00:00:00.000 The quest for good explanations is, I believe, the basic regulating principle not only of science,
00:00:07.280 but of the enlightenment generally. It is the feature that distinguishes those approaches to knowledge
00:00:13.120 from all others, and it implies all those other conditions for scientific progress I have discussed.
00:00:19.520 It trivially implies the prediction alone is insufficient. Somewhat less trivially,
00:00:25.280 it leads to the rejection of authority, because if we adopt a theory on authority,
00:00:30.960 that means that we would also have accepted a range of different theories on authority.
00:00:36.960 And hence, it also implies the need for a tradition of criticism. It also implies a
00:00:42.800 methodological rule, a criterion for reality, namely, that we should conclude that a particular
00:00:50.080 thing is real, if, and only if, it figures in our best explanation of something. End quote.
00:00:57.680 From David Deutsch, the beginning of infinity explanations that transformed the world,
00:01:02.240 page 22 to 23, welcome to Topcast, end to episode 105, where today I will be providing a breakdown
00:01:10.240 of chapter 4, which is criteria for reality from the fabric of reality by David Deutsch.
00:01:17.200 Now, what you heard at the beginning there was a quote from the beginning of infinity,
00:01:22.880 from chapter 1 of that book, which contains not only a summary, basically, for the motivation
00:01:28.320 of the book, placing this quest for good explanations at the foundation of our civilization,
00:01:33.920 of the enlightenment, but it also contains an important kernel linking David's two books together.
00:01:40.400 It speaks of a criterion for reality, what it means for something to be real.
00:01:46.800 And this explanation, given by David, this criterion, is, so far as I know, unique to his philosophy
00:01:54.480 and basically solves a problem at the intersection of ontology and epistemology or metaphysics.
00:02:00.960 Whatever you want to call this thing this study of existence, and I think it is actually an
00:02:05.440 improvement on what Popper said about realism and existence. It's something I've discussed with
00:02:11.840 people over the years now, many times, because it is something people criticize, but we have to be careful
00:02:17.920 with what David is saying here. He says that we should conclude that a thing is real or that a thing
00:02:24.160 exists if and only if it figures in our best explanation of something. This is the condition
00:02:31.120 under which we can conclude its existence. If among our best explanations of the world,
00:02:36.800 unicorns appear nowhere, then there is no reason to conclude they are real. But they exist.
00:02:42.880 Now, does this rule out unicorns being found in the future? Of course not. Nothing can.
00:02:48.080 They may exist. We haven't ruled out their possibility of existing. We are merely saying that we cannot
00:02:54.080 conclude they exist now, given our best explanations. Concluding they exist now would be to use
00:03:00.960 something other than reason to come to that conclusion. But in day to day language, we do not need
00:03:07.440 to preface all claims that a thing exists or that a thing is real with, for example, we can conclude
00:03:14.960 koalas exist because they feature in our best explanations. We simply say koalas exist,
00:03:20.880 and the rest goes without saying. So, two, four things we say do not exist.
00:03:25.520 Unicorns do not exist, and that means the same thing as we know unicorns do not exist,
00:03:31.440 which means unicorns do not feature in our best explanations of reality. Now, it could turn out
00:03:36.320 that we are wrong about the existence of unicorns. But saying something like, we don't know if
00:03:42.240 unicorns exist and thinking that that is the same kind of claim as we don't know if alien life
00:03:47.680 exists. Confuses problem situations. These claims, we don't know if alien life exists,
00:03:55.760 and we don't know if unicorns exist. Look kind of similar, but actually they're not symmetrical.
00:04:02.800 Our best theories of life seem to predict that it will arise if and where it can,
00:04:08.880 but those same theories do not allow us to predict what particular species will arise.
00:04:14.560 For example, unicorns, in other words, life beyond the solar system is postulated as a
00:04:20.080 reasonable hypothesis by some precisely because they do exist good explanations of why a life
00:04:25.760 should be possible beyond the solar system. And this would solve a problem, the problem of
00:04:30.880 earth being uniquely suited in the universe for life of any kind. Again, this is not symmetric
00:04:37.120 with postulating unicorns exist because postulating the very special case of unicorns solves
00:04:44.160 no outstanding problem in science, and that's the difference. Does the thing solve a problem or not?
00:04:49.520 I've actually made podcasts before about existence in general and realism.
00:04:54.480 Go all the way back to episode 55 for an episode titled existence, where I have a 15 minute
00:05:00.480 discussion about what it means for something to exist, and so I'm going to be going over some of
00:05:05.920 that material today, but in great a depth from a perspective of what the fabric of reality has to say,
00:05:11.440 and towards the end, what even Papa himself had to say about all this. But this chapter, a chapter
00:05:16.880 four of the fabric of reality, is even more famous among some fans of the book for another reason.
00:05:24.240 It has perhaps the best refutation of solipsism known, and hence the best defense of realism.
00:05:31.280 It is often claimed in philosophical circles that we cannot prove we are not in a simulation,
00:05:36.880 or dreaming everything that we experience moment to moment, or another way to put this is that there
00:05:42.880 is no experimental test, no observation we can make, and hence no scientific explanation that allows
00:05:49.440 us to falsify the claim that we exist in a simulation. So apparently, both mathematics or logic,
00:05:56.240 as well as science, are impotent in the face of claims that this is all a simulation,
00:06:01.920 or a dream, or a deception from an evil demon. This chapter does away with all of those concerns
00:06:07.280 by revealing that mathematics and science are not the only games in town when it comes to
00:06:13.520 comprehensively refuting bad explanations like those. We will come in this chapter very quickly
00:06:19.760 to the supposed hierarchy of academic disciplines, with the certainty of mathematics supposedly
00:06:25.200 at the pinnacle, scientific claims just a little less than certain, and the supposed mere matter
00:06:30.080 of taste arguments that exist in philosophy, but let's not steal all of that thunder right now.
00:06:37.120 I've hinted enough at what's to come in this chapter, and so let's get straight into it.
00:06:42.160 Chapter 4 Criteria for Reality, which begins with David Writing, and I quote,
00:06:47.600 The Great Physicist Galileo Galilei, who was arguably also the first physicist in the modern sense,
00:06:54.480 made many discoveries not only in physics itself, but also in the methodology of science.
00:06:59.760 He revived the ancient idea of expressing general theories about nature in mathematical form,
00:07:06.080 and improved upon it by developing the method of systematic experimental testing,
00:07:11.920 which characterizes science as we know it. He aptly called such tests, cementi, or deals.
00:07:18.480 He was one of the first to use telescopes to study celestial objects,
00:07:21.920 and he collected an analyzed evidence for the heliocentric theory.
00:07:25.440 The theory that the earth moves in orbit around the sun and spins about its own axis,
00:07:31.360 end quote, and just my brief reflection on that, prior to Galileo, there was indeed a dominant
00:07:38.160 school of philosophy or science or knowledge, whatever you want to call it, the intelligentsia,
00:07:42.720 that assumed knowledge came to us by pure reason alone, more than anything else.
00:07:49.360 Pure reason, namely mathematics, logic, the use of the mind without needing to consult
00:07:55.440 external reality was perfect, they thought, in a way that the physical world wasn't,
00:08:01.440 so it was really a Galileo who began the practice, the formal practice of focusing on experiment,
00:08:10.160 as distinguishing between theories. It did, of course, take Papa to begin constructing the
00:08:15.920 theoretical apparatus, which allowed us to focus on the philosophy of how exactly all of that worked,
00:08:21.680 and of course today we're brought to when David Deutsch explains how all of that is necessary,
00:08:27.360 experimental work is of course necessary in science, but it's not sufficient. And this, in fact,
00:08:33.840 interestingly enough, given the existence of things like or stances, like instrumentalism,
00:08:39.520 means that we still have work to do in this area. Back to the book, and David writes, quote,
00:08:44.000 he, Galileo, is best known for his advocacy of that theory, and for the bitter conflict with the
00:08:50.400 church, into which that advocacy brought him in 1633, the Inquisition tried him for heresy,
00:08:57.120 and forced him under the threat of torture to kneel and read aloud a long object
00:09:01.920 recantation, saying that he absurd, cursed, and detested the heliocentric theory,
00:09:07.920 legend has it probably incorrectly, that as he rose to his feet he muttered the words,
00:09:12.800 a percy mueve, meaning, and yet it does move, despite his recantation,
00:09:18.480 he was convicted and sentenced to house arrest under which he remained for the rest of his life,
00:09:23.440 although this punishment was comparatively lenient, it achieved its purpose.
00:09:27.760 Handsomely, as Jacob Brunowski put its quote, the result was silence among Catholic scientists
00:09:33.840 everywhere from then on. The effect of the trial and of the imprisonment was to put a total stop
00:09:39.760 to the scientific tradition in the Mediterranean, and quote, that's from the assentive man
00:09:45.200 page 218 by Jacob Brunowski. And just my reflection on that, it seems to me that there in a nutshell,
00:09:52.640 so to speak, is why free speech is such an important or even foundational value,
00:09:58.240 without it, progress ceases. The threat of punishment of coercion, of violence,
00:10:04.880 can stifle speech. As many have observed, I think this began with John Stuart Mill,
00:10:10.240 self-censorship, can be of this kind. Today there has been a real resurgence of interest in
00:10:16.320 the issue of free speech, but when some people speak about it, they are almost exclusively
00:10:22.720 focused on that American set of concerns, the first amendment that says that the government
00:10:27.920 will not censor or pass laws to prevent the freedom of speech. In other countries, there are
00:10:33.360 similar concerns, what laws might the government pass and put in place, that prevent people freely
00:10:40.480 expressing themselves. But this issue of government censorship, perhaps the only form of true
00:10:46.480 censorship in the legal sense, is as many philosophers have observed, really only half the story,
00:10:54.320 important as that part of the story is. John Stuart Mill got there in his work on liberty,
00:11:00.080 so I'll quote a passage from chapter 2 of on liberty and explain it here. Mill wrote, quote,
00:11:06.800 in respect to all persons, but those whose pecuniary circumstances make them independent
00:11:12.560 of the goodwill of other people, opinion on this subject, is as efficacious as law.
00:11:19.440 Men might as well be imprisoned as excluded from the means of earning their bread and quote.
00:11:25.760 So what he's saying there is that if your pecuniary interests, your job in other words,
00:11:31.760 depends on your saying or not saying certain things, then this is as efficacious as law.
00:11:38.000 If you would lose your job for saying something, then it's not really like having freedom is it?
00:11:42.960 He goes on, quote from Mill, those whose bread is already secured and whose designer favors
00:11:48.960 from men in power or from bodies of men or from the public have nothing to fear from the open
00:11:54.880 a vowel of any opinions but to be ill thought of and ill spoken of. And this it ought not to
00:12:01.280 require a very heroic mould to enable them to bear, end quote. And so what he's saying there is
00:12:07.040 that if you've got your bread secured, in other words you've got enough money and you don't want
00:12:10.720 anything from other people in power, then you're free to say what you like, except that you might
00:12:15.520 be ill spoken of how many people want to put up with social ostracism we might wonder.
00:12:20.560 The state might very well have no laws against speech, but your community might very well
00:12:26.000 effectively cut you off. And last quote from Mill, quote, there is no room for any appeal,
00:12:32.560 add mister accordium in behalf of such persons. By the way, just an aside from me, add mister accordium.
00:12:38.960 That means don't appeal to pity, don't feel sorry for people who won't speak up for fear
00:12:44.160 of being ostracized and mill goes on, but though we do not now inflict so much evil on those who
00:12:51.040 think differently from us, as it was formally our custom to do, it may be that we do ourselves as
00:12:57.920 much evil as ever buy our treatment of them end quote. So there's the key points. This social
00:13:05.920 thing, Mill thinks, is as important as the legal thing. Now this is very important today,
00:13:11.120 Facebook, Twitter, YouTube, et cetera, should have the legal right to set their rules and
00:13:15.600 censor, although there is a dispute in the community about this. You know, some people think that
00:13:20.800 the government really should intervene. Now, I think that that is wrong that Facebook, Twitter,
00:13:25.760 et cetera, whatever social media company it happens to be, should be perfectly free to
00:13:30.720 on their platforms, set the rules. But we also have to consider the effects of banning people,
00:13:38.000 as they seem to do rather routinely swiftly and readily with little recourse, and they have the
00:13:43.200 legal right. But on Mill's view, and those of others, Roger Scooten is a more recent example of
00:13:48.560 arguing for this, what tends to happen is that if those platforms do become known as they seem
00:13:54.640 to be for their internal censorship practices, which might be seen as arbitrary and harsh,
00:14:01.120 the effect is for people to self censor, because they do not wish to be ostracized from the
00:14:08.240 community, the online community. Even if they did not get banned, many may not say what they would
00:14:13.840 prefer to say for fear of being deboosted as it's called, or simply poorly treated by their
00:14:19.920 social media circle. So when we've never had more opportunity to share ideas and learn knowledge
00:14:25.840 and network, we might likewise, simultaneously, have a modern day silencing of a kind by proxy.
00:14:33.200 So Mill foresaw this and Mill was concerned about this when he was writing centuries ago.
00:14:39.680 So if what you're concerned about is progress, then yes, any legal imposition on people being
00:14:46.400 free to speak is anathema to solving problems and understanding reality. It is preventing the
00:14:52.240 collision of ideas with each other as well as with reality. This was the issue Galileo had,
00:14:58.240 a legal constraint on what he could say and then a chilling effect on the rest of the scientific
00:15:03.840 community. But let's be clear that this is not the only chilling effect that can occur when it
00:15:09.920 comes to speech. There are real social pressures as well and today, because we have this thing
00:15:15.040 called social media, it may well be amplified. My guess is that any stifling of speech might
00:15:22.320 well be mitigated today by the fact that so much more of it is out there and being amplified.
00:15:28.480 But this will have a selection effect associated with it, especially courageous people,
00:15:33.360 or people of a certain kind, let's say, of a prickly nature, or people in a position of as
00:15:39.680 mill hints at personal means will find it easier to speak out. Those who work for wages or a
00:15:46.160 salary might be legally free to say whatever they like. But if you're immediate concern is
00:15:50.880 putting bread on the table, then risking that by speaking the truth might not be a gamble you
00:15:56.400 will take. Okay, back to the book and David Rants. How could I dispute about the land of the
00:16:02.000 solar system, have such far-reaching consequences and why did the participants pursue it so
00:16:07.360 passionately? Because the real dispute was not about whether the solar system had one layout
00:16:12.240 rather than another. It was about Galileo's brilliant advocacy of a new and dangerous way of
00:16:18.240 thinking about reality. Not about the existence of reality, for both Galileo and the church believed
00:16:23.920 in realism, the common sense view that an external physical universe really does exist,
00:16:29.360 and does affect our senses, including senses enhanced by instruments such as telescopes.
00:16:34.160 Where Galileo differed was in his conception of the relationship between physical reality on the
00:16:40.560 one hand, and human ideas, observations, and reason on the other. He believed that the universe
00:16:47.040 could be understood in terms of universal, mathematically formulated laws, and that a reliable
00:16:52.480 knowledge of these laws was accessible to human beings if they applied his method of mathematical
00:16:58.560 formulation and systematic experimental testing. As he put it, the book of nature is written in
00:17:04.240 mathematical symbols. This was in conscious comparison with that other book on which it was more
00:17:09.840 conventional to rely and quote. Now let's just consider there, David claimed, that both Galileo
00:17:16.320 and the church believed in realism. This is a commonly misunderstood point. Religious people
00:17:23.920 can, and often are, in fact, realists, even people who have otherwise unscientific beliefs
00:17:30.560 can be realists. It's rather like how religious people often have a realistic or objective view
00:17:36.960 of morality. They think there exists a difference in reality between good and evil,
00:17:42.560 and both of those things really exist. But being a realist, of course, does not make you
00:17:47.120 invaluable. You can still make errors. In fact, you would expect to make errors because you
00:17:51.520 understand there is an objective reality out there about which you can be wrong. So the thing about
00:17:56.400 religious people on this account, the Christians of this kind that, for example, Galileo is debating
00:18:02.960 against, they don't fall for the It's All-a-Dream argument and logically equivalent claims,
00:18:08.880 but of course that doesn't mean that what they think is real actually is real. Let's go back to
00:18:13.440 the book and David writes. Galileo understood that if his method was indeed reliable, then wherever
00:18:19.280 it was applicable its conclusions had to be preferable to those obtained by any other method.
00:18:24.480 Therefore, he insisted that scientific reasoning took precedence, not only over intuition and common
00:18:30.880 sense, but also over religious doctrine and revelation. It was specifically that idea, and not
00:18:36.480 the heliocentric theory as such, that the authorities considered dangerous, and they were right.
00:18:42.640 For if any idea can be said to have initiated the scientific revolution and the enlightenment,
00:18:47.680 and to have provided the secular foundation of modern civilization, it is that one. It was forbidden
00:18:53.920 to hold or defend the heliocentric theory as an explanation of the appearance of the night sky,
00:19:01.120 but using the heliocentric theory, writing about it, holding it as a mathematical supposition,
00:19:07.360 or defending it as a method of making predictions, they were all permitted. That was why Galileo's
00:19:12.720 dialogue of the two chief world systems, which compared the heliocentric theory, with the official
00:19:18.480 geocentric theory, had been cleared for printing by church sensors. The pope had even acquiesced in
00:19:24.880 advance to Galileo's writing such a book, though at the trial a misleading document was produced,
00:19:30.320 claiming that Galileo had been forbidden to discuss the issue at all. It is an interesting
00:19:35.120 historical footnote that in Galileo's time it was not yet indisputable, but the heliocentric theory
00:19:41.440 gave better predictions than the geocentric theory. The available observations were not very accurate,
00:19:46.640 and hawk modifications had been proposed to improve the accuracy of the geocentric theory,
00:19:52.240 and it was hard to quantify the predictive powers of the two rival theories. These are just
00:19:58.160 end quote there, just my reflection list. These ad hawk modifications to the geocentric theory
00:20:03.280 were basically, well, if you consider what the geocentric theory was all about, you have the earth
00:20:07.200 the center, and then all the other celestial bodies are going around the earth. If you just assume
00:20:11.520 that they're moving in circles around the earth, then the predictions of the geocentric
00:20:15.200 theory makes over time tend to move out of sync with what's going on in reality. What you do
00:20:21.600 is instead of having the celestial objects, like the sun and the moon and the other planets,
00:20:26.240 moving in circles around the earth, you have them moving in slightly more complicated motions where
00:20:30.480 you have, well, what is called a circle on a circle or an epicycles. You have the planets, for
00:20:36.000 example, doing little circles as they're going around the sun, they're moving in circles
00:20:42.560 on the circular orbits, and then if you need to have further epicycles, circle, circular orbits
00:20:47.520 on circular orbits on circular orbits, you can do that as well, but it's ad hawk because you can just
00:20:52.400 keep adding on these epicycles. There's no reason for postulating the reality of these things,
00:20:57.040 other than to try and match what's really going on in reality. Let's go back to the book,
00:21:00.800 David Wright. Furthermore, when it comes to the details, there is more than one heliocentric theory.
00:21:06.800 Galileo believed that the planets move in circles, while in fact their orbits are very nearly
00:21:12.480 ellipses. So the data did not fit the particular heliocentric theory that Galileo was defending
00:21:17.600 either, so much then for his having been convinced by accumulated observations. But for all that,
00:21:24.000 the church took no position on this controversy. The Inquisition did not care where the planets
00:21:30.080 appeared to be, what they cared about, was reality. They cared where the planets really were,
00:21:34.880 and they wanted to understand the planets through explanations, just as Galileo did.
00:21:40.400 Instrumentalists and positivists would say that since the church was perfectly willing to accept
00:21:45.360 Galileo's observational predictions, further argument between them was pointless,
00:21:50.080 and his muttering a poor sea mueve was strictly meaningless. But Galileo knew better and so did
00:21:56.320 the Inquisition, when they denied the reliability of scientific knowledge, it was precisely
00:22:01.920 the explanatory part of that knowledge that they had in mind. Their worldview was false,
00:22:07.920 but it was not illogical. Admittedly, they believed in revelation and traditional authority
00:22:12.880 as sources of reliable knowledge, but they also had an independent reason. For criticizing the
00:22:18.160 reliability of knowledge obtained by Galileo's methods, they could simply point out that no
00:22:23.200 amount of observation or argument can ever prove that one explanation of a physical phenomena
00:22:29.600 is true and another false. As they would put it, God could produce the same observed effects
00:22:35.520 in an infinity of different ways, so it is pure vanity and arrogance to claim to possess a way
00:22:42.480 of knowing merely through one's own fallible observation and reason. Which way he, God, chose.
00:22:50.960 To some extent, they were merely arguing for modesty, for a recognition of human fallibility,
00:22:55.760 and if Galileo was claiming that the heliocentric theory was somehow proven or nearly so,
00:23:00.640 in some inductive sense, they had a point. If Galileo thought that his methods could confer
00:23:05.120 on any theory and authority comparable to which the church claimed, for its doctrines,
00:23:09.520 they were right to criticise him as arrogant, or as they would have put it blasphemous. Though,
00:23:13.920 of course, by the same standard, they were much more arrogant themselves. So how can we defend Galileo,
00:23:20.640 against the Inquisition? What should Galileo's defense have been in the face of this
00:23:25.520 charge of claiming too much when he claimed that scientific theories contain reliable knowledge
00:23:30.000 of reality? The Papurian defense of science, as a process of problem solving and explanation
00:23:35.280 seeking, is not sufficient in itself. For the Church, too, was primarily interested in
00:23:41.120 explanations and not predictions, and it was quite willing to let Galileo solve problems using
00:23:46.640 any theory he chose. It was just that they did not accept Galileo's solutions, which they would call
00:23:52.080 me mathematical hypotheses, had any bearing on physical reality. Problem solving, after all,
00:23:57.760 is a process that takes place entirely within human minds, so Galileo may have seen the world,
00:24:03.360 as a book in which the laws of nature are written in mathematical symbols, but that is strictly
00:24:08.080 a metaphor. There are no explanations in all but out there with the planets. The fact is that
00:24:13.360 all our problems and solutions are located within ourselves. Having been created by ourselves,
00:24:19.920 when we solve problems in science, we arrive through argument, theories, those explanations
00:24:26.000 seem best to us. Pause their, going back, let's just read that again, because it's important to
00:24:31.280 keep that front of mind when we're considering the world view of David Deutsch coming from Papa.
00:24:37.280 I'll say it again, quote from David. The fact is that all our problems and solutions are located
00:24:43.120 within ourselves. Isn't that wonderful? So that saying that there's no way of deriving anything
00:24:48.640 from outside. The only purpose for referring to external reality is to decide between those things
00:24:56.240 within yourself, the problem within yourself and the solution you conjecture within yourself,
00:25:00.400 the purpose of observation is to check which of the solutions really do solve the problem that
00:25:06.560 you have or another way of putting that is which of the explanations that you conjecture
00:25:11.040 actually turn out to be go unrefuted and the other ones go refuted by the observation that you
00:25:16.160 make. So let's go on, David writes. Again, when we solve problems in science, we arrive through
00:25:22.640 argument at theories whose explanation seem best to us. So without in any way denying that it
00:25:29.840 is right and proper and useful for us to solve problems, the inquisition and modern skeptics
00:25:36.080 might legitimately ask what scientific problem solving has to do with reality. We may find our
00:25:42.880 best explanations psychologically satisfying. We may find them helpful in making predictions.
00:25:48.240 We certainly find them essential in every area of technological creativity. All this does
00:25:53.120 justify our continuing to seek them and to use them in those ways. But why should we be obliged
00:25:59.360 to take them as fact? The proposition that the inquisition Fort Galileo to endorse
00:26:04.160 was in effect this, that the earth is in fact at rest with the sun and planets in motion around it,
00:26:10.080 but that the paths on which these astronomical bodies travel are laid out in a complex way
00:26:15.520 when viewed from the vantage point of earth is also consistent with the sun being at rest
00:26:20.480 and the earth and the planets being in motion. Let me call that the inquisitions theory of the
00:26:26.240 solar system. If the inquisitions theory were true, we should still expect the heliocentric theory
00:26:31.600 to make accurate predictions of the results of all earth-based astronomical observations,
00:26:37.440 even though it would be factually false. It would therefore seem that any observations that appear
00:26:42.320 to support the heliocentric theory lend equal support to the inquisitions theory. Okay, pausing
00:26:47.440 their my reflection. So the thing here is, and this is a theme that runs through the philosophy of
00:26:54.240 David Deutsch throughout both of his books, is that using observations to support your theory is a
00:27:01.040 dead end. Because inconsistent theories can be regarded as containing the same amount of support
00:27:08.000 given a certain amount of observations. Here we see an example of this. Almost any observation we
00:27:13.360 make of the sky is going to support this geocentric theory. After all, you can walk outside right
00:27:20.000 now and plot the position of the celestial objects in the sky, including the sun over the course
00:27:25.920 of the 24-hour period, and those observations are going to be using a naked eye consistent with
00:27:32.080 geocentrism. They're going to support geocentrism, because if what you think the project of science
00:27:38.080 is about is supporting a particular theory with ever more accumulated evidence, you're going to
00:27:43.680 succeed in being able to support that theory, false know where it is. And indeed, you can use such a
00:27:49.920 theory, this geocentric theory, in order to predict the position of the celestial bodies on the
00:27:55.200 sky day after day. You can make extremely accurate predictions of where the sun's going to be
00:28:00.800 tomorrow in the sky. If you were shown that the earth is at the center, if all you're interested
00:28:05.680 in is supporting particular theories and making predictions, you can rely upon known to be false
00:28:12.320 explanations. In fact, you don't really have to be concerned about explanations at all to begin with,
00:28:18.080 because if what you're really after are predictions, and this is David Deutsch's deep point about
00:28:24.640 the project of science. So we need to be focused on explanations. If we are realists, we can
00:28:30.880 conceive that not everyone's a realist, but that doesn't prevent us from remaining committed to
00:28:36.800 the project of science as being about good explanations, because we want to come to a deeper and
00:28:41.520 deeper understanding of the reality that we inhabit. We are not primarily concerned in any area
00:28:47.440 outside of science in predicting what's going to happen next. In the special case of science,
00:28:52.720 yes, we are, but it's only a small part of the scientific project, after all, if we consider the
00:28:56.720 entire science of biology, sometimes what we're interested in is how exactly species arise over time,
00:29:03.200 evolution by natural selection is an explanation of the biological diversity that we see.
00:29:08.480 However, simultaneously, it doesn't allow you necessarily to make accurate predictions about what
00:29:14.480 species will arise next. In fact, it tells you why that project of trying to explain the direction
00:29:21.840 of evolution is a fool's error, and because, as we like to say, evolution by natural selection
00:29:26.480 is a blind process that cannot see ahead as to how life will change over time, given a change in
00:29:32.880 conditions in ecosystems and niches that life might evolve into might adapt itself towards.
00:29:38.880 So I'm skipping a part. David talks about how the fact, well, there's no way in which we could
00:29:44.640 rule out using experiment. A theory like, for example, that the earth is just at the center of
00:29:51.120 a ginormous planetarium, and that planetarium was giving us a apparent feedback that was
00:29:58.720 consistent with a heliocentric theory. This is the simulation argument in disguise. This idea that
00:30:06.240 there might be this hugely complicated entity that is giving us the appearance of realism and
00:30:13.360 external reality, but which actually forms the border between what we experience as reality and
00:30:19.680 outside of that thing, being something that we have no access to. So I'm skipping that,
00:30:24.800 and I'll just pick it up where David writes, quote, to us, the inquisitions theory looks hopelessly
00:30:30.800 contrived. Why should we accept such a complicated and ad hoc account of why the sky looks as it
00:30:36.800 does when the unadorned heliocentric cosmology does the same job with less fuss. We may cite the
00:30:43.520 principle of Occam's razor, do not multiply entities beyond necessity, or as I prefer to put it,
00:30:48.400 do not complicate explanations beyond necessity, because if you do, the unnecessarily complications
00:30:53.360 themselves remain unexplained. However, whether an explanation is or is not contrived or unnecessarily
00:31:00.240 complicated depends on all the other ideas and explanations that make up one's worldview.
00:31:05.280 The inquisition would have argued that the idea of the earth moving is an unnecessary complication.
00:31:10.720 It contradicts common sense, it contradicts scripture, and they would have said there is a perfectly
00:31:14.960 good explanation that does without it, but is there? Does the inquisition's theory really
00:31:19.600 provide alternative explanations without having to introduce the counterintuitive complication
00:31:25.280 of the heliocentric system? Just pausing their more reflections. So today, using the best
00:31:30.560 explanation of epistemology in the philosophy of science, given to us in the beginning of infinity,
00:31:35.200 we would say that heliocentricism is the hard to vary explanation while geocentrism in order to
00:31:41.840 continue to make more and more accurate predictions had to be easy to vary. It had to allow the
00:31:46.240 adding on of more epicycles whenever the predictions were out by a certain amount. Adding epicycles
00:31:51.680 is an easy variation. However, it's very difficult to vary heliocentricism in the same way.
00:31:57.920 Let's go back to the book and David writes, quote, let us take a closer look at how the inquisitions
00:32:02.720 theory explains things. It explains the apparent stationarity of the earth by saying that it
00:32:08.720 is stationary. So far, so good. On the face of it, that explanation is better than Galileo's
00:32:13.840 for here to work very hard and contradicts some common sense notions of force and inertia
00:32:18.560 to explain why we do not feel the earth move. But how does the inquisition theory cope with
00:32:24.240 the more difficult task of explaining planetary emotions? The heliocentric theory explains
00:32:29.520 them by saying that the planets are seen to move in complicated loops across the sky because
00:32:34.880 they are really moving in simple circles or ellipses in space, but the earth is moving as well.
00:32:39.680 The inquisitions explanation is that the planets are seen to move in complicated loops because
00:32:43.440 they are really moving in complicated loops in space, but, and here according to the inquisitions
00:32:47.920 theory comes the essence of the explanation, this complicated motion is governed by a simple,
00:32:53.200 underlying principle. Namely, that the planets move in such a way that, when viewed from earth,
00:32:58.800 they appear just as they would, if they and the earth were, in simple orbit around the sun.
00:33:06.080 To understand the planetary emotions in terms of the inquisition theory, it is essential
00:33:10.960 that one should understand this principle for the constraints it imposes are the basis
00:33:16.080 of every detailed explanation that one can make under the theory. For example, if one were asked
00:33:21.040 why a planetary conjunction occurred on such and such a date, or why a planet backtracked across
00:33:25.680 the sky in a loop of a particular shape, the answer would always be because that is how it would
00:33:30.880 look if the heliocentric theory were true. So here is a cosmology, the inquisitions cosmology
00:33:36.160 that can be understood only in terms of a different cosmology, the heliocentric theory,
00:33:40.640 that it contradicts, but faithfully mimics pausing their my reflection. So as we might say of this
00:33:47.600 theory using this argument, namely the inquisitions theory, the geocentric theory taken seriously,
00:33:53.840 this version of the geocentric theory simply is heliocentricism with some additional assumptions,
00:34:00.880 namely that everything appears to be consistent entirely and explained well by heliocentricism,
00:34:08.480 except we're going to add the assumption that heliocentricism is not actually true and geocentrism
00:34:14.400 is true. But otherwise everything else works out the same, all the predictions that one makes
00:34:19.200 is perfectly consistent with heliocentricism being true, but we're just going to tack on
00:34:23.440 this negation of the entire theory that although it does appear to be true and appear to be the
00:34:27.840 best explanation, we're going to nonetheless regard it as axiomatically false because geocentrism
00:34:34.240 we just take as dogmatically the truth about our cosmology. And I'm skipping a part and I'll just
00:34:39.120 pick it up where David says on this exact point, quote, therefore we are right to regard the
00:34:44.240 inquisitions theory as a convoluted elaboration of the heliocentric theory rather than vice versa.
00:34:50.800 We have arrived at this conclusion not by judging the inquisitions theory against modern cosmology,
00:34:55.360 which would have been a circular argument, but by insisting on taking the inquisitions theory
00:34:59.600 seriously in its own terms as an explanation of the world. I've mentioned the grass
00:35:03.840 cure theory which can be ruled out without experimental testing because it contained no explanation.
00:35:08.560 Here we have a theory which can also be ruled out without experimental testing because it
00:35:13.520 contains a bad explanation, an explanation which in its own terms is worse than a travel
00:35:18.880 pausing their just my reflection. Yes, so what we're saying here is we have two theories,
00:35:22.960 both of them make exactly the same predictions. One of them is simpler than the other,
00:35:26.800 namely heliocentricism is simpler than the geocentric theory as presented here because the
00:35:31.280 geocentric theory assumes that all the positions of the planets that we observe are perfectly
00:35:36.640 consistent with heliocentricism except it's not true. So it is, as we say, heliocentricism
00:35:42.240 plus this additional assumption of it not being true. And there it goes on to say, quote,
00:35:45.680 as I have said, the Inquisition were realists, yet their theory has this in common with
00:35:50.160 solipsism. Both of them draw an arbitrary boundary beyond which they claim human reason has no
00:35:56.080 access, or at least beyond which problem-solving is no path to understanding. For solipsists,
00:36:01.840 the boundary tightly encloses their own brains, or perhaps just their abstract minds or in
00:36:06.160 corporeal souls for the Inquisition, it enclosed the entire earth, some present day creationists,
00:36:11.040 believe in a similar boundary, not in space. But in time, for they believe that the universe
00:36:15.680 was created a six thousand years ago, complete with misleading evidence of earlier events
00:36:20.400 pausing their just my reflection on this. We might well add to this any of the modern
00:36:25.760 incantations of solipsism. One of which is, well, this is all a simulation of some kind or other,
00:36:31.760 including the so-called simulation argument from Boschdom, it stands on the same logical footing
00:36:36.800 as these ideas about solipsism. It postulates a reality beyond which we have no access
00:36:42.960 experimentally scientifically and perhaps even using our reason. What we say is that the only thing
00:36:47.520 we have access to are the contents of the simulation or the dream or the deceptions that are
00:36:52.560 going on caused by the evil demon, whatever it happens to be. If it is a simulation, if we are
00:36:57.120 living in a computer simulation, then it postulates a world outside the one we're experiencing
00:37:02.080 in which the computer on which this reality we experience is running. But we don't have access
00:37:07.600 to that computer or the universe in which that computer actually exists. It's postulating a
00:37:12.400 metaphysical reality on the same footing as whatever is doing the dreaming in which whatever the
00:37:18.000 entity is, presumably it's you, if you're dreaming all of this, in which that entity exists
00:37:23.440 as David says on this point after I skip another paragraph, he writes, quote, there is a large
00:37:29.840 class of related theories here but we can usefully regard them all as variants of solipsism.
00:37:36.320 They differ in where they draw the boundary of reality or the boundary of that part of reality,
00:37:41.200 which is comprehensible through problem solving and they differ in whether and how they
00:37:45.440 seek knowledge outside that boundary. But they all consider scientific rationality and other
00:37:50.400 problem solving to be in applicable outside the boundary. A mere game, they might concede that it
00:37:56.640 can be a satisfying and useful game but it is nevertheless only a game from which no valid
00:38:02.880 conclusion can be drawn about the reality outside end quote. Yes, so as I say, these other versions
00:38:11.520 of solipsism, you know, the one that says that you're dreaming all of this into existence or
00:38:16.240 that you want to friend a dreaming all of this into existence or that all conscious creatures on
00:38:20.560 planet earth are dreaming reality into existence. Plato's Cave was one of the earliest versions
00:38:25.920 of this that because we don't have direct access to reality, we might be utterly deceived about
00:38:33.120 the true nature of reality in some way or other. Descartes came along and talked about how a
00:38:37.680 demon could be deceiving us and said this that him down a router of his so-called method of doubt.
00:38:43.040 The movie, the movie series, the matrix and the simulation arguments, it's all the same,
00:38:48.320 all these things are versions of solipsism. Perhaps no philosopher is more closely
00:38:54.640 associated with solipsism than Descartes because Descartes had this idea but there's one thing that
00:39:01.360 could not be doubted and that is the individual's own mind, the existence of their own mind and
00:39:06.960 he said it was basically a logical necessity if you read the meditation. He doesn't really
00:39:11.120 regard it as an argument. He says it's a necessary truth. I think I am is true whenever I think it.
00:39:18.000 Now I used to buy this, I used to think yes, this is the only thing that we cannot doubt. If you're
00:39:22.320 thinking then therefore you exist but as David says in the fabric of reality, in the very next
00:39:28.160 paragraph I'm about to read, this entails taking on board a whole bunch more things that one
00:39:35.280 regards as being absolutely true. Let's just read what David says here, quote, despite Descartes'
00:39:41.040 desire to base his philosophy on this supposedly firm foundation, he actually allowed himself
00:39:45.600 any other assumptions and was certainly no solipsist, end quote. So what does David mean by these many
00:39:52.320 other assumptions? What I think is meant here is if you're going to argue in the same way that
00:39:58.480 Descartes did that I think I am is a necessary truth or is it's usually rendered and I think he
00:40:03.600 said this elsewhere, cogito ergo sum which is I think therefore I exist. So that sort of suggests
00:40:09.920 that it's kind of an argument whereas I think David, whereas I think Descartes in the meditations
00:40:14.320 was actually saying it's just a necessary truth. It's just if you if you are able to think those
00:40:19.040 words I think or I exist or something you can think anything at all, then you exist necessarily
00:40:24.560 exist. But whatever the case, you're formulating those thoughts in language. So therefore you
00:40:30.000 think the language renders reality perfectly well. So not only do you think that this captures
00:40:35.840 a necessary truth, a firm foundational which to base everything else, you're also thinking the
00:40:40.480 language is inherent as well. It's able to capture your thoughts inherently, which means that you
00:40:44.720 will you cannot possibly be mistaken about the meanings of words or what the letters that make
00:40:50.320 up the words happen to be. There's a whole bunch that you're admitting are also equally true as
00:40:56.720 the claim I think therefore I exist. If I think therefore I exist is your foundational truth,
00:41:03.520 then that amounts to an argument. So you're thinking that logic is perfectly inherent,
00:41:07.600 you're thinking that language is perfectly inherent, you're thinking that what you think now is
00:41:12.160 equivalent to what you think in the future, that these words like exist, for example, label a concept
00:41:18.480 which also you cannot be mistaken about. So there's rather much that you're claiming to not
00:41:24.560 possibly be mistaken about when you say there's only one thing that I think I cannot be mistaken
00:41:30.480 about, namely that I exist. Well, if you truly think that then you're also trying to say that
00:41:35.440 you can't possibly be mistaken about the word I, the word exists, what I exist, the conjunction of
00:41:40.960 those two things means, what the letters in those words mean, what the noises coming out of your
00:41:45.440 mouth mean, or what the supposed thoughts in your head really means. So you're arguing for
00:41:52.240 a vast ensemble of things that you think you are infallible about. But if we're fallibleists,
00:41:59.200 we can reject all of that and we can say, well, we could still be mistaken about any one of those
00:42:03.920 things because that's the nature of creating knowledge that we have, it's error prone,
00:42:08.800 and we could be wrong about it. It's not to say that you don't exist, by the way, it's just to
00:42:12.960 say that you can't be absolutely 100% certain that you exist, that's all, that's all we're saying,
00:42:19.200 that there's a possibility. Now, even if you can't think of a way in which you might be mistaken,
00:42:24.960 that's no refutation of the fact that you could be mistaken, as I like to say,
00:42:28.320 your inability to imagine how you might be mistaken is not a refutation of the fact that you could
00:42:33.840 be mistaken. It just means you have a poor imagination or an insufficiently good imagination
00:42:38.800 to imagine all the ways in which you might be mistaken. You are fallible, after all.
00:42:43.280 Okay, so let's go to the part of the chapter where David is,
00:42:47.600 Refuting Solipsism, not by experiment, not biological proof, but by arguments.
00:42:53.040 If we take solipsism seriously, what it's saying is basically your dreaming things into existence.
00:42:59.200 So you're the only person that exists, and everything you experience, all of reality,
00:43:04.000 is nothing but a product of your dreaming. You are born dreaming, you're dreaming now,
00:43:08.880 and you will die dreaming. So the external reality, none of it really, truly exists,
00:43:13.600 is just part of your dream. What's wrong with this? Well, let's read what David says about this.
00:43:19.360 Quote, If there are sources of ideas that behave as if they were independent of oneself,
00:43:25.120 then they necessarily are independent of oneself. For if I define myself as the conscious
00:43:31.040 entity that has the thoughts and feelings I am aware of having, then the dream people I
00:43:36.320 seem to interact with are by definition something other than that narrowly defined self.
00:43:42.000 And so I must concede that something other than myself exists, pausing their my reflection.
00:43:47.520 And so this is the beginning of the refutation of solipsism, namely that if you're dreaming
00:43:53.760 into existence, a reality, which is independently so complex, as to be unpredictable by yourself,
00:44:01.360 by your dreaming self, then those other entities are indeed real, real in the sense that they appear
00:44:08.400 in whatever way you're going to explain this dream like reality. Everything you're interacting with
00:44:14.720 is a source of an idea or a prompt, an observation, another person might be a source of an
00:44:20.960 idea as well. So some of the ideas are not coming from inside you, but you're getting them
00:44:26.880 from other people that you're interacting with. And if they're just a product of your mind,
00:44:30.640 if these other people are a product of your mind, then that's a rather unusual way of defining
00:44:34.880 oneself, not only as these source of particular ideas about those people, but those people has
00:44:40.160 being sources of ideas that are not you. So your conscious self is not really all that you are.
00:44:47.520 What you are is your conscious self and then all these other entities that you're interacting with,
00:44:52.720 the dream people that you interact with on a daily basis. As David goes on to say, quote,
00:44:57.920 my only other option, if I were a committed solipsist would be to regard the dream people
00:45:03.200 as creations of my unconscious mind and therefore as part of myself in a loose sense.
00:45:08.640 But then I should be forced to concede that myself had a very rich structure, most of which is
00:45:13.440 independent of my conscious self within that structure, our entities, dream people who despite being
00:45:19.360 mere constituents of the mind of a supposed solipsist behave exactly as if they were committed
00:45:24.800 antisolipsists. So I could not call myself holy a solipsist for only my narrowly defined self would
00:45:31.680 take that view. Many apparently most of the opinions held within my mind as a whole would oppose
00:45:38.880 solipsism, poor say, my reflection. So what's he saying here saying here that if you're really
00:45:43.680 truly going to try and believe that you're a solipsist. In other words, you're the only thing that
00:45:47.360 exists in reality and everything is being dreamed into existence. Most of that reality that's
00:45:52.400 being dreamed into existence consists of, well, the people in that reality hold the view that
00:45:58.880 solipsism is not true. And so you, if you're dreaming all of this into existence, primarily consists
00:46:05.680 of ideas, minds that object to your apparent belief in solipsism, they're the ones, they're the
00:46:12.880 people you're going to interact with who are going to say, you're foolish for believing that you're
00:46:16.640 a solipsist after all. Here am I, supposedly part of you, part of your dream that is telling you
00:46:22.800 solipsism as false out of square that circle that most of you, most of your mind actually
00:46:29.280 reject solipsism because after all, your mind also consists of the dream people. Isn't that
00:46:34.480 bizarre? There goes on to say, quote, I could study the outer region of myself and find that it
00:46:39.920 seems to obey certain laws. The same laws as the dream textbooks say apply to what they call the
00:46:46.160 physical universe. I would find that there is far more of the outer region than the inner
00:46:50.400 region. Aside from containing more ideas, it is also more complex, more varied and has more measurable
00:46:56.080 variables by a literally astronomical factor than the inner region. Moreover, this outer region
00:47:02.640 is amenable to scientific study using the methods of Galileo because I have now been forced
00:47:08.000 to define that region as part of myself. Solipsism no longer has any argument against the validity
00:47:13.840 of such study, which is now defined as no more than a form of introspection, porting him or
00:47:19.200 reflection. That's basically it. Okay, that's the refutation. Solipsism basically begins by saying
00:47:25.280 it's all a dream, but taken seriously, the contents of the dream act unpredictably in many cases
00:47:32.160 autonomously and the physical world can even be studied. So basically, nothing has changed except
00:47:38.080 the addition of a useless assumption, namely the assumption that it's all a dream. Duran Lenny
00:47:42.240 air makes this point in a particular discussion I'm linking to here. I'll put that up on the screen
00:47:46.640 and in the notes of the podcast that this is a closer to truth interview he has. And he talks about
00:47:52.480 the simulation argument, you know, basically a form of solipsism where he says, well, look, if science
00:47:57.040 still works under this metaphysical assumption of it all being simulated or dreamed, then what does
00:48:02.880 it's a simulation actually add to our understanding of reality? Again, this whole simulation dream
00:48:08.480 thing is refuted, not by a mathematical or logical disprove of the hypothesis, nor by any experimental
00:48:15.760 evidence, but rather something in a sense way more compelling. A philosophical argument that the
00:48:21.360 simulation or solipsism claim is a bad explanation. We should notice in beginning of infinity terms,
00:48:27.840 it's easier to vary. After all, this solipsism claim that one person is dreaming could easily be
00:48:33.840 varied to and maintain all the same predictions by saying that two such people are dreaming three,
00:48:38.800 pick your number of people are dreaming this reality into existence or the number of computers on
00:48:43.680 which it's being simulated or the number of demons deceiving people into thinking this is true
00:48:48.080 and so on and so forth. All of these different ways of denying basic realism are easy to vary
00:48:55.920 and therefore bad explanations and can be rejected on that basis. David goes on to say,
00:49:00.880 quote, thus we see that if we take solipsism seriously, if we assume that it is true and that
00:49:07.520 all valid explanations must scrupulously conform to it itself to structs. How exactly does
00:49:14.080 solipsism take in seriously differ from its common sense rival realism? The difference is based on
00:49:20.640 no more than a renaming scheme. Solipsism insists on referring to objectively different things,
00:49:26.480 such as external reality and my unconscious mind or introspection and scientific observation
00:49:31.840 by the same names, but then it has to reintroduce the distinction through explanations in terms of
00:49:38.320 something like the outer part of myself, but no such extra explanations would be necessary without
00:49:44.800 its insistence on an inexplicable renaming scheme. Solipsism must also postulate the existence
00:49:51.120 of an additional class of processes, invisible inexplicable processes which give the mind the illusion
00:49:57.840 of living in an external reality. The solipsist who believes that nothing exists other than the
00:50:03.840 contents of one mind must also believe that the mind is a phenomenon of greater multiplicity
00:50:10.240 than is normally supposed. It contains other people like thoughts, planet life thoughts, and laws
00:50:16.240 of physics like thoughts. These thoughts are real. They develop in a complex way or pretend to,
00:50:21.360 and they have enough autonomy to surprise, disappoint, and liven or thwart that other class of
00:50:27.920 thoughts which call themselves I, thus the solipsists explanation of the world is in terms of
00:50:34.240 interacting thoughts rather than interacting objects, but those thoughts are real and interact,
00:50:39.840 according to the same rules that the realists says govern the interaction of objects. Thus,
00:50:45.120 solipsism, far from being a worldview stripped to its essentials, is actually just realism,
00:50:51.280 disguised, and weighed down by additional unnecessary assumptions, worthless baggage introduced
00:50:58.400 only to be explained away, pausing their my reflection. I just love that line. It's probably one
00:51:04.000 of my favorite lines in all the fabric of reality. This idea of the additional unnecessary assumptions
00:51:10.240 being worthless baggage introduced only to be explained away, I've probably repurposed or
00:51:15.920 rephrased it a number of times over the years in response to various different kinds of anti-realist,
00:51:22.720 metaphysic claims, and bad philosophy and bad explanations. So that refutation of solipsism,
00:51:28.480 and all similar arguments is basically where I'm going to finish it today. I'll read one more
00:51:34.000 paragraph, because I think that this is one of the most powerful, and in my experience,
00:51:38.320 most talked about parts of the fabric of reality, that here we have a refutation,
00:51:44.160 an argument that shows the poverty of these anti-realistic arguments. You know, you go along to
00:51:51.520 a philosophy lecture at university, and eventually you come across, usually it comes via data.
00:51:56.480 This idea that it might all be a dream that what is really real, and you get into these deep
00:52:00.480 philosophical arguments and you are told, there's no way that science can disprove this,
00:52:05.440 or no way that usually it's put in those kind of terms. There's no scientific evidence that
00:52:09.840 you can bring forth to show that it's not all a dream. But who cares? Who cares about the fact
00:52:14.720 there's no scientific evidence to show that this is false? That's to privilege a particular
00:52:19.520 way of refuting bad ideas. There's a better way. In this circumstance, certainly, the better way
00:52:26.080 is to reveal the poverty of the explanation that is solipsism, or the simulation argument. To say,
00:52:33.520 look, it's basically just realism plus additional unnecessary assumptions that don't help us to
00:52:39.520 understand reality any better. And if you assume that it's all going on in your mind,
00:52:44.960 then you're assuming that your mind is just equally as complex as what realism says the physical
00:52:50.160 world happens to be. It's just that you're saying it's not really a physical world. It's all in
00:52:55.120 my head. But then this raises all sorts of questions about what's really going on in your head,
00:53:00.240 if we take it seriously, then reality is just reality. It's just that it's in your head,
00:53:04.960 but how and why and so on and so forth become questions that would need to be asked if we would
00:53:10.240 take this seriously. So we refuse it, not by experiment, not by logical disprove, but simply by
00:53:16.560 philosophical argument, as David goes on to say in the last paragraph that I'll read, quote,
00:53:21.040 by this argument, we can dispense with solipsism and all the related theories. They are all
00:53:27.360 indefensible. Incidentally, we have rejected one world view on these grounds, namely,
00:53:32.720 positivism, the theory that all statements other than those describing or predicting observations
00:53:37.200 are meaningless. How's our remark? In chapter one, positivism assert its own meaninglessness
00:53:41.840 and therefore cannot be consistently defended. So we can continue reassured with common sense,
00:53:48.080 realism and the pursuit of explanations by scientific methods end quote. And in the next episode,
00:53:53.760 I'll introduce pop or into the mix. I'll bring pop or into the mix as well because
00:53:57.680 pop or wrote about realism, common sense realism in objective knowledge, and it comes to bear
00:54:03.760 directly on this. But for now, until next time, bye bye.