Dave: Welcome back to Rationally Minded Podcast. Irrational or poor patterns of reasoning are called fallacies. Each week, we invite an EFL educator and expert critical thinker to discuss different kinds of fallacies that come up in our everyday lives. We also discuss how you can learn to recognize fallacies and respond to other people’s fallacious statements and arguments with common and useful English expressions. I’m David Gann and this is Rationally Minded Podcast.
Dave: Today we’re pleased to have with us, Fuad Olajuwon, an instructor in the Tokyo area. Although he has only been in Japan for a few years but he is already an active member in JALT—that is the Japan Association of Language Teaching–and as a member of the JALT Saitama prefectural chapter, has served both as Publicity Chair and now as the Program Chair. His interests include critical thinking, global issues, and politics. He is a prolific writer on political issues and a regular contributor to the Foreign Policy Project Think-tank. Good afternoon, Fuad.
Fuad: Good afternoon.
Dave: This program about fallacies, as you know, and over the course of this series we’re going to cover about thirty different fallacies. But in these several episodes we are covering fallacies that are closer to formal logic. Later, we’ll be discussing more classical fallacies, but, in order to be complete in our coverage, we really need to cover these logical ones first. So Fuad you’ve come to tell us today about Affirming the Disjunct and Denying the Conjunct. Yes?
Fuad: Yes, I understand that you covered Affirming the Consequent and Denying the Antecedent in your previous episode. Most books on logic and fallacies will follow this with Affirming the Disjunct and Denying the Conjunct. They’re very closely related, because, yeah, like you said, they both deal with form, syllogistic form. It’s okay if I use that word, syllogism?
Dave: Yes, it should be. We talked about syllogisms in the previous episode and Nick and I discuss syllogisms A LOT in Critically Minded.
Fuad: Sure, so your previous guest, Vanessa talked about the words affirm and deny?
Dave: Yes, she did that.
Fuad: And she said that affirming means to say that something is true that denying is to say something is not true.
Dave: Right. So how about these new words, disjunct and conjunct.
Fuad: Okay, well first there’s disjunct in the term affirm the disjunct. The word disjunct has two parts: dis and junct. Dis means apart or separate from or a negation or negative form of. We find dis at the beginning of many words, like disability; disbelief; discontent; dishearten; dislike; disown.
Dave: Disaster?
Fuad: Yes, and that’s a really interesting one. It comes from the 16th century Italian word disastro.
Dave: Disastro. Interesting. I think I can guess.
Fuad: Yes, well the dis means negation as we said and astro is–
Dave: That has to do with space, right? Like astrology, astronomy and astronaut.
Fuad: And the heavens, by which the Italians meant stars. And people thought that the future could be told by the stars.
Dave: Right, like astrology. So disaster, literally means bad star.
Fuad: Or an ill-omened or unlucky star.
Dave: Fascinating. Okay, so I guess we should get back to uh–
Fuad: Right, disjuncts.
Dave: So, junct
Fuad: Yes, junct is related to the word junction, the act of joining two things together, or a place where two things join.
Dave: Junction is often used to talk about a place where two roads cross.
Fuad: Or a train station where two or more lines meet. So—to affirm a disjunct means to say that Statement A or Statement B may be true. A really simple example of this is—alright—say that you watch the weather report and the Weather Reporter says: “The weather tomorrow may be windy–or it may be rainy—and so be sure to check before you leave your house tomorrow morning!”
Dave: Okay, windy or rainy.
Fuad: And so you wake up and you can hear the wind blowing outside, a strong wind howling and rattling your window. And so based on having heard the wind, you leave your apartment with no umbrella. You say, “I don’t need my umbrella because the weather report said wind or rain.” And you take the elevator down to the ground floor, step outside your apartment building and–
Dave: It’s raining.
Fuad: Right, it’s raining. Pouring down. So you’re really in a bad mood now and you have to go back up the elevator and get your umbrella and go back down and now you’ve missed your train and your whole day is getting off to a bad start.
Dave: It’s a disaster!
Fuad: Right, a disaster, except not like the Italians understood in the 16th century, because bad luck had nothing to do with it. You have no one to blame but yourself because of your own poor reasoning.
Dave: So the error in the reason is that if A is said to be true or B is said to be true, and later you find that A is true–
Fuad: That does not mean that B is not true. Likewise, if B is true, that doesn’t mean that A is also not true.
Dave: So, it was possible that although the weather forecast said that the weather might be A: windy or might be, B: rainy, it is possible that it may be both windy and rainy.
Fuad: Or rainy, but not windy. Or windy but not rainy. Any of those combinations.
Dave: Okay, I can see the poor reasoning here, but you’d have to be a complete fool not to know–
Fuad: Sure, but I was keeping it simple.
Dave: But, you know, I see a problem here. Okay, I understand cases like this where it is clear that both A and B may be true. But what about cases where it’s 100% or 99.9% certain that A and B cannot both be true at the same time and no one would think I was foolish for thinking so.
For example, I come home from a long bicycle ride. I’m hot and sweaty and I want to take a shower, but the bathroom door is locked and I can hear that someone is already taking a shower. I can also hear that someone is in the kitchen using the blender. My mother and father are in the living room watching television. So I can safely conclude that the person using the shower is my elder brother or my elder sister. It makes a difference to me because my brother usually takes very short showers, around five minutes or so, but my sister tends to stay in there for nearly thirty minutes or more.
Fuad: Given that you have an elder brother and and elder sister, yes, I would agree with your conclusion.
Dave: So I walk into the kitchen and I see that my brother is using the blender to make a sports shake. He usually drinks a sports shake after weight-training.
Fuad: I see what you’re getting at. Without thinking too hard about it you can conclude that your sister is the one taking a shower. And that, therefore, you may have to wait up to thirty minutes before you get in there. This is a real problem in logic, because there are two meanings to the word “or”. One meaning is inclusive and the other meaning is exclusive. A disjunctive statement is generally assumed to be inclusive if it is possible for both A and B to be true.
Dave: Could you say that again?
Fuad: Okay. A disjunctive statement is generally assumed to be inclusive if it is possible for both A and B to be true.
Dave: Right, and inclusive means that both possibilities are included – and excluded means that either one possibility can be true and the other is excluded.
Fuad: And in this example, we have a case of a disjunctive statement of the second kind. The exclusive.
Dave: Yes, one would certainly hope so.
Fuad: So we looked at two examples. The first, about the weather, is clearly inclusive, because, as we all know, it can rain but not be windy; or it can rain and also be windy. And the second example about who’s taking a shower is clearly exclusive, because, well, uh, in most normal families, uh, let’s just say that we hope that it is exclusive and leave it at that. But yes, there will often be cases where you cannot know whether the “or” in a disjunctive statement is inclusive or exclusive.
Dave: In that case, then, what can we do?
Fuad: Maybe the best thing you can do is simply ask, if you’re speaking to the person and if it’s a text you’re reading, just proceed cautiously and make sure other people involved have share your concern and understanding. So shall, we move onto the next fallacy then? Denying the conjunct?
Dave: Sure. Go ahead.
Fuad: To understand the language behind this term, all we need to explain here is the prefix con-. Con comes from the Latin con meaning “with” or “together”. So, if your listeners understood the first fallacy of affirming disjunction, then can they guess what it means to deny a conjunction?
Dave: Again, the word “deny” means to say that something is not true. And conjunction must mean . . . together, or true, at the same place and time?
Fuad: Right, so in short we might say that denying a conjunct means to say that two things must not both be true.
Dave: Fuad, I’ve got a real problem understanding the difference affirming a disjunct and denying a conjunct. They sound very similar. But isn’t saying “This or That” and saying “Not This and That basically the same thing?
Fuad: Just remember that each of those is just the first line in a three-line syllogism. You have to look at each line of reason from beginning to end. So let’s look at the first one, affirming a disjunct:
This OR That.
This.
Therefore, not that.
Now look at denying the conjunct:
NOT This and That.
Not This.
Therefore, That.
Fuad: Right, so in short we might say that denying a conjunct means to say that two things must not both be true. So if one’s not true, then the other must be true. Does that help to understand?
Dave: Yes, it helps a lot and you explained that very clearly. I think this kind of fallacy can occur during a criminal investigation. Or, say an armed robbery is committed at a liquor store during the evening of April 1st and a witness identifies John Smith as the person who did the crime. But John Smith says, I couldn’t have been at the scene of the crime, because I was with my friend Tom Jones. So the police speak to Tom Jones and Tom Jones says, “Yes, that’s right. John Smith was with me the night of the crime. Later, the police find the gun used in the crime was accidentally dropped as the robber was running away with the money. They check the gun for fingerprints and they find the fingerprints are those of a man named Frank Harris. So what do the police conclude about where John Smith was the night of the robbery?
Fuad: Well if they are inexperienced and are not good critical thinkers, they are going to conclude that Harris was with Tom Jones.
Dave: But then the police find that Tom Jones’ ex-wife Linda Kirby, who lived in a nearby town has been found shot to death and forensics determines that she was murdered on the same night as the robbery. They check the scene of the crime for evidence and they find fingerprints belonging to . . .
Fuad: John Smith?
Dave: Yeah, John Smith. As it turns out, Tom Jones paid his friend, John Smith, to kill Linda Kirby so that he could get his children back.
Fuad: Wow! So, the fallacy: NOT the liquor store and Tom Jones’ house . . . Not the liquor store . . . Therefore, Tom Jones’ house . . . turns out to be fallacious and poor reasoning. And almost allowed a murderer to go free.
Dave: And that’s why we hope that our police are good students of critical thinking. Don’t you think?
Fuad: Absolutely.
Dave: Well okay, it’s now time for Name That Fallacy! In this part of the show we present you, our listeners, with dialogues, and challenge you to match each example dialogue to the correct fallacy. Lastly, we tell you how you can respond to fallacies, using some easy English. Are you ready, Fuad?.
Fuad: Let’s have it.
Dave: Excellent. So here is the first dialogue:
—-
[A woman has taken her computer to the shop to have the staff look at a technical problem].
Woman: So have you found the problem?
Shop staff: Yes, well almost.
Woman: Almost?
Shop staff: Yes, ma’am. There can be a lot of reasons for this kind of problem, but the two most likely sources of trouble are a flawed video card or your computer has a virus.
Woman: A computer virus? We don’t even have Internet on this computer.
Shop staff: Yes, well. An infected file from a USB drive could also transfer a virus and in fact, ma’am, the anti-virus software has detected a virus that causes this kind of problem.
Woman: Oh great, then I guess, ‘problem solved’ right? You guys can clean out the bug and—how long will it take? Can I pick it up later today?
Shop staff: Well, you could, but I’d recommend that you let us run more tests. It is possible that, in addition to the virus, you might also have a faulty video card.
—-
Dave: Alright, Fuad, I think our listeners probably have a good idea about what kind of fallacy this is but can you tell us . . . the answer is . . .
Fuad: Affirming the disjunct. The woman seems to think the computer can only have one problem or the other, but there is no reason why the computer could not have both problems or even one of the other less likely problems as well.
Dave: Her computer could be ALL MESSED UP.
Fuad: You’re right. It could be All Kinds of Messed Up.
Dave: Alright then, let’s go straight into the next dialogue.
—-
[John is out with his friend Craig, who has just won the lottery.]
John: Well, old friend. What a lucky thing for you, winning the lottery. It won’t be easy thinking of ways to spend all that money.
Craig: Yes, I am very lucky! Just a month ago, I was voted employee of the month; and now I’ve won 20 million dollars buying a lottery ticket!
John: Well, it is getting late; and I think this restaurant is about to close.
Craig: Yeah. It was a great idea coming to this high class French restaurant – and the wine was excellent! But you’re right. We’d better get the bill and pay up.
John: Pay up?
Craig: I hope you can afford it! Let’s see. That should be about 175 dollars each.
John: A hundred and seventy-five dollars? I didn’t even bring any money tonight.
Craig: You didn’t bring any money? Why on earth not? I hope you don’t expect me to pay for you, just because I won the lottery.
John: Craig, last year, you said, “You will know I’ve won the lottery, when I pay your half of the bill.” And yesterday you won the lottery, so I thought that –
Craig: Well, you thought wrong! Your poor reasoning skills have led your making a fool of yourself and ruin tonight’s celebration of my becoming rich.
—-
Dave: Fuad, could you comment on this?
Fuad: Yes, what an interesting turn of events. And I don’t particularly like this Craig fellow. He’s a little self-centered and not the kind of person I’d like to spend my time with. As for the argument itself, that is, the argument that John is making; this is a case of affirming the consequent, but it’s not so easy to see that because the way the speaker expresses it, the consequent, “I’ve won the lottery,” comes first, and the antecedent, “I pay your half of the bill,” comes last. The statement, “You will know I’ve won the lottery, when I pay your half of the bill,” and the statement “When I pay your half of the bill, you will know I’ve won the lottery,” are ordered differently, but they mean exactly the same thing.
Dave: Right. In the first case, you find these statements ordered consequent-first, and antecedent-last. And in the second case it’s ordered antecedent-first, and consequent-last, but the logical relation between cause and effect is the same in both statements. Okay, shall we go on?
Fuad: Sure.
Dave: The next one could be Denying the Antecedent, from our previous episode or Denying the Conjunct from this episode. Listeners, which will it be?
—-
[At the English-only sports gym, a coach is giving some advice about physical training.]
Student: So, coach, what you’re saying is that if I overeat all the time, over the next ten or fifteen years, I’ll get fat.
Coach: Yes, that’s what will happen.
Student: Okay, well then, I’m not going to overeat. That way, I’m guaranteed not to get fat.
Coach: Well hold on! Wait a minute! I didn’t say that. There are a lot of ways you could get fat without overeating. You could sit around watching sports on T.V., drinking beer and getting no exercise. That can make you fat too.
—-
Fuad: Nice try, David, but you can’t fool me. This is from the previous episode that you did with Vanessa Armand. And that’d be, as you said Denying the Antecedent. So you had two dialogues based on fallacies from the previous episode and only one from this one. Very tricky.
Dave: Yes, well, apparently, not tricky enough for you. But you’re right, we did only do one dialogue from today’s lesson, but not to worry, listeners, because there’s going to be a special “Point Two” episode coming up that will quiz you on all four fallacies from last episode and the ones before. As well as a new fallacy called The Undistributed Middle; and that is all coming up next time, so I’d like to say one more time, thank you so much Fuad Olajuwon for being with us today.
Fuad: Thank you for having me.
Dave: And that’s all for this episode. So, listeners, watch your step, don’t FALL for any FALLacies, and until next time this has been Rationally Minded Podcast.