 1 – Identify the premises and the conclusion. • P2 – Eliminate excess verbiage. • P3 – Employ uniform language. • P4 – Be fair and charitable in interpreting an argument. • P5 – Do not confuse subconclusions with the final conclusion.

• These will help you engage better (more fruitfully and honestly) with your fellow interlocutor.

INFORMAL FALLACIES

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• These can be put into broader categories, which should help in remembering and understanding them.

• Fallacies of Relevance

• Ad hominem ("Argument against the man" from Latin): Such arguments attempt to disprove another argument by undermining the integrity of the person making the argument. In this case, one critiques the person rather than the belief itself, or the argument itself. Often, this strategy makes an appeal to the reader based on some bias of the person making the argument.

• Ex XX. Bob’s argument against abortion cannot be believed, because Bob is a committed Catholic, and he’s biased in favor of pro-life.

• Ex XX. Jones argues for vegetarianism. He says it is wrong to kill animals unless you really need them for food, and that, as a matter of fact, nearly everyone can get enough food without eating meat. But Jones is just a nerdy intellectual. So, we can safely conclude that vegetarianism remains what it has always been—nonsense!

• EX. XX. This theory about a new cure for cancer has been introduced by a women known for her Marxist sympathies. We shouldn’t listen to her ideas because egalitarians are all socialist assholes.

INFORMAL FALLACIES

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• Ad hominem • Ex. XX.

INFORMAL FALLACIES

• A last note on Ad Hominum:

•Only if we can show that someone’s character somehow makes the claim dubious are we justified in rejecting the claim because of a individual's personality. Though such a circumstance is rare, not all appeals to character are irrelevant. When might it be relevant? When the circumstance of the person in question pertains to his/her qualifications to be a legitimate authority on the matter. When the character of the person in question is in question with respect to something known about him/her specifically regarding the present deliberation.

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• Tu Quoque ("You, also" or "You're another", from Latin): This is a form of the ad hominem. Often a person will dismiss some belief or argument from another person because that other person does not act consistently with the belief they recommend. In short, whether or not a person is a hypocrite is irrelevant regarding the truth of their claim.

• Ex 10. Dad tells me I should not lie. He says lying is wrong because it makes people stop trusting one another. But I’ve heard my Dad lie. Sometimes he calls in “sick” to work when he isn’t really sick. So, lying isn’t actually wrong—Dad just doesn’t like it when I lie.

• Ex 11. Bin Laden and U.S. sponsored terrorism.

• EX. XX. If you think communal living is the way to go, then why aren’t you living in a kibbutz!

• EX. XX. German Chancellor's outrage over being wiretapped.

• Ad Baculum Fallacy (Appeal to Force): These sorts of arguments involve defending/justifying the conclusion by a threat to the well-being of those who do not accept it. The threat may be implicit or explicit.

• Ex 12. Mr. Jones you helped us import the drugs. For this, the Boss is grateful. But now you say you’re entitled to 50 percent of the profits. The Boss says you’re entitled to 10 percent. Unless you see things the Boss’s way, you’re going to have a very nasty accident. So, you’re entitled to 10 percent. Got it?

• Ex 13. Lately, there has been a lot of negative criticism of our policy on dental benefits. Let me tell you something, people. If you want to keep working here, you need to understand that our policy is fair and reasonable. I won’t have anybody working here who thinks our policy is unfair or unreasonable.

INFORMAL FALLACIES

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• Ad Populum (Appeal to the People): is an attempt to persuade a person (or group) by appealing to the desire to be accepted or valued by others. Politicians often do this at political rallies by pumping up a crowd and making those individuals within the crowd (because of their desire to be part of the group) feel l ike his/her point is more persuasive because they are amongst a cheering crowd, like in the example below.

• Ex 14. I look at you all, and I tell you, I am proud to be here. Proud to belong to a party that stands for what is good for America. Proud to cast my lot with the kind of people who make this nation great. Proud to stand with men and women who can get our nation back on its feet. Yes, there are those who criticize us, who label our view of trade agreements as “protectionist”. But when I look at you hard-working people, I know we’re right, and the critics are wrong (-the crowd cheers!-).

• Ex 15. Ms. Riley, are you saying that President Bush made a moral error when he decided to go to war with Iraq? I can’t believe my ears. That’s not how Americans feel. Not true Americans, anyway. You are an American, aren’t you, Ms. Riley?

• Red Herring: The raising of an irrelevant issue during an argument. This is one of the favorite techniques of political spin doctors. It usually comes into play when someone wants to convince you that the opponent’s position is wrong.

• Ex. XX. “Every woman ought to have the right to abortion. All those pro-lifers obstruct the entrance of clinics, get in women’s faces, and threaten doctors.”

• All of this may be true, but no matter because the behavior of the pro-lifers has absolutely no relevance to whether or not women should have a right to abortion.

INFORMAL FALLACIES

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• Ad Misericordiam (Appeal to Pity) • Is an argument mean to win someone over by playing with their

emotions (namely, sympathy or pity). • Ex. XX. Jil l : "He'd be a terrible coach for the team."

Bill: "He had his heart set on the job, and it would break if he didn't get it." Ji l l : "I guess he'll do an adequate job.”

• Ex. XX. "I 'm positive that my work will meet your requirements. I really need the job since my grandmother is sick”

• Ex. XX. "I should receive an 'A' in this class. After all, if I don't get an 'A' I won't get the fellowship that I want."

• Fallacies involving insufficient evidence

• Appeal to Ignorance: When someone uses a lack of knowledge as a jumping off point for their own otherwise unfounded speculations. It does not follow that, simply because we have not confirmed that something is true, that it is false, nor does it follow that, simply because we haven’t shown that something is false, that it is true (or worthy of belief).

• Ex 16. After Centuries of trying, no one has been able to prove that reincarnation occurs. So, at this point, I think we can safely say conclude that reincarnation does not occur.

• Ex 17. Evolution and the God of the gaps.

INFORMAL FALLACIES

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INFORMAL FALLACIES

• False Cause Fallacy • occurs when one cites to sequential events as evidence

that the first caused the second.

• Ex. XX. Obama is a terrible president because he is black.

• Ex. XX. Every day, I eat cereal for breakfast. One time, I had a muffin instead, and there was a major earthquake in my city. I've eaten cereal ever since.

• Ex. XX. "Defense attorney Ellis Rubin claims Ronald Zamora's constant exposure to TV crime shows such as re-runs of 'Kojak' and 'Police Woman' was responsible for 'diseasing his mind and impairing his behavior controls.' 'Without the influence of television ... there would not have been any crime,' Rubin argued."

• False Cause Fallacy • Ex. XX.

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• Fallacies involving ambiguity

• Equivocation Fallacy: It occurs when two (or more) meanings of a word (or phrase) are used in a context in which validity requires a single meaning.

• Ex 19. I agree with Christians in their claims that God is love. But unlike Christians, I’m not afraid to draw the obvious logical consequence: Love is God.

• Ex XX. The priest told me I should have faith. I have faith that my son will do well in school this year. Therefore, the priest should be happy with me.

• Ex XX. Why should you question the Theory of Evolution? Because it's called the 'theory of evolution', so evolution is an unproven assumption!

• Ex.XX. The elements of the moral argument on the status of unborn life… strongly favor the conclusion that this unborn segment of humanity has a right not to be killed, at least. Without laying out all the evidence here, it is fair to conclude from medicine that the humanity of the life growing in a mother's womb is undeniable and, in itself, a powerful reason for treating the unborn with respect.

• Composition: This is the flipside of the below (Division). Just because something is true of the members of a group (eg, possess some trait), it does not follow that the group as a whole possesses that trait. These come in two forms

• Part-Whole • Ex 21. Every part of that car is light, therefore the car is light.

• Ex 22. The atoms that make up the body are invisible (to the naked eye), therefore the body should be invisible (to the naked eye).

• Members-Group

• Ex 24. Elephants eat more than humans. So, elephants as a group eat more than humans as a group.

INFORMAL FALLACIES

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• Division: It is a mistake to think that because something is true of a whole it is also true of its parts. Similarly, one errs when thinking that, necessarily, if something is true of a group of people it is true of each member of the group.

• Ex 25. The Senate committee on Intelligence is a very influential group in Washington. Jim is on that committee, and is thus very influential in Washington.

• Ex 26. Einstein’s brain is more effective than my brain, thus the cells that make up Einstein’s brain are more effective than the cells that make up my brain.

• Fallacies involving unwarranted premises

• Petitio Principii (Begging the Question): This occurs when the conclusion is used somewhere as a premise in the argument.

• Ex 27. The Bible says that God exists. The Bible is true because God wrote it. Therefore, God exists.

• Ex XX. If it’s on TV, it has to be a good show, because only good shows get on TV.

• Ex. XX. John: "Why didn't you include Lorena's poetry in the student publication?" Anne: "Because it was judged as not sufficiently worthy of publication."

INFORMAL FALLACIES

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• Quick aside on the use of “begging the question”:

• The phrase “beg the question” is frequently misused. You might hear someone say, “And that statistic begs the following question …” No! It might prompt the question, it might raise the question, but it does not beg the question. You can’t have the conclusion also be one of the premises, otherwise the whole notion of an argument (when one claim is used to support some other claim) makes no sense. To put it another way, the formal expression of this fallacy is: P is untrue because P is untrue.

• False Dilemma: We frequently read and hear that one must pick a side, one must stand for or against something. In most cases, there are more than just two alternatives or possibilities. But the person who makes the false dilemma tries to force you to agree with his side, since if you don’t that would make you look either like an idiot or immoral.

• Ex 28. You either go to college and make something of yourself or you fail at life with no chance of making good money and living a good life.

• Ex 29. “You’re either for us or against us.” You’re either a patriot or a traitor.” “Either we have to fight an all out military war against the countries that support terrorists or we must die as spineless victims.”

• Ex. XX. Good students will study and learn without the threat of an exam, and bad students won't study and learn even with the threat of an exam. So, exams serve no purpose

INFORMAL FALLACIES

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• Slippery Slope: This is a conclusion based on the premise that i f A happens, then eventual ly through a series of small steps, through B, C, . . . , X, Y, Z wil l happen, too, basical ly equating A and Z. So, i f we don't want Z to occur, A must not be al lowed to occur either. These are given without cit ing much evidence.

• Ex. XX. The rul ing seems l ike the beginning of a total i tarian state. Judge Owens is v iolat ing the concept of the secret bal lot by demanding that faculty members reveal how they voted. Next the government wil l want to prohibit secret voting in unions, professional organizations, corporations, and final ly in the general election.

• Ex. XX If we ban Hummers because they are bad for the environment eventually the government wil l ban al l cars, so we should not ban Hummers.

• EX. XX (1) I f you buy a Green Day album, then next you’ l l be buying Buzzcocks albums, and before you know it you’ l l be a punk with green hair and everything. You don’t want to become a punk. So, you shouldn’t buy a Green Day album.

• Straw Man: Such arguments are direct responses to an opposing position. Straw man arguments distort their opposition, changing their meaning, distorting them in such a way as to make it very easy to topple them. In this case, one makes differing opinions look like they support positions which

• (i) are easy to disprove, and

• (ii) are not in fact the position of the opposition.

INFORMAL FALLACIES

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• Ex XX. Jim says: I think that some of the poor ought to receive limited public assistance in the form of housing and job training. Bob responds: Your position is ultimately communist, which was shown to be a failure in the economic failure of the Soviet Union and the rest of Eastern Europe.

• Ex XX. Susan advocates the legalization of cocaine. But I cannot agree with any position based on the assumption that cocaine is bad for you and that a society of drug addicts can’t flourish. So, I disagree with Susan.

• See how this violates principle 4 above?!?!

• EX. XX. From a draft of a bill (HCR 74) considered by the Louisiana State Legislature in 2001:[7] Whereas, the writings of Charles Darwin, the father of evolution, promoted the justification of racism, and his books On the Origin of Species and The Descent of Man postulate a hierarchy of superior and inferior races. . . . Therefore, be it resolved that the legislature of Louisiana does hereby deplore all instances and all ideologies of racism, does hereby reject the core concepts of Darwinist ideology that certain races and classes of humans are inherently superior to others, and does hereby condemn the extent to which these philosophies have been used to justify and approve racist practices.

INFORMAL FALLACIES