1 00:00:00,012 --> 00:00:07,212 We've looked at some examples of unjustified ad hominem arguments, and 2 00:00:07,212 --> 00:00:14,082 we've looked at some examples of unjustified appeals to authority. 3 00:00:14,082 --> 00:00:19,864 Now, all of those arguments, the unjustified ones, are examples of 4 00:00:19,864 --> 00:00:25,449 fallacies of relevance. And because they're fallacies, they're 5 00:00:25,449 --> 00:00:30,333 bad arguments. Now, remember I said, at the beginning of 6 00:00:30,333 --> 00:00:36,837 the lecture on fallacies of relevance, that a fallacy of relevance could still 7 00:00:36,837 --> 00:00:40,572 have some other good qualities of an argument. 8 00:00:40,572 --> 00:00:45,012 So, for instance a fallacy of relevance could be valid. 9 00:00:45,012 --> 00:00:51,172 It could be an argument where there is no possible way for the conclusion to be 10 00:00:51,172 --> 00:00:56,663 false if the premise is true. Now I'd like to give you an example of a 11 00:00:56,663 --> 00:01:00,594 fallacy of relevance that is nonetheless valid. 12 00:01:00,594 --> 00:01:05,722 Consider something very strange that I just saw the other day. 13 00:01:05,722 --> 00:01:11,429 Speaker: You know why I'm so nervous? Because I've got a nervous system, I 14 00:01:11,429 --> 00:01:17,397 assure you I have a nervous system. Speaker: Now suppose, after seeing what I 15 00:01:17,397 --> 00:01:23,104 just saw, I made the following argument, which is an appeal to authority. 16 00:01:23,104 --> 00:01:27,453 I say. Walter offered his assurance that he has 17 00:01:27,453 --> 00:01:31,992 a nervous system. And from that premise I draw the 18 00:01:31,992 --> 00:01:36,144 conclusion that Walter has a nervous system. 19 00:01:36,144 --> 00:01:43,200 That looks like an appeal to authority. He offered his assurance that he has a 20 00:01:43,200 --> 00:01:50,431 nervous system So you must have a nervous system, right? Well if that argument is 21 00:01:50,431 --> 00:01:57,674 an appeal to authority, it's unjustified. And the reason why it's unjustified is 22 00:01:57,674 --> 00:02:04,917 that even thought Walter thinks that he has a nervous system, his merely thinking 23 00:02:04,917 --> 00:02:11,265 it Doesn't gaurantee that he's right, does it? Trick question. 24 00:02:11,265 --> 00:02:16,989 Trick question. Because nothing, in fact, can offer it's 25 00:02:16,989 --> 00:02:24,483 assurance that it has a nervous system, unless it really does have a nervous 26 00:02:24,483 --> 00:02:27,981 system. Consider, for instance, Walter's 27 00:02:27,981 --> 00:02:33,197 mechanical toy parrot, Sebastian. Whenever Sebastian hears Walter say 28 00:02:33,197 --> 00:02:39,055 something at a certain volume, Sebastian repeats back whatever it is that Walter 29 00:02:39,055 --> 00:02:42,271 said. So, when Walter says, I have a nervous 30 00:02:42,271 --> 00:02:48,222 system, in Sebastian's presence, Sebastian repeats back I have a nervous 31 00:02:48,222 --> 00:02:53,092 system. Now even though Sebastian repeats back, I 32 00:02:53,092 --> 00:02:59,172 have a nervous system. Sebastian isn't offering its assurance 33 00:02:59,172 --> 00:03:05,352 that it has a nervous system. It's just a mechanical toy parrot. 34 00:03:05,352 --> 00:03:12,208 So it's making sounds to the effect that, it has a nervous system, but it's not 35 00:03:12,208 --> 00:03:18,837 offering its assurance, about anything. A mechanical toy parrot doesn't have any 36 00:03:18,837 --> 00:03:23,505 assurance to offer. It's also true, that a mechanical toy 37 00:03:23,505 --> 00:03:30,052 parrot, doesn't have a nervous system. So, this argument here, while it might be 38 00:03:30,052 --> 00:03:33,686 valid, is nonetheless, i fallacy of relevance. 39 00:03:33,686 --> 00:03:40,031 It's an unjustified appeal to authority. Nonetheless, perhaps unbeknownst to the 40 00:03:40,031 --> 00:03:43,377 person who makes the argument, it is valid. 41 00:03:43,377 --> 00:03:49,933 There is no possible way for the premise to be true if the conclusion is false. 42 00:03:49,933 --> 00:03:53,122 Now I realize this may be hard to believe, 43 00:03:53,122 --> 00:03:58,494 but recently, over recent generations that is, pigs have been evolving to 44 00:03:58,494 --> 00:04:03,224 acquire opposable thumbs. And given the general level of porcine 45 00:04:03,224 --> 00:04:08,012 intelligence, this could mean a complete reshaping of the planet. 46 00:04:08,012 --> 00:04:11,321 Speaker: Trust me, I am not lying about this. 47 00:04:11,321 --> 00:04:13,653 This is for real. Speaker: Hmm. 48 00:04:13,653 --> 00:04:18,948 Well, Ron said he wasn't lying. So I guess pigs are developing opposable 49 00:04:18,948 --> 00:04:22,535 thumbs. Speaker: Now the reasoning that you just 50 00:04:22,535 --> 00:04:29,468 saw Anthony do might have looked simple, but actually it involved 2 steps. Let's 51 00:04:29,468 --> 00:04:35,194 analyze those steps. First, he heard me say that I was not 52 00:04:35,194 --> 00:04:40,957 lying when I said that pigs are evolving opposable thumbs. 53 00:04:40,957 --> 00:04:45,542 So from the premise that I said I was not lying, 54 00:04:45,542 --> 00:04:53,798 when I said pigs were evolving oposable thumbs, Anthony concluded that indeed I 55 00:04:53,798 --> 00:04:59,998 was not lying when I said pigs are evolving oposable thumbs. 56 00:04:59,998 --> 00:05:06,862 I noticed that first step in reasoning is an appeal to authority. 57 00:05:06,862 --> 00:05:14,437 Anthony is appealing to my authority, when I said that I was not lying, because 58 00:05:14,437 --> 00:05:20,422 I said I was not lying, Anthony concludes that I was not lying. 59 00:05:20,422 --> 00:05:25,292 But now consider the second step of his reasoning. 60 00:05:25,292 --> 00:05:32,293 From the premise that I was not lying when I said pigs are evolving opposable 61 00:05:32,293 --> 00:05:39,223 thumbs, Anthony drew the conclusion that pigs really are evolving opposable 62 00:05:39,223 --> 00:05:43,862 thumbs. But that, is another appeal to authority. 63 00:05:43,862 --> 00:05:50,400 From the fact that I was not lying when I said pigs are evolving opposable thumbs 64 00:05:50,400 --> 00:05:57,192 all that follows is that I really believe that pigs are evolving opposable thumbs. 65 00:05:57,192 --> 00:06:02,979 It doesn't yet follow that pigs really are evolving opposable thumbs. 66 00:06:02,979 --> 00:06:09,186 Am I someone who knows what I'm talking about when I talk about porcine 67 00:06:09,186 --> 00:06:16,216 evolution? If not, then this second step in reasoning is not justified, it's an 68 00:06:16,216 --> 00:06:22,738 unjustified appeal to authority. Simply because I believe that pigs are 69 00:06:22,738 --> 00:06:28,086 evolving oposable thumbs doesn't mean that they really are. 70 00:06:28,086 --> 00:06:34,351 So in the apparently simple reasoning that we just saw Anthony perform, there 71 00:06:34,351 --> 00:06:40,277 were really 2 steps, and each one of those steps was itself an unjustified 72 00:06:40,277 --> 00:06:45,425 appeal to authority. See, appeals to authority can be very 73 00:06:45,425 --> 00:06:49,152 tricky. They can go past without our even 74 00:06:49,152 --> 00:06:49,989 noticing.