1 00:00:00,012 --> 00:00:06,256 Today, we're going to talk about fallacies, of relevance. 2 00:00:06,256 --> 00:00:11,967 Lets start, by talking about ad hominem arguments. 3 00:00:11,967 --> 00:00:20,012 Ad hominem means to the person. An ad hominem argument is an argument 4 00:00:20,012 --> 00:00:26,367 that starts with premises about a particular person, a person who is 5 00:00:26,367 --> 00:00:30,464 engaged in making some point or defending some claim. 6 00:00:30,464 --> 00:00:36,446 And then, it draws a conclusion from those premesis against the point that the 7 00:00:36,446 --> 00:00:42,152 person was making, the conclusion that they were attempting to defend. 8 00:00:42,152 --> 00:00:49,154 So, I can try to make this idea clearer by giving three kinds of examples of ad 9 00:00:49,154 --> 00:00:54,733 hominem arguments. The three kind of examples that I'm going 10 00:00:54,733 --> 00:01:00,932 to be talking about today are deniers, silencers, and dismissers. 11 00:01:00,932 --> 00:01:16,567 Let's consider an example from each kind. 12 00:01:16,567 --> 00:01:19,679 [SOUND] 13 00:01:19,679 --> 00:01:23,523 So, a denier ad hominem argument is an 14 00:01:23,523 --> 00:01:29,474 argument that begins with premises about a person who is making a certain point or 15 00:01:29,474 --> 00:01:35,179 defending a certain claim and concludes that a point that they were making or a 16 00:01:35,179 --> 00:01:41,041 claim that they were defending is false. Let me give you an example of a denier ad 17 00:01:41,041 --> 00:01:45,602 hominem argument. Suppose that Lucy has been accused of 18 00:01:45,602 --> 00:01:51,942 murder. And her alibi is that, at the time the murder was committed, she was 19 00:01:51,942 --> 00:01:56,207 with Louie. Now, Louie gets up and testifies that he 20 00:01:56,207 --> 00:02:02,687 was with Lucy at the time the murder was committed and she was nowhere near the 21 00:02:02,687 --> 00:02:07,389 scene of the murder. But now, suppose we find out that Louie 22 00:02:07,389 --> 00:02:11,119 has a history of perjuring himself on the stand. 23 00:02:11,119 --> 00:02:16,428 He's paid to purger himself. He's a very good perjurer because he can 24 00:02:16,428 --> 00:02:21,314 pass lie detector tests with flying colors even when he's lying. 25 00:02:21,314 --> 00:02:26,399 And he doesn't exhibit any of the behavioral signs of lying that's 26 00:02:26,399 --> 00:02:30,912 detectable by the police or any other courtroom expert. 27 00:02:30,912 --> 00:02:34,366 So, Louis makes a living as a hired perjurer. 28 00:02:34,366 --> 00:02:40,487 That's something we find out about Louie. Now, if we find this out about Louie, 29 00:02:40,487 --> 00:02:46,316 that could lead us to conclude that what Louie said on the stand was false. 30 00:02:46,316 --> 00:02:49,932 He was purjuring himself, as he normally does. 31 00:02:49,932 --> 00:02:56,495 So, here we have an ad hominem argument. We start with premises about Louie, that 32 00:02:56,495 --> 00:03:03,076 he's a hired perjurer, that he perjures himself regularly in the courtroom when 33 00:03:03,076 --> 00:03:07,904 he's on the stand. And, we draw a conclusion about the truth 34 00:03:07,904 --> 00:03:14,226 of what it was that Louie said on this occasion, namely that it's false that he 35 00:03:14,226 --> 00:03:18,756 was with Lucy at the time of the murder was committed. 36 00:03:18,756 --> 00:03:23,102 That's an example of a denier ad hominem argument. 37 00:03:23,102 --> 00:03:29,211 Now notice, the particular argument I just gave seems like a pretty good 38 00:03:29,211 --> 00:03:33,296 argument. In fact, this is a case of an ad hominem 39 00:03:33,296 --> 00:03:39,652 argument that is not fallacious. It doesn't commit a fallacy of relevance. 40 00:03:39,652 --> 00:03:45,022 If, in fact, we do find out that Louie is a hired perjurer, that he's a career 41 00:03:45,022 --> 00:03:50,670 perjurer, then we should conclude that what he's saying on the stand, in this 42 00:03:50,670 --> 00:03:55,127 instance, is false. That's at least pretty good evidence that 43 00:03:55,127 --> 00:03:58,568 it's false. So, this is a case where we have an ad 44 00:03:58,568 --> 00:04:03,362 hominem argument that's not guilty of a fallacy of relevance. 45 00:04:03,362 --> 00:04:09,237 But consider another case where we have an ad hominem argument that's a denier 46 00:04:09,237 --> 00:04:12,632 but that is guilty of a fallacy of relevance. 47 00:04:12,632 --> 00:04:16,307 Suppose that Louie is not a career purgerer at all. 48 00:04:16,307 --> 00:04:21,892 Louie gets on the stand and testifies that he was with Lucy at the time that 49 00:04:21,892 --> 00:04:27,411 the murder was committed. But, Louie is dressed in really, really 50 00:04:27,411 --> 00:04:32,341 shabby clothing that he probably bought in the 1970s. 51 00:04:32,341 --> 00:04:39,451 Under these circumstances, we might conclude that what he's saying is false. 52 00:04:39,451 --> 00:04:44,122 But why would we conclude that? Well, we might say, 53 00:04:44,122 --> 00:04:50,066 look, the guy dresses in really shabby clothing that he bought in the 1970s. 54 00:04:50,066 --> 00:04:54,816 He's got to be lying. Now, that's an ad hominem argument also. 55 00:04:54,816 --> 00:05:01,024 It starts with premises about the person who is testifying, in this case Louie, 56 00:05:01,024 --> 00:05:05,852 and it draws a conclusion about the truth of his testimony. 57 00:05:05,852 --> 00:05:08,673 In this case, that what he was saying was false. 58 00:05:08,673 --> 00:05:13,202 But that ad hominem argument, though it is a denier like the first ad hominem 59 00:05:13,202 --> 00:05:16,601 argument that we considered, is a fallacious argument. 60 00:05:16,601 --> 00:05:20,929 It's not a good argument at all. Just because Louie is dressed in shabby 61 00:05:20,929 --> 00:05:25,659 clothing that he bought in the 1970s, that has no tendency whatsoever to show 62 00:05:25,659 --> 00:05:30,985 that what he's saying was false. So, deniers are a kind of ad hominem 63 00:05:30,985 --> 00:05:34,876 argument. But, some of them commit the fallacy of 64 00:05:34,876 --> 00:05:40,797 relevance and some of them do not. Now, let's consider another kind of ad 65 00:05:40,797 --> 00:05:45,559 hominem argument. The second kind of ad hominem argument 66 00:05:45,559 --> 00:05:52,667 I'm going to call a silencer. [SOUND] The second kind of ad hominem 67 00:05:52,667 --> 00:06:01,697 argument that I want to discuss is the kind of argument that we're going to call 68 00:06:01,697 --> 00:06:07,687 a silencer. A silencer is an argument that starts 69 00:06:07,687 --> 00:06:13,615 from premises about a person who is trying to make a point or defend a 70 00:06:13,615 --> 00:06:19,508 conclusion, and that person's entitlement to make that point or defend that 71 00:06:19,508 --> 00:06:23,673 conclusion in the situation which they were doing so. 72 00:06:23,673 --> 00:06:29,775 It starts from premises about that and moves to a conclusion about the point 73 00:06:29,775 --> 00:06:34,916 that they were making, or the conclusion that they were defending. 74 00:06:34,916 --> 00:06:40,243 So, let me give you an example. Suppose that while Lucy is on trial for 75 00:06:40,243 --> 00:06:46,552 murder, and witnesses are being called to the stand, lawyers are questioning them 76 00:06:46,552 --> 00:06:52,752 and cross examining them. All of a sudden, Charlie runs into the 77 00:06:52,752 --> 00:07:01,675 courtroom, breaks open the door and yells at the top of his lungs, I saw Lucy kill 78 00:07:01,675 --> 00:07:03,720 the victim. Okay. 79 00:07:03,720 --> 00:07:10,161 Now, Charlie might say that. But in that situation, in the middle of a 80 00:07:10,161 --> 00:07:16,556 courtroom, that is not something that we can take into account in determining 81 00:07:16,556 --> 00:07:22,436 whether Lucy is innocent or guilty. The jury cannot consider Charlie's 82 00:07:22,436 --> 00:07:26,162 testimony, if that's what you want to call it. 83 00:07:26,162 --> 00:07:32,005 That testimony does not count as evidence in a courtroom. 84 00:07:32,005 --> 00:07:40,020 So, we could say Charlie had no right to say what he did in the situation in which 85 00:07:40,020 --> 00:07:44,728 he said it. He was not entitled to speak in that 86 00:07:44,728 --> 00:07:48,607 context. So, his testimony is invalid. 87 00:07:48,607 --> 00:07:51,632 Discard it, don't pay any attention to it. 88 00:07:51,632 --> 00:07:54,737 That's an example of, a silencer argument. 89 00:07:54,737 --> 00:08:00,157 It's an argument that starts from premises, about Charlie's entitlement to 90 00:08:00,157 --> 00:08:05,837 speak in that situation, and moves to a conclusion about whether we should pay 91 00:08:05,837 --> 00:08:12,032 attention to what he was saying. That's an example of a silencer argument. 92 00:08:12,032 --> 00:08:16,313 But that silencer argument is a justified one. 93 00:08:16,313 --> 00:08:21,476 It's not fallacious. Here's an example of a fallacious 94 00:08:21,476 --> 00:08:26,718 silencer argument. Suppose that Charlie is called to the 95 00:08:26,718 --> 00:08:33,392 witness stand and he's examined by one lawyer and cross examined by another 96 00:08:33,392 --> 00:08:37,442 lawyer. And during the course of his testimony, 97 00:08:37,442 --> 00:08:42,277 Charlie testifies that he did see Lucy murder the victim. 98 00:08:42,277 --> 00:08:46,632 He saw with his own eyes. But, as he's testifying, 99 00:08:46,632 --> 00:08:54,008 he speaks in an unusual foreign accent. Now, someone might say, well, Charlie 100 00:08:54,008 --> 00:09:01,552 speaks with an unusual foreign accent, therefore, we should pay no attention to 101 00:09:01,552 --> 00:09:06,598 his testimony. Now, that's also a silencer at hominem 102 00:09:06,598 --> 00:09:10,830 argument. But that's an example of an unjustified 103 00:09:10,830 --> 00:09:16,549 silencer ad hominem argument. Just because Charlie speaks in an unusual 104 00:09:16,549 --> 00:09:22,952 foreign accent, that's no good reason to think that we shouldn't pay attention to 105 00:09:22,952 --> 00:09:26,819 his testimony. So, there's a case of an ad hominem 106 00:09:26,819 --> 00:09:30,892 silencer that does commit a fallacy of relevance. 107 00:09:30,892 --> 00:09:40,378 The third kind of ad hominem argument that I want to talk about is a kind of 108 00:09:40,378 --> 00:09:44,686 argument that we're going to call a dismisser. 109 00:09:44,686 --> 00:09:54,827 [SOUND] A dismisser is an argument that starts from premises about a particular 110 00:09:54,827 --> 00:09:59,102 person who's trying to defend a conclusion or make a point. 111 00:09:59,102 --> 00:10:04,707 And the dismisser argument moves from those premesis to a conclusion that says 112 00:10:04,707 --> 00:10:10,282 that we have no reason to believe the conclusion the person is trying to defend 113 00:10:10,282 --> 00:10:15,851 or the point they are trying to make. The dismisser argument doesn't conclude 114 00:10:15,851 --> 00:10:21,087 that we should not believe what the person is trying to defend or the point 115 00:10:21,087 --> 00:10:25,209 they're trying to make. Rather it concludes that we have no 116 00:10:25,209 --> 00:10:30,679 reason to believe, the conclusion the person is trying to defend, or the point 117 00:10:30,679 --> 00:10:31,924 they're trying to make. Rather it concludes that we have no 118 00:10:31,924 --> 00:10:31,924 reason to believe the conclusion of the person that's trying to defend or the 119 00:10:31,924 --> 00:10:35,035 point they're trying to make. Now, what's an example of the dismisser 120 00:10:35,035 --> 00:10:41,191 argument? Well again, consider the situation where Lucy is on trial for 121 00:10:41,191 --> 00:10:45,129 murder. And now, Linus is called as a witness. 122 00:10:45,129 --> 00:10:51,667 So, lawyers are questioning Linus and Linus says that he saw Lucy kill the 123 00:10:51,667 --> 00:10:58,284 victim with her Acme double-edged knife. And then, Linus throws in, for good 124 00:10:58,284 --> 00:11:05,169 effect, acme, there's no knife like it. Now, as Linus offers this testimony, he 125 00:11:05,169 --> 00:11:11,731 happens also to be wearing his Acme promotional t-shirt, his Acme baseball 126 00:11:11,731 --> 00:11:16,442 cap and carrying a big briefcase that says acme on it. 127 00:11:16,442 --> 00:11:24,327 The cross examining lawyer finds out that Linus is actually a sales representative 128 00:11:24,327 --> 00:11:32,046 for the Acme Double-edged Knife Company. Now, under these circumstances, we might 129 00:11:32,046 --> 00:11:39,584 wonder whether Linus isn't just saying that he saw Lucy kill the victim with her 130 00:11:39,584 --> 00:11:46,994 Acme double-edged knife in order to promote Acme knives as effective knives, 131 00:11:46,994 --> 00:11:52,308 as useful tools. Now, if that's why Linus is offering his 132 00:11:52,308 --> 00:11:58,749 testimony, then, we should think of his testimony as a form of advertising. 133 00:11:58,749 --> 00:12:05,268 Not as something that gives us a reason to believe that Lucy actually did kill 134 00:12:05,268 --> 00:12:09,045 the victim with her Acme double-edged knife. 135 00:12:09,045 --> 00:12:14,876 Linus has an interest In getting us to believe that Lucy killed the victim with 136 00:12:14,876 --> 00:12:19,615 her Acme double-edged knife. But his interest in getting us to believe 137 00:12:19,615 --> 00:12:25,122 that is not just an interest in getting us to believe the truth, it's an interest 138 00:12:25,122 --> 00:12:28,683 in making some money for the company he represents. 139 00:12:28,683 --> 00:12:33,532 So, that leads us to wonder whether Linus's testimony is trustworthy. 140 00:12:33,532 --> 00:12:39,644 So we can say, Linus is a representative for the Acme Double-Edged Knife Company, 141 00:12:39,644 --> 00:12:45,842 therefore, his testimony to the effect that Lucy used an Acme double-edged knife 142 00:12:45,842 --> 00:12:50,245 to murder the victim is not testimony that we should trust. 143 00:12:50,245 --> 00:12:55,072 Because he has a vested interest in offering that testimony. 144 00:12:55,072 --> 00:12:59,228 There's a case of a dismisser ad hominem argument. 145 00:12:59,228 --> 00:13:02,925 But that dismisser argument may be justified. 146 00:13:04,289 --> 00:13:10,498 We could give another example, though, of a dismisser argument that is clearly 147 00:13:10,498 --> 00:13:14,722 unjustified but commits a fallacy of relevance. 148 00:13:14,722 --> 00:13:18,602 An example like that would be the following. 149 00:13:18,602 --> 00:13:24,777 While Linus is saying testifying in the courtroom that Lucy killed the murder 150 00:13:24,777 --> 00:13:31,092 victim with her Acme double-edged knife. Linus actually doesn't work as a sales 151 00:13:31,092 --> 00:13:37,357 representative for the Acme Company not does he have any interest in promoting 152 00:13:37,357 --> 00:13:42,720 Acme double-eded knives. But Linus might look like someone who 153 00:13:42,720 --> 00:13:46,969 used to work for the Acme Double-edged Knife Company. 154 00:13:46,969 --> 00:13:53,439 and because of that resemblance, we might be led to think that Linus is as much of 155 00:13:53,439 --> 00:13:59,812 a salesman for the Acme Double-edged Knife Company as this other person was. 156 00:13:59,812 --> 00:14:03,662 They look like each other, maybe Linus reminds us of him. 157 00:14:03,662 --> 00:14:09,062 And so, we might be led to think, based on the resemblance between Linus and this 158 00:14:09,062 --> 00:14:14,287 Acme double-edged knife salesman, that Linus himself has a vested interest in 159 00:14:14,287 --> 00:14:19,287 promoting Acme double-edged knives, and so would be willing to offer false 160 00:14:19,287 --> 00:14:24,280 testimony in order to have a product placement opportunity for Acme 161 00:14:24,280 --> 00:14:28,200 double-edged knives. Now, that would be an example of a 162 00:14:28,200 --> 00:14:31,883 dismisser ad hominem argument that is fallacious. 163 00:14:31,883 --> 00:14:37,012 It draws a conclusion based not on any good reason for that conclusion, 164 00:14:37,012 --> 00:14:42,303 bu rather, based on some resemblance between Linus and somebody else. 165 00:14:42,303 --> 00:14:47,851 A resemblance which is presumably irrelevant to the truth of what Linus is 166 00:14:47,851 --> 00:14:51,753 saying. And so, our argument would in that case 167 00:14:51,753 --> 00:14:55,804 be fallacious. It would be a fallacy of relevance.