Chapter Eleven. (Problems printing? Click here.)
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Presumption

A presumption fallacy occurs when an arguer shirks the burden of proof by presenting a premise that is just as much in need of proof as his conclusion. Remember that an argument is supposed to support a claim that we don't already believe by means of premises that we do already believe. If we don't already believe those premises, then those premises need to be supported by their own arguments. When an arguer relies on a premise that is clearly just as much in need of support as his conclusion, then he commits a presumption fallacy. Basically, in a presumption fallacy an arguer explicitly or implicitly assumes something that logically should not be assumed. 

The difference between relevance fallacies and presumption fallacies is that in the former the premises offered simply fail to support the conclusion while in the latter the premises offered do support the conclusion, but themselves have no more support than that conclusion has without them.

Recall that a premise is supposed to meet two different requirements. First, it is supposed to provide support for the conclusion. Second, It is supposed to be either uncontroversial or independently supported. That is, it is to be supposed to either be something that a properly educated, reasonable person would generally agree to without argument, or it is supposed to be backed up by a good argument of its own. Of course, reasonable people often disagree about what is uncontroversial, so some unsupported premises may be considered controversial by some people but not by others. That's fine in itself. The problem of presumption appears when an unsupported premise turns out to be pretty much exactly as controversial, and in the same way, as the conclusion it supports. People who already agree with the conclusion won't worry about this, but then, these people don't need an argument to convince them. People who don't already believe the conclusion won't believe the premise either, so this argument won't ever convince them. Either way, a question begging argument won't ever change any logical person's mind, so as far as logic is concerned, it isn't even an argument.

In this chapter, I'm going to say that a claim is "controversial" if it is something that at least some well-informed reasonable people would tend not to agree with and/or it is something that people would generally only agree with if they also already agreed with the conclusion of the relevant argument. If people who do not already agree with the conclusion of an argument would also strongly tend to disagree with one of that argument's premises, then that premise is controversial, as far as I'm concerned.

Begging the Question

An argument is begging the question when its main "premise" is either a restatement of its conclusion, or is otherwise so clearly unsupported that the listener instinctively wants to jump in and question that main premise. In other words, the argument relies upon a premise that's at least as controversial as the conclusion.
(It's called "begging the question" because it makes the listener want to jump in with "say what? How do you know that...")

The weakest of the weak is a claim made with no support whatsoever. The speaker expects you to take his unsupported word for something about which he has no claim to expertise.

Wheatgrass contains as much nutrients as two and a half pounds of vegetables. (How on earth do you know that?)

Another way to beg the question is to provide a "premise" that is nothing more than the conclusion expressed in different words.
 
We know that alien abduction stories are valid and accurate because the abductees are completely accurate in their reccollections of events. (And how do you know that these "abductees" are completely accurate?)

The question can be begged by presenting the conclusion as a specific instance of some general rule that itself is not backed up by any reasons.

My refusal to allow make-up exams is justified by the fact that it is not my policy to allow make-up exams. (And what justifies the policy?)

Another way to beg the question is to think that because one has already made up one's mind, arguments can be judged good or bad based solely on whether or not their conclusions agree with one's pre-existing opinion.

I can't tell much about the logic of this argument, but it's conclusion is true so, yeah, I guess it's a good argument. (It's only a good argument if it's good enough to change somebody's mind. Even if the conclusion was true, how could that make the argument good? And how do you know that conclusion's true?)

The conclusion of this argument isn't true, so it's logic must be inadequate. (If you haven't looked at the logic, how could you know that it's inadequate? And how do you know that conclusion isn't true? If there's no problem with the logic of the argument, the conclusion is true, whether you like it or not.)

Rilda. That Punter Dublin is such a liar!
Joyce. Can you tell me one lie he's told?
Rilda. Well... no. But he's a liar, I know that!(How can you know that someone is a liar without knowing of any lies he's told?)
Joyce. What about Farmer Shrub? I can tell you a dozen lies he's told.
Rilda. Not in this house you won't! (How can you think that somebody's honest if you're unwilling to look at the evidence?)

Things that look like authority arguments can turn out to be mere question-begging. If someone says that some authority supports his conclusion, but doesn't tell us who that authority is, he then begs the question, and we can dismiss his argument.

Scientists have proved that we only use ten percent of our brains. (What scientists? When? How did they prove this?)

And here's a personal favorite.

Delilah. I don't think we should consider President Suharto of Indonesia a humanitarian leader. After all, he did lead Indonesia in an invasion and occupation of East Timor in which they killed about a third of the East Timorese.
Garrison. You're making that up!

This should be fairly easy, right? I mean, it should be clear that Garrison is begging the question. The trouble is, this set is based on a real conversation with a fellow graduate student. He really reacted like that. He heard something he didn't want to believe, so he immediately jumped to the conclusion that I had made it up. He even laughed. So let's make this perfectly clear: the automatic dismissal of information you don't like is always a fallacy. Always.


False Choice

An arguer commits a false choice fallacy when she leaves out a viable alternative. The usual way of doing this is to pretend that there are only two alternatives when there are fact more than two. (There's a name for doing it with exactly two alternatives but it won't be on the test.)

Chaz. You should stop that protesting and support our president. It's America. Love it or leave it!

Russia has a choice. Stride forward in capitalism or turn back to communism.

Shamu is not a dog, therefore he's a cat.

Candidate principles:
1. You cannot love a country without unconditionally supporting it's leaders.
2. Capitalism and communism are the only two possible political systems.
3. All animals are either cats or dogs.

This kind of fallacy can be committed with any number of alternatives, just so long as a reasonable alternative is left out.

Circular Argument

An argument is circular when questioning its dubious premise sooner or later leads right back to the unsupported restatement of the conclusion. (This can happen when someone attempts to save a question-begging argument by coming up another question begging argument for that question-begging premise. Keep doing that over and over, and you'll eventually start to repeat yourself.) An argument can only work if its premises are supported by existing, well-established knowledge, or by premises that themselves are supported by existing, well-established knowledge. An argument that attempts to support itself in mid air will always fall.
 
I know Jeff is honest because Marie insists that he is. And we can trust Marie because Rudy swears that Marie is absolutely honest. As for Rudy, well, Jeff insists that Rudy is absolutely reliable! (So the claim that Jeff is honest ultimately rests on... the claim that Jeff is honest!)

We know that astrology works because it has been validated by our best psychics. How do we know that validation by these psychics can be trusted? Simply because each of them has an astrological chart that indicates absolutely stunning psychic ability. (So astrology tells us that astrology is reliable.)

Benjamin. You should believe Rush Limbaugh is a political expert because Ben Stein says he is.
Shaylee. But is Ben Stein a good judge of political expertise?
Benjamin. Of course he's a good judge of political expertise! Rush Limbaugh says he's a genius!

Accident

The fallacy of accident, a presumption fallacy, occurs when an arguer applies a rule of thumb or general principle to a case that it clearly does not cover. He fails to recognize a valid exception to the rule. It's like equivocation because it stems from confusion (or dishonesty) about the meaning of a rule or saying, whereas equivocation stems from confusion (or dishonesty) about the meaning of a word.

Discrimination on the basis of race is wrong, so minority scholarship funds should be open to everyone.

Violence is wrong, so the cops shouldn't shoot back at that guy blazing away with an AK47.

Never draw to an inside straight, so I shouldn't draw even though my X-ray vision reveals that the cards I'd draw would fill my straight and win me that $42,000.000.00 pot.

Candidate principles:
1. You should never, never, never follow any policy that discriminates on the basis of race, no matter how morally necessary a particular such policy might be.
2. You should never use violence, even when you are being unjustly attacked in the performance of your morally necessary duties.
3. You should never draw to an inside straight, even when you know absolutely that doing so would make you an awful lot of money.

The reason for this fallacy is that people often forget that most of the rules we live by are rules of thumb rather than laws of nature. They were made up by smart people to cover situations that occur over and over again but they don't necessarily cover all possible situations. (Practice thinking up exceptions to various rules like "never play with matches," "never run with scissors" or "never eat anything bigger than your head.")

A version of this fallacy is committed by people who object to affirmative action on the basis that it is a form of discrimination. (There may be other reasons to criticize various programs of affirmative action, but I'll ignore them.) Segregation was outlawed because that it was a form of racial discrimination that caused great and long-lasting harm to all members of a segment of the American population. But it was the fact that it did unjustified, serious harm that justified banning it, not the mere fact that it was discrimination on the basis of race. Affirmative action, when properly applied, does justified and trivial harm to a few members of an otherwise generally privileged section of our society. We may criticize affirmative action for other reasons, but the mere fact that it is discrimination on the basis of race is not enough reason to ban it.

Special Pleading

The fallacy of Special Pleading is when the arguer simultaneously claims that a particular argument or standard of proof is both good and bad. It's good when he uses it, bad when you use it. (We will see special pleading again, and again, and again.)

Elron. You should worship the true god Fnorbert, and not the false god Eki-Eki-Eki-Fatang-Fatang because the followers of Eki-Eki-Eki-Fatang-Fatang base their belief on nothing but their faith that Eki-Eki-Eki-Fatang-Fatang exists, and as we all know, faith is just another word for belief, and belief by itself proves nothing.
Princess. Well, that seems to refute Eki-Eki-Eki-Fatang-Fatang, but why should I believe in Fnorbert?
Elron. If you just have faith, then you will know for certain that Fnorbert exists.

Zoomer. We can discount professor Toohey's hypothesis because it's only 92% probable according to our available data. With professor Toohey's hypothesis out of the way, we are left with my hypothesis. My hypothesis is supported to 89% probability by the available data, which means we should accept it, since it's the only hypothesis we have left.

Stinky. The great god Vuntag determines what morality is.
Potch. How ya figure?
Stinky. Well, Vuntag can condemn us to everlasting torment, so obviously what ever she says to do is the morally right thing to do.
Potch. Well, Saddam Hussein can condemn people to years of torment, does that mean that what he says to do is the morally right thing to do?
Stinky. Of course not!
Potch. But if Saddam Hussein could condemn people to everlasting torment, that would mean that what he says to do is the morally right thing to do, wouldn't it?
Stinky. Don't be stupid. Being able to inflict everlasting torment wouldn't make Saddam Hussein determine what morality is.

If faith works for Fnorbert, it works for Eki-Eki-Eki-Fatang-Fatang. If 92% is low enough to reject professor Toohey's hypothesis, 89% is low enough to reject Zoomer's hypothesis. If the ability to inflict everlasting torment wouldn't make Saddam Hussein determine what morality is, then it wouldn't make Vuntag determine what morality is.

Basically, in a presumption fallacy an arguer explicitly or implicitly assumes something logically should not be assumed. In begging the question, the arguer more-or-less assumes the very thing he is supposedly trying to prove, so something that is so close to it that it might as well be the same thing. In other types of presumption fallacy, the arguer illegitimately assumes things that would, if true, imply that his conclusion is true.

Here are some exercises to work on before you attempt the homework.

A. (Paraphrased from an actual column by Ann Coulter) It's ridiculous to say that the US government is engaged in a relentless, single-minded march towards war with Iraq, since it will be two whole years after 9/11 before we attack. (Answer)

B. Robert: I really don't see why I should believe in Vuntag, after all, there really isn't any concrete evidence of her existence.
Mary: But you are ignoring the fact that Vuntag condemns all unbelievers to an eternity of being forced to watch Dukes of Hazzard reruns! So you'd better believe in Vuntag or you will find yourself spending all of eternity having to watch Bo and Luke foil Sheriff Lobo. (Answer)

C. Elizabeth. I want to thank you for this book you gave me on voodoo. And I appreciate your attempt to help me deal with my many enemies, but I really don't see how sticking pins into little wax figurines is going to kill anyone.
David. I understand that you need some reason to believe that voodoo works. I can give you that reason. You can be sure that voodoo works, because it really is an effective way of hurting your enemies. (Answer)

D. James. We have good reason to think that the universe is deterministic. After all, all our technology, and in fact all of our attempts to accomplish anything at all always assume that each particular cause will inevitably bring about the same effect it has always done. We couldn't make any plans if we didn't assume that the universe is deterministic. Since we successfully make and carry out all kinds of plans, it follows that the universe is deterministic.
William. You're forgetting one thing. Free will. We know that determinism isn't true because we also know that we have free will. (Answer)

E. Ruskin. It seems to me that of all the Christian sects, Mormonism is the most misunderstood. I think it is somewhat unfair for the World Council of Churches to exclude the Mormon Church as non-Christian, since all the Mormons I've ever heard of treat the figure of Jesus with exactly the same significance as all the churches that the WCC does consider "Christian."
Dusty. I'm tired of hearing Mormonism described as a Christian religion. It seems that people like you are willfully ignorant about the facts of Christianity. It is easy to see that Mormonism is not a Christian religion. All you have to do is pay attention to the fact that the "Jesus" of Mormonism is not the Jesus of Christianity. Mormonism could only be a Christian religion if their Jesus was the same as Christianity's Jesus. Since he is not, they are not Christians. (Answer)

F. Reanna. The first thing you have to realize is that The Book of Vuntag is absolutely right about everything, particularly in it's claims about morality. In fact, the Book of Vuntag actually defines what morality is.
Johan. But The Book of Vuntag tells me that it is immoral for someone to be left-handed. It also tells me that everybody should persecute left-handed people until they change their ways, and torture or kill them if they don't. Left-handed people don't hurt anyone else, and they can't help being left-handed, so the Book of Vuntag has to be wrong about that.
Reanna. Much as we might regret the unfortunate necessity of persecuting left-handed people, we know that the Book of Vuntag is right about morality because Vuntag says so! And Vuntag cannot lie.
Johan. But what makes you think that Vuntag even exists? And how can you be certain that Vuntag cannot lie?
Reanna. Oh Johan, Johan, my poor foolish Johan. Don't you know that it's all written in the Book of Vuntag? (Answer)

Homework 11. Identify the weaker argument in each dialog and describe the problem with that argument, including the fallacy name if any. Make sure you include all necessary details, including the "crucial fact," and the precise way the argument goes wrong. You can do this exercise on your own lined paper, (if it doesn't have curly edges from ripping it out of a spiral notebook), or you can use Homework 11 Answer Sheet 1. Isaias. You know, you'd better start believing in Fnorbert. Joaquin. Not that again! You still haven't given me any credible reason to believe in Fnorbert. Isaias. Here's your reason. Fnorbert punishes unbelievers very harshly, so you'd better get on the right side now. Joaquin. So if he exists, and I don't believe, eventually he'll hurt me very badly? Isaias. Exactly. You've got it now! Joaquin. But you still haven't given me any reason to believe he exists, so I don't think he does. Isaias. What are you, stupid? I just gave you a heck of a good reason! Joaquin. Nope, you didn't give me any reason at all. 2. Jane. The state should legalize gay marriage, because people in committed homosexual relationships deserve exactly the same legal protections as people in committed heterosexual relationships. Welsh. You're forgetting the fact that there are only two kinds of relationships, the committed, deeply loving relationships we have between heterosexual couples, and the impoverished, purely sexual relationships that exist between homosexual couples. 3. Vaughn. I think you are finally going to be convinced about the reality of the god Vuntag. Professor Slobbert's book Footsteps of Divine Vuntag finally has the proof you're looking for. Anjali. I read that book ten years ago! It's best argument was the claim that Mat Tel, a priest of Vuntag, raised Clay Moore from the dead in the town of Punji Stick. I would have been impressed, but it wasn't documented with any evidence from Punji Stick, and so I had to discount it. Vaughn. Well, the second edition of Footsteps has the documentation you're looking for. It turns out that the people of Punji Stick put up a monument to the day that Mat Tel raised Clay More. Here's a picture of the monument. Anjali. Wow, it's a big one! And it even has a picture of Mat Tel raising Clay More. Wait, this picture looks exactly like the sketch of Mat Tel raising Clay More that Prof. Slobbert drew in his book! That's a bit of a weird coincidence, isn't it? Vaughn. Oh I can explain that. The town council decided to build the monument after they all read Professor Slobbert's book five years ago, so naturally they used the sketch from the book since no-one in the town happened to know anything about the story before they read the book. 4. Diana: I sympathize with you about Abmiel, but he's entitled to follow his own religious beliefs. Theresa: Abmiel won't marry me just because I'm a consecrated priestess of the fiery leaping goat-goddess Bloodfang and he is committed to building a christian family as part of creating the Kingdom of God on earth. That's religious discrimination, so he should marry me!

Practice for Quiz 10

Do these questions closed book, and then test yourself by looking up the answers in this chapter. Repeat until you can answer every question correctly off the top of your head.

1. In logic, is an arguer allowed to assume controversial claims as premises?

2. Can an argument that relies on ruling out alternatives to the conclusion succeed if it fails to rule out all of the alternatives to that conclusion?

3. Can a group of "authorities" succeed in certifying each other as real authorities if the only reason for thinking that any one of them is a real authority is the fact that one of the others says that he is?

4. What is a rule-of-thumb? Is a rule of thumb the same as a genuine logical (or moral) principle?

5. Is a rule-of-thumb valid in a case where the underlying justification for having the rule clearly doesn't apply?

6. Can I rationally say that some rule is a true logical principle if it's obvious that this rule would be absolutely invalid if applied outside of my argument?

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