WEBVTT 00:00:05.650 --> 00:00:08.513 My name is Jennifer Nagel. 00:00:09.020 --> 00:00:11.011 I teach philosophy at the university of Toronto, 00:00:11.450 --> 00:00:13.692 and today I want to talk to you about knowledge. 00:00:13.901 --> 00:00:17.312 Knowledge is something human beings naturally crave, 00:00:17.312 --> 00:00:19.081 we spend a lot of time and effort 00:00:19.081 --> 00:00:21.252 trying to gain it, for example by 00:00:21.252 --> 00:00:22.801 watching videos like this one. 00:00:23.391 --> 00:00:25.550 We also have natural instincts to keep 00:00:25.550 --> 00:00:27.929 track of what other people do and don't know 00:00:27.930 --> 00:00:30.632 in order to make sense of what they're doing. 00:00:31.188 --> 00:00:33.508 But it's suprisingly difficult to give a good 00:00:33.512 --> 00:00:36.979 explanation of the nature of knowledge itself, 00:00:36.979 --> 00:00:38.919 and to say how knowing that something is 00:00:38.919 --> 00:00:41.837 true, differs from just thinking that it's true. 00:00:42.803 --> 00:00:45.028 When we try to figure out what knowledge is, 00:00:45.028 --> 00:00:47.474 we encounter some interesting questions 00:00:47.474 --> 00:00:51.333 and paradoxes. This series explores these problems, 00:00:51.333 --> 00:00:54.519 and explains how philosophers have tried to solve them. 00:00:54.958 --> 00:00:57.644 This particular video will focus on some basic 00:00:57.644 --> 00:01:00.074 features of knowledge, features that any good 00:01:00.074 --> 00:01:02.424 theory of it should try to explain. 00:01:02.970 --> 00:01:05.694 So, what kinds of things can you know? 00:01:06.463 --> 00:01:09.198 The english verb "know" is used in several ways; 00:01:09.509 --> 00:01:12.549 you can know a person, "Alice knows Pierre"; 00:01:12.638 --> 00:01:15.418 a place, "Pierre knows Paris"; 00:01:15.418 --> 00:01:17.899 or a language, "Alice knows french". 00:01:18.449 --> 00:01:20.744 But the most common way of using the verb 00:01:20.744 --> 00:01:23.409 "to know" is the way we use it when we're 00:01:23.419 --> 00:01:26.307 speaking of someone knowing a fact, as in 00:01:26.756 --> 00:01:28.979 "Alice knows that it's raining outside". 00:01:29.318 --> 00:01:32.621 In this series we'll be focusing on this 00:01:32.621 --> 00:01:36.318 knowing-a-fact sense of the verb "to know". 00:01:37.248 --> 00:01:39.667 Sometimes this is called "knowledge-that", 00:01:39.887 --> 00:01:43.299 but actually, along with "that", you can use 00:01:43.299 --> 00:01:45.773 question words like "where" or "when". 00:01:46.059 --> 00:01:49.139 "Pierre knows when the party will start" 00:01:49.430 --> 00:01:52.489 or "Pierre knows where the party is". 00:01:52.732 --> 00:01:55.666 Knowing where the party is means knowing the 00:01:55.666 --> 00:01:58.468 answer to the question "where's the party?", 00:01:58.468 --> 00:02:01.609 and that's going to be a fact, like the fact 00:02:01.609 --> 00:02:04.589 that the party is at Alice's place. Knowledge is 00:02:04.589 --> 00:02:07.358 a way of being latched on to a fact. 00:02:08.719 --> 00:02:10.723 It is thought that every language in the world 00:02:10.723 --> 00:02:13.711 has a word that works to translate this fact-grabbing 00:02:13.711 --> 00:02:16.153 sense of the word "to know". 00:02:16.313 --> 00:02:19.430 And this kind of global popularity is very rare, 00:02:19.454 --> 00:02:21.703 only about a hundred words are thought 00:02:21.703 --> 00:02:23.833 to be universal in this way. 00:02:24.274 --> 00:02:27.244 Around the world, words meaning "to know" are 00:02:27.266 --> 00:02:30.505 also very heavily used. It's one of the top ten 00:02:30.507 --> 00:02:33.456 most common words in english for example. 00:02:34.154 --> 00:02:36.803 So we often find ourselves talking about 00:02:36.803 --> 00:02:39.613 knowledge, but when we say someone knows 00:02:39.613 --> 00:02:42.019 something, what do we mean? 00:02:42.762 --> 00:02:45.501 It can help to compare knowing and just believing. 00:02:46.171 --> 00:02:48.354 Consider these two sentences: 00:02:48.779 --> 00:02:52.243 1. "Alice knows that it's raining outside." 00:02:52.662 --> 00:02:56.402 2. "Pierre believes that it's raining outside." 00:02:57.154 --> 00:03:00.023 We instinctively feel some difference between 00:03:00.024 --> 00:03:02.347 Alice and Pierre, but what is it? 00:03:02.687 --> 00:03:05.383 Actually, we'll see there's several possible 00:03:05.383 --> 00:03:07.094 points of contrast here. 00:03:07.632 --> 00:03:10.010 The first and easiest has to do with truth. 00:03:10.682 --> 00:03:13.301 If Pierre just believes that it's raining outside, 00:03:13.301 --> 00:03:16.281 where he is, maybe he's wrong. Maybe the 00:03:16.291 --> 00:03:18.211 rain has stopped, and he's fooled by the 00:03:18.221 --> 00:03:20.872 sound of water dripping from the trees. 00:03:21.541 --> 00:03:24.280 The things we believe are sometimes true 00:03:24.280 --> 00:03:25.681 and sometimes false. 00:03:26.191 --> 00:03:28.192 What we actually know on the other hand, 00:03:28.192 --> 00:03:33.031 has to be true, or factual. So there's no problem saying 00:03:33.031 --> 00:03:35.503 "Pierre believes it's raining, but it isn't." 00:03:35.523 --> 00:03:37.022 While it sounds weird to say 00:03:37.022 --> 00:03:39.501 "Alice knows it's raining, but it isn't." 00:03:39.501 --> 00:03:42.366 This is because attachment to the truth 00:03:42.366 --> 00:03:44.847 is built into the meaning of knows-that. 00:03:45.365 --> 00:03:47.997 Beyond truth, another key feature of 00:03:47.997 --> 00:03:49.776 knowledge is confidence. 00:03:49.826 --> 00:03:51.556 Let's suppose that Pierre is in a windowless 00:03:51.556 --> 00:03:54.017 room, and he's been there for an hour. 00:03:54.322 --> 00:03:56.481 He could suspect that it's still raining 00:03:56.481 --> 00:03:58.812 outside, even of he's not totally sure. 00:03:59.092 --> 00:04:01.881 But if Alice knows that it's raining, she has 00:04:01.901 --> 00:04:03.542 no doubt. She's confident. 00:04:04.292 --> 00:04:07.653 So, is confident belief in a truth enough 00:04:07.653 --> 00:04:10.041 for knowing? Apparently not. 00:04:10.756 --> 00:04:13.076 There's at least one more thing we need. 00:04:13.786 --> 00:04:17.496 Imagine that Pierre is really pessimistic, 00:04:17.496 --> 00:04:19.586 he's always strongly convinced that 00:04:19.586 --> 00:04:22.102 things will go badly. He's often wrong, 00:04:22.102 --> 00:04:25.746 but sometimes he's right. Today he wakes up 00:04:25.746 --> 00:04:28.758 in a windowless room, aware that Alice has 00:04:28.758 --> 00:04:31.297 planned a picnic because the forecast was 00:04:31.297 --> 00:04:34.616 for sunny weather. "It's going to be terrible", 00:04:34.616 --> 00:04:38.957 he thinks. "I'm sure it's already raining right now". 00:04:40.107 --> 00:04:43.277 He's entirely confident that it's raining, 00:04:43.297 --> 00:04:45.897 although he can't actually see or hear the rain. 00:04:46.268 --> 00:04:48.698 And let's say by chance it turns out he's 00:04:48.698 --> 00:04:51.897 right this time. Does Pierre actually know 00:04:51.897 --> 00:04:53.937 that it's raining outside? 00:04:54.132 --> 00:04:57.105 If he doesn't know, then it seems knowledge 00:04:57.105 --> 00:04:59.815 requires something more than confident 00:04:59.815 --> 00:05:03.575 belief in a truth. Feeling pessimistic isn't 00:05:03.575 --> 00:05:06.035 a good basis for judgements about the weather. 00:05:06.628 --> 00:05:08.986 Your judgement needs to have a good basis 00:05:08.986 --> 00:05:10.755 in order to count as knowledge. 00:05:11.448 --> 00:05:14.387 But what kind of basis counts as good? 00:05:15.154 --> 00:05:17.446 Do you have to be standing outside, 00:05:17.446 --> 00:05:20.268 getting wet? As you will see, 00:05:20.268 --> 00:05:22.527 in the upcoming videos on the analysis of 00:05:22.527 --> 00:05:25.179 knowledge, this is a controversial question. 00:05:25.876 --> 00:05:28.328 But before we get to that problem, we'll 00:05:28.328 --> 00:05:32.598 tackle a more basic problem: is knowledge even 00:05:32.703 --> 00:05:35.913 possible for us? Even in the best case 00:05:35.913 --> 00:05:38.318 scenario, when it feels like you're standing 00:05:38.318 --> 00:05:40.565 right outside, right in the rain, can you 00:05:40.565 --> 00:05:42.709 really know that it's raining outside? 00:05:43.560 --> 00:05:46.220 Could you be dreaming for example, 00:05:46.220 --> 00:05:47.571 on a clear night? 00:05:48.330 --> 00:05:50.541 This is the problem of skepticism, 00:05:50.541 --> 00:05:53.000 explored in the next video. 00:05:53.000 --> 00:05:55.690 The two following videos will explain 00:05:55.690 --> 00:05:58.374 possible solutions to skepticism.