WEBVTT - Thought Experiments 0:00:00.160 --> 0:00:05.520 My welcome to Stuff to Blow Your Mind from how 0:00:05.559 --> 0:00:13.960 Stuff Works dot com. Hey you welcome to Stuff to 0:00:13.960 --> 0:00:16.000 Blow your Mind. My name is Robert Lamb and I'm 0:00:16.079 --> 0:00:19.239 Joe McCormick. Hey, Robert, what are we talking about today? Oh? Well, 0:00:19.239 --> 0:00:22.040 we're talking about thought experiments, the things that make some 0:00:22.120 --> 0:00:24.840 people really mad and make other people talk for way 0:00:24.840 --> 0:00:27.360 too long into time. Well, the thought experiments can have 0:00:27.440 --> 0:00:29.680 both effects on an individual at the same time. That's 0:00:29.680 --> 0:00:31.880 the beauty of a thought experiment. I think. So now, 0:00:31.920 --> 0:00:35.760 we've discussed individual thought experiments on the show many times before, 0:00:35.760 --> 0:00:38.279 but I think today we're gonna try to look at 0:00:38.320 --> 0:00:41.280 the idea of a thought experiment on the show. In 0:00:41.280 --> 0:00:45.160 the past, we've talked about specific thought experiments. We've talked 0:00:45.159 --> 0:00:48.000 about Stranger's Cat, We've talked about the Infinity Hotel, the 0:00:48.040 --> 0:00:52.200 Ship of Theseus. Other times it comes up kind of informally. 0:00:52.320 --> 0:00:54.720 We might say that a particular paper we're talking about 0:00:54.800 --> 0:00:57.080 is more kin to a thought experiment. And I know 0:00:57.320 --> 0:01:00.360 that I've I've talked before about how I think of 0:01:00.440 --> 0:01:04.080 certain short stories as being more thought experiments than you know, 0:01:04.160 --> 0:01:07.040 true narratives. I think of Library of Babbel, Library of 0:01:07.080 --> 0:01:09.880 Babble other works of a lot of the short stories 0:01:09.920 --> 0:01:12.040 of Jor Haluis Borges, as well as a number of 0:01:12.040 --> 0:01:13.880 the short stories of Philip K. Dick. They're a number 0:01:13.920 --> 0:01:16.680 of those where you know, it's not really important who's 0:01:16.720 --> 0:01:19.520 doing what exactly. You know you're not you're not really 0:01:19.520 --> 0:01:22.319 invested in a story per se, but the story is 0:01:22.360 --> 0:01:24.360 there to make you think, to turn some sort of 0:01:24.400 --> 0:01:27.320 weird idea on its head, the concept driven more than 0:01:27.400 --> 0:01:30.160 character driven exactly. Now, I have to say that one 0:01:30.200 --> 0:01:33.000 of my favorite comical treatments of thought experiments is the 0:01:33.120 --> 0:01:37.200 humorous essay Shreddnger's Cat by Steve Martin, collected in his 0:01:38.240 --> 0:01:40.920 book Pure Drivel. And there's a wonderful audio book of 0:01:40.920 --> 0:01:44.080 this as well, because Steve Martin himself is reading it. 0:01:44.200 --> 0:01:47.440 Always great when you can get one read by the author. Yeah. Now, 0:01:47.560 --> 0:01:51.800 Martin begins this particular essay by presenting the Streusenger's Cat 0:01:52.040 --> 0:01:55.200 thought experiment just pretty much as it is, and from 0:01:55.240 --> 0:01:58.520 there he proceeds through an increasingly ridiculous mix of thought 0:01:58.520 --> 0:02:02.400 experiments that he's made up in self, such as uh 0:02:02.480 --> 0:02:07.360 vitkin Stein's banana, Elvis's charcoal briquette, Chef boy r ds 0:02:07.400 --> 0:02:13.160 bungee cord, soakagaway is rain bonnet, Apollo's non apple, non strutal, 0:02:13.680 --> 0:02:19.280 Jim Dandy's bucket of goo, and the Finnman dilemma. Since 0:02:19.320 --> 0:02:21.000 it's one of the shorter ones, I'd like to read 0:02:21.080 --> 0:02:26.960 Steve Martin's description of the thought experiment. Elvis's charcoal briquette. 0:02:27.200 --> 0:02:29.800 A barbecue is cooking wieners in an air tight space. 0:02:30.360 --> 0:02:33.239 As the charcoal consumes the oxygen, the integrity of the 0:02:33.280 --> 0:02:36.919 briquette is weakened. An observer riding a roller coaster will 0:02:36.919 --> 0:02:39.640 become hungry for wieners, but will be thrown from the 0:02:39.680 --> 0:02:43.080 car when he stands up and cries, Elvis, get me 0:02:43.120 --> 0:02:47.320 a hot dog. Yeah, that's got the right mouth field. 0:02:47.840 --> 0:02:51.840 I mean, it's it's absurd, it's ridiculous and uh, but 0:02:51.880 --> 0:02:54.000 it's effective as comedy because it does have that feel 0:02:54.000 --> 0:02:56.919 of a thought of experiment. And and many of them 0:02:56.919 --> 0:03:00.120 are exactly this sort of absurd little logic problem a 0:03:00.160 --> 0:03:03.320 more physical scenario, but it's utilized not for laughs but 0:03:03.400 --> 0:03:06.880 to explore some sort of generally a complex topic. I 0:03:06.880 --> 0:03:08.880 thought this was going to be the seven thought experiments 0:03:08.919 --> 0:03:12.440 You can't say on TV that it does make me 0:03:12.480 --> 0:03:15.720 wonder what the most risk a thought experiments are. Oh, 0:03:15.760 --> 0:03:18.240 there are actually quite a few. Yeah all right, well 0:03:18.320 --> 0:03:21.600 let's we'll save that for the midnight show. So let's 0:03:21.680 --> 0:03:24.760 let's talk about thought experiments just definition wise, Like, what 0:03:25.000 --> 0:03:27.520 is the thought experiment? Well, guess, first, you could consult 0:03:27.560 --> 0:03:31.440 the idea of an experiment. An experiment is basically a test, 0:03:31.720 --> 0:03:35.880 like you have a condition and you you instantiate the 0:03:35.880 --> 0:03:39.680 condition and you see what happens. Yeah. But on the 0:03:39.680 --> 0:03:41.839 other hand, it's worth pointing out that to merely think 0:03:41.880 --> 0:03:46.040 about an experiment is not a thought experiment. So if 0:03:46.080 --> 0:03:48.200 you if you say, for instance, think about the nine 0:03:48.960 --> 0:03:53.000 social psychology Stanford prison experiment, that's not a thought experiment. 0:03:53.560 --> 0:03:56.400 Um why not? Well, because you are You're thinking about 0:03:56.400 --> 0:03:59.360 an actual experiment that has been carried out. I mean 0:03:59.400 --> 0:04:01.880 this is kind of obvious, right, but but still it 0:04:01.360 --> 0:04:04.280 it it's worth going through. Now if you if you 0:04:04.320 --> 0:04:08.040 think about an experiment you might conduct, say to see 0:04:08.080 --> 0:04:10.760 if movie goers who eat twizzlers are more likely to 0:04:10.280 --> 0:04:12.520 do to enjoy sci fi films and those who eat 0:04:12.560 --> 0:04:15.360 red vines. Well, that's not a thought experiment either. That's 0:04:15.640 --> 0:04:20.080 something you could conceivably do. That's like imagining an experiment 0:04:20.120 --> 0:04:23.159 you could carry out, but thinking about the experiment doesn't 0:04:23.200 --> 0:04:27.680 really reveal anything right now. Very often the experiment in 0:04:27.680 --> 0:04:30.479 a thought experiment is exactly not the sort of thing 0:04:30.560 --> 0:04:32.800 that could be carried out in real life for a 0:04:32.880 --> 0:04:37.799 number of reasons. Maybe it's catastrophically dangerous or in or involves, 0:04:38.320 --> 0:04:41.440 you know, in encountering some feature of the universe that 0:04:41.560 --> 0:04:45.039 is not readily it's accessible, that sort of thing. Very 0:04:45.040 --> 0:04:48.760 often thought experiments, as they apply to science, involved the 0:04:48.760 --> 0:04:53.680 the removal of things that you couldn't actually remove as variables, 0:04:53.720 --> 0:04:57.800 so like imagine a frictionless plane, or involve something that 0:04:57.880 --> 0:05:00.280 just simply does not exist, like a train go near 0:05:00.320 --> 0:05:02.200 the speed of light. We do not do not have 0:05:02.279 --> 0:05:04.479 such a thing. We're probably not gonna have such a 0:05:04.480 --> 0:05:07.520 thing anytime soon, but it's useful in the thought experiment. 0:05:07.880 --> 0:05:10.400 And then on top of that, they frequently are narrative 0:05:10.400 --> 0:05:13.239 in nature. There's a sequence to things. In a way, 0:05:13.279 --> 0:05:16.880 they're they're almost like a joke in many senses. You know, 0:05:16.920 --> 0:05:19.200 it feels like the set up for a joke. It 0:05:19.240 --> 0:05:22.000 feels like there's going to be a punch line. Um 0:05:22.040 --> 0:05:24.240 and I also I wondered to what extent like really 0:05:24.279 --> 0:05:27.479 successful and quote unquote successful thought experiments, like ones that 0:05:27.560 --> 0:05:31.400 really resonate culturally if if there is a sense of 0:05:32.520 --> 0:05:35.880 counterintuitive elements to the narrative, I wonder if there's something 0:05:35.960 --> 0:05:39.279 about that as well. Well. Yeah, thought experiments are an 0:05:39.320 --> 0:05:42.760 interesting thing. So like a good thought experiment, what it 0:05:42.800 --> 0:05:48.760 should do is reveal something that is true simply by 0:05:48.960 --> 0:05:51.880 making up a story in your mind and working through 0:05:52.000 --> 0:05:55.760 the conclusions that would result from it. Now, often there 0:05:55.760 --> 0:05:58.600 are a lot of coincidental details of this story that 0:05:58.760 --> 0:06:01.839 do not matter. Uh, they don't have any effect on 0:06:02.040 --> 0:06:05.240 what this thought experiment reveals, if it reveals anything, and 0:06:05.320 --> 0:06:08.160 yet they can be enormously predictive of whether or not 0:06:08.279 --> 0:06:11.680 this is like a popular meme or not how well 0:06:11.720 --> 0:06:14.440 it spreads. Like cats, an example, like if it were 0:06:14.560 --> 0:06:17.040 a dog, it would probably still resonate, but in a 0:06:17.080 --> 0:06:19.800 slightly different way. But if it were just a lizard 0:06:19.920 --> 0:06:22.960 or a slug, yes, people would be far less compelled 0:06:23.040 --> 0:06:26.600 by the idea of Shreddinger's bug, but they would be 0:06:26.640 --> 0:06:31.440 far more upset by the idea of Shreddinger's child or something. 0:06:31.560 --> 0:06:33.440 So like if it's a cat, that's the bull's eye, 0:06:33.480 --> 0:06:36.359 that's right in the red zone. It's like interesting enough 0:06:36.760 --> 0:06:39.080 to be killing a cat that people are on board 0:06:39.120 --> 0:06:41.560 to to remember to pay attention, but it's not so 0:06:41.640 --> 0:06:45.200 troubling that you're turned off and you don't want to listen, right, 0:06:45.279 --> 0:06:46.960 And and then also the cat kind of makes it 0:06:47.040 --> 0:06:52.200 more palpable. Like if it was Shreddinger's um, let's say, basilisk, 0:06:52.760 --> 0:06:55.599 that would it would instantly sound a little more threatening somehow, 0:06:55.800 --> 0:07:00.640 How about Shreddinger's apparently conscious AI Yes, or uh, that's 0:07:00.680 --> 0:07:03.760 the that's next level. Yeah, that's that's pretty good. Now. 0:07:04.400 --> 0:07:08.200 Another important aspect of thought experiments is that it's something 0:07:08.240 --> 0:07:11.800 that should generally be visualized in the mind as this, 0:07:12.280 --> 0:07:16.240 as the thought experiment has rolled out, you you're picturing it. Uh. 0:07:16.240 --> 0:07:18.960 It's in doing this it makes a concept more digestible, 0:07:19.120 --> 0:07:23.440 or it explains a you know, fundamental paradox, etcetera. And uh, 0:07:23.480 --> 0:07:24.920 and and and this again. It has a lot in 0:07:24.920 --> 0:07:27.000 common with jokes, It has a lot in common with riddles, 0:07:27.000 --> 0:07:30.000 and they just sort of the basic structure. But it's 0:07:30.000 --> 0:07:33.360 not necessarily bringing you to uh, it's not bringing you 0:07:33.440 --> 0:07:35.520 a punch line. It's not necessarily a correct answer at 0:07:35.520 --> 0:07:38.240 the end, but there is hopefully a deeper understanding of 0:07:38.240 --> 0:07:41.440 a concept via the thought experiment. Now that being said, 0:07:41.560 --> 0:07:44.480 a thought experiment is also not a pristine, blameless thing 0:07:44.600 --> 0:07:47.720 or something set in stone. So others may take issue 0:07:47.720 --> 0:07:50.160 with the thought experiment or just completely knock it down. 0:07:50.200 --> 0:07:53.120 They may roll out their own thought experiment that attempts 0:07:53.160 --> 0:07:56.200 to put your thought experiment to shame and uh. And 0:07:56.240 --> 0:07:58.640 there may be you know, additional interations off and we've 0:07:58.640 --> 0:08:01.280 certainly explored that on the show before with things such 0:08:01.280 --> 0:08:06.320 as the ship of Theseus. And then finally, one of 0:08:06.320 --> 0:08:10.360 the really cool things about thought experiments is that it's 0:08:11.040 --> 0:08:14.680 ideally this this chance to learn about reality, learn more 0:08:14.680 --> 0:08:18.000 about reality by simply thinking about it. And that would, 0:08:18.160 --> 0:08:20.920 on the surface of things, seem rather odd, right, because 0:08:21.560 --> 0:08:23.960 it would be an exception to the empirical nature of 0:08:23.960 --> 0:08:26.760 how we learn about the world by seeing it, by 0:08:26.800 --> 0:08:30.000 touching it, by feeling it, by poking it, by dissecting 0:08:30.040 --> 0:08:32.880 it and running, um, you know, more or less physical 0:08:32.920 --> 0:08:36.120 experiments upon it. But to simply think about something and 0:08:36.160 --> 0:08:39.199 the idea that that will reveal something that we had 0:08:39.240 --> 0:08:42.320 not seen before or it was not clear to us beforehand. Uh. 0:08:42.480 --> 0:08:45.160 That that's rather curious, isn't it. Well, yeah, I mean 0:08:45.200 --> 0:08:48.839 a thought experiment is a type of logic, which means 0:08:48.880 --> 0:08:53.360 it it lacks the empirical data gathering part of learning 0:08:53.400 --> 0:08:56.280 about the world, so all it can do is draw 0:08:56.400 --> 0:09:00.559 conclusions from what is already known or assumed, though there 0:09:00.600 --> 0:09:03.120 have been plenty of cases where in fact, in the 0:09:03.200 --> 0:09:07.000 history of science, interesting stuff has come to be known 0:09:07.200 --> 0:09:11.080 without anybody going out and measuring anything new, but just 0:09:11.240 --> 0:09:14.800 by applying what was already known in a logical way 0:09:14.840 --> 0:09:17.320 to arrive at a new conclusion. We'll talk about examples 0:09:17.320 --> 0:09:18.719 of that in a minute, all right, So I want 0:09:18.760 --> 0:09:22.360 to mention one quick example. Uh, it's not so quick 0:09:22.440 --> 0:09:27.640 in the original text, but Lucretius, who lived nine BC 0:09:27.960 --> 0:09:32.520 to b C, wrote on the Nature of Things suntura. Yeah, 0:09:33.000 --> 0:09:35.400 and uh, and he has a fun little thought experiment 0:09:35.520 --> 0:09:40.000 he rolls out. So, um, Lucretius argues that space is 0:09:40.559 --> 0:09:43.480 is infinite and what you say it isn't? Well, fine, 0:09:43.720 --> 0:09:46.679 then let's march a soldier to the edge of the 0:09:46.800 --> 0:09:50.520 finite universe and have him throw a spear at the edge. Wait, 0:09:50.600 --> 0:09:53.160 what is the soldier's name? This is crucial? Oh, I 0:09:53.240 --> 0:09:55.120 see I skipped that part. What is the soldier's name? No, 0:09:55.200 --> 0:09:56.839 I don't know. It's not. We don't need to know 0:09:56.920 --> 0:09:59.480 his name. It's just a soldier. Yeah we could, we 0:09:59.520 --> 0:10:02.880 could call him hat I guess. But um, his original 0:10:02.920 --> 0:10:06.280 write up of it is a bit longer. This boiled down. So, yeah, 0:10:06.480 --> 0:10:08.319 march the soldier up to the edge of the universe, 0:10:08.400 --> 0:10:10.959 having throw a spear at the edge. Well, one of 0:10:11.040 --> 0:10:13.000 two things is going to happen, he says. Well, if 0:10:13.040 --> 0:10:16.439 it flies through, then there is something beyond and your 0:10:16.480 --> 0:10:20.640 barrier is nonsense. So the universe is not actually bounded there, right, 0:10:20.679 --> 0:10:24.200 because you just threw a spear beyond the edge. Now, 0:10:24.280 --> 0:10:26.439 if the spear bounces off the barrier, well then the 0:10:26.520 --> 0:10:30.120 wall itself is proof of something beyond your your your 0:10:30.160 --> 0:10:32.600 spear just bounced off of something. What is that something? 0:10:32.760 --> 0:10:37.120 A wall is a thing? Yeah, so it In looking 0:10:37.160 --> 0:10:40.280 at this, you can see that it illustrates a conceived 0:10:40.480 --> 0:10:43.360 version of reality and lays out an experiment. And of 0:10:43.440 --> 0:10:45.760 course it also illustrates one of the other features of thought. 0:10:45.800 --> 0:10:49.360 Experiments you can pick at them. So Lucretius may have 0:10:49.480 --> 0:10:51.800 presented this, as you know, as a real sentence stopping 0:10:51.960 --> 0:10:53.720 comment on the nature of the universe at the time. 0:10:53.760 --> 0:10:56.120 But certainly if you if you think back of even 0:10:56.160 --> 0:10:59.319 discussions that we've had on the show about infinities and 0:10:59.440 --> 0:11:02.240 different type to the infinities, and and some of the 0:11:02.360 --> 0:11:05.800 arguments for you know, for exactly how I finite universe 0:11:05.880 --> 0:11:09.200 would work, then you can see that his argument doesn't 0:11:09.280 --> 0:11:12.360 quite hold up to modern cosmology well as you've presented 0:11:12.400 --> 0:11:15.120 it here. This is actually a great example of how 0:11:15.240 --> 0:11:19.520 thought experiments can seem brilliant but actually produce flawed conclusions 0:11:19.640 --> 0:11:24.880 because they contain drum roll hidden assumptions. Here, I would 0:11:24.920 --> 0:11:29.679 say one fatal hidden assumption is that Lucretius takes on 0:11:29.880 --> 0:11:35.559 board without considering the geometry of a finite universe. Now again, 0:11:35.600 --> 0:11:38.080 I'm certainly not going to go and argue that space 0:11:38.200 --> 0:11:40.920 is finite. That's not my goal here, But my I 0:11:40.960 --> 0:11:43.520 would say there are ways in which space could be 0:11:43.679 --> 0:11:48.560 finite that Lucretius is overlooking with this example, because there 0:11:48.559 --> 0:11:51.120 are different ways you could imagine a finite universe. One 0:11:51.320 --> 0:11:54.880 is a sort of closed three D space with exterior 0:11:55.000 --> 0:11:57.480 walls like the inside of a box. And this is 0:11:57.520 --> 0:11:59.960 sort of what Lucretius seems to have in mind here, 0:12:00.559 --> 0:12:02.679 and of course it does seem somewhat absurd. How could 0:12:02.679 --> 0:12:04.720 the universe be like that? It seems like it probably 0:12:04.760 --> 0:12:08.920 couldn't be. But what if the universe is simultaneously finite 0:12:09.120 --> 0:12:14.679 and without boundaries, like the length dimension of a mobius strip? Robert, 0:12:14.920 --> 0:12:17.880 have you ever made a mobius strip, like in geometry 0:12:17.920 --> 0:12:20.920 and school? Yeah, so you just take like one length 0:12:21.040 --> 0:12:22.959 of a piece of paper and then give it a 0:12:23.040 --> 0:12:25.920 half turn and then tape its ends together, and what 0:12:26.040 --> 0:12:29.439 you have created is a piece of paper that has 0:12:29.559 --> 0:12:32.400 one continuous side. You can start drawing a line and 0:12:32.480 --> 0:12:35.160 it goes on the entire thing. So for instance, and 0:12:35.240 --> 0:12:39.720 this this version, the soldier throws the spear and impales 0:12:39.800 --> 0:12:42.319 himself in the back exactly as long as the spear 0:12:42.400 --> 0:12:45.240 goes long enough. Yeah. So the idea, or it could 0:12:45.280 --> 0:12:48.319 be another analogy here, could be that the geometry of 0:12:48.559 --> 0:12:51.000 the three D universe is sort of like the two 0:12:51.120 --> 0:12:54.960 D geometry of the surface of a sphere. It's not infinite. 0:12:55.080 --> 0:12:57.480 The surface area of a sphere is finite. There is 0:12:57.520 --> 0:13:00.199 a limit to it, but it has no boundaries. You 0:13:00.320 --> 0:13:03.520 never reached the edge. So yeah, that's soldier. Let's let's 0:13:03.520 --> 0:13:06.160 call him Tim tim throws the spear and it hits 0:13:06.200 --> 0:13:09.120 him in the butt. Yeah. Yeah. This also reminds, you know, 0:13:09.200 --> 0:13:12.040 the idea of saying, well, hey, my soldier throws a 0:13:12.160 --> 0:13:14.360 spear at the edge of the universe and it keeps going, 0:13:14.440 --> 0:13:16.920 then your your argument is nonsense. It also kind of 0:13:16.960 --> 0:13:18.920 sounds like, oh, we had a really cold weather today. 0:13:19.160 --> 0:13:21.520 I guess there's no global warming. I guess there's no 0:13:21.640 --> 0:13:25.000 climate change. Using a far simpler model than the than 0:13:25.040 --> 0:13:28.160 the complexities of reality, try and make your argument. Well, yeah, 0:13:28.240 --> 0:13:30.400 but it does also. I mean, I would say that 0:13:30.520 --> 0:13:33.079 this is a good argument against a certain type of 0:13:33.240 --> 0:13:37.440 idea of the bounded universe, because if if the universe 0:13:37.559 --> 0:13:40.880 were actually finite in that it had walls on the 0:13:41.000 --> 0:13:43.920 outside of it, at any place you approached the wall, 0:13:44.080 --> 0:13:46.800 you could test that condition, right. So I would say 0:13:46.800 --> 0:13:49.959 that highlighting absurdity is in a single test case of 0:13:50.080 --> 0:13:52.960 the idea of a universe with walls on the outside 0:13:52.960 --> 0:13:54.959 of it, that I think that's a valid way to 0:13:55.040 --> 0:13:57.800 criticize the concept. Now, I do have to say at 0:13:57.840 --> 0:14:01.319 the same time, Lucretius is a little thought experiment here, 0:14:02.160 --> 0:14:05.200 even to modern readers it it still does something when 0:14:05.240 --> 0:14:06.880 you think about it like it does force you to 0:14:06.960 --> 0:14:10.199 think about the uh these ideas of the finite and 0:14:10.240 --> 0:14:13.600 the infinite. Uh So, just as like a simple thought 0:14:13.640 --> 0:14:16.720 experiment is kind of a logic puzzle, it still carries 0:14:16.760 --> 0:14:20.640 its own weight. Now, they're absolutely have been thought experiments 0:14:20.960 --> 0:14:25.600 that have been extremely useful and powerful in the history 0:14:25.680 --> 0:14:28.600 of the advancement of science, that have not just like 0:14:28.840 --> 0:14:33.560 made a clever seeming point, but have actually pushed science forward. 0:14:34.040 --> 0:14:35.520 And these happen a lot of time in the history 0:14:35.560 --> 0:14:38.600 of physics because physics experiments work best when you can 0:14:38.720 --> 0:14:42.280 tightly limit the variables. But in reality, it is very 0:14:42.360 --> 0:14:47.080 hard to tightly limit the variables on pure physics experiments. Uh. 0:14:47.200 --> 0:14:49.880 There there's often just a lot of like more more friction, 0:14:50.160 --> 0:14:54.280 more resistance, more whatever than you actually want. But here's 0:14:54.280 --> 0:14:57.240 an example. Let's say you go up on top of 0:14:57.480 --> 0:15:01.200 the Washington Monument and you drop to objects side by side. 0:15:01.640 --> 0:15:04.320 They're the same shape, but one is heavier than the other. 0:15:04.400 --> 0:15:07.240 Let's say one is a plastic DVD of Flubber and 0:15:07.360 --> 0:15:10.440 the other is the new Criterion edition of RoboCop two, 0:15:10.520 --> 0:15:13.160 which has a jewel case made out of lead. So 0:15:13.440 --> 0:15:15.840 which one hits the ground first? Well, ideally they're both 0:15:15.840 --> 0:15:17.640 going to hit the ground at the same time, right, 0:15:17.760 --> 0:15:19.840 And you know that because we live in a post 0:15:20.040 --> 0:15:24.400 Galileo age, the post Copernican post Galileo age. But this 0:15:24.560 --> 0:15:26.360 might have been kind of a shock to you if 0:15:26.400 --> 0:15:30.120 you lived in say, ancient Rome, or in medieval Europe, 0:15:30.400 --> 0:15:32.960 where it might well have been assumed that the heavier 0:15:33.120 --> 0:15:38.080 object would hit the ground first because heavier objects fall faster. 0:15:38.600 --> 0:15:43.320 For hundreds of years, the conventional wisdom was along these lines. 0:15:43.400 --> 0:15:47.120 It followed our intuitions, like, it makes intuitive sense that 0:15:47.240 --> 0:15:50.960 a heavier object falls faster because let's say it's harder 0:15:51.040 --> 0:15:54.200 to push a heavier object up a hill, right, So 0:15:54.400 --> 0:15:56.560 it would seem that a heavier object should fall to 0:15:56.640 --> 0:15:59.440 the ground through the air faster than a lighter object. 0:16:00.200 --> 0:16:02.680 This was the dominant strain of thinking also in in 0:16:02.880 --> 0:16:06.280 the sphere of scholars who revered the physics of Aristotle. 0:16:06.680 --> 0:16:09.720 Aristotle wrote in in his work on Physics, that objects 0:16:09.800 --> 0:16:12.840 have a natural motion, They have a nature, and they 0:16:12.920 --> 0:16:16.200 have motions specific to their nature, and that part of 0:16:16.280 --> 0:16:19.360 that nature is mass. And so heavier objects fall to 0:16:19.440 --> 0:16:23.440 the ground faster than lighter objects. Now, Galileo GALILEI was 0:16:23.520 --> 0:16:26.880 reported by some biographers to have actually performed an experiment 0:16:27.040 --> 0:16:30.520 of this kind by like dropping cannonballs of different weights 0:16:30.560 --> 0:16:32.640 from a tower. But whether or not this story is 0:16:32.720 --> 0:16:36.760 true about the physical experiment, Galileo definitely showed that you 0:16:36.840 --> 0:16:39.880 don't even need an experiment to prove that there is 0:16:40.000 --> 0:16:44.040 something wrong with the Aristotelian view of falling bodies. He 0:16:44.080 --> 0:16:46.400 could show it was wrong just by dreaming up a 0:16:46.480 --> 0:16:49.760 scenario in his head. As and as with many of 0:16:49.840 --> 0:16:54.280 the great intellectual smackdowns in history, Galileo didn't just explain 0:16:54.440 --> 0:16:59.360 his position. He wrote a fictional Socratic style dialogue, complete 0:16:59.400 --> 0:17:03.080 with a act jawed fool to represent the opinion he 0:17:03.240 --> 0:17:08.400 was attacking. And that fool is named Simplicio. That's pretty good. 0:17:08.640 --> 0:17:11.400 Then he's also he's got a smart guy named Salviati 0:17:11.520 --> 0:17:13.920 to represent his own point of view. And this was 0:17:14.000 --> 0:17:18.720 in dialogues concerning two new sciences in sight. So first 0:17:18.960 --> 0:17:24.160 Salviati and Simplicio argue about experiments concerning cannonballs and bird 0:17:24.240 --> 0:17:27.760 shot and stuff. And Simplicio is not moved from the 0:17:27.840 --> 0:17:31.159 Aristotelian position that objects fall through a medium with a 0:17:31.320 --> 0:17:34.800 speed proportional to their mass. And so I've tried to 0:17:34.880 --> 0:17:37.879 reconstruct the next moment in the dialogue, but sort of 0:17:37.960 --> 0:17:41.320 rewritten in more modern English and simplified to the main points. Robert, 0:17:41.359 --> 0:17:44.200 would you like to do a reading with me? Sure? 0:17:44.240 --> 0:17:46.320 What kind of accents are we going for here? Robert, 0:17:46.320 --> 0:17:48.159 you're gonna be the smart guy. How about you give 0:17:48.240 --> 0:17:54.200 me a combination of like Gandalf wizard Saruman pronouncing from 0:17:54.440 --> 0:17:57.800 from the top of the Tower of Knowledge, combined with 0:17:58.160 --> 0:18:02.000 like Sam Elliott Wisel cowboy. All right, I'll give that 0:18:02.080 --> 0:18:06.399 a goin Now, look here, we don't even need to 0:18:06.480 --> 0:18:09.520 do any experiments to prove that Aristotle is wrong and 0:18:09.600 --> 0:18:12.840 a heavier body does not fall faster than a lighter one. 0:18:13.240 --> 0:18:16.320 Let's take Aristotle's principles as granted for a minute. What 0:18:16.520 --> 0:18:20.760 are those principles. Well, body falling in a fixed medium 0:18:20.880 --> 0:18:24.119 like air has a fixed velocity, and that's determined by 0:18:24.160 --> 0:18:27.359 its nature. And you can increase this speed unless you 0:18:27.400 --> 0:18:30.720 add momentum. And you can't decrease this speed unless you 0:18:30.800 --> 0:18:33.600 offer some resistance to slow it down. It's all there 0:18:33.680 --> 0:18:37.760 and its nature. It's a fixed velocity. Great, So imagine 0:18:37.800 --> 0:18:41.560 two objects with different natural speeds, maybe a pebble which 0:18:41.640 --> 0:18:45.160 falls very slowly, and a great millstone which falls very fast. 0:18:45.280 --> 0:18:49.520 Now time together, the fallen millstone will be slowed down 0:18:49.600 --> 0:18:51.840 by being tied to the pebble, which is forced by 0:18:51.880 --> 0:18:55.160 its nature to fall slower. Right right, You are, according 0:18:55.240 --> 0:18:57.720 to Aristotle, that pebble is going to slow down the 0:18:57.760 --> 0:19:00.760 bigger rock because it falls slower. Go okay, So by 0:19:00.880 --> 0:19:04.200 by tying the two stones together, the slower fall on 0:19:04.320 --> 0:19:07.840 pebble should reduce the speed at which the millstone falls, 0:19:07.920 --> 0:19:10.680 making its speed less than it would have been alone. 0:19:11.359 --> 0:19:13.560 But at the same time, when you tie them together, 0:19:13.640 --> 0:19:17.360 their combined masses greater than the millstone alone. So shouldn't 0:19:17.400 --> 0:19:21.760 they together fall even faster than either one individually? From 0:19:21.800 --> 0:19:24.680 your principles of motion, we are forced to conclude that 0:19:24.800 --> 0:19:27.440 by tying the two stones together, the falling speed of 0:19:27.480 --> 0:19:31.520 the millstone is both increased and decreased. Well, dang it, 0:19:32.000 --> 0:19:35.480 I am stumped, all right, So that that's that's pretty 0:19:35.480 --> 0:19:38.960 fun because it basically illustrates how he's created kind of 0:19:39.200 --> 0:19:42.159 like a little political cartoon right here, right right. And 0:19:42.240 --> 0:19:46.640 I also absolutely love that he makes the representative of Aristotle, 0:19:46.720 --> 0:19:49.800 who was during the seventeenth century widely considered like the 0:19:50.040 --> 0:19:55.240 smartest guy of all time. He names him Simplicito, which 0:19:55.400 --> 0:19:58.480 is like if somebody today wrote a dialogue trying to 0:19:58.560 --> 0:20:02.960 refute Einstein's relati civity and had the character representing Einstein's 0:20:03.000 --> 0:20:07.199 point of view named like cletaus t dip Wad. But anyway, 0:20:07.280 --> 0:20:11.159 Karl Popper apparently wrote of this thought experiment quote one 0:20:11.200 --> 0:20:14.600 of the most important imaginary experiments in the history of 0:20:14.720 --> 0:20:18.360 natural philosophy and one of the simplest and most ingenious 0:20:18.520 --> 0:20:21.760 arguments in the history of rational thought about our universe. 0:20:22.760 --> 0:20:26.960 And as far as like imagining physical scenarios goes, I 0:20:27.080 --> 0:20:30.520 think this is the equivalent of a reductio ad absurd 0:20:30.600 --> 0:20:33.760 um argument. So reduction reductio ad absurd um is one 0:20:33.760 --> 0:20:36.440 of the most powerful logical tools we have. It's when 0:20:36.480 --> 0:20:39.879 you combine premises that somebody holds to be true and 0:20:39.960 --> 0:20:43.320 you demonstrate that when they're taken together, they force you 0:20:43.480 --> 0:20:47.800 to conclude something absurd that cannot possibly be true, which 0:20:47.880 --> 0:20:50.200 means at least one of the premises, even though you 0:20:50.320 --> 0:20:54.320 believe them, actually cannot be right. And so here Galileo 0:20:54.520 --> 0:20:57.440 is basically using two premises. One is that the the 0:20:57.560 --> 0:21:01.160 idea that objects of different mass have different natural speeds 0:21:01.240 --> 0:21:03.920 at which they fall. And the other is that you 0:21:04.040 --> 0:21:06.720 can add the mass of two objects together to create 0:21:06.760 --> 0:21:10.240 a greater combined mass. And so he constructs a scenario 0:21:10.440 --> 0:21:13.280 when it's actually not implausible at all to show that, 0:21:13.400 --> 0:21:16.960 when taken together, these two premises implied something absurd and 0:21:17.080 --> 0:21:20.639 self contradictory. So one of the premises has got to 0:21:20.760 --> 0:21:23.760 be wrong. And since we accept the basic arithmetic of 0:21:23.880 --> 0:21:26.040 mass that you can add the mass of two objects 0:21:26.080 --> 0:21:28.920 together to create a greater combined mass, it showed that 0:21:29.000 --> 0:21:31.879 the idea of a fixed falling speed determined by an 0:21:31.920 --> 0:21:34.840 object's mass had to be wrong. So I would say 0:21:34.880 --> 0:21:38.840 this is absolutely a case where a thought experiment actually 0:21:39.000 --> 0:21:44.040 did reveal something useful about reality. Though of course it's 0:21:44.160 --> 0:21:45.879 it's helpful as well that you could go out and 0:21:46.000 --> 0:21:48.600 test this with physical objects later. You you know, you 0:21:48.680 --> 0:21:52.119 do so, even if there's some hidden assumption that's guming 0:21:52.200 --> 0:21:55.159 up the conclusions you're drawing from this thought experiment, you 0:21:55.240 --> 0:21:58.280 could do physical experiments that would sort you out later. 0:21:58.720 --> 0:22:00.480 All right, Well, on that note, let's take a break, 0:22:00.520 --> 0:22:03.080 and when we come back, we'll explore some more examples 0:22:03.119 --> 0:22:05.720 of thought experiments before we discuss a little bit of 0:22:05.760 --> 0:22:08.240 a bit more about what exactly that they are and 0:22:08.359 --> 0:22:13.800 how we might categorize them. Thank alright, we're back. So 0:22:13.920 --> 0:22:16.359 Joe is a time for Jim Dandy's bucket of goose. No, 0:22:16.520 --> 0:22:19.639 let's do Newton's bag of cheese. Sounds good? Okay? So 0:22:20.080 --> 0:22:24.840 Galileo's rocks obviously are not the only famous imaginary falling 0:22:24.920 --> 0:22:28.639 objects to provoke advances in physics. Uh The seventeenth and 0:22:28.720 --> 0:22:32.240 eighteenth century English poly math Isaac Newton was also responsible 0:22:32.320 --> 0:22:36.359 for many famous thought experiments that illustrated his revolutionary ideas. 0:22:36.840 --> 0:22:40.160 Probably the most famous and enduring is what I'm gonna 0:22:40.240 --> 0:22:44.600 call ballistic mountain. So back in Newton's day and there 0:22:44.680 --> 0:22:47.679 was a lot of confusion about different types of motion 0:22:48.200 --> 0:22:51.000 and what explained the motion of objects in the heavens. 0:22:51.400 --> 0:22:53.920 A good example would be, let's say you drop a 0:22:54.040 --> 0:22:57.640 wool sack full of goat cheese from a tower. Which 0:22:57.720 --> 0:23:01.040 direction does it travel? Goes straight down right? You wouldn't 0:23:01.040 --> 0:23:03.959 want to be standing under that goat cheese. And at 0:23:04.000 --> 0:23:07.520 the same time, scholars recognize that the Earth was spherical 0:23:07.720 --> 0:23:10.560 or roughly spherical, as had been proved for many hundreds 0:23:10.600 --> 0:23:13.679 of years, and it almost seemed as if objects were 0:23:13.720 --> 0:23:16.960 being pulled straight down towards the center of the Earth, 0:23:17.680 --> 0:23:19.920 and the Earth seemed to pull all objects toward it 0:23:20.000 --> 0:23:23.040 at a constant rate, as Galileo had showed, regardless of 0:23:23.119 --> 0:23:25.919 the mass of that object. And you see this all 0:23:25.960 --> 0:23:28.800 the time, even if you throw an object horizontally. Let's 0:23:28.800 --> 0:23:31.800 say you are hurling a wool sack full of goat 0:23:31.920 --> 0:23:36.119 cheese at your enemy, the Royal astronomer John Flamsteed. If 0:23:36.119 --> 0:23:38.639 Flamsteed is too far away when you throw the sack, 0:23:38.800 --> 0:23:41.360 obviously the gravity is going to pull the sack down 0:23:41.400 --> 0:23:44.200 to the Earth before it hits him. Gravity always pulls down. 0:23:44.800 --> 0:23:47.239 But then contrast that with if you look up at 0:23:47.240 --> 0:23:50.160 the heavens at night, you will observe that the motion 0:23:50.240 --> 0:23:53.480 of the planet seems to be governed by another force entirely. 0:23:53.880 --> 0:23:57.600 Instead of falling straight into the Sun or into the Earth, 0:23:57.920 --> 0:24:00.840 the planet seemed to travel through the heaven in smooth, 0:24:01.280 --> 0:24:05.720 roughly circular elliptical orbits, just as the Moon seems to 0:24:05.840 --> 0:24:09.760 travel in a smooth elliptical track around the Earth. So 0:24:10.359 --> 0:24:12.800 how could the motion seen in the heavens be so 0:24:13.000 --> 0:24:15.840 different from the motion scene on Earth? Like was there 0:24:15.880 --> 0:24:19.480 a divine hand guiding how the planets traveled through the void. 0:24:19.880 --> 0:24:22.960 So Newton proposed a thought experiment in his Principia, and 0:24:23.000 --> 0:24:25.879 it went roughly like this, Robert, imagine, we're gonna get 0:24:25.960 --> 0:24:27.800 up on top of the tallest mountain on Earth, the 0:24:27.880 --> 0:24:31.639 Gigantic Monster Mountain. Maybe it's on the North Pole, all right. 0:24:32.320 --> 0:24:34.359 I guess it wouldn't because there's no land there. But 0:24:34.840 --> 0:24:38.520 maybe it could be the Mountain of Purgatory from from 0:24:38.880 --> 0:24:41.800 Dante's Divine Comedy. For all of Isaac newton sins, of 0:24:41.880 --> 0:24:44.200 which there were many, because he was a jerk, so 0:24:44.440 --> 0:24:46.960 work off those piece. So he climbs up to the 0:24:47.000 --> 0:24:49.040 top of the Mountain of Purgatory, oh, which I guess 0:24:49.119 --> 0:24:52.200 is earthly paradise, right. But but he gets up there 0:24:52.600 --> 0:24:55.800 and he brings a cannon with him. Oh that's that's. 0:24:55.880 --> 0:24:58.440 That's already. I feel like it's probably breaking some rules, 0:24:58.480 --> 0:25:00.440 but okay, yes, and it's in a salt on the 0:25:00.520 --> 0:25:03.240 heavens already. But it's an assault on the heavens in 0:25:03.320 --> 0:25:06.040 more ways than one, more way than one, more ways 0:25:06.080 --> 0:25:10.159 than one. I never know how to pluralize that correctly anyway, 0:25:10.200 --> 0:25:11.600 So let's say you got the cannon up at the 0:25:11.640 --> 0:25:13.960 top of the mountain. You shoot a cannon ball out 0:25:14.000 --> 0:25:16.600 parallel to the ground at a hundred kilometers per hour. 0:25:17.119 --> 0:25:20.200 What happens, Well, it travels in the familiar arc that 0:25:20.320 --> 0:25:23.960 any anybody who has used a firearm like that will recognize. 0:25:24.320 --> 0:25:26.760 So it goes horizontally at a hundred kilometers per hour 0:25:27.119 --> 0:25:31.080 while simultaneously falling towards the ground at the normal acceleration, 0:25:31.680 --> 0:25:33.879 and eventually it hits the ground with a thud. But 0:25:34.040 --> 0:25:37.200 let's say you pack more gunpowder into the cannon and 0:25:37.320 --> 0:25:40.040 shoot the ball out of the barrel faster, say two 0:25:40.200 --> 0:25:43.520 hundred kilometers per hour. What happens, Well, it makes an 0:25:43.680 --> 0:25:46.479 arc again, but the arc is a slightly different shape. 0:25:46.600 --> 0:25:49.720 It falls to the ground at the same rate as before, 0:25:50.160 --> 0:25:53.200 but this time it travels a lot farther horizontally before 0:25:53.240 --> 0:25:56.760 it hits the ground. Now, imagine you just keep packing 0:25:56.880 --> 0:25:59.359 more and more power into the cannon, so that the 0:25:59.440 --> 0:26:02.639 ball goes farther every time before it hits the ground. 0:26:03.080 --> 0:26:05.200 The rate at which the cannonball falls is going to 0:26:05.320 --> 0:26:08.159 always stay the same, but the horizontal speed and the 0:26:08.240 --> 0:26:12.920 horizontal distance covered keeps increasing. And then combine this with 0:26:13.080 --> 0:26:15.560 the idea that the Earth is a sphere, which they 0:26:15.640 --> 0:26:18.159 knew at the time of of Newton. This means that 0:26:18.240 --> 0:26:21.760 eventually you will shoot the cannonball at a speed where 0:26:21.840 --> 0:26:25.760 it travels so fast that it's falling arc is greater 0:26:26.160 --> 0:26:29.000 than the curve of the Earth. So it flies and 0:26:29.160 --> 0:26:32.800 it falls, but it never hits the ground. It travels 0:26:32.840 --> 0:26:36.040 around the Earth in a continuous circle. So the cannonball 0:26:36.119 --> 0:26:39.160 is still governed by the same two forces, gravity which 0:26:39.240 --> 0:26:41.240 wants to pull the cannonball towards the center of the 0:26:41.280 --> 0:26:44.520 Earth in inertia, which wants to keep the cannonball traveling 0:26:44.560 --> 0:26:47.960 in a straight line. But they these forces combine to 0:26:48.080 --> 0:26:51.160 cause the ball to just keep flying around the Earth 0:26:51.200 --> 0:26:53.960 in a circle in space. And Newton had a very 0:26:54.000 --> 0:26:57.239 famous illustration of this that that sort of helped make 0:26:57.320 --> 0:27:00.280 his point, where he showed arcs of of cannon balls 0:27:00.400 --> 0:27:03.680 falling off and becoming longer and longer until they just 0:27:03.960 --> 0:27:07.800 became a circle. And now the crucial extrapolation is this 0:27:08.040 --> 0:27:10.560 is what planets due to the Sun and what the 0:27:10.640 --> 0:27:13.840 Moon does to the Earth. So Newton had used nothing 0:27:13.920 --> 0:27:17.600 more than an imaginary scenario to demonstrate good reason for 0:27:17.720 --> 0:27:22.000 believing something shocking that the forces that govern the heavens 0:27:22.400 --> 0:27:24.920 and the forces that govern the movement of objects on 0:27:24.960 --> 0:27:28.399 the Earth like cannonballs or wool sacks full of cheese 0:27:28.720 --> 0:27:32.560 are exactly the same. This is the unification of terrestrial 0:27:32.720 --> 0:27:35.720 and celestial forces. And this this is a key principle 0:27:36.080 --> 0:27:39.520 in establishing the modern age of physics. And it's rather 0:27:39.600 --> 0:27:42.359 brilliant too. And then he took something that was there 0:27:42.440 --> 0:27:45.560 was so so much more relatable in order to explain, 0:27:46.200 --> 0:27:49.119 you know, the movement of the spheres. Yeah, exactly. And 0:27:49.200 --> 0:27:51.320 of course this is a case where a thought experiment, 0:27:51.400 --> 0:27:55.280 while revolutionary, was not enough to prove the case. Fortunately 0:27:55.359 --> 0:27:59.680 Newton had conducted ingenious real world experiments also, so in 0:27:59.760 --> 0:28:02.560 this case it was the use of a pendulum combined 0:28:02.640 --> 0:28:06.639 with astronomical observations to show that the Moon falls towards 0:28:06.680 --> 0:28:09.639 the Earth at about the same speed as objects dropped 0:28:09.720 --> 0:28:12.280 on Earth fall toward the ground, which is a funny 0:28:12.320 --> 0:28:15.320 thing to consider whether you're dropping a bag of cheese 0:28:15.359 --> 0:28:17.640 out of an airplane or watching the Moon fall toward 0:28:17.680 --> 0:28:20.080 the Earth. They followed about the same rate, but the 0:28:20.119 --> 0:28:23.440 Moon's competing inertia and position of course keep it in orbit, 0:28:23.840 --> 0:28:27.080 and there are of course powerful implications that followed from Newton. 0:28:27.160 --> 0:28:29.480 These could be put to use in rocketry, like ultimately 0:28:29.920 --> 0:28:32.280 we had to figure out the delta V required to 0:28:32.320 --> 0:28:35.520 achieve lower thorbit and to escape Earth's orbit entirely if 0:28:35.560 --> 0:28:38.760 we wanted to say, send probes to other planets. Uh 0:28:38.840 --> 0:28:40.640 And and by the way, I didn't make up the 0:28:40.680 --> 0:28:43.200 part about the sack of cheese. But Newton did actually 0:28:43.280 --> 0:28:46.920 have enemies. And just to tell one quick story, there 0:28:47.000 --> 0:28:50.480 was this astronomer named John Flamsteed. I mentioned him earlier, 0:28:51.000 --> 0:28:54.400 and Newton was pretty much a total jerk. Flamsteed was 0:28:54.600 --> 0:28:57.720 this English astronomer. He was the English Astronomer Royal during 0:28:57.760 --> 0:29:01.400 Newton's time, and he was working on catalog of objects 0:29:01.480 --> 0:29:06.240 in the heavens. And Newton wanted access to Flamsteed's catalog. Basically, 0:29:06.320 --> 0:29:08.440 he wanted data so he could use it to prove 0:29:08.520 --> 0:29:12.280 his theories. But Flamesteed wasn't done putting it together yet, 0:29:12.720 --> 0:29:16.880 believing it wasn't ready for publication. So Newton constantly harassed 0:29:16.960 --> 0:29:20.080 and bullied him to get this information. Eventually threw his 0:29:20.160 --> 0:29:23.400 weight around with the English Royalty to get Flamsteed's catalog 0:29:23.560 --> 0:29:26.560 published early before it was ready, which Flamsteed did not 0:29:26.720 --> 0:29:29.480 like at all. There's also a story that Newton, as 0:29:29.560 --> 0:29:32.360 the president of the Royal Society, went to the Royal 0:29:32.440 --> 0:29:36.040 Observatory to inspect Flamsteed's equipment and they got into a fight, 0:29:36.520 --> 0:29:40.360 and Flamesteed wrote that quote Newton ran himself into a 0:29:40.480 --> 0:29:44.760 great heat and very indecent passion, and he used knavish 0:29:44.840 --> 0:29:48.480 talk and called me all the ill names puppy, etcetera 0:29:48.680 --> 0:29:52.160 that he could think of. So like Newton's out there 0:29:52.200 --> 0:29:55.560 like screaming and other scientists calling them puppies, just thinking 0:29:55.600 --> 0:29:59.360 a real real ass of himself. Yeah, anyway, shows that 0:29:59.440 --> 0:30:01.880 even some of the smartest people ever can are not 0:30:02.080 --> 0:30:05.440 above you know, puppy calling. Well, I mean it makes sense. 0:30:05.520 --> 0:30:07.440 Wasn't new In a a more of a cat person? 0:30:07.680 --> 0:30:11.440 Didn't he uh oh for cats to move in and 0:30:11.520 --> 0:30:13.840 out of the chambers of his house. I didn't look 0:30:13.880 --> 0:30:16.480 up the usage history of that word, so I don't 0:30:16.560 --> 0:30:18.840 know exactly what it meant to call somebody a puppy 0:30:18.960 --> 0:30:22.920 and whatever year this was, but profanity scholars right in 0:30:23.320 --> 0:30:26.080 might a smart Yeah what does that mean? Did he 0:30:26.160 --> 0:30:29.080 just literally mean like a young dog? I hope. So 0:30:29.240 --> 0:30:32.000 that's the that's that's a funny interpretation. Well it sounds 0:30:32.000 --> 0:30:35.360 like Navish talk either way totally. So what are the 0:30:35.400 --> 0:30:37.440 examples do you have for us? Well, just a few 0:30:37.640 --> 0:30:40.560 quicker ones in in physics, and of course one of 0:30:40.640 --> 0:30:43.600 my favorites is that people dreamed up the concept of 0:30:43.680 --> 0:30:46.680 a black hole as a mathematical thought experiment, long before 0:30:46.760 --> 0:30:49.120 any evidence of such a thing had ever been detected, 0:30:49.280 --> 0:30:52.560 Like we talked about this in our black Holes episode. 0:30:52.600 --> 0:30:55.560 But around seventeen eighty three and seventeen eighty four, the 0:30:55.640 --> 0:30:59.520 English natural philosophers John Michelle and Henry Cavendish dared to 0:30:59.640 --> 0:31:03.040 ask a bizarre question. So they knew that light itself 0:31:03.200 --> 0:31:06.240 had a speed, and they were armed with Newton's insights 0:31:06.280 --> 0:31:10.040 about gravity, inertia, orbits, and escape velocity, So they asked, 0:31:10.440 --> 0:31:13.280 what if there were a star so massive with with 0:31:13.520 --> 0:31:17.960 such a great gravitational attraction that escape velocity for this 0:31:18.160 --> 0:31:21.480 star was greater than the speed of light. In other words, 0:31:21.520 --> 0:31:24.600 a star so massive that even light could not escape it. 0:31:25.000 --> 0:31:28.720 And this was perhaps the earliest formulation of the concept 0:31:28.800 --> 0:31:31.080 of a black hole, which would later be developed by 0:31:31.160 --> 0:31:35.800 so many other important astrophysicist Karl Schwartz, Shield, Chander, Shaker, 0:31:35.920 --> 0:31:38.960 Oppenheimer and others. And and if you want more on that, 0:31:39.120 --> 0:31:41.280 we have a whole episode about it from earlier this year. 0:31:41.320 --> 0:31:44.360 Oh yeah, we did a three parter on black holes. Uh. Then, 0:31:44.400 --> 0:31:47.920 of course, the thought experiments are huge in illustrating the 0:31:48.040 --> 0:31:51.400 concepts of relativity in the speed of light, Like Einstein 0:31:51.600 --> 0:31:54.920 is famous for influential thought experiments, But we shouldn't just 0:31:55.040 --> 0:31:58.200 focus on the ones that have been very influential in physics, because, 0:31:58.240 --> 0:32:01.240 of course, thought experiments are probably even more common in 0:32:01.360 --> 0:32:04.600 philosophy than they are in physics, even more common. And 0:32:05.400 --> 0:32:07.360 I don't want to be insulting to philosophy because I 0:32:07.480 --> 0:32:10.160 value philosophy, but I would say even more common and 0:32:10.840 --> 0:32:15.960 less often useful. Uh, they can still be illuminating, but 0:32:16.440 --> 0:32:19.600 I think we need to realize that, especially in scenarios 0:32:19.720 --> 0:32:23.000 where we can't actually test the conclusions of a thought 0:32:23.040 --> 0:32:25.840 experiment in any kind of way, we should be careful 0:32:25.920 --> 0:32:30.360 that thought experiments don't cloud are thinking more than they reveal. Well, 0:32:30.760 --> 0:32:33.880 don't encounter thought experiments to deal with things like morality, right, 0:32:34.680 --> 0:32:37.440 and ultimately, how do you measure those things? Yes? And 0:32:37.800 --> 0:32:39.959 the I feel like those kinds of thought experiments are 0:32:40.160 --> 0:32:43.600 especially prone to be confusing because they deal with the 0:32:43.680 --> 0:32:48.520 lucretious problem. We talked about bringing in unexamined assumptions that 0:32:48.600 --> 0:32:52.360 are influencing our thinking without us realizing it. So I 0:32:52.440 --> 0:32:55.480 think we should mention just one example of a prominent, 0:32:55.600 --> 0:33:00.720 extremely controversial thought experiment in philosophy. There's been a mountain 0:33:00.800 --> 0:33:02.840 of debate on this one, so I know we're not 0:33:02.920 --> 0:33:04.480 going to be able to do it justice in the 0:33:04.560 --> 0:33:06.360 time we have, we'll try to give it the best 0:33:06.640 --> 0:33:10.640 quickest version we can. So this is John Searle's Chinese 0:33:10.840 --> 0:33:13.640 Room thought experiment. Robert, I know you must have encountered 0:33:13.720 --> 0:33:17.680 this one before. Yeah, So the question is, we know 0:33:17.800 --> 0:33:22.920 we can program computers to mimic the intelligent behavior of humans, 0:33:23.280 --> 0:33:25.640 but would it ever be possible for a computer to 0:33:25.760 --> 0:33:32.000 truly understand something? Or can it only simulate understanding? And 0:33:32.080 --> 0:33:34.240 this has often taken as sort of an analog of 0:33:34.280 --> 0:33:37.120 the question of can machines be conscious? Right, And no, 0:33:37.320 --> 0:33:39.880 we've we've discussed this quite a bit on the show before. 0:33:40.080 --> 0:33:43.280 Maybe not specifically this thought experiment I don't recall off hand, 0:33:43.360 --> 0:33:47.120 but just the idea that, yeah, if a robot may 0:33:47.200 --> 0:33:51.040 know what it is to stub one's toe, but does 0:33:51.040 --> 0:33:54.560 a robot really know what it's like to stub your toe? Like? 0:33:54.680 --> 0:33:57.080 Does it? It doesn't, doesn't? Does it have that experience? 0:33:57.160 --> 0:33:59.320 Does it have that knowledge? Can it? Can it sort 0:33:59.360 --> 0:34:03.400 of whole the information in its hands and squish it around. 0:34:03.840 --> 0:34:06.480 We know it can act like it understands what it 0:34:06.640 --> 0:34:10.160 means to feel pain, But does it really understand what 0:34:10.280 --> 0:34:13.400 it means to feel pain? Uh? So? The American philosopher 0:34:13.480 --> 0:34:16.240 John Searle proposed a thought experiment to answer this question 0:34:16.320 --> 0:34:18.359 in the early nineteen eighties. I think it was first 0:34:18.400 --> 0:34:21.360 in the year nineteen eighty, and his work asked us 0:34:21.400 --> 0:34:23.960 to imagine the following scenario. You already to go there 0:34:24.000 --> 0:34:27.160 with me, okay, So imagine you are an English speaker 0:34:27.520 --> 0:34:30.680 that does not understand a single word of written Chinese, 0:34:30.880 --> 0:34:34.640 absolutely nothing. Then you are locked in a room with 0:34:34.800 --> 0:34:37.560 a slot in the wall, a pencil and paper, and 0:34:37.680 --> 0:34:41.400 a giant book of instructions written in English. Every now 0:34:41.480 --> 0:34:44.920 and then someone from the outside slips a piece of 0:34:44.960 --> 0:34:47.160 paper through the slot in the wall, and it has 0:34:47.280 --> 0:34:50.239 a string of Chinese characters written on it. And then 0:34:50.320 --> 0:34:52.840 you look at this piece of paper and you consult 0:34:52.960 --> 0:34:56.920 your giant instruction manual, and the manual tells you, given 0:34:57.040 --> 0:35:01.120 certain Chinese character inputs coming through the wall, which Chinese 0:35:01.280 --> 0:35:03.799 characters to write on a piece of paper and put 0:35:04.080 --> 0:35:06.160 back out through the slot in the wall. So you 0:35:06.239 --> 0:35:09.280 write down what the instructions tell you to write based 0:35:09.320 --> 0:35:11.400 on what has come in, and then you slip the 0:35:11.440 --> 0:35:14.600 output through the slot. Now, Carl says that in this scenario, 0:35:14.800 --> 0:35:18.440 with a sufficiently powerful instruction manual, the person in the 0:35:18.520 --> 0:35:21.960 room would be able to simulate being able to understand 0:35:22.040 --> 0:35:26.600 the Chinese language despite not actually understanding a single word 0:35:26.680 --> 0:35:29.160 of it. The person is just an operator. They're just 0:35:29.320 --> 0:35:32.960 blindly copying symbols from a rule book. They don't understand 0:35:33.040 --> 0:35:36.239 what any of the symbols mean. So in the same way, 0:35:36.760 --> 0:35:40.760 Carl says that this gets extrapolated to any computer program 0:35:40.880 --> 0:35:45.279 that would supposedly pass quote pass the Turing tests, which 0:35:45.880 --> 0:35:47.880 we've discussed the turning test on the show before. But 0:35:48.000 --> 0:35:51.120 basically it means to be able to have a text 0:35:51.239 --> 0:35:54.759 based conversation with the human such that the human would 0:35:54.760 --> 0:35:57.320 believe that the machine they were chatting with was actually 0:35:57.440 --> 0:35:59.520 human as well. Can you can you fool a human 0:35:59.600 --> 0:36:02.000 into thing king you're a human by talking to them 0:36:02.040 --> 0:36:06.439 through text, and Searle says, it doesn't matter how convincingly 0:36:06.560 --> 0:36:10.040 the computer simulates being able to have a conversation in 0:36:10.160 --> 0:36:14.360 any language. It's still like the non Chinese speaker in 0:36:14.440 --> 0:36:18.120 the Chinese room. It can't really understand what it's doing. 0:36:18.200 --> 0:36:22.239 It's only blindly following instructions that create an illusion of 0:36:22.400 --> 0:36:27.080 understanding where true understanding is impossible. Now, there have been 0:36:27.320 --> 0:36:30.040 tons of responses to this scenario over the years, and 0:36:30.080 --> 0:36:32.000 I think we'll come back to this towards the end 0:36:32.040 --> 0:36:36.200 of the episode. But the idea is the thought experiment 0:36:36.360 --> 0:36:39.560 of imagining the person in the Chinese room leads you 0:36:39.719 --> 0:36:42.280 to new knowledge. It should lead you to the correct 0:36:42.400 --> 0:36:46.560 conclusion that it's impossible for a machine to understand something, 0:36:46.719 --> 0:36:51.759 or at least a machine interpreting formal instructions. Robert, I, 0:36:51.960 --> 0:36:54.160 I could almost detect by the way you're furrowing your 0:36:54.200 --> 0:36:57.319 brow that this this one's filling you with venom. Well, 0:36:57.400 --> 0:37:00.520 the Chinese room, Yeah, um no, I mean I love it. 0:37:00.600 --> 0:37:03.719 I keep I keep wanting to say something kind of 0:37:04.080 --> 0:37:08.560 snarky about like just the human experience itself being you know, 0:37:08.719 --> 0:37:11.160 like the Chinese room where there's so much that we're 0:37:11.239 --> 0:37:13.719 doing that that we're we're not really understanding. We're just 0:37:13.840 --> 0:37:17.960 responding to stimuli and giving back what the instruction manual 0:37:18.000 --> 0:37:20.560 says we should give back. But then I do have 0:37:20.680 --> 0:37:23.759 in a way articulated one of the main types of 0:37:23.840 --> 0:37:27.040 responses to it. Yeah, but that it said yeah, but that, 0:37:27.200 --> 0:37:28.799 in my opinion, like, this is the great thing about 0:37:29.040 --> 0:37:31.719 a solid thought experiment and is in that it it 0:37:31.800 --> 0:37:36.000 provokes conversation and subsequent sort of answers and critiques of 0:37:36.080 --> 0:37:38.680 the thought experiments. Right, So I guess in a minute 0:37:38.680 --> 0:37:41.239 we are going to end up talking about sort of 0:37:41.440 --> 0:37:45.280 formal classification systems for types of thought experiments and considering 0:37:45.320 --> 0:37:49.239 how thought experiments might or might not be useful. But uh, there, 0:37:49.320 --> 0:37:51.440 I can see that there are multiple ways that one 0:37:51.520 --> 0:37:54.040 could be useful. Immediately, one could be useful in the 0:37:54.120 --> 0:37:56.799 way it's intended, meaning it can prove what it sets 0:37:56.840 --> 0:38:00.120 out to prove, or it could also be inadvertently is 0:38:00.160 --> 0:38:02.600 full in that even if it fails to prove what 0:38:02.719 --> 0:38:07.759 it sets out to prove, it could make common misunderstandings clear, right, 0:38:07.840 --> 0:38:11.000 does that make sense? YEA like reveal ways in which 0:38:11.080 --> 0:38:14.520 people's thinking is going wrong on a particular subject. Like 0:38:14.640 --> 0:38:17.719 it's like saying, here is a scenario that illustrates a 0:38:17.800 --> 0:38:20.879 way of thinking about this. And then even if if 0:38:21.120 --> 0:38:24.080 what it is presenting you with is incorrect, or has 0:38:24.120 --> 0:38:28.760 some problems, or doesn't fully match up to um scientific reality, 0:38:28.960 --> 0:38:32.960 or or just preconceived notions, then at least you have 0:38:33.160 --> 0:38:35.600 you've created the model. You have you have the model 0:38:35.640 --> 0:38:38.400 on the table, and other people can come along and say, well, 0:38:38.440 --> 0:38:40.279 you know, this is interesting, but what happens when we 0:38:40.320 --> 0:38:42.560 put a hat on this guy? What happens when there 0:38:42.600 --> 0:38:45.600 are two instruction manuals, what happens when you know the 0:38:45.800 --> 0:38:48.880 ship of theseus also has a crew, etcetera. You know, 0:38:48.920 --> 0:38:52.279 all the various complications are little tweaks that can can 0:38:52.440 --> 0:38:56.680 change the model just a little bit. I think sometimes 0:38:56.800 --> 0:38:59.359 thought experiments, even if they fail at proving what they 0:38:59.400 --> 0:39:01.680 set out to roof, can be useful in the same 0:39:01.719 --> 0:39:06.040 way that introducing terminology to a discussion can be useful, 0:39:06.360 --> 0:39:08.800 just because, like if you put an image to something 0:39:08.920 --> 0:39:11.280 or put a name to something, that makes it easier 0:39:11.360 --> 0:39:14.920 to understand what it is you're talking about. Alright, Well, 0:39:14.920 --> 0:39:16.880 on that note, let's take one more break and when 0:39:16.920 --> 0:39:20.120 we come back, we're gonna get more into this idea 0:39:20.120 --> 0:39:21.960 of what is the thought experiment and indeed, where does 0:39:22.000 --> 0:39:26.520 the term come from? Thank? Thank alright, we're back. So 0:39:27.040 --> 0:39:29.840 in looking at the history of thought experiments, you know 0:39:29.880 --> 0:39:31.880 where you able to find the oldest one on a 0:39:32.360 --> 0:39:34.759 like a like a cave wall. Uh No. But I 0:39:34.840 --> 0:39:37.560 mean we kind of end up getting into a similar 0:39:37.760 --> 0:39:40.400 situation when we start trying to think about this, because 0:39:40.960 --> 0:39:43.880 certainly we know that thought experiments were employed by a 0:39:44.120 --> 0:39:47.919 pre Socratic philosopher, So this has been before the life 0:39:47.960 --> 0:39:52.880 of Socrates, before four seventy BC. And and thought experiments 0:39:53.080 --> 0:39:55.840 are things that were essentially thought experience, were popular throughout 0:39:55.880 --> 0:39:58.040 the Middle Ages, and of course came into their own 0:39:58.239 --> 0:40:02.000 in the seventeenth century. In the centuries to follow. The 0:40:02.200 --> 0:40:06.480 term itself is often attributed to one Ernst Mock who 0:40:06.560 --> 0:40:09.239 lived at eight thirty eight through nineteen sixteen. He was 0:40:09.280 --> 0:40:13.960 an Austrian physicist and philosopher. And they point this out 0:40:14.000 --> 0:40:16.319 because he used the term, let's see, if I get 0:40:16.400 --> 0:40:21.239 this right, gadoncan experimente uh. But it seems though that 0:40:21.400 --> 0:40:23.600 like it was already in use by the time he 0:40:23.840 --> 0:40:26.000 used it, and it may have derived from the Danish 0:40:26.560 --> 0:40:31.040 uh Tunka experiment. And then it turns out that GEORGA. 0:40:31.200 --> 0:40:35.840 Lichtenberg through seventeen ninety nine he discussed quote experiments with 0:40:36.000 --> 0:40:39.200 thoughts and ideas. So funny, like all of these are 0:40:39.239 --> 0:40:43.280 coming after the advent, you know, after Galileo, like Galileo 0:40:43.400 --> 0:40:46.799 and Newton, and people had already been using these, As 0:40:46.960 --> 0:40:48.640 we said, they weren't the first to use them, but 0:40:48.719 --> 0:40:53.239 they used them in really profoundly influential ways in real science. Yeah, 0:40:53.520 --> 0:40:55.600 So it's kind of like we're looking at three phases here. 0:40:55.600 --> 0:40:57.920 There's the phase where people are actually calling it a 0:40:57.960 --> 0:41:01.239 thought experiment, there's the phase where people are using them 0:41:01.360 --> 0:41:04.440 to great effect, and ultimately, I think if we if 0:41:04.480 --> 0:41:06.759 you go back further in time, you know, get lost 0:41:06.800 --> 0:41:10.359 in the mists of of of earlier history. I think 0:41:10.400 --> 0:41:12.600 it's fair to say that thought experiments are generally a 0:41:12.719 --> 0:41:16.040 more refined idea of something that we just do as humans, 0:41:16.120 --> 0:41:20.120 and internal simulation of of observed empirical data and processes. 0:41:20.800 --> 0:41:23.520 Trying to run an experiment in your mind given what 0:41:23.680 --> 0:41:26.040 you know, right, and you know, I can imagine this 0:41:26.080 --> 0:41:27.920 is kind of getting into the territory of our our 0:41:27.960 --> 0:41:31.480 other show Invention, which everyone can can learn about invention 0:41:31.560 --> 0:41:34.600 pod dot com. It's a podcast about inventions and where 0:41:34.640 --> 0:41:39.280 they come from. Subscribe now, subscribe now now, Uh, seriously, 0:41:39.360 --> 0:41:42.640 stop and go and subscribe. But but you know, you 0:41:42.719 --> 0:41:44.799 can imagine with any of these inventions. This is even 0:41:44.840 --> 0:41:46.800 some of the ancient ones that we've talked about, Like 0:41:46.960 --> 0:41:50.880 there is a thought experiment level that is that is 0:41:50.920 --> 0:41:53.800 in play. But I don't think it's a great stretch 0:41:53.880 --> 0:41:57.480 to imagine some of these ancient inventors and inventive minds 0:41:57.640 --> 0:42:00.799 essentially engaging and thought experiments. Oh well, yeah, I mean 0:42:01.239 --> 0:42:03.279 that's an interesting way of putting it that you have 0:42:03.480 --> 0:42:06.680 to sort of before you create a tool, you have 0:42:06.840 --> 0:42:10.560 to imagine what would happen if you use something of 0:42:10.600 --> 0:42:13.680 a certain shape in a certain way without having seen 0:42:13.840 --> 0:42:16.160 something like that done before. Right. But then again, of 0:42:16.200 --> 0:42:17.680 course we go back to what we said earlier about 0:42:17.680 --> 0:42:20.080 how just envisioning an experiment you could carry out is 0:42:20.120 --> 0:42:23.839 not in and of itself a thought experiment, but it's 0:42:23.840 --> 0:42:27.160 still kind of the roots of the thought experiment, right, Um, 0:42:27.920 --> 0:42:30.440 in terms of thinking about like, well, what are some 0:42:30.600 --> 0:42:34.160 taxonomies we can refer to for thought experiments? Uh, they're 0:42:34.200 --> 0:42:38.239 basically various ways you could categorize thought experiments, but there's 0:42:38.280 --> 0:42:42.400 not really a fully agreed upon standards so much. Obviously 0:42:42.520 --> 0:42:45.680 you can categorize them by the discipline that they stem from. 0:42:45.880 --> 0:42:48.520 So here's a bunch of physics thought experiments. Here's some 0:42:48.600 --> 0:42:52.560 quantum physics thought experiments. Here's some some economic thought experiments, 0:42:52.600 --> 0:42:55.000 so psychological thought experiments. You know, we could also break 0:42:55.040 --> 0:42:57.600 them up based on their features, I guess, but I'm 0:42:57.640 --> 0:42:59.879 not surely really sure that does any good, because again, 0:43:00.400 --> 0:43:02.600 if it's a cat or a dog or basilisk, it 0:43:02.640 --> 0:43:06.480 doesn't matter. That's just some some flavoring that's added to 0:43:06.680 --> 0:43:09.720 the little story of the thought experiment. Well, I'm already 0:43:10.000 --> 0:43:12.920 seeing in the examples we've discussed so far, one clear 0:43:13.040 --> 0:43:17.040 distinction that emerges, which is the thought experiment that shows 0:43:17.280 --> 0:43:22.520 the absurdity or contradictions inherent in some pre existing idea, 0:43:23.320 --> 0:43:27.000 versus the thought experiment that demonstrates a new conclusion or 0:43:27.080 --> 0:43:32.200 show reveals new knowledge based on premises you already accept. Right, 0:43:32.480 --> 0:43:35.040 And that's that's where we come back to Karl Popper, 0:43:35.080 --> 0:43:38.759 who we talked about briefly earlier. Karl Popper was an 0:43:38.760 --> 0:43:42.440 Austrian British philosopher and professor who lived nineteen o two 0:43:42.480 --> 0:43:46.239 through and he this is this is basically how he 0:43:46.360 --> 0:43:51.240 divided up thought experiments. He said, they're basically three types heuristic, 0:43:51.480 --> 0:43:54.080 in other words, to illustrate a theory. Okay, so this 0:43:54.120 --> 0:43:56.719 would be the kind that just helps clarify what you're 0:43:56.719 --> 0:44:00.200 talking about, gives people something to picture. And you would 0:44:00.239 --> 0:44:03.160 argue that maybe I don't know what, I'm not quite 0:44:03.200 --> 0:44:06.120 sure how Newton's canon would fit in there. Was that 0:44:06.280 --> 0:44:10.280 just to illustrate or did he actually prove something using 0:44:10.360 --> 0:44:13.239 the image of the canon? Well, you could also argue 0:44:13.280 --> 0:44:16.120 that it falls into the next category, right critical against 0:44:16.200 --> 0:44:19.279 the theory, because he's kind of playing with the preconceived 0:44:19.320 --> 0:44:21.520 notions about how these things would work. Right Well, I 0:44:21.560 --> 0:44:24.200 guess yeah. It does challenge the idea that they're different 0:44:24.320 --> 0:44:27.279 mechanics at operation in the heavens than there are on 0:44:27.360 --> 0:44:30.839 the earth. And now the Carl Popper's third category then 0:44:31.080 --> 0:44:34.480 is apologetic in favor of a theory. Okay, so you've 0:44:34.520 --> 0:44:38.080 got the kind that illustrates, the kind that challenges, and 0:44:38.200 --> 0:44:41.680 the kind that argues in favor of Now, on a 0:44:41.760 --> 0:44:45.160 similar note, you have Canadian philosopher of science James Robert 0:44:45.200 --> 0:44:50.480 Brown still still alive and kicking as of this recording, 0:44:51.120 --> 0:44:55.920 and he's divided thought experiments into two major categories similar 0:44:55.920 --> 0:45:00.160 along similar lines, constructive and destructive. Okay, there's of the 0:45:00.239 --> 0:45:03.640 broad categories, okay, and then there are some some subtypes 0:45:03.760 --> 0:45:07.960 to the destructive category. So there's contradictive, this is a 0:45:08.000 --> 0:45:11.560 thought experiment that points out a contradiction to a given idea. 0:45:13.000 --> 0:45:16.560 Then there's paradoxical, so you have a thought experimentment here 0:45:16.640 --> 0:45:19.239 that shows how a given idea is conflicting with a 0:45:19.320 --> 0:45:22.560 commonly held belief. Then you have the undermine, or a 0:45:22.600 --> 0:45:26.279 thought experiment that actively undermines an idea. And then there's 0:45:26.320 --> 0:45:28.920 the counter thought experiment, a thought experiment that serves as 0:45:28.960 --> 0:45:31.640 a rebuttal to another thought experiment. You know, I think 0:45:31.680 --> 0:45:35.360 I generally would find that thought experiments are more often 0:45:35.640 --> 0:45:40.239 sound when deployed as destructive or critical tools than as 0:45:40.480 --> 0:45:44.400 constructive or apologetic tools. And I think this is because, 0:45:45.160 --> 0:45:47.920 of course, as we know, thought experiments do not provide 0:45:48.280 --> 0:45:51.640 new data or new evidence of anything. They only illustrate 0:45:51.760 --> 0:45:55.680 logical relationships between things that we already know or already believe, 0:45:56.360 --> 0:45:59.440 So they can take existing knowledge and use that to 0:45:59.560 --> 0:46:02.279 extract late to new knowledge, but it's much easier to 0:46:02.480 --> 0:46:05.600 use them in a way that's reasonable to demonstrate a 0:46:05.719 --> 0:46:09.800 contradiction between existing pieces of knowledge or principles that the 0:46:09.920 --> 0:46:13.560 extended version of the reductive ad absurdom. These are I 0:46:13.600 --> 0:46:16.960 think some of the most powerful uses of thought experiments 0:46:17.320 --> 0:46:19.279 when they when they have the power to clearly show 0:46:19.400 --> 0:46:22.839 that things that you already believe or accept or are 0:46:23.040 --> 0:46:27.320 you know, bound to accept, are in fact self contradictory. 0:46:27.760 --> 0:46:30.200 All right, so let's let's get down to one of 0:46:30.239 --> 0:46:34.440 the questions that has often discussed your regarding thought experiments. Uh, 0:46:34.800 --> 0:46:37.239 people say, well, do they really tell us anything? Oh yeah, 0:46:37.320 --> 0:46:40.279 some people hate thought experiments. I think it really just 0:46:40.560 --> 0:46:42.960 just riled up because it's like, oh, you know, it 0:46:43.040 --> 0:46:45.239 seems like this navel gazing kind of thing, Like, if 0:46:45.280 --> 0:46:47.799 you're not going to go out and do physical experiments 0:46:47.920 --> 0:46:50.960 in the physical world, what are you even talking about? 0:46:51.080 --> 0:46:53.600 Why you know, why are you wasting your time? Armchair 0:46:53.680 --> 0:46:57.080 science is is one of the criticisms is often thrown 0:46:57.120 --> 0:47:00.360 out regarding thought experiments. But of course thought experi erments 0:47:00.400 --> 0:47:02.600 have been really useful in the history of science, as 0:47:02.640 --> 0:47:06.440 we've talked about before, a lot of important advances in 0:47:06.520 --> 0:47:09.400 the history of science have been before they were confirmed 0:47:09.560 --> 0:47:14.040 in fact by physical experiments, were predicted by thought experiments. 0:47:14.120 --> 0:47:17.080 That this is a very common feature, especially in physics. 0:47:17.520 --> 0:47:19.480 I mean you could even say in fact that there 0:47:19.560 --> 0:47:22.400 there are whole realms of physics today. It's probably what 0:47:22.520 --> 0:47:25.720 you would call theoretical physics. You often hear this division 0:47:25.800 --> 0:47:30.120 of theoretical physics, physics and experimental physics. Uh, there, there's 0:47:30.200 --> 0:47:32.920 all this stuff in theoretical physics right now that we 0:47:33.040 --> 0:47:36.399 don't have a way of testing with physical experiments yet. 0:47:36.440 --> 0:47:38.719 And you can, you can kind of try to make 0:47:38.800 --> 0:47:41.960 your arguments one way or another stronger about string theory 0:47:42.200 --> 0:47:44.799 or something like that, but it just we we don't 0:47:44.880 --> 0:47:47.719 have a test for it yet. So you could say 0:47:47.840 --> 0:47:49.720 that all of that is in a way a type 0:47:49.840 --> 0:47:54.120 of mathematically elegant thought experiment. But but if you go 0:47:54.280 --> 0:47:56.480 back and look at you know, Newton and Galileo and 0:47:56.520 --> 0:47:59.719 all this, and certainly Einstein, there's no denying that thought 0:47:59.760 --> 0:48:03.759 ex periments have been extremely useful and productive in the 0:48:03.880 --> 0:48:07.560 history of physics. But thought experiments can sometimes also, as 0:48:07.600 --> 0:48:10.759 we've acknowledged, be confusing and misleading, even though there are 0:48:10.800 --> 0:48:13.640 other times illuminating. A favorite of ours on here is, 0:48:13.680 --> 0:48:16.280 of course Daniel Dennett. You know, he likes to highlight 0:48:16.360 --> 0:48:18.680 that the different kinds of thought experiments that try to 0:48:18.800 --> 0:48:23.560 leverage our intuitions into new discoveries simply by tightly controlling 0:48:23.600 --> 0:48:26.920 the variables of an imagined scenario. And some of the 0:48:27.040 --> 0:48:30.160 most famous thought experiments in history, actually, I think maybe 0:48:30.239 --> 0:48:33.480 confuse more than they illuminate. I don't want to put 0:48:33.520 --> 0:48:35.799 words in his mouth, but I think Dinnett would say 0:48:35.840 --> 0:48:39.239 this about Donald Davidson's swamp Man, which we discussed in 0:48:39.320 --> 0:48:43.399 our ship Thesist episode, or Searle's Chinese Room, which maybe 0:48:43.440 --> 0:48:46.000 we should come back to now. So we explain searles 0:48:46.120 --> 0:48:49.000 Chinese Room earlier, with the person exchanging the symbols in 0:48:49.040 --> 0:48:51.400 the room, and the question of does the person in 0:48:51.480 --> 0:48:55.120 the room who doesn't speak Chinese but can simulate perfect 0:48:55.320 --> 0:49:00.480 conversational output in Chinese by following this instruction manual, does 0:49:00.560 --> 0:49:04.120 that person really understand Chinese? And a lot of people 0:49:04.200 --> 0:49:06.920 have thought, yeah, this is a powerful disproof of the 0:49:07.040 --> 0:49:11.480 notion that computers could ever think, understand, or be conscious, 0:49:11.800 --> 0:49:14.600 and a lot of other thinkers have been incredibly critical 0:49:14.680 --> 0:49:17.000 of this. An example of a reply to the Chinese 0:49:17.120 --> 0:49:20.080 room that makes sense to me is what if what's 0:49:20.160 --> 0:49:22.320 true of the part might not be true of the 0:49:22.400 --> 0:49:26.360 system as a whole. So imagine again this person in 0:49:26.400 --> 0:49:29.240 the room. The person in the room doesn't understand Chinese, 0:49:29.280 --> 0:49:32.239 and thus the responses they produce are not meaningful to them. 0:49:32.719 --> 0:49:35.799 But you could argue that the room itself, the set 0:49:35.880 --> 0:49:40.400 of instructions, combined with the memories and sensory experiences and 0:49:40.560 --> 0:49:44.400 logic that went into the creation of the instructions, and 0:49:44.600 --> 0:49:48.440 the human operator and the pencil and paper taken together 0:49:48.680 --> 0:49:53.880 perhaps do understand Chinese. And Crle rejects this line of thinking. 0:49:54.200 --> 0:49:55.840 One of the reasons is he says, you know, this 0:49:55.960 --> 0:50:00.239 is a kind of illicit externalizing of thoughts, saying like 0:50:00.360 --> 0:50:03.359 paper could think, or a book of instructions could think, 0:50:04.360 --> 0:50:06.920 but but like I think, like he's the person who 0:50:06.960 --> 0:50:09.719 put this system together. You know, you are the one 0:50:09.760 --> 0:50:12.280 who put a human inside a room as the metaphor 0:50:12.440 --> 0:50:15.760 for a computer. Computers do not actually have a tiny 0:50:15.880 --> 0:50:20.800 human inside them that's performing operations with opportunities to understand 0:50:20.960 --> 0:50:24.120 or not understand. Likewise, there is not actually a little 0:50:24.239 --> 0:50:27.759 human sitting inside your brain with the job of understanding 0:50:27.920 --> 0:50:31.320 or not understanding inputs and outputs. Your brain is a 0:50:31.480 --> 0:50:34.640 system in many ways. You might say that system of 0:50:34.840 --> 0:50:38.960 your brain that produces your mind is more comparable to 0:50:39.080 --> 0:50:42.480 the entire system of the person in the room, the room, 0:50:42.640 --> 0:50:45.239 the instructions and all that, than it is just the 0:50:45.320 --> 0:50:48.719 person inside. I think the evidence is pretty clear that 0:50:48.840 --> 0:50:51.719 the mind is not one thing, and there's no evidence 0:50:51.800 --> 0:50:55.360 of an observer within the observer. The mind is that, 0:50:55.560 --> 0:50:59.000 at the very least a system of information processing but 0:50:59.120 --> 0:51:02.840 also story inputs and outputs all working together. There's not 0:51:03.520 --> 0:51:06.359 there's no evidence of a pilot inside who does all 0:51:06.440 --> 0:51:09.799 of the final understanding. Right. That's rights as simple as 0:51:09.800 --> 0:51:11.480 it would be to imagine that, you know, because it 0:51:11.480 --> 0:51:14.040 would reduce whatever we're trying to figure out, would reduce 0:51:14.120 --> 0:51:16.920 it to a person would get back into that that 0:51:17.040 --> 0:51:19.920 that kind of you know, neolithic mindset. And so I 0:51:20.040 --> 0:51:22.719 think this now, I certainly don't want to say that 0:51:23.560 --> 0:51:27.480 that I'm not like casting expersions on John Searle. I'm 0:51:27.520 --> 0:51:30.880 sure he is a very brilliant man, much smarter than me. 0:51:31.000 --> 0:51:33.399 And there's been a lot more you know, complex back 0:51:33.440 --> 0:51:35.799 and forth on this. But just to somebody who's right 0:51:35.840 --> 0:51:37.640 about this a good bit, it seems to me like 0:51:37.840 --> 0:51:41.280 this is one of those thought experiments that needlessly turns 0:51:41.400 --> 0:51:45.239 up confusion just by bringing in a lot of unnecessary 0:51:45.320 --> 0:51:49.360 assumptions and the connotations of the imagery you use in 0:51:49.480 --> 0:51:51.919 the thing, like we've got a person inside a room 0:51:52.080 --> 0:51:54.960 that that's making you think of analogies to a person 0:51:55.160 --> 0:51:59.000 sitting inside the computer or an observer inside the observer 0:51:59.160 --> 0:52:01.759 in the brain right now. I I do take the 0:52:01.800 --> 0:52:04.279 problem of consciousness seriously. I'm not one of those people 0:52:04.360 --> 0:52:06.399 who you know, would hand awave and say, oh, yeah, 0:52:06.480 --> 0:52:08.920 consciousness is easy to explain, it's just a you know, 0:52:09.040 --> 0:52:13.240 systems theory or whatever. But I don't think the Chinese 0:52:13.360 --> 0:52:17.960 room proves machines can't think or understand, or have intentional 0:52:18.080 --> 0:52:21.480 or meaningful internal representations or be conscious. I think that's 0:52:21.520 --> 0:52:24.000 still an open question into my mind. The Chinese room 0:52:24.040 --> 0:52:27.400 experiment is one of these thought experiments that creates a 0:52:27.480 --> 0:52:30.520 lot of confusion by the hidden assumptions it imports with 0:52:30.640 --> 0:52:33.840 its central imagery. I don't know, am I being unfair? No? 0:52:34.120 --> 0:52:36.320 I think you're being being very fair. I mean again, 0:52:36.360 --> 0:52:40.680 I come back to um to certainly like political cartoons 0:52:41.000 --> 0:52:42.960 as as a reference, you know, not that not to 0:52:43.040 --> 0:52:45.480 reduce the Chinese Room to something so you know, ultimately 0:52:45.600 --> 0:52:49.840 kind of base. But there is a boiling down of 0:52:50.080 --> 0:52:52.680 of a process. There's a boiling down of a of 0:52:52.760 --> 0:52:55.560 a problem that takes place in a thought experiment like this, 0:52:56.160 --> 0:52:58.240 and then you do have to ask, well, in reducing 0:52:58.280 --> 0:53:02.080 it to this model, what of the necessary complexity is 0:53:02.200 --> 0:53:06.439 lost that is necessary to understanding what's going on. Yeah, 0:53:06.440 --> 0:53:08.640 I think that's exactly right, and I would say for me, 0:53:08.840 --> 0:53:12.359 crucially it's the image of the person in the room 0:53:12.520 --> 0:53:16.600 that's the especially confusing thing in this thing here, Like 0:53:16.719 --> 0:53:18.719 what if there wasn't a person there. What if you 0:53:18.840 --> 0:53:21.720 just instead said the room is a machine that takes 0:53:21.840 --> 0:53:25.080 in that takes in symbols and puts out symbols, then 0:53:25.120 --> 0:53:27.640 you're basically not really changing much. You're just saying, well, 0:53:27.680 --> 0:53:31.080 it's a computer, and then that's what we're talking about originally. 0:53:31.680 --> 0:53:36.080 But anyway, so we mentioned Daniel Dennet. He's written extensive 0:53:36.160 --> 0:53:38.719 criticism of the Chinese Room. I think this was even 0:53:38.800 --> 0:53:42.200 the context of his coinage of the term intuition pump, 0:53:42.280 --> 0:53:45.600 which is the title of one of his books, Intuition Pumps, Uh, 0:53:45.880 --> 0:53:49.320 dinn It writes, quote, Intuition pumps are cunningly designed to 0:53:49.440 --> 0:53:53.759 focus the reader's attention on the important features and to 0:53:53.920 --> 0:53:57.400 deflect the reader from bogging down in hard to follow details. 0:53:57.880 --> 0:54:00.600 There's nothing wrong with this in principle. Indeed, one of 0:54:00.680 --> 0:54:04.520 philosophy's highest callings is finding ways of helping people see 0:54:04.600 --> 0:54:08.160 the forest and not just the trees. But intuition pumps 0:54:08.200 --> 0:54:11.440 are often abused, though seldom deliberately. Of course, dann It 0:54:11.560 --> 0:54:15.279 himself has has played with thought experiments before. Absolutely, I'm 0:54:15.400 --> 0:54:17.400 instantly reminded of the it was almost kind of a 0:54:17.440 --> 0:54:20.160 little short story he wrote about those A robot with 0:54:20.200 --> 0:54:23.600 a human brain. Wonderful. Yes, the where am I? I 0:54:23.680 --> 0:54:26.799 think it was called? So dan It is as he says, 0:54:26.880 --> 0:54:30.799 they're certainly not opposed to thought experiments, but he uh, 0:54:31.120 --> 0:54:35.200 he points out, I think quite correctly that sometimes they 0:54:35.239 --> 0:54:38.480 actually confuse more than they illuminate. Whether that's true of 0:54:38.520 --> 0:54:40.839 the ones he himself is put together, it's it's hard 0:54:40.920 --> 0:54:44.520 to say. I mean a lot of times. The benefits 0:54:44.600 --> 0:54:47.160 of these physics thought experiments, as we've been saying, is 0:54:47.400 --> 0:54:49.480 you can eventually go out and test and see whether 0:54:49.560 --> 0:54:51.719 they were on the right track or whether they were 0:54:51.840 --> 0:54:55.080 confused by some you know, hidden assumption taken on board. 0:54:55.120 --> 0:54:56.839 It's harder to do with a lot of these thought 0:54:56.880 --> 0:55:01.200 experiments about say the physical location of consciousness or something 0:55:01.320 --> 0:55:05.840 like that. Uh So, one example from Dennett's book Intuition 0:55:05.920 --> 0:55:08.320 Pumps that we talked about in our Ship of Theseus episode. 0:55:08.400 --> 0:55:12.520 You remember the Swampman because it's essentially swamp thing from 0:55:12.520 --> 0:55:15.080 the comic book, right, Yeah, So this was an example 0:55:15.160 --> 0:55:18.640 of you know, Dinnett explaining how intuition pumps can go wrong. 0:55:18.920 --> 0:55:21.640 And again, intuition pumps are just thought experiments that that 0:55:21.800 --> 0:55:25.959 rely on our intuitions that don't like take specific data 0:55:26.080 --> 0:55:28.640 on board. Really, I'll try to do very very quick. 0:55:29.040 --> 0:55:31.680 The example was this guy named Donald Davidson. He was 0:55:31.719 --> 0:55:35.440 a philosopher. So he said, assume lightning strikes me while 0:55:35.480 --> 0:55:37.680 I'm out walking in the swamp, and it evaporates my 0:55:37.800 --> 0:55:40.600 body and I'm just gone. And then meanwhile, it also 0:55:40.760 --> 0:55:43.919 strikes a tree next door, and it rearranges that tree 0:55:44.000 --> 0:55:47.040 into an exact adom for Adam copy of me with 0:55:47.239 --> 0:55:50.160 all my memories, and he calls this creature swamp Man. 0:55:50.920 --> 0:55:54.720 And so he asks, is that copy really me? Davidson says, 0:55:54.960 --> 0:55:58.000 you know, is it really friends with my friends even 0:55:58.080 --> 0:56:00.640 though it has never met them before? Does it really 0:56:00.800 --> 0:56:03.319 know what a banana tastes like even though it has 0:56:03.400 --> 0:56:06.680 never tasted or even touched one? This was offered, I think, 0:56:06.760 --> 0:56:10.319 to interrogate the question of how the history of an 0:56:10.440 --> 0:56:14.640 object is related to the identity of that object. Is 0:56:14.680 --> 0:56:17.040 a thing that is an exact copy of you, that 0:56:17.160 --> 0:56:20.239 behaves exactly like you, but hasn't been where you've been 0:56:20.320 --> 0:56:23.200 and done what you've done in what ways? Is that 0:56:23.360 --> 0:56:27.359 actually different from you? But didn't responds to this story 0:56:27.480 --> 0:56:30.400 by saying, you know, this thought experiment might not actually 0:56:30.480 --> 0:56:33.360 reveal all that much. And as a point of analogy, 0:56:33.719 --> 0:56:37.200 he asks us to consider the cow shark. So the 0:56:37.320 --> 0:56:40.480 cow shark again, is it's created when a normal cow 0:56:40.800 --> 0:56:43.680 gives birth to an animal that is adam, For Adam 0:56:43.880 --> 0:56:47.000 exactly like a shark that you would find swimming in 0:56:47.080 --> 0:56:50.320 the ocean. And he asks, now, is this newborn animal 0:56:50.400 --> 0:56:53.840 a cow or a shark? Oh, but also take on 0:56:53.960 --> 0:56:57.080 board that it has cow DNA in all of its cells. 0:56:57.800 --> 0:57:01.440 Now a question like this, it might do something useful, 0:57:01.560 --> 0:57:05.279 like it might help us identify what features we think 0:57:05.320 --> 0:57:08.800 are important when we use words like cow and shark, 0:57:09.200 --> 0:57:12.240 But it really doesn't reveal anything about biology or about 0:57:12.280 --> 0:57:14.120 the world. You know, you're not going to get new 0:57:14.200 --> 0:57:17.720 information about reality from it. I think the best it 0:57:17.800 --> 0:57:20.120 could hope to do is help us figure out what 0:57:20.320 --> 0:57:22.960 we mean by words, and not to say there isn't 0:57:23.040 --> 0:57:25.080 value in that. But yeah, that seems to be about 0:57:25.080 --> 0:57:28.120 all that it does. Yes, so then it actually arrives 0:57:28.120 --> 0:57:30.840 at a claim. He says, quote, the utility of a 0:57:30.920 --> 0:57:34.680 thought experiment is inversely proportional to the size of its 0:57:34.840 --> 0:57:38.200 departures from reality. That's why he's saying. You know, Swampman 0:57:38.640 --> 0:57:41.160 just doesn't seem to be all that useful and understanding 0:57:41.720 --> 0:57:44.360 what it what it means to be a physical object 0:57:44.480 --> 0:57:47.400 like a person, because something like that is never going 0:57:47.520 --> 0:57:50.080 to happen in reality. I also, and I felt this 0:57:50.120 --> 0:57:52.760 way before too. I also feel like swamp Man is 0:57:52.840 --> 0:57:57.360 just a little too complicated, Like just use Star Trek. 0:57:57.480 --> 0:58:01.360 Just say Cat to Picard teleports down to Planet X 0:58:01.400 --> 0:58:04.440 and then back up to the Enterprise, Like is then 0:58:04.520 --> 0:58:06.600 what happens when he hangs out with his friends, what 0:58:06.640 --> 0:58:08.720 happens when he plays the flute, etcetera. Well, I guess 0:58:08.760 --> 0:58:12.560 it's the same problem either way. But to answer that question, 0:58:12.720 --> 0:58:16.960 you're using your intuitions, which are trained on a world 0:58:17.400 --> 0:58:21.439 where that never happens. So your intuitions just don't do much. 0:58:21.600 --> 0:58:25.120 They're there, They are not honed to solving this kind 0:58:25.200 --> 0:58:28.840 of problem. Your intuitions are much more useful in say, 0:58:28.960 --> 0:58:33.720 like combining premises about how things fall and stuff like that, right, 0:58:33.920 --> 0:58:36.920 because actually you're quite experienced with falling, and you can 0:58:36.960 --> 0:58:39.960 combine that with observations about gravity and stuff. Now, I 0:58:40.040 --> 0:58:43.600 don't I don't think uh. Dennett's little proclamation there about 0:58:43.640 --> 0:58:46.480 the size of its departures from reality is then again 0:58:47.160 --> 0:58:50.440 like a solvent that will that will fix all the problems, 0:58:50.480 --> 0:58:52.640 because it can be very hard to measure the size 0:58:53.280 --> 0:58:56.080 of a departure from reality in the consistent way, Like 0:58:56.480 --> 0:59:00.160 does the Chinese room experiment depart more or less from 0:59:00.240 --> 0:59:04.280 reality than Einstein imagining a train traveling near the speed 0:59:04.320 --> 0:59:07.840 of light? Right? Because the Chinese room you could do that, 0:59:08.160 --> 0:59:10.080 I mean, maybe somebody has done that. I mean, all 0:59:10.120 --> 0:59:12.360 you need is just a person in a room and 0:59:13.600 --> 0:59:16.720 an individual on the outside writing Chinese characters down right, 0:59:16.800 --> 0:59:19.800 I mean you know, and also speaking and being able 0:59:19.840 --> 0:59:21.800 to being able to speak and write Chinese. Obviously you 0:59:21.840 --> 0:59:24.480 can't have just nonsense going in, but that are the 0:59:24.520 --> 0:59:27.120 only two components, and we could we could pull this 0:59:27.240 --> 0:59:29.520 off today if we needed to. Though, I would say 0:59:29.640 --> 0:59:32.720 that the problem with the Chinese room actually is not 0:59:32.960 --> 0:59:36.400 its departures from reality, as in, like, it's not plausible 0:59:36.480 --> 0:59:38.240 that you could make a room like this and put 0:59:38.320 --> 0:59:40.440 somebody in it because you have a determined if it's 0:59:40.440 --> 0:59:45.160 illustrating anything about how a proposed machine is thinking or 0:59:45.200 --> 0:59:47.400 not thinking, right, the lack of its use, I think 0:59:47.560 --> 0:59:50.840 is it's in its departures from the thing it's supposed 0:59:50.880 --> 0:59:54.400 to represent. It's supposed to be an analogy for a computer, 0:59:54.880 --> 0:59:57.640 but it's actually not a good analogy for a computer, 0:59:57.800 --> 1:00:00.360 because it's a room and a person and some pencil 1:00:00.400 --> 1:00:02.480 and paper that just like they're not the same thing. 1:00:02.800 --> 1:00:05.840 But with Swampman, Yeah, they're all these fantastic ideas in 1:00:05.920 --> 1:00:08.200 it that don't match up with reality. Whereas the ship 1:00:08.280 --> 1:00:11.400 of theseus is a is A is so brilliant and 1:00:11.560 --> 1:00:13.480 and as and as to the test of time, because 1:00:13.880 --> 1:00:17.200 everybody can can associate with that, like the upkeep of 1:00:17.360 --> 1:00:23.480 physical structures and devices, the constant replacement of those things, 1:00:23.600 --> 1:00:28.600 the constant change to things that we think have autonomy, 1:00:28.720 --> 1:00:33.720 like like ourselves or or sports teams, clubs, buildings, etcetera. Well, 1:00:33.760 --> 1:00:36.800 a kind of chilling takeaway from from that distinction you 1:00:36.880 --> 1:00:39.200 make between the ship of theseus and the ship of 1:00:39.280 --> 1:00:43.880 theseus version as instantiated in Swampman, is that maybe it 1:00:44.000 --> 1:00:47.000 makes more sense to have to answer questions about the 1:00:47.080 --> 1:00:50.080 meaning of identity as it refers to things than as 1:00:50.120 --> 1:00:52.480 it does refer to people. Yeah, in many ways, it 1:00:52.560 --> 1:00:54.520 is easier to think of people as things if you're 1:00:54.560 --> 1:00:58.640 just doing these kind of computations. I also want to 1:00:58.680 --> 1:01:01.960 clarify that if you're more interested in the Chinese Room, 1:01:02.000 --> 1:01:05.040 they're like a billion other classes of responses to it 1:01:05.160 --> 1:01:07.960 you can go look up. Like one is that you know, 1:01:08.160 --> 1:01:11.320 you should really maybe think about putting that computer inside 1:01:11.400 --> 1:01:14.400 a robot and then that would be more consistent with 1:01:14.640 --> 1:01:16.960 the type of experience that a human has. And so 1:01:17.160 --> 1:01:19.560 like what if you put the Chinese room in a 1:01:19.680 --> 1:01:22.320 thing that could go around and look with cameras outside 1:01:22.440 --> 1:01:24.440 and you know all that kind of So there are 1:01:24.440 --> 1:01:27.480 just tons of different responses. While I don't find it 1:01:27.600 --> 1:01:30.680 convincing on on what it tries to prove. I do 1:01:30.800 --> 1:01:33.280 think it's one of these things that is at least 1:01:33.360 --> 1:01:37.360 inadvertently useful for clarifying what people mean when they're talking 1:01:37.400 --> 1:01:40.720 about this subject, because usually if you start asking something 1:01:40.800 --> 1:01:43.520 like can a machine be conscious? You just don't even 1:01:43.560 --> 1:01:46.120 have a foothold to start reasoning. Just where do you go? 1:01:46.240 --> 1:01:48.840 It's just I don't know, yeah, because on one hand, 1:01:48.920 --> 1:01:51.040 it's hard enough to know what consciousness is for us 1:01:51.080 --> 1:01:53.160 and then to extrapolate what that would mean to a machine. 1:01:53.240 --> 1:01:55.720 You there's just no like, how do you feel in 1:01:55.720 --> 1:01:58.000 the values on that equation? So I give it credit 1:01:58.080 --> 1:02:00.160 for that. It it I don't think it's all us 1:02:00.200 --> 1:02:02.800 the question, but it does give you a first place 1:02:02.920 --> 1:02:05.560 to start climbing where you can even contemplate what it 1:02:05.600 --> 1:02:08.160 would mean to solve this question. Now, to return back 1:02:08.200 --> 1:02:09.920 just the idea of what is the thought experiment? What 1:02:10.040 --> 1:02:11.959 is an a thought experiment? I do want to refer 1:02:12.040 --> 1:02:14.320 to just a few ideas that have been pointed out 1:02:14.880 --> 1:02:18.160 by Dan Falk and his Ian article Armchair science. Thought 1:02:18.200 --> 1:02:21.120 experiment played a crucial role in the history of science, 1:02:21.160 --> 1:02:22.880 But do they tell us anything about the real world? 1:02:23.560 --> 1:02:26.200 He points out that John Norton, a philosopher at the 1:02:26.360 --> 1:02:28.919 University of Pittsburgh, has argued that we shouldn't elevate thought 1:02:28.960 --> 1:02:34.000 experiments too highly. They are essentially quote elegantly crafted arguments 1:02:34.040 --> 1:02:38.640 that bring vivid pictures to the mind's eye. So the 1:02:38.760 --> 1:02:42.000 argument here is that the thought experiments, as we've been discussing, 1:02:42.040 --> 1:02:45.720 don't produce any new knowledge themselves, but rather constituted deduction 1:02:45.840 --> 1:02:49.400 of existing knowledge. And he maintains that all thought experiments 1:02:50.160 --> 1:02:53.680 are are simply restate, can simply be restated. His arguments, 1:02:53.880 --> 1:02:56.280 like his challenge, his sort of rough challenges, you can 1:02:56.480 --> 1:03:00.400 bring me a thought experiment, I'll just restate it as argument, 1:03:00.440 --> 1:03:02.160 and that's all there is to it. Well, I think 1:03:02.240 --> 1:03:05.400 he's essentially correct that any good thought experiment can be 1:03:05.600 --> 1:03:08.560 restated as a deductive argument, you know, with the kind 1:03:08.560 --> 1:03:12.960 of the boring you know, logic class style logical premises. Right, 1:03:13.160 --> 1:03:16.880 But thought experiments are useful because they're easier to remember, 1:03:17.040 --> 1:03:20.320 they're easier to understand, and they give you pictures that 1:03:20.400 --> 1:03:23.280 you can wrap your mind around, right exactly. They change 1:03:23.320 --> 1:03:25.480 the way you think about something, and and that's ultimately 1:03:25.520 --> 1:03:27.920 I believe the point. The counterpoint that is made by 1:03:28.280 --> 1:03:30.720 James Robert Brown, a philoso for the University of Toronto, 1:03:31.320 --> 1:03:33.960 who points out that like, Okay, yeah, Norton, you may 1:03:34.000 --> 1:03:36.160 be right, and he even says, I think Norton probably 1:03:36.240 --> 1:03:39.880 could restate all thought experiments as arguments, but we don't 1:03:39.960 --> 1:03:42.280 really work them out in our heads as arguments. We 1:03:42.360 --> 1:03:45.000 work them out in the form of these thought experiments. 1:03:45.480 --> 1:03:47.840 The cognitive process here because is much is much more 1:03:47.880 --> 1:03:53.160 intuitive and less analytical thought experiments. Therefore, they transformed the 1:03:53.240 --> 1:03:56.880 ad the analytical into the intuitive. What did we evolve 1:03:57.040 --> 1:04:01.520 thinking for? What was it use full four? I mean, 1:04:02.080 --> 1:04:04.760 can't be sure, but it really seems like what's likely 1:04:04.960 --> 1:04:08.360 is not that, say, our boreal primates were trying to 1:04:08.480 --> 1:04:12.240 work out analytical premises of an argument and say, you know, 1:04:12.400 --> 1:04:16.600 premise one is no. I mean, they were imagining scenarios, 1:04:16.760 --> 1:04:20.320 like thinking is useful for saying, Okay, if I went 1:04:20.520 --> 1:04:23.959 down on the ground right now, what would happen? Oh, yeah, 1:04:24.080 --> 1:04:26.680 that's right. There was a leopard down there. So if 1:04:26.840 --> 1:04:30.040 leopard and me on the ground, that that's not good. 1:04:31.120 --> 1:04:34.440 Imagining scenarios is so much more natural and intuitive to 1:04:34.560 --> 1:04:38.160 us than than formal syllogistic arguments. Now, Falk also points 1:04:38.160 --> 1:04:40.640 out that there's a third possibility here. The third argument 1:04:40.680 --> 1:04:44.960 presented by cognitive scientists Nancy Nurcessian of the Georgian Institute 1:04:45.000 --> 1:04:48.040 of Technology, as she argues that thought experiments are simply 1:04:48.200 --> 1:04:52.680 middle mental modeling. If Falk provides a quote for her 1:04:52.960 --> 1:04:55.720 from her in his article, quote, a mental model is 1:04:55.760 --> 1:04:59.280 basically a representation of the structure, function, or behavior of 1:04:59.400 --> 1:05:02.320 some system. You're interested in, some real world system that 1:05:02.400 --> 1:05:06.200 retains its sensory and motor properties that you get from perception. 1:05:06.720 --> 1:05:09.800 When we manipulate a mental model, she argues, we use 1:05:09.920 --> 1:05:12.400 quote some of the same kind of processing that you 1:05:12.440 --> 1:05:16.000 would use to manipulate things in the real world. So, yeah, 1:05:16.320 --> 1:05:19.000 the idea here, it's it's the example that has often 1:05:19.040 --> 1:05:22.160 put forth is if someone says, hey, how many windows 1:05:22.200 --> 1:05:24.640 are there in your house? And then how unless you 1:05:24.760 --> 1:05:27.680 just carry around that raw data in your head, the 1:05:27.840 --> 1:05:30.720 way you solve that is probably to form a mental 1:05:30.800 --> 1:05:33.720 image of your house or room by room, form the 1:05:33.800 --> 1:05:36.240 mental images and then count the windows. But you had 1:05:36.320 --> 1:05:38.920 to have looked at your house already, right, Yeah, you 1:05:39.000 --> 1:05:42.800 can't just have just you know, uh, you know, experimental 1:05:42.880 --> 1:05:44.680 knowledge like you have to have some real knowledge you 1:05:44.760 --> 1:05:47.240 have walked through your house, you've seen your house, and 1:05:47.440 --> 1:05:50.520 then and that's what you're using to reconstruct this this model. 1:05:50.920 --> 1:05:53.840 On the other hand, it's worth pointing out that just 1:05:54.000 --> 1:05:57.800 counting the windows in your house is probably a quicker 1:05:57.880 --> 1:06:00.040 way essentially falling back on the sign on sign of 1:06:00.120 --> 1:06:03.640 an invest investigation is going to be the clearcut method 1:06:03.720 --> 1:06:07.640 of solving that particular question. Yes, especially if you care 1:06:07.640 --> 1:06:12.000 about getting the right answer right. Yes, Uh, those sometimes, 1:06:12.040 --> 1:06:15.440 I mean, I thought experiments can be very useful, especially 1:06:15.480 --> 1:06:19.240 in scenarios where you're not super concerned with precision, but 1:06:19.360 --> 1:06:22.640 you're more concerned with like the directionality of an answer. 1:06:23.200 --> 1:06:26.520 Like a thought experiment can be quite useful in uh, 1:06:26.800 --> 1:06:30.720 just getting a guess about whether a quantity in reality 1:06:30.840 --> 1:06:34.640 is going to increase or decrease without knowing exactly how 1:06:34.760 --> 1:06:36.600 much it's going to increase or decrease, you know what 1:06:36.640 --> 1:06:38.600 I mean. Yeah, And then of course it to go 1:06:38.680 --> 1:06:40.800 back to black holes for instance. Like that's an example 1:06:40.880 --> 1:06:43.680 of counting windows in a house you haven't been to yet, 1:06:44.280 --> 1:06:48.280 by by your by your understanding of everything surrounding whatever 1:06:48.400 --> 1:06:51.320 that house should be, so that there there are cases 1:06:51.400 --> 1:06:54.600 where that is the best method for trying to count 1:06:54.640 --> 1:06:56.800 the windows in a given house. Well, it's almost like knowing, 1:06:56.920 --> 1:06:59.520 like what is the what is the tension and support 1:06:59.600 --> 1:07:02.520 strength of glass? Now trying to imagine how big of 1:07:02.600 --> 1:07:06.080 a glass house could exist before it falls over. You know, 1:07:06.240 --> 1:07:09.280 you don't have to build that house. If you already 1:07:09.360 --> 1:07:12.000 know some things about glass, you can run that experiment 1:07:12.120 --> 1:07:14.760 on paper or in your head. But anyway, what I 1:07:14.800 --> 1:07:17.040 think this all means is that we should build two 1:07:17.280 --> 1:07:20.480 glass towers, one bigger than the other, and drop them 1:07:20.600 --> 1:07:23.840 both but tie them together, and then shoot a cannon 1:07:23.960 --> 1:07:26.280 off of them, and then drop a bag of cheese 1:07:26.440 --> 1:07:31.760 from them. And basically you're you're arguing for a shared 1:07:31.800 --> 1:07:35.600 cinematic universe of thought experiments. I mean, I think most 1:07:35.680 --> 1:07:37.680 of them are in the public domain, So this would 1:07:37.680 --> 1:07:40.400 be a great This would be a great franchise for 1:07:40.480 --> 1:07:42.560 somebody to to pick up and run with. You know, 1:07:42.600 --> 1:07:44.200 at this point, I think a good number of the 1:07:44.240 --> 1:07:47.080 most famous thought experiments have at some point had like 1:07:47.200 --> 1:07:50.120 an indie movie made out of them. You know, there's 1:07:50.160 --> 1:07:51.920 got to be I would be shocked if there is 1:07:51.960 --> 1:07:55.960 not a Chinese room movie. Well, I'm sure we'll we'll 1:07:55.960 --> 1:07:58.760 hear about it from listeners if there is one. Uh. 1:07:58.880 --> 1:08:02.080 So there you have it. Thought experiments. Uh, hopefully a 1:08:02.160 --> 1:08:04.480 nice overview of what they are, what they are not, 1:08:05.520 --> 1:08:08.680 some different ways of classifying them, some different examples both 1:08:08.720 --> 1:08:11.959 from past episodes and some that we haven't really picked 1:08:12.040 --> 1:08:15.320 up and looked at here on the show. But hopefully 1:08:15.360 --> 1:08:17.320 this will this will be useful moving forward as we 1:08:17.439 --> 1:08:23.280 inevitably encounter other thought experiments in our consideration of various topics. 1:08:23.560 --> 1:08:25.280 What I hope this allows us to do is to 1:08:25.360 --> 1:08:29.680 be more confident in dismissing the ones they're not useful. Yes, 1:08:30.120 --> 1:08:32.519 you have to realize that they are not. You know, 1:08:32.560 --> 1:08:35.120 they're not holy scripture set in stone, that that that 1:08:35.680 --> 1:08:38.320 they can be flawed. There in many cases they are flawed. 1:08:38.840 --> 1:08:41.600 And uh, but then that's also part of their usefulness 1:08:41.680 --> 1:08:44.200 is that the flawed model can be presented and someone 1:08:44.280 --> 1:08:46.479 can say, well, let's look at this, look at let's 1:08:46.560 --> 1:08:50.479 change something in this model and see what happens. All right. Well, hey, 1:08:50.560 --> 1:08:52.240 if you you want to check out more episodes of 1:08:52.240 --> 1:08:54.200 stuff to blow your mind, you want to check out, say, 1:08:54.240 --> 1:08:56.280 for instance, the episodes we did on black Holes, the 1:08:56.320 --> 1:08:59.519 Ship of THESEUS uh any of these These various topics 1:08:59.560 --> 1:09:01.680 were heard too in this episode, Well, you can find 1:09:01.720 --> 1:09:03.439 them all. It's stuff to blow your Mind dot com. 1:09:03.840 --> 1:09:06.040 That's the mothership. That's where you'll find them all. That's 1:09:06.040 --> 1:09:07.800 where you'll find links out to our very social media 1:09:07.800 --> 1:09:10.080 accounts to find a tab for our store, place where 1:09:10.080 --> 1:09:14.400 you can buy merchandise with cool shirt designs, stickers, et cetera. 1:09:14.520 --> 1:09:16.679 It's a cool way to support the show, and another 1:09:16.720 --> 1:09:18.680 way to support the show is to simply rate and 1:09:18.800 --> 1:09:21.080 review the show wherever you have the power to do so. 1:09:21.280 --> 1:09:24.679 Big thanks, as always to our excellent audio producers Alex 1:09:24.720 --> 1:09:27.479 Williams and Tory Harrison. If you would like to get 1:09:27.520 --> 1:09:30.000 in touch with us directly with feedback on this episode 1:09:30.120 --> 1:09:32.439 or any other, to suggest topic for the future, or 1:09:32.560 --> 1:09:35.080 just to say hi, you can email us at blow 1:09:35.200 --> 1:09:46.880 the Mind at how stuff works dot com for more 1:09:46.960 --> 1:09:49.240 on this and thousands of other topics. Is it how 1:09:49.280 --> 1:10:06.200 stuff works dot com. B The Press point four part 1:10:06.400 --> 1:10:09.439 Part par