1 00:00:00,580 --> 00:00:06,010 OK, here we are at week six. The very last week of our course this week, we're going to have a bit of a romp. 2 00:00:06,010 --> 00:00:13,960 We're going to start looking at phalluses. Fallacies are bad arguments that look like good arguments and can easily be confused for them. 3 00:00:13,960 --> 00:00:19,570 OK, let's get started. Just a recap of last week, as always. 4 00:00:19,570 --> 00:00:27,970 If you remember, we looked at what makes a deductive argument sound. And we looked at what makes such an argument valid. 5 00:00:27,970 --> 00:00:37,570 So just a quick reminder for you. Would the argument be sound in this situation where it's valid but it has false premises? 6 00:00:37,570 --> 00:00:44,860 Put your hands up if you think that sound. So it's a valid argument, but false premises. 7 00:00:44,860 --> 00:00:51,580 OK. What about if it's an invalid argument with false premises? 8 00:00:51,580 --> 00:01:00,230 OK. What, Walter, it's an invalid argument with true premises. And a valid argument with true premises. 9 00:01:00,230 --> 00:01:09,950 Okay, good. Well done. It's only sound if it's a valid argument and it has two premises at it all, its premises must be true and it's valid. 10 00:01:09,950 --> 00:01:13,790 Well done. OK. Now, here's the tricky one. OK. 11 00:01:13,790 --> 00:01:22,160 The question is, could the argument be valid when it's got false premises and a false conclusion? 12 00:01:22,160 --> 00:01:28,550 It could be valid. Well done. Could it be invalid? Well done, good. 13 00:01:28,550 --> 00:01:33,320 Okay. What if it has false premises and a true conclusion? Could it be valid? 14 00:01:33,320 --> 00:01:40,780 Put your hand up this time. Could it be valid if it has false premises and the true conclusion? 15 00:01:40,780 --> 00:01:45,550 Could it be valid? OK. 16 00:01:45,550 --> 00:01:50,770 Those few without your hands up. Is that because you don't know? Okay. 17 00:01:50,770 --> 00:01:56,320 What about if it's got true promise isn't a true conclusion. Could it be valid then. 18 00:01:56,320 --> 00:02:04,180 Okay. Could it be invalid then. Oh yes, it could be. 19 00:02:04,180 --> 00:02:09,250 Okay. There is only one situation in which it couldn't be valid. 20 00:02:09,250 --> 00:02:14,920 Only one situation which it couldn't be valid. And that's this one. 21 00:02:14,920 --> 00:02:20,440 If it's got through premises and a false conclusion, it couldn't be valid. 22 00:02:20,440 --> 00:02:29,470 Otherwise it could be it could be either valid or invalid. And the reason for that is because an argument is valid. 23 00:02:29,470 --> 00:02:37,180 If and only if there's no possible situation in which all the premises are true and its conclusion false. 24 00:02:37,180 --> 00:02:47,110 So it's a sufficient condition for an argument being valid that it there's no possible situation in which its premises are true, in conclusion, false. 25 00:02:47,110 --> 00:02:53,530 And that's a necessary condition, too. And if you remember, I said to you last week that two things you've got to remember. 26 00:02:53,530 --> 00:03:00,670 One is that it's the possibility, not the actuality of the combination of true premises and false conclusion. 27 00:03:00,670 --> 00:03:07,040 That's important. And the other is it's the combination of true premises and false conclusion. 28 00:03:07,040 --> 00:03:12,100 That's important. Okay, I gave you another test. 29 00:03:12,100 --> 00:03:17,770 So if that was one test of validity and the other test I gave you is that an argument is valid. 30 00:03:17,770 --> 00:03:28,990 If an only if it's counter example set is consistent and the example set is the sets consisting of the premises plus the negation of the conclusion. 31 00:03:28,990 --> 00:03:32,650 So if you have if it's Friday, Marianne's wearing jeans. 32 00:03:32,650 --> 00:03:37,240 It is Friday. Therefore, Marianne's wearing jeans. That's an argument. 33 00:03:37,240 --> 00:03:42,010 An argument. If you take the conclusion Marianne's wearing jeans and negate it. 34 00:03:42,010 --> 00:03:50,830 So you've got it's not the case that Marianne's wearing jeans. The counterexamples set then becomes if it's Friday, Marianne's wearing jeans. 35 00:03:50,830 --> 00:03:57,040 Marianne Wear is wearing jeans. It's not the case. 36 00:03:57,040 --> 00:04:03,190 It's not what the premises inclusion on it is Friday. 37 00:04:03,190 --> 00:04:07,210 It's not the case that Marianne's wearing jeans. That's the counterexample set. 38 00:04:07,210 --> 00:04:12,340 Now, listen, again, is that consistent? Could all these sentences be true together? 39 00:04:12,340 --> 00:04:16,870 If it's Friday? Marianne's wearing jeans. It is Friday. 40 00:04:16,870 --> 00:04:24,460 It's not the case that Marianne's wearing jeans. Could those be true together? 41 00:04:24,460 --> 00:04:29,530 They couldn't. Could they? And that shows that the original argument is valid. 42 00:04:29,530 --> 00:04:34,000 It shows there is no possible situation where the premises are true. 43 00:04:34,000 --> 00:04:43,480 And the conclusion is false because the set consisting of the premises and the negation of the conclusion is inconsistent. 44 00:04:43,480 --> 00:04:47,860 In other words, there is no possible situation where they're all true together. 45 00:04:47,860 --> 00:04:51,370 That's why that test works well. So. Okay. 46 00:04:51,370 --> 00:04:55,630 And I said to though, to test you will have understood the concept of validity. 47 00:04:55,630 --> 00:05:02,260 Once you've understood, firstly, the paradoxes of entailment. And secondly, why this works. 48 00:05:02,260 --> 00:05:05,380 If you understand why this works. You're getting there. 49 00:05:05,380 --> 00:05:12,450 If you understand why the paradoxes of entailment are valid arguments, you will see why you've. 50 00:05:12,450 --> 00:05:15,940 You'll have understood the concept of validity. Okay. 51 00:05:15,940 --> 00:05:19,780 I can see there's still people worrying about the concept of validity. 52 00:05:19,780 --> 00:05:24,690 But only if there is time for questions. We'll have a look at the questions that you might have then. 53 00:05:24,690 --> 00:05:29,740 But we must go on today. I'm afraid so. We'll move straight on. 54 00:05:29,740 --> 00:05:33,540 This week we're going to be looking at common fallacies. 55 00:05:33,540 --> 00:05:40,120 And a fallacy is an argument that looks like a good argument can easily, easily be mistaken for a good argument. 56 00:05:40,120 --> 00:05:43,540 But that isn't a good argument. 57 00:05:43,540 --> 00:05:51,250 And you won't believe how many fallacies there are, fallacies that you can just identify and explain why their fallacies, 58 00:05:51,250 --> 00:05:58,360 why they look as if they're good arguments and they're not. But I've listed a whole load of fallacies. 59 00:05:58,360 --> 00:06:06,340 I've I've taken the form of a Web site that I've mentioned on the top and that there are I think they're four pages or something of fallacies all in. 60 00:06:06,340 --> 00:06:13,230 I apologise for the smallness of the print, but they wouldn't have let me photocopy it if I'd put it any larger. 61 00:06:13,230 --> 00:06:17,990 And I'd just like to point out the top one fallacy is now I've got my glasses on. 62 00:06:17,990 --> 00:06:26,530 So it says something like, please note that the argument from fast talking on page eight. 63 00:06:26,530 --> 00:06:30,520 That tells you that if somebody talks fast, 64 00:06:30,520 --> 00:06:36,310 you haven't got a chance to work out for yourself whether the premises are true and the conclusion is valid. 65 00:06:36,310 --> 00:06:39,250 And I'd just like to point out that I've gone through these ideas in these 66 00:06:39,250 --> 00:06:44,520 lectures so quickly in some cases that there's no way you'll have had time to. 67 00:06:44,520 --> 00:06:47,940 Stop and think about them as I've been talking, 68 00:06:47,940 --> 00:06:56,010 and so you could say that the whole of these series of lectures has been a giant fallacy of fast talking. 69 00:06:56,010 --> 00:07:02,280 I promise you it's not. And that if you go back and consider what I've said and of course, they'll all be on the podcast, 70 00:07:02,280 --> 00:07:06,300 so you'll be able to actually go back and listen to what I've said again. 71 00:07:06,300 --> 00:07:10,690 You'll be able to listen to all my mistakes as well as the things I've said correctly. 72 00:07:10,690 --> 00:07:14,540 I hope we've identified all my mistakes as we've gone through. 73 00:07:14,540 --> 00:07:20,790 But but that'll give you time to actually think about what I've said and work it out for yourself is actually. 74 00:07:20,790 --> 00:07:26,880 Nobody can teach anybody else anything. You can learn from what I say. 75 00:07:26,880 --> 00:07:30,510 There's nothing I can do to make you understand the concept of validity. 76 00:07:30,510 --> 00:07:37,440 You've got to put that effort in for yourself. One thing I will promise you, though, if you do put that effort in, you will understand. 77 00:07:37,440 --> 00:07:39,870 And if you still don't, after putting in a lot of effort. 78 00:07:39,870 --> 00:07:47,880 Email me and I'll give you a tutorial all on your own, because it really is easy to understand once you've seen it. 79 00:07:47,880 --> 00:07:52,610 And it really is just a question of looking at it in a slightly different way. 80 00:07:52,610 --> 00:07:59,410 And I and you'll see it. It's it's one of those rather irritating things you'll probably remember from maths, from school. 81 00:07:59,410 --> 00:08:04,680 Okay. So fallacy of fast talking. But the list of fallacies is down there. 82 00:08:04,680 --> 00:08:08,820 Just for your amusement. Okay. 83 00:08:08,820 --> 00:08:12,990 Here's a fallacy or rather his deductively valid argument. 84 00:08:12,990 --> 00:08:20,970 And here's a fallacy that looks like it. Okay. Here's an example of modest pronouns you come across before. 85 00:08:20,970 --> 00:08:32,050 I think you'll agree. Could these be true and this one false? If these two are true, could this be false? 86 00:08:32,050 --> 00:08:33,400 No, absolutely not. 87 00:08:33,400 --> 00:08:43,330 So if you negated that conclusion and took away the therefore, if you negated that conclusion, the set would be inconsistent, wouldn't it? 88 00:08:43,330 --> 00:08:48,370 And that shows you it's a valid argument. Would you like us to do that there? 89 00:08:48,370 --> 00:09:03,100 We can look at this counterexamples set. If it is snowing, the mail will be late. 90 00:09:03,100 --> 00:09:11,920 It is snowing. The mail will be late. 91 00:09:11,920 --> 00:09:17,160 And we're going to tack on it's not the case that which is just that symbol there. 92 00:09:17,160 --> 00:09:25,000 OK. That's what that means. It is not the case that so we've got the set consisting of if it's snowing, the mail will be late. 93 00:09:25,000 --> 00:09:28,690 It is snowing. It's not the case. The mail will be late. 94 00:09:28,690 --> 00:09:38,700 Do you agree that's inconsistent, that there is no possible situation in which all those three sentences can be true together? 95 00:09:38,700 --> 00:09:45,690 Okay, well, if there's no possible situation in which those three sentences can be true together, 96 00:09:45,690 --> 00:09:55,140 then the set consisting of the premises plus the sorry, there is no possible situation where the premises are true and the conclusion is false. 97 00:09:55,140 --> 00:09:59,610 Is that because that's what the counterexample says is the truth? 98 00:09:59,610 --> 00:10:04,930 The premises, just as they are and the negation of the conclusion. OK. 99 00:10:04,930 --> 00:10:10,150 That's why that test works. But look at this one. If it's snowing, the mail will be late. 100 00:10:10,150 --> 00:10:16,210 The mail will be late. Therefore, it's snowing. Let's create the counterexamples set of that. 101 00:10:16,210 --> 00:10:28,500 So tell me what to write. Somebody. If it's snowing, the male. 102 00:10:28,500 --> 00:10:38,670 We'll be late. What do I write next? The mail will be late. 103 00:10:38,670 --> 00:10:42,480 No, we do not put the therefore in because we're creating the counterexample set now. 104 00:10:42,480 --> 00:10:48,720 We're just making a set of sentences. So I'm putting it is snowing. And then what do I do? 105 00:10:48,720 --> 00:10:52,950 I put the negation sign in front of that and say it's not the case. 106 00:10:52,950 --> 00:10:58,740 It's no. So we've now got the set consisting of the premises just as they are. 107 00:10:58,740 --> 00:11:05,370 Plus, we're pretending the conclusion is false. OK, we're putting and not the case in front of the conclusion. 108 00:11:05,370 --> 00:11:11,910 Pretending it's false now is that it could these sentences be true together? 109 00:11:11,910 --> 00:11:16,260 Is there a possible situation in which all these sentences are true? 110 00:11:16,260 --> 00:11:23,230 Where if it's snowing, the mail will be late. The mail is late, but it's not snowing. 111 00:11:23,230 --> 00:11:27,570 Yes. OK. Give me a couple. The postal strike. 112 00:11:27,570 --> 00:11:34,440 Yes, exactly, so. OK. Give me another one. If you can think of one. 113 00:11:34,440 --> 00:11:40,680 The male van's broken down. Exactly. So there are all sorts of situations in which these two premises are true. 114 00:11:40,680 --> 00:11:48,660 And so is the negation of the conclusion. Therefore, it's obvious there's more than one possible situation in which the premises are true. 115 00:11:48,660 --> 00:11:58,320 And the conclusion is false. So making a counterexample set enables you to think about situations where the premises are true. 116 00:11:58,320 --> 00:12:04,650 And the conclusion is false. And that's why it tells you whether the argument is valid or not. 117 00:12:04,650 --> 00:12:08,880 So this is a deductively valid argument and this is a fallacy. 118 00:12:08,880 --> 00:12:13,500 This is the fallacy of affirming the consequence. So if you like, 119 00:12:13,500 --> 00:12:20,160 you take the consequence of the conditional instead of the antecedent and you put 120 00:12:20,160 --> 00:12:25,560 that as the second premise and then derive the antecedent instead of the consequent. 121 00:12:25,560 --> 00:12:30,660 It doesn't work, as you can see. Okay, so that's a formal fallacy. 122 00:12:30,660 --> 00:12:37,770 And we're going to look at fallacies informally and some of the fallacies that we'll look at are actually formal fallacies. 123 00:12:37,770 --> 00:12:42,960 But I'll talk about them informally because it's it's just as easy for you to understand. 124 00:12:42,960 --> 00:12:46,020 Okay. We're going to have a look at three types of fallacy. 125 00:12:46,020 --> 00:12:52,950 We're going to look at fallacies of relevance, parliament, fallacies of vacuity and fallacies of clarity. 126 00:12:52,950 --> 00:12:59,790 And even then, we're just skimming the surface. Okay, so let's look at fallacies of relevance. 127 00:12:59,790 --> 00:13:02,380 The first one is a non sequitur. 128 00:13:02,380 --> 00:13:14,430 And you you commit a fallacy of non sequitur when you cite in support of a conclusion, something that's true but irrelevant. 129 00:13:14,430 --> 00:13:18,840 Okay. So you cite in support of a conclusive one of your premises. 130 00:13:18,840 --> 00:13:25,200 It's true. So that's fine. But it's irrelevant to the conclusion now. 131 00:13:25,200 --> 00:13:28,920 You might be a bit worried about this, but let me just give you an example of non sequiturs. 132 00:13:28,920 --> 00:13:33,270 That will be obviously non sequiturs. Bill lives in a large building. 133 00:13:33,270 --> 00:13:43,300 Therefore, his apartment is large. OK. Is there any situation in which this premise is true and this conclusion false? 134 00:13:43,300 --> 00:13:50,890 Hundreds of. Yeah. I mean, he may live in a large apartment, large building, but his apartment may maybe no bigger than a broom cupboard. 135 00:13:50,890 --> 00:14:00,460 But it's so you can see that that isn't a valid argument. And the reason it isn't is because the premise doesn't matter how true the premises. 136 00:14:00,460 --> 00:14:07,810 It's completely irrelevant to the conclusion, isn't it? You cannot derive the truth of the conclusion from the truth of that premise. 137 00:14:07,810 --> 00:14:13,440 Now, I can imagine that you're thinking, well, what about those paradoxes of entailment then? 138 00:14:13,440 --> 00:14:23,210 You surely that was a case, a paradigm Mattick case of irrelevance. 139 00:14:23,210 --> 00:14:29,240 You remember I had grass is green. 140 00:14:29,240 --> 00:14:34,650 Therefore, two plus two equals four. 141 00:14:34,650 --> 00:14:40,410 OK, now, surely that premise is irrelevant to the conclusion. 142 00:14:40,410 --> 00:14:49,950 But let me ask again. Is there any possible situation in which that premise is true and that conclusion is false? 143 00:14:49,950 --> 00:14:57,810 Is that any possible situation? Let me ask again in which that premise is true and that conclusion false. 144 00:14:57,810 --> 00:15:05,580 Why not? You're right. There isn't. But why isn't the. We saw here that this premise can be true and that conclusion false. 145 00:15:05,580 --> 00:15:11,910 Can't we? That's that's not a problem. That is a non sequitur. Commits the fallacy of irrelevance. 146 00:15:11,910 --> 00:15:20,750 But what why it doesn't this one do that? That's all I got us. 147 00:15:20,750 --> 00:15:27,130 The conclusion is dependent on the. Well, no, there's not one. 148 00:15:27,130 --> 00:15:33,310 I mean, that's that's what's wrong with this one is that the premise and the conclusion are completely irrelevant to each other, aren't they? 149 00:15:33,310 --> 00:15:40,300 So so why isn't that a problem with this one? The conclusion is necessarily true. 150 00:15:40,300 --> 00:15:48,040 That's right. So so the reason this is a paradox is that the premise is completely irrelevant to the conclusion, 151 00:15:48,040 --> 00:15:57,340 but it satisfies the definition of validity because there can't be any possible situation in which the premise is true and the conclusion false. 152 00:15:57,340 --> 00:16:07,780 If there isn't any possible situation in which the conclusion is false. How can P and Q be true if Q isn't true? 153 00:16:07,780 --> 00:16:13,000 If CU is necessarily false, then how can P and Q be true? 154 00:16:13,000 --> 00:16:17,380 The truth of P just becomes irrelevant, doesn't it? 155 00:16:17,380 --> 00:16:21,640 The truth appears is just unnecessary to the whole claim. 156 00:16:21,640 --> 00:16:26,640 Are you with me? I'm I'm seeing light sort of going on here, but it's difficult, isn't it? 157 00:16:26,640 --> 00:16:34,540 Okay, so this commits the. This is a non sequitur, whereas that's not that's a case of of of a paradox, of entailment. 158 00:16:34,540 --> 00:16:38,950 And the difference between them is that two plus two equals four is a necessary truth. 159 00:16:38,950 --> 00:16:43,750 It cannot be false. So how could the premise be true? And the conclusion false. 160 00:16:43,750 --> 00:16:49,930 But if it can't be the case that the premise is true and the conclusion false, then it satisfies the definition of validity. 161 00:16:49,930 --> 00:16:54,220 Whereas this doesn't. OK, here's another non sequitur. 162 00:16:54,220 --> 00:16:58,450 Every year many people are supported through like life by their religious beliefs. 163 00:16:58,450 --> 00:17:06,970 Therefore, their religious beliefs must be true. OK. Does that premise give any support at all to that conclusion? 164 00:17:06,970 --> 00:17:11,680 No, I mean, perhaps your religious beliefs really do help you live a good life. 165 00:17:11,680 --> 00:17:18,760 Live a life that's satisfying to you, too. That doesn't necessarily mean they're true because false beliefs. 166 00:17:18,760 --> 00:17:24,640 If you believe false beliefs are true, they're going to give you everything that they would give you if they were true. 167 00:17:24,640 --> 00:17:26,470 If you see what I mean. OK. 168 00:17:26,470 --> 00:17:37,270 So those are two non sequiturs and we can see why a non sequitur is an invalid argument, that there's easily a possible situation, which. 169 00:17:37,270 --> 00:17:45,790 That's true and that's false. Therefore, it's not valid. Again, the truth of that bears no relation to the truth of that. 170 00:17:45,790 --> 00:17:52,800 So, again, the two arguments are not valid. Okay, what how to arguments like this work? 171 00:17:52,800 --> 00:17:56,820 I mean, one of the things we've got to work for ever falling for fallacies. 172 00:17:56,820 --> 00:18:00,000 I mean, we we argue incorrectly. 173 00:18:00,000 --> 00:18:08,750 We either make fallacies, we argue fallacious ourselves, or we fall for the flat fallacies that other people offer us. 174 00:18:08,750 --> 00:18:11,640 How do I talk to you about the principle of charity? 175 00:18:11,640 --> 00:18:20,880 The principle of charity tells you that your interlocutor's silliness is less likely than your bad interpretation. 176 00:18:20,880 --> 00:18:30,590 Okay. What does that mean? Okay. What's your name? I just think if the lady in front with a nice necklace, you've probably got a nice necklace too. 177 00:18:30,590 --> 00:18:39,800 Okay. Margaret. Margaret and I are arguing. Margaret said something that I think is blindingly obviously stupid. 178 00:18:39,800 --> 00:18:45,240 Okay. Now I've got two possibilities. I can think Margaret's just said something blindingly, obviously stupid. 179 00:18:45,240 --> 00:18:55,410 I'm not going to talk to her anymore. You know, she's obviously not worth talking to because she said not P, whereas surely pee is obvious. 180 00:18:55,410 --> 00:19:01,530 Now, what the principle of charity tells me to do in that case is to say, well, that's interesting. 181 00:19:01,530 --> 00:19:06,690 Margaret says, not P? I think not P is definitely false. 182 00:19:06,690 --> 00:19:15,690 Therefore, I must have misunderstood Margaret because her silliness is far less likely than my misunderstanding. 183 00:19:15,690 --> 00:19:23,240 Her argument. Are you with me? Okay. So instead of saying to Margaret, you must be joking. 184 00:19:23,240 --> 00:19:27,980 Oh, stupid. Can you get. Or anything like that. Or just saying to myself how. 185 00:19:27,980 --> 00:19:31,390 Right. Okay. Thanks, Margaret. Nice to see you, etc. 186 00:19:31,390 --> 00:19:36,420 I'm walking off. I say to Margaret. That's interesting. You think not pee? 187 00:19:36,420 --> 00:19:42,500 I think pee. Why do you think not pee? And you give me your reasons and I give you read my reasons for thinking appear. 188 00:19:42,500 --> 00:19:49,310 And we have a proper argument. We discover actually that pee and not pee are not in this case inconsistent. 189 00:19:49,310 --> 00:19:55,560 That we've both got a slight misunderstanding. Let me give you an example. I don't know why use this example, but I always do. 190 00:19:55,560 --> 00:20:01,830 So I'm going to do it again to rats in a cage. They both come from different cages. 191 00:20:01,830 --> 00:20:09,450 And in one of those cages, one of the rats was given an electric shock every time a certain sound was made. 192 00:20:09,450 --> 00:20:15,000 The same sound was resulted in the other rats being given a food pellet. 193 00:20:15,000 --> 00:20:21,210 Okay, so the experiments are finished. They've now been put in the same cage and this sound happens. 194 00:20:21,210 --> 00:20:27,330 Sounds. Sounds. Now, what's going to happen? One rat is going to rush, shaking into the corner of the cage, waiting for an electric shock. 195 00:20:27,330 --> 00:20:33,060 And the other rat is going to be rushing up to the food bowl looking for food. Isn't it okay? 196 00:20:33,060 --> 00:20:40,170 And then they look at each other and think, you're mad. You know, why have you done that? 197 00:20:40,170 --> 00:20:44,670 What they if they were talking to this, I don't know. I and some I used this example. 198 00:20:44,670 --> 00:20:51,960 If they were able to talk to each other, they would then discover that actually they both overgeneralise, too, didn't they? 199 00:20:51,960 --> 00:20:56,850 Because one's experience was that whenever that this and the other's experience was 200 00:20:56,850 --> 00:21:03,030 whenever that that they assumed that's all they experienced there was in the world. 201 00:21:03,030 --> 00:21:09,210 And in fact, they've now got two counterexamples. That one is there in a cage where the sound goes off, nothing happens. 202 00:21:09,210 --> 00:21:14,670 And the other is that there are places in the world where something completely different happens, 203 00:21:14,670 --> 00:21:19,530 and it's only if they talk about it that they'll discover that. 204 00:21:19,530 --> 00:21:26,580 So arguing is the life blood of of cooperating in the search for truth. 205 00:21:26,580 --> 00:21:31,440 If you want to know what the truth is, you cooperate with other rational animals. 206 00:21:31,440 --> 00:21:38,490 In other words, other people like us. And if you find that there's a constant contradiction. 207 00:21:38,490 --> 00:21:45,930 Don't assume that the other person is wrong, because the only rational thing to assume is that one of you is wrong. 208 00:21:45,930 --> 00:21:49,470 And even that might be false. But it certainly might be you. 209 00:21:49,470 --> 00:21:56,520 And it's the principle of charity that you observe when you argue in order not to do the irrational 210 00:21:56,520 --> 00:22:02,790 thing and to assume that the other person is wrong rather than assume that you've misunderstood them. 211 00:22:02,790 --> 00:22:10,230 So that's what the principle of charity is. And what happens in this case and in the case of non sequiturs is that the principle of charity 212 00:22:10,230 --> 00:22:17,730 can take you get you into the wrong place because you might not notice the irrelevance. 213 00:22:17,730 --> 00:22:22,110 I mean, that that can happen if, for example, large apartment, large building, 214 00:22:22,110 --> 00:22:27,600 you might think the two large is there is enough to make it relevant and you'll let the argument go through. 215 00:22:27,600 --> 00:22:37,000 You wouldn't be right to do that. But it maybe is understandable. But sometimes when people are arguing, you might think, well, hang on. 216 00:22:37,000 --> 00:22:40,000 I'm sure that was irrelevant, but it can't have been because, you know, 217 00:22:40,000 --> 00:22:45,310 Margaret's too rational for it to allow and the relevance to go through non sequitur like that, 218 00:22:45,310 --> 00:22:50,500 or you might just want to not be not admit that you can't see the connexion. 219 00:22:50,500 --> 00:22:57,370 So the thing to do is to be aware that there should be an interest in any conversation. 220 00:22:57,370 --> 00:23:03,340 The implication is that there's a connexion between premises and conclusion, like the sea is salts. 221 00:23:03,340 --> 00:23:09,100 Melbourne's in Australia. When I gave you the context, you could see the connexion. 222 00:23:09,100 --> 00:23:15,700 So if you can't see the connexion, ask for it. So don't be too generous. 223 00:23:15,700 --> 00:23:22,900 Because it's possible that this person is putting forward a non sequitur and certainly don't be too proud to ask for the relevance. 224 00:23:22,900 --> 00:23:27,370 If you can't see it. Okay. Here's an ad. 225 00:23:27,370 --> 00:23:32,260 So this is the second fallacy of relevance. 226 00:23:32,260 --> 00:23:37,420 So the second one is attacking the person is the second one we're looking at. There are many more than this. 227 00:23:37,420 --> 00:23:42,100 You might attack the person making the arguments rather than the argument that's made. 228 00:23:42,100 --> 00:23:53,420 And this is called an ad hominem fallacy. And you may have heard it was it's Miliband. 229 00:23:53,420 --> 00:24:00,620 On the Today programme the other day talking. Now, who was he talking to, talking to William Hague. 230 00:24:00,620 --> 00:24:04,100 And he accused William Hague of an ad hominem fallacy. 231 00:24:04,100 --> 00:24:12,950 He said, you're arguing against the man, not against the arguments on your your stopping the man, not the ball or something. 232 00:24:12,950 --> 00:24:18,530 He said it was a very good example. OK. Here's an ad hominem fallacy. 233 00:24:18,530 --> 00:24:25,310 Nick Griffin is leader of the BNP. Therefore, his claim that some people worry about immigration is rubbish. 234 00:24:25,310 --> 00:24:30,350 Now, I actually heard that fallacy loud and clear the other night on Question Time. 235 00:24:30,350 --> 00:24:42,020 I'm sure you did, too. Does the truth of the fact that Nick Griffin is leader of the BNP bear at all on the claim? 236 00:24:42,020 --> 00:24:47,230 The truth of the claim that some people worry about immigration. 237 00:24:47,230 --> 00:24:52,490 And it could it be the case that Nick Griffin is leader of the BNP and some people worry about it? 238 00:24:52,490 --> 00:24:56,550 Immigration. Course it could. Couldn't it? 239 00:24:56,550 --> 00:25:00,590 Yes. OK. Here's another one, Von Duncan, that you may not even remember him. 240 00:25:00,590 --> 00:25:07,010 He was the chap who wrote books about people coming from space and building the pyramids and so on. 241 00:25:07,010 --> 00:25:12,420 His books about ancient astronauts are worthless because he's a convicted forger and embezzler. 242 00:25:12,420 --> 00:25:18,780 Now he is actually a convicted for forger, an embezzler. Does that mean that his books are worthless? 243 00:25:18,780 --> 00:25:26,160 OK. So could this premise be true and this conclusion false? 244 00:25:26,160 --> 00:25:34,940 Yes. Could this premise be true? The conclusion false. So the arguments he uses, aren't they, they're both invalid. 245 00:25:34,940 --> 00:25:38,720 There are possible situations in which the premise is true, inclusion, false. 246 00:25:38,720 --> 00:25:40,970 They're not good arguments. 247 00:25:40,970 --> 00:25:50,120 Now, it's very important when thinking about ad hominem fallacies to distinguish between ad hominem attacks and ad hominem fallacies. 248 00:25:50,120 --> 00:25:55,130 And the difference between the two is this. You can attack somebody is right to say something. 249 00:25:55,130 --> 00:26:04,570 So you can cast doubt on on why they're saying what they're saying by saying something about who they are. 250 00:26:04,570 --> 00:26:09,230 And what you can't do is cast doubt on the truth of what they're saying. 251 00:26:09,230 --> 00:26:14,420 So here's a different. The difference between the two. Here's an ad hominem attack. 252 00:26:14,420 --> 00:26:20,150 Nick Griffin is a self professed racist. So you should take care when listening to his claims about immigration. 253 00:26:20,150 --> 00:26:24,440 Now, that just seems sensible, doesn't it? That's an ad hominem attack. 254 00:26:24,440 --> 00:26:33,500 That's not a fallacy at all. All you're doing is warning somebody that this person has a vested interest in making you believe something. 255 00:26:33,500 --> 00:26:38,720 So you should take his claims with an extra pinch of salt. 256 00:26:38,720 --> 00:26:42,650 But it doesn't say anything about the truth of the claim. 257 00:26:42,650 --> 00:26:47,030 So here. Well, the only thing it says about the truth of the claim is, 258 00:26:47,030 --> 00:26:53,990 is that you should be aware of the truth of trading claim because this person wants you to believe that. 259 00:26:53,990 --> 00:26:59,330 And of course, that's not a good enough reason for believing it. Nick Griffin is leader of the BNP. 260 00:26:59,330 --> 00:27:04,890 Therefore, his claim that some people worry about immigration is rubbish. That is a fallacy. 261 00:27:04,890 --> 00:27:13,920 If you attack a person instead of what he says and your attack on the person is actually irrelevant to the truth of what he says, 262 00:27:13,920 --> 00:27:17,430 in other words, your attack might be a correct attack. 263 00:27:17,430 --> 00:27:23,010 You're not saying something false about this person. But the truth of what you're saying bears. 264 00:27:23,010 --> 00:27:27,360 No has no bearing at all on the truth of what he is saying. 265 00:27:27,360 --> 00:27:35,540 That's a fallacy. What do you what you could be saying is warning somebody so, so. 266 00:27:35,540 --> 00:27:44,870 I've gotten your name again. Ashley comes to me and tells me that, oh, so-and-so came and told her that the coffee's ready in the common room. 267 00:27:44,870 --> 00:27:51,380 And I say, yes, but I know why he told you that. That's because he likes everyone else to go to the common room first and then discover 268 00:27:51,380 --> 00:27:56,540 it's actually being served upstairs today and he gets all the chocolate biscuits. 269 00:27:56,540 --> 00:28:04,570 I mean that when I'm doing that, I'm giving her a reason for why he said something. 270 00:28:04,570 --> 00:28:12,230 It doesn't actually bear on the truth of what, sir, but is a good reason not to to be sceptical about whether the coffees being in the common room, 271 00:28:12,230 --> 00:28:17,860 you'd want to cheque with someone else that the coffee was in the common room before you went there, perhaps. 272 00:28:17,860 --> 00:28:27,020 Or you wouldn't come down from your house in order to get coffee from the common room on the basis of what Ashley said or what what this person said. 273 00:28:27,020 --> 00:28:32,170 Okay, so that's the difference between ad hominem. So I don't know if that's answered your question. 274 00:28:32,170 --> 00:28:36,830 Yeah, I mean, an ad hominem is an attack on the person making an argument, 275 00:28:36,830 --> 00:28:44,000 not on the arguments he's making, and therefore that the attack, even if they attack, is justified. 276 00:28:44,000 --> 00:28:51,700 It doesn't question the argument itself. So those were fallacies of relevance. 277 00:28:51,700 --> 00:28:58,840 Now moving on to fallacies of vacuity. OK, the first one is a circular argument that we'll be looking at. 278 00:28:58,840 --> 00:29:04,990 And what do you when you argue in a circle, you, Supai, sort cite in support of a conclusion? 279 00:29:04,990 --> 00:29:13,510 That's a very conclusion. So your premise or your conclusion is amongst your premises here? 280 00:29:13,510 --> 00:29:18,250 A second fallacy we're looking at here is the fallacy of question begging. 281 00:29:18,250 --> 00:29:26,530 And thirdly, a self sealing argument. So let's start with circular arguments, then come back and look at these again, a circular argument. 282 00:29:26,530 --> 00:29:29,410 The conclusion is one of the premises. 283 00:29:29,410 --> 00:29:38,050 And the difference between that and a question begging argument is that here the conclusion actually is one of the premises, exactly the same thing. 284 00:29:38,050 --> 00:29:41,500 And here the conclusion is assumed by one of the premises. 285 00:29:41,500 --> 00:29:49,540 So you haven't actually got the conclusion amongst the premises, but you've got amongst the premises of a premise that assumes the conclusion. 286 00:29:49,540 --> 00:29:53,200 So here's an example of a circular argument. All whales are mammals. 287 00:29:53,200 --> 00:30:00,070 Therefore, all whales are mammals. Now, that argument valid. 288 00:30:00,070 --> 00:30:04,210 Well done. You're absolutely right. It is valid. All circular arguments valid. 289 00:30:04,210 --> 00:30:09,160 How could there be a possible situation? That's true. And that's false. 290 00:30:09,160 --> 00:30:13,690 If there's the same thing. If that's true, that's got to be true, hasn't it? 291 00:30:13,690 --> 00:30:17,680 So there's no possible situation in which that's true and that's false. 292 00:30:17,680 --> 00:30:23,560 Therefore, that argument is valid. So circular arguments are always valid. 293 00:30:23,560 --> 00:30:28,730 And what that tells you is that there's got to be more to a good argument than validity. 294 00:30:28,730 --> 00:30:32,740 And what's more true premises, because this is actually a true premise as well. 295 00:30:32,740 --> 00:30:37,270 So that's a sound argument, but it's not very good, is it? 296 00:30:37,270 --> 00:30:43,960 It wouldn't convince anybody of anything. But do you remember last week I got myself into a bit of a tangle by trying to 297 00:30:43,960 --> 00:30:48,460 draw truth tables on here and convince you that once you've got a premise, 298 00:30:48,460 --> 00:30:56,020 once you've got a conclusion in amongst the premises, it doesn't matter what you add to the argument, it remains valid. 299 00:30:56,020 --> 00:31:00,700 This is called the monotonic property of entailment. 300 00:31:00,700 --> 00:31:09,400 And if I had lots of other premises to that, the circularity will no longer be as obvious as it is now, will it? 301 00:31:09,400 --> 00:31:15,520 But actually, you are validity detected. That's what you are in virtue of being rational animals. 302 00:31:15,520 --> 00:31:21,550 So somebody stands up in parliament and gives a circular argument that's long and convoluted and so on. 303 00:31:21,550 --> 00:31:24,760 It's a valid argument. And you hear that. 304 00:31:24,760 --> 00:31:30,220 You can tell that it's a valid argument that there is no possible situation where the premises are true and the conclusion false. 305 00:31:30,220 --> 00:31:35,150 But what you don't see is that it's only valid because it's circular. 306 00:31:35,150 --> 00:31:41,180 Do you see how it happens so nobody would put forward an argument like that. 307 00:31:41,180 --> 00:31:47,210 But if they embed that premise in with the sorry, that conclusion in with the premises, 308 00:31:47,210 --> 00:31:54,410 they've set up a situation in which there's no possible situation where all the premises are true and the conclusion false. 309 00:31:54,410 --> 00:31:58,400 How could that be? Because it doesn't matter what other premises are there. 310 00:31:58,400 --> 00:32:05,390 If all the premises are true, the conclusion must be true as well, because a conclusion is one of the premises. 311 00:32:05,390 --> 00:32:12,440 So circular arguments are always valid and some secular arguments like this one are sound. 312 00:32:12,440 --> 00:32:20,220 But that doesn't make them good. There must be more to a valid argument. Sorry to a good argument than just soundness. 313 00:32:20,220 --> 00:32:25,650 In the final analysis, the point of an argument is to persuade someone of something. 314 00:32:25,650 --> 00:32:34,920 So it's to persuade you. If you don't believe me, and I think you should believe me, I think peer's true and therefore you should believe it. 315 00:32:34,920 --> 00:32:39,630 I put together an argument in the hope of convincing you that P. Okay. 316 00:32:39,630 --> 00:32:45,490 So what I want from an argument more than anything else is that it should be persuasive. 317 00:32:45,490 --> 00:32:50,460 Okay. But I do not want it to be persuasive because of a fallacy. 318 00:32:50,460 --> 00:32:57,330 I actually wanted to be a good argument as well. And therefore, I want it to be sound and valid. 319 00:32:57,330 --> 00:33:06,350 But if it sounds invalid, not persuasive. It's pretty useless for any practical purpose. 320 00:33:06,350 --> 00:33:11,750 So you actually you can't have a productive argument with somebody unless you agree with them. 321 00:33:11,750 --> 00:33:17,140 Didn't anyone tell me why that might be the case? Productive disagreement. 322 00:33:17,140 --> 00:33:26,320 Always depends on on agreement. Which is why if you've really got two sides who absolutely disagree on everything. 323 00:33:26,320 --> 00:33:33,760 You may as well forget it. Why should. Productive disagreements depends on agreement. 324 00:33:33,760 --> 00:33:38,570 I can only argue with you if you're prepared to accept my premises, if you reject my premises, 325 00:33:38,570 --> 00:33:44,380 then then I can't draw anything from those premises that's going to convince you of anything. 326 00:33:44,380 --> 00:33:51,450 Can I? So I've got to convince you of at least one of my premises before we can even get started. 327 00:33:51,450 --> 00:34:00,970 And of course, what I might do is say, will you agree to take this for the sake of argument and then take you through the arguments. 328 00:34:00,970 --> 00:34:07,510 But of course, if you still don't accept the premise, really, you know, you're never actually going to accept the conclusion of my argument, are you? 329 00:34:07,510 --> 00:34:13,350 So in order to disagree productively, you've got to agree on something. 330 00:34:13,350 --> 00:34:20,930 You've got to agree on the premises. Okay, so that's a circular argument and it's a valid one, 331 00:34:20,930 --> 00:34:29,870 but it's no good and it's no good because there's no possible situation which the premise is true and the conclusion false. 332 00:34:29,870 --> 00:34:35,050 But that's because the conclusion is amongst the premises. OK. 333 00:34:35,050 --> 00:34:41,020 Let's look at begging the question. Here's an argument. It's always wrong to murder human beings. 334 00:34:41,020 --> 00:34:46,860 Capital punishment involves murdering human beings. Therefore, capital punishment is wrong. 335 00:34:46,860 --> 00:34:51,370 What s question begging about this argument is. 336 00:34:51,370 --> 00:34:57,040 Exactly. This, too, to talk about capital punishment as if it were murder. 337 00:34:57,040 --> 00:35:02,750 Just to assume that capital punishment is murder is to assume your conclusion, isn't it? 338 00:35:02,750 --> 00:35:09,130 I mean, most people say that actually capital punishment isn't murder because murder is illegal killing, 339 00:35:09,130 --> 00:35:14,680 whereas capital punishment is legal killing, isn't it? Judicial killing. 340 00:35:14,680 --> 00:35:22,840 So by talking as if capital punishment to murdering human beings are interchangeable here. 341 00:35:22,840 --> 00:35:26,500 You're actually begging the question, aren't you? You're begging the question. 342 00:35:26,500 --> 00:35:33,790 Well, hang on a second. You know. Why should I believe capital punishment is wrong on the basis of these two premises? 343 00:35:33,790 --> 00:35:38,830 I do not accept that one at all. Because you're just assuming your conclusion here. 344 00:35:38,830 --> 00:35:41,010 You with me. 345 00:35:41,010 --> 00:35:50,040 So so when you say that an argument is a fallacy, you're not necessarily saying it's invalid, but you are saying there's something wrong with it. 346 00:35:50,040 --> 00:35:55,050 There's something wrong that means it's not persuasive. It shouldn't persuade you. 347 00:35:55,050 --> 00:36:04,510 Often that'll be the case because it's invalid, but not always. And certainly with cases of circularity and question begging, that isn't the case. 348 00:36:04,510 --> 00:36:08,590 Okay. Any other question? We'll move on now. 349 00:36:08,590 --> 00:36:14,980 Okay, let's. Okay. Where are the question begging premises in each of the following arguments? 350 00:36:14,980 --> 00:36:22,690 Let's do it. So intoxication. Intoxicated beverages should be banned because they make people drunk. 351 00:36:22,690 --> 00:36:28,030 Let's set out the arduous logic bookstall. Before we do that, we might need to suppress Froese. 352 00:36:28,030 --> 00:36:34,910 So what's the argument here? Think about it for yourself and then put your hands up when you when you've put out the argument. 353 00:36:34,910 --> 00:36:43,510 Logic books style. Yes, being drunk is bad or something like that, or beverages that make people drunk should be bad. 354 00:36:43,510 --> 00:36:48,220 That's probably the right one. Beverages that make people drunk should be bad. Should be banned. 355 00:36:48,220 --> 00:36:53,440 Intoxicated beverages, beverages make people drunk. Therefore, intoxicating beverages should be banned. 356 00:36:53,440 --> 00:36:59,400 What's the question? Begging bit. Which premise would you reject? 357 00:36:59,400 --> 00:37:03,270 You couldn't have a beverage that's intoxicating without having your beverage. 358 00:37:03,270 --> 00:37:09,600 That would make you drunk because an intoxicating beverage is exactly a beverage that makes you drunk, isn't it? 359 00:37:09,600 --> 00:37:19,590 The fact is, you're not going to be able to reject that argument because it's is assuming its conclusion in its premises. 360 00:37:19,590 --> 00:37:24,570 So beverages that make people drunk should be banned. 361 00:37:24,570 --> 00:37:32,040 Intoxicating beverages make people drunk, therefore, intoxicating beverages should be banned. 362 00:37:32,040 --> 00:37:38,400 It's a valid argument, but it's not ever going to persuade you. Well, let's go back to this one. 363 00:37:38,400 --> 00:37:42,630 Let's go back to Candy. Can you see that? 364 00:37:42,630 --> 00:37:51,210 Now, you might be for capital punishment or against it, but anyone who made this argument is clearly against capital punishment, aren't they? 365 00:37:51,210 --> 00:38:01,320 Okay, so they would be making the argument in order to try and persuade someone who is for capital punishment or neutral either way, 366 00:38:01,320 --> 00:38:06,930 to agree with them that capital punishment is wrong. Right. OK. 367 00:38:06,930 --> 00:38:16,650 And the problem with the argument they offer is that it's not going to convince anyone who isn't already convinced of the argument. 368 00:38:16,650 --> 00:38:21,660 Is it because I might say I'm against capital punishment? 369 00:38:21,660 --> 00:38:26,740 Sorry, I'm no, I'm for capital punishment. I might accept that premise. 370 00:38:26,740 --> 00:38:31,650 There's a is our starting point of agreement. But as soon as we get to that one, I'm going to say, boy, what? 371 00:38:31,650 --> 00:38:39,250 Hang on. Hang on. No. Why? Why should I set that? You're assuming that capital punishment is wrong in making that premise. 372 00:38:39,250 --> 00:38:45,030 You know, if you change that premise to capital punishment involves killing human beings, that's fine. 373 00:38:45,030 --> 00:38:51,630 But then your argument isn't valid. The only way you make your argument valid is by putting murdering in. 374 00:38:51,630 --> 00:38:56,330 And then it's valid because it begs the question. OK. 375 00:38:56,330 --> 00:39:02,580 And therefore, it's not persuasive. So in exactly the same way. 376 00:39:02,580 --> 00:39:07,020 If somebody was making this argument, say, I didn't believe whales were mammals. 377 00:39:07,020 --> 00:39:15,030 I thought whales were fish. Whales, obviously fish, aren't they? I mean, we've discussed this before anyway. 378 00:39:15,030 --> 00:39:20,220 They told me whales are mammals. Okay. So I don't believe whales are mammals. 379 00:39:20,220 --> 00:39:27,270 And you're trying to convince me if you offer me this argument and say, well, here's a good argument of whales being mammals. 380 00:39:27,270 --> 00:39:31,500 I would say no. No, that's not a good argument at all. 381 00:39:31,500 --> 00:39:35,040 Why should I agree with you on that premise, in that premise? 382 00:39:35,040 --> 00:39:43,380 You're just assuming your answer the obvious or your conclusion. So you've got a valid argument, but it's hopelessly unpersuasive. 383 00:39:43,380 --> 00:39:45,140 Therefore, it's not a good argument. 384 00:39:45,140 --> 00:39:54,930 And this one is only slightly difference in its instead of the the premise actually being the same as the conclusion, 385 00:39:54,930 --> 00:39:57,720 the premise assumes the conclusion. 386 00:39:57,720 --> 00:40:06,630 So if I actually if I'm if you're arguing using this argument against me, it's not going to persuade me of anything is it. 387 00:40:06,630 --> 00:40:13,310 And that's what's wrong with it. Not that it's not valid. So we're looking at fallacies of vacuity. 388 00:40:13,310 --> 00:40:17,600 OK? We've looked at fallacies of relevance. We're now looking at fallacies of vacuity. 389 00:40:17,600 --> 00:40:25,160 And we've looked first at circular arguments where the the the conclusion is one of the premises. 390 00:40:25,160 --> 00:40:31,940 Why? Tell me again why that would convince anyone if you've made an argument whether the conclusion is amongst the premises because 391 00:40:31,940 --> 00:40:38,600 it's valid and because the fact that the conclusion is amongst the premises may be hidden amongst all sorts of other premises. 392 00:40:38,600 --> 00:40:42,230 So you just don't notice that the conclusion is there. 393 00:40:42,230 --> 00:40:48,820 Okay, then we looked at question bagging arguments and we tied ourselves in knots or I tied myself in a knot. 394 00:40:48,820 --> 00:40:50,180 But the idea here is this. 395 00:40:50,180 --> 00:40:59,880 Instead of the premise, the conclusion being amongst the premises itself, there is amongst the premises a premise that assumes the conclusion. 396 00:40:59,880 --> 00:41:04,250 That's the difference between those two. And finally, we're going to look at arguments. 397 00:41:04,250 --> 00:41:08,090 This is self sealing. Okay. A self sealing argument. 398 00:41:08,090 --> 00:41:12,830 Two weeks from today at two forty five, you're going to be doing exactly what you are doing. 399 00:41:12,830 --> 00:41:18,200 Well, it will be a true statement, won't it? I mean, yeah, that couldn't be false, could it? 400 00:41:18,200 --> 00:41:22,130 But it's not a persuasive argument. Why not? It's completely vacuous. 401 00:41:22,130 --> 00:41:28,430 It says absolutely nothing doesn't it doesn't give you any prediction. It doesn't limit the possibilities at all. 402 00:41:28,430 --> 00:41:34,980 It just tells you you're going to be doing whatever you're going to be doing, which has to be true, not persuasive. 403 00:41:34,980 --> 00:41:40,280 Here's one that that actually lots of people do think is persuasive. We must respect all moral beliefs. 404 00:41:40,280 --> 00:41:50,600 Therefore, relativism is moral. Relativism is true. This is called vulgar relativism by chuckle Bernard Williams, famous philosopher. 405 00:41:50,600 --> 00:41:57,560 And the reason that's a self sealing argument is that is a moral absolute. 406 00:41:57,560 --> 00:42:04,700 We must respect all moral beliefs. You cannot derive moral relativism from a moral absolute. 407 00:42:04,700 --> 00:42:08,810 If that premise is true, then that conclusion is false. 408 00:42:08,810 --> 00:42:16,310 And if the conclusion is true, the premise is false. So it's it's a bad argument because it goes around in circles. 409 00:42:16,310 --> 00:42:22,830 It's self-defeating, actually self-defeating rather than self sealing. Yes. 410 00:42:22,830 --> 00:42:30,900 That's actually should be in a slightly different category. But here's another one that you may have variants of. 411 00:42:30,900 --> 00:42:32,700 It will have caught you out at some point. 412 00:42:32,700 --> 00:42:40,740 I'm sure global economy is controlled by Jews and any parents to the country is the result of Jewish cleverness. 413 00:42:40,740 --> 00:42:49,140 Women are stupid, and any appearance to the country is just because they're quite good at covering it over sometimes, you know? 414 00:42:49,140 --> 00:42:55,290 So, again, a self sealing argument because you know that you can't be refuted because whatever happens, 415 00:42:55,290 --> 00:43:00,300 you've got some reason for why what you're saying is is true. 416 00:43:00,300 --> 00:43:05,830 So some self sealing arguments move back and forth from interesting but false claims. 417 00:43:05,830 --> 00:43:11,430 For example, you might say all human beings are selfish and you won't say, well, hang on, that's not true. 418 00:43:11,430 --> 00:43:15,030 Lots of people are altruistic. Then they do things for other people. 419 00:43:15,030 --> 00:43:20,550 And then you say, oh, yes, but they still do. It does. They want to. I mean, Mother Teresa. 420 00:43:20,550 --> 00:43:26,430 I mean, she wouldn't have helped all these people. And if she wanted to. And you say she did it out of duty. 421 00:43:26,430 --> 00:43:30,900 And so you say, well, yes, she wanted to do her duty, didn't she? 422 00:43:30,900 --> 00:43:36,090 I mean, she still wanted to do what she did. So the only thing she did was what she wanted to do. 423 00:43:36,090 --> 00:43:42,030 So she's as selfish as everyone else. And her you know what's happening here? 424 00:43:42,030 --> 00:43:49,470 Well, what's happening is that someone's moving from an interesting but false claim to a true but vacuous claim. 425 00:43:49,470 --> 00:43:57,470 And what they'll do is they'll move backwards and forwards between the two until you've got yourself thoroughly tied in a knot. 426 00:43:57,470 --> 00:44:08,880 And what do you need to do is separate, separate out the two claims that are being made and show why one of them is meaningless, even if true. 427 00:44:08,880 --> 00:44:15,720 So three ways that an argument can be self see the ceiling. It can invent ad hoc ways to dismiss criticism. 428 00:44:15,720 --> 00:44:20,760 So if my prediction didn't work, it's because there are negative vibes in the room. 429 00:44:20,760 --> 00:44:28,890 Okay. You know, it's all your fault. It can attack its critics as unable to see the benefits of the position. 430 00:44:28,890 --> 00:44:34,560 So, you know, the only reason you don't see that the world's being taken over by Jews or women 431 00:44:34,560 --> 00:44:39,930 or or blacks or whatever is because you've been taken in by them or another one. 432 00:44:39,930 --> 00:44:51,400 There is you know, you're in denial. Therefore, you you don't understand what I'm saying about your appalling desires and what have you. 433 00:44:51,400 --> 00:44:59,440 It can also redefine key words. So it's selfish to always be doing just what you wants to do. 434 00:44:59,440 --> 00:45:05,270 Well. It depends what how you interpret just what you want to do there. 435 00:45:05,270 --> 00:45:14,430 If you interpret so you've Mother Teresa was doing just what she wanted to do, then you might need to have another look at what you mean by selfish. 436 00:45:14,430 --> 00:45:19,660 OK. And finally, we're going to look at fallacies of clarity. And I want to lose you some time for questions. 437 00:45:19,660 --> 00:45:33,300 Sorry, you've got a question. Well, on on the on this one. 438 00:45:33,300 --> 00:45:38,730 As soon as you have the feeling that you're being moved from between two different propositions, 439 00:45:38,730 --> 00:45:43,980 one of which is false, an interesting and the other is is safe. 440 00:45:43,980 --> 00:45:47,850 Ask for time out. If you can, because that's the only way you're going to do it. 441 00:45:47,850 --> 00:45:53,580 And of course, this is what you won't get. And try and identify what the two propositions are. 442 00:45:53,580 --> 00:46:03,810 So in this case, you want to say, OK. The meaning of selfish is usually isn't interested in what anyone else wants. 443 00:46:03,810 --> 00:46:10,770 In which case, Mother Teresa wouldn't be selfish because she is interested in what other people want. 444 00:46:10,770 --> 00:46:15,480 Then you say, but then your other claim is that somebody is selfish. 445 00:46:15,480 --> 00:46:24,030 Only if they saw something. It's sufficient for being selfish that somebody acts on what they they themselves want. 446 00:46:24,030 --> 00:46:26,560 And actually, that's not usually the definition of self. 447 00:46:26,560 --> 00:46:41,200 So identify the weasel words and get out the two definitions and then show that somebody is flipping between one and the other is the way to do that. 448 00:46:41,200 --> 00:46:46,690 OK, fallacies of the heap. If you have only one penny, you're not rich. 449 00:46:46,690 --> 00:46:53,710 If you're not rich and I give you a penny, then you still won't be rich. Doesn't matter how many pennies I give you, then you won't be rich. 450 00:46:53,710 --> 00:47:02,570 OK. Is that a good argument? No one not. 451 00:47:02,570 --> 00:47:06,650 I mean, is that false? No. 452 00:47:06,650 --> 00:47:14,950 OK. Is that false? Is that new, is not false, is it? 453 00:47:14,950 --> 00:47:18,850 I mean, that's true. If you gave me a penny, sadly, you wouldn't make me rich. 454 00:47:18,850 --> 00:47:22,660 Sir, fully, you know. Okay, so that's true. 455 00:47:22,660 --> 00:47:26,500 And that's true. Is that true? Okay. Is this valid? 456 00:47:26,500 --> 00:47:32,940 Is there any possible situation where those two are both true and this is false? 457 00:47:32,940 --> 00:47:36,890 Yes. Okay. This is actually not a valid argument at all, is it? 458 00:47:36,890 --> 00:47:41,330 It's it's trading on the fact that many words are vague. 459 00:47:41,330 --> 00:47:45,740 They admitted borderline cases. So any word you can think of, like tall, fat? 460 00:47:45,740 --> 00:47:50,210 Clever. Can you think of a few others? Richard is one of them. 461 00:47:50,210 --> 00:47:54,230 Yes. Long. Poor. Yep. 462 00:47:54,230 --> 00:48:01,550 And any word that admits of of degrees Mitsu borderline cases. 463 00:48:01,550 --> 00:48:05,810 You can construct a heap of arguments for the fallacy of the heap. 464 00:48:05,810 --> 00:48:10,340 And so that's the fact the words do admit are borderline cases. 465 00:48:10,340 --> 00:48:16,070 And the idea that a series of insignificant differences can't result in a significant difference. 466 00:48:16,070 --> 00:48:22,100 And of course, it's this one here that's that's at fault because a series of insignificant differences. 467 00:48:22,100 --> 00:48:30,710 If we take blue at this end of the stage and read at this ends of the stage, they're two different colours, aren't they? 468 00:48:30,710 --> 00:48:38,330 But we can go from one to the other in a series of gradations where you would say in each case of the same colour, 469 00:48:38,330 --> 00:48:44,360 the same colour, the same colour, but so A and B, the same B and C are the same. 470 00:48:44,360 --> 00:48:50,750 But ANC are not the same. OK. The intransitive. 471 00:48:50,750 --> 00:48:59,280 So when you're making an argument, you should try and avoid words that are grading words, scaling words. 472 00:48:59,280 --> 00:49:05,390 And how would you stop these being vague if you had John has a nice income. 473 00:49:05,390 --> 00:49:15,200 What might you say instead of that Set-aside again, some new good. 474 00:49:15,200 --> 00:49:20,940 John, this is in the top ten percent tenth percentile of income earners or something like that. 475 00:49:20,940 --> 00:49:26,640 Yeah. Okay. Cocaine is a dangerous drug. Cocaine is addictive or cocaine. 476 00:49:26,640 --> 00:49:31,290 And cocaine. You could say the same sort of thing. 477 00:49:31,290 --> 00:49:37,900 Yep. Or whatever. Exactly. That's what you're trying to do, is eliminate the vagueness by being more exact in some way or another. 478 00:49:37,900 --> 00:49:46,300 So Mary is a clever woman in just say Mary has got three degrees and APHC or something like that. 479 00:49:46,300 --> 00:49:52,990 Jane is a terrific tennis player. Jane is what? 480 00:49:52,990 --> 00:49:57,910 Yes. Okay, good. That easy. Slippery slope fallacy. 481 00:49:57,910 --> 00:50:02,110 This is another fallacy of ambiguity. Humans are rational. 482 00:50:02,110 --> 00:50:09,010 Sorry if in clarity human irrational because they act for reasons radiator's turn themselves on when it's cold. 483 00:50:09,010 --> 00:50:18,400 Therefore radiators are rational. Now don't laugh because actually lots of people try and convince me of this because I. 484 00:50:18,400 --> 00:50:27,550 I do not believe animals are rational. And people always told me that I should believe animals rational because they act for reasons. 485 00:50:27,550 --> 00:50:34,450 And some people want to say that even radiator's irrational because when it's cold they turn themselves on except in Rowly House. 486 00:50:34,450 --> 00:50:37,360 But I mean, it's usually the case. 487 00:50:37,360 --> 00:50:46,090 And therefore there is it has a belief that it's cold and a desire that it should not be cold and therefore it acts. 488 00:50:46,090 --> 00:50:52,350 Why isn't that rational? But again, we're doing the same thing, aren't we, 489 00:50:52,350 --> 00:51:00,030 because here are radiator's down at one end of of acting for reasons and here are human beings up at the other end of acting for reasons. 490 00:51:00,030 --> 00:51:09,660 And we're saying that there's no difference between the two. So any slippery slope argument can fall foul of that. 491 00:51:09,660 --> 00:51:16,920 Just quickly, slippery slope. Depends on the idea that we shouldn't distinguish between things that are not significantly different. 492 00:51:16,920 --> 00:51:25,530 And the belief that if A isn't significantly different from B and B, not significantly different from C, then A isn't significantly different from C. 493 00:51:25,530 --> 00:51:30,450 And again, that's true. Only if you've got something that's transitive. 494 00:51:30,450 --> 00:51:34,790 And there are many, many things that are not transitive. Of course, sometimes. 495 00:51:34,790 --> 00:51:39,210 And you I mean, one way of avoiding a slippery slope is actually to define something. 496 00:51:39,210 --> 00:51:42,690 We have to use slippery slope sometimes, don't we? 497 00:51:42,690 --> 00:51:52,290 When we think about, you know, well, why should we have the age of being allowed to marry at 16 without your parents permission or whatever it is, 498 00:51:52,290 --> 00:51:56,830 or the age of being able to drink whatever it is. 499 00:51:56,830 --> 00:52:00,910 I have no idea which this 18. Is it right. 500 00:52:00,910 --> 00:52:05,700 And what happens between the last day that you're 17 and the first day that you're 18? 501 00:52:05,700 --> 00:52:09,720 That makes it possible for you to drink on one day and not drink on the other. Legally. 502 00:52:09,720 --> 00:52:14,060 I mean, this is just daft, isn't it? Well, it is daft, of course. 503 00:52:14,060 --> 00:52:18,230 But but here you you have to make a Cut-Off point at some point. 504 00:52:18,230 --> 00:52:24,540 And what the slippery slope is, it can say, well, OK, there isn't an obvious difference, 505 00:52:24,540 --> 00:52:30,300 but we have to make it on somewhere or that we can just make one by regulation or whatever. 506 00:52:30,300 --> 00:52:36,420 But slippery slopes trade on this particular problem. Here's another one. 507 00:52:36,420 --> 00:52:40,830 Mary had a little lamb. He followed her to school. Mary had a little lamb. 508 00:52:40,830 --> 00:52:46,710 Then she had a little broccoli. We can see that that's an equivocation. 509 00:52:46,710 --> 00:52:53,740 It's not actually clear what it's an equivocation on, is it? Is it lamb or is it had. 510 00:52:53,740 --> 00:53:05,020 Or little well, and little actually, isn't it, because had means possessed, whereas in the first one and the second one, it means AIDS, doesn't it? 511 00:53:05,020 --> 00:53:09,130 Little Lamb in the first one is a bit different from Little Lamb in the second one. 512 00:53:09,130 --> 00:53:12,620 And so on. And here's an equivocation. Yep. 513 00:53:12,620 --> 00:53:17,620 Okay. A feather is light. What is light cannot be dark. Therefore, a feather cannot be dog. 514 00:53:17,620 --> 00:53:22,000 What's the equivocation there? The word light. 515 00:53:22,000 --> 00:53:26,200 In the first case, it means light as a feather weight wise. 516 00:53:26,200 --> 00:53:30,190 And the second case, we're talking about light as opposed to dark. 517 00:53:30,190 --> 00:53:38,440 So that's the fallacy of equivocation. There are three types of ambiguity, lexical. 518 00:53:38,440 --> 00:53:43,750 So what's wrong with that one? I thought it was rum. Is that rum is itself ambiguous. 519 00:53:43,750 --> 00:53:50,560 That's a word that can mean different things. The second one, Berts, was a fat stock breeder. 520 00:53:50,560 --> 00:53:59,510 What's the ambiguity there? Give me the two understandings of that term. 521 00:53:59,510 --> 00:54:03,700 Right. Either Bert was fat or the stock was fat. 522 00:54:03,700 --> 00:54:14,560 That's right. So is the scope of fat. Just so Bert was fat and Bert was a stock read breeder. 523 00:54:14,560 --> 00:54:20,860 Or is it the fat goes with stock breeder? So Bert was a fat stock breeder. 524 00:54:20,860 --> 00:54:26,260 Those are the two. And then finally cross-reference my wife's cousin engaged for her former husband. 525 00:54:26,260 --> 00:54:39,160 What's the ambiguity there? So either my wife's cousin's engaged to my wife's former husband or my wife's cousin is engaged to the cousin Chey, 526 00:54:39,160 --> 00:54:44,440 the wife's cousin had before now that she's married for the second time to the same person. 527 00:54:44,440 --> 00:54:51,550 Okay, explain the ambiguities in this sentence. These sentences, no one likes Oxford and Cambridge as students. 528 00:54:51,550 --> 00:55:01,610 Good. Okay. Nobody likes students who've been to Oxford and Cambridge or nobody likes Oxford students and nobody likes Cambridge students. 529 00:55:01,610 --> 00:55:06,010 Oh, yes. No one likes Oxford and no one likes Cambridge students. 530 00:55:06,010 --> 00:55:10,810 Yes, that would be another one. OK. Every nice girl loves a sailor, actually. 531 00:55:10,810 --> 00:55:14,740 If you were able to formalise things, you would find it very easy to do this, 532 00:55:14,740 --> 00:55:26,120 because this could mean there is a sailor such that every nice girl loves him or every nice girl is such that there is a sailor whom she loves. 533 00:55:26,120 --> 00:55:37,260 With me. So every girl is such sorry. There is a sailor such that every girl loves him or every nice girl loves some sailor. 534 00:55:37,260 --> 00:55:44,400 OK, so in the second case, there are lots of different sailors in the first cases, just one sailor who is loved by all the girls. 535 00:55:44,400 --> 00:55:50,460 So that's a structural ambiguity. Our shoes are guaranteed to give you a fit. 536 00:55:50,460 --> 00:55:56,250 I can see you've got that one. Okay. Irritating children should be banned. 537 00:55:56,250 --> 00:56:02,550 That's right there. What are we banning? Children who are irritating or the irritating of children. 538 00:56:02,550 --> 00:56:07,230 Okay. What about the last one? Can anyone tell me what the ambiguity is here? 539 00:56:07,230 --> 00:56:13,430 This is more difficult. You'll kick yourselves. But but you'll also think that I've cheated you. 540 00:56:13,430 --> 00:56:19,140 Why do swallows fly south for winter? Why do swallows fly south for winter? 541 00:56:19,140 --> 00:56:25,500 Why does swellest vice south for winter? Why do swallows fire south for winter? 542 00:56:25,500 --> 00:56:31,380 Is that ambiguous? Okay. And all it was is the intonation there. 543 00:56:31,380 --> 00:56:33,690 I managed to give it lots of different meanings. 544 00:56:33,690 --> 00:56:43,650 So you shouldn't think that actually the ambiguity might just be in this in the lexicon, in the structure and in the cross references. 545 00:56:43,650 --> 00:56:51,620 Sometimes you can put it in just by the tone, the emphasis you give on the words that you use. 546 00:56:51,620 --> 00:56:56,610 Right. Okay. That's it for the lectures. Thank you. 547 00:56:56,610 --> 00:57:02,667 Thank you. Well, thank you to.