00:00:11.840 Welcome to Topcast. Episode one of another new series. At the moment on juggling essentially
00:00:19.280 three series concluding the beginning of infinity chapter explorations. I have just commenced and
00:00:26.480 just recorded the first episode of the science of canon Kant, the popular science book,
00:00:34.880 in addition to being a popular science book, it's a groundbreaking revolutionary exploration of
00:00:40.800 constructive theory. They knew physics theory by Kiara Mileto, who's the author of the book,
00:00:45.920 and David Deutsch, who is the originator of the theory. And now I am beginning for the first time
00:00:53.280 and exploration of David Deutsch's first book, the fabric of reality. The book that introduced me
00:01:00.720 to the work of David Deutsch and really changed my mindset in ways more fundamental than I think
00:01:07.600 anything else that came before. And it may seem odd that I'm doing two books in parallel,
00:01:13.360 but my reason for that is twofold. I can't wait for either of them. I want to do both now that I'm
00:01:19.040 finishing up with the beginning of infinity. I've been in my mind, I've prepared myself for doing
00:01:24.800 the fabric of reality. And the fact that Kiara has just released this book, it really means that
00:01:31.120 I can kind of bookend the beginning of infinity with its predecessor, which is the fabric of reality.
00:01:39.040 And in some sense, some sense its intellectual success or certainly a descendant of a kind which
00:01:46.320 is the science of can and can't by Kiara. But this one is about the fabric of reality. So let me get
00:01:52.560 into the fabric of reality. Let me first explain why the fabric of reality is so exciting. And I've
00:01:58.480 said this many times before in many different places in different forums, but the basic
00:02:03.680 thing is that I have a number of popular science books here on the bookshelf behind me.
00:02:09.200 Dominant among the authors there is Paul Davies. And Paul Davies wrote some wonderful books that
00:02:17.040 were summaries of our best understanding of science at any particular given point in time.
00:02:21.600 And he would connect these, unlike many other authors, he would connect these to the history of
00:02:26.960 ideas and to philosophy and to other areas of our intellectual endeavors, things like religion,
00:02:34.960 theology, mathematics, chemistry. He would explain how physics is tied into these different areas.
00:02:43.120 But what I would say about that is it provided a wonderful overview and exciting overview
00:02:48.080 of some of the latest parts of science, especially in physics, some of the mystery,
00:02:53.360 some of the open questions as well. But it is the kind of, they were the kind of books broadly
00:03:00.240 speaking that anyone who read them, anyone knowledgeable in those areas would probably think is
00:03:08.160 uncontroversial. This is different to David Deutsch's work. David Deutsch's fabric of reality
00:03:15.600 is not merely a summary of extent knowledge, the stuff that everyone agrees on.
00:03:22.400 It is taking the best theories and explaining them, number one, how they are in a sense,
00:03:30.400 I go here at home, hence the fabric of reality. And how there is a particular way that one should
00:03:39.360 understand these things in realistic terms. And so the fabric of reality is about the four strands,
00:03:45.280 so they're talked about, the four strands of the fabric of reality. And David takes a scalpel,
00:03:51.040 a scalpel to trying to remove errors from our understanding of these different theories in order
00:03:59.040 to clarify exactly what our best understanding is, as hard as it may be sometimes to accept.
00:04:06.320 And in particular, the theory of quantum physics is explained here in a popular account for the
00:04:16.080 first time, as far as I'm aware, the first time in a popular account. We explain the realistic
00:04:22.000 conception of quantum theory. Prior to this, as I was struggled through university trying to
00:04:27.040 understand quantum theory, I was told the usual nonsense about if you think you understand quantum
00:04:32.800 theory, then you don't. Okay, this is what Richard Feynman said. What David Deutsch does is he
00:04:37.760 will acknowledge the existence of various other so-called interpretations. And one of the books I
00:04:42.800 have up here right here is The Ghost in the Atom by Paul Davies and John Brown, Julian Brown.
00:04:51.360 Yeah. By another author and Paul Davies. And they go through, well, just about every interpretation
00:04:58.560 of quantum theory that existed at the time of the publication of the book. This was back in the
00:05:01.760 late 80s. One of the people I interview is David Deutsch. And in that book, he does try to explain
00:05:08.080 the many worlds interpretation of quantum theory. What was called many worlds interpretation of quantum
00:05:13.600 theory at that time. And at that time, I was still struggling to understand it and I didn't really
00:05:17.680 understand even that explanation. But here in the fabric of reality, we get an explanation of quantum
00:05:24.560 theory that is just as clear as one can hope for at the time. And even through to today, it is
00:05:31.840 still my go-to explanation for how to understand quantum theory. And there's only one way to understand
00:05:37.200 quantum theory that we know of. And that is the existence of quasi or semi parallel universes where
00:05:46.240 there are entities existing in those other universes, which we don't have easy access to,
00:05:51.280 except for interference experiments and so on. That's explained in this book. And that's the thing
00:05:56.640 that really hooked me for sticking with the book from beginning to end and being wowed on almost
00:06:03.120 every other page. But the thing that drew me in, that was the thing that sort of enticed me to
00:06:07.840 continue reading, but the thing that drew me in was chapter one, chapter one where David sort of
00:06:13.760 seemed to dive into my own psychology somehow, because again, this book was published in 1997.
00:06:22.080 And at the time, I was doing, you know, at uni undergraduate doing physics, doing mathematics,
00:06:28.080 doing philosophy and kind of having the sense that there has to be a way in which all of this
00:06:35.520 comes together. I kind of somehow subconsciously accepted that reality was just a coherent whole
00:06:42.160 out there that you could come to have a better and better understanding of, that it didn't have
00:06:46.960 to make no sense. But at the same time, everyone seemed to be aspiring for specialization. So the
00:06:55.520 more that you knew, the more that you specialize. So I was interested in astronomy. But astronomy
00:07:00.480 wasn't enough. You need to be in astrophysicist, but that wasn't enough. You needed to be an
00:07:04.400 astrophysicist. And then stars, but that wasn't enough. You need to be an astrophysicist. After
00:07:07.440 a physicist was interested in variable stars, but that wasn't enough. You need to be an astrophysicist
00:07:11.360 and very reliable stars called Cepheid Variables. And you had to use them in order to find the
00:07:15.520 distance to distance galaxies and so you'd become ever more specialized as someone who gained more
00:07:20.560 and more knowledge. This seemed disappointing to me. I wanted to be more broad than that. I wanted
00:07:26.400 to have a broad understanding of everything. And that leads me to the beginning of the book.
00:07:32.720 And so I'm just going to dive in and we'll come back to what the other strands of the fabric of
00:07:37.040 reality are. But this is what David says in chapter 1 of the fabric of reality, titled,
00:07:43.280 The Theory of Everything in David Rights. I remember being told when I was a small child
00:07:49.680 that in ancient times it was still possible for a very learned person to know everything
00:07:54.560 that was known. I was also told that nowadays so much is known that no one could conceivably
00:08:00.960 learn more than a tiny fraction of it, even in a long lifetime. The latter proposition,
00:08:06.720 surprise and disappointed me. In fact, I refuse to believe it. I did not know how to justify my
00:08:11.600 disbelief, but I knew that I did not want things to be like that. And I envied the ancient scholars.
00:08:17.760 It was not that I wanted to memorize all the facts that were listed in the world in Cyclopedias
00:08:22.960 on the contrary. I hated memorizing facts. That is not the sense in which I expected it to be
00:08:28.560 possible to know everything that was known. It would not have disappointed me to be told
00:08:33.440 that more publications appear every day than anyone could read in a lifetime.
00:08:38.800 Although there are 600,000 known species of beetle, I'd know wish to track the fall of every
00:08:44.080 sparrow, nor did I imagine that an ancient scholar who supposedly knew everything
00:08:48.720 that was known would have known everything of that sort. I had in mind a more discriminating
00:08:53.680 idea of what should count as being known. By known, I meant understood. The idea that one person
00:09:01.120 might understand everything that is understood may still seem fantastic, but it is distinctly
00:09:06.320 less fantastic than the idea that one person could memorize every known fact. For example,
00:09:10.960 no one could possibly memorize all known observational data on even so narrower subject
00:09:16.160 as the motion of the planets. But many astronomers understand those motions to the full extent
00:09:21.680 that they are understood. This is possible because understanding does not depend on knowing a lot
00:09:27.200 of facts such, but on having the right concepts, explanations and theories. One comparatively simple
00:09:33.920 and comprehensible theory can cover an infinity of digestible facts. Our best theory of planetary
00:09:39.920 motions is Einstein's general theory of relativity, which early in the 20th century superseded
00:09:45.600 Newton's theory of gravity and motion, it correctly predicts in principle not only all planetary
00:09:50.240 motions, but all other effects of gravity through the limits of accuracy of our best measurements.
00:09:56.400 For a theory to predict something in principle means that the predictions
00:10:00.080 follow logically from the theory, even if in practice the amount of computation that will be
00:10:04.080 needed to generate some of the predictions is too large to be technologically feasible or even too
00:10:08.400 large for it to be physically possible for us to carry it out in the universe as we find it
00:10:12.560 pausing their just my reflection and going back to where David talks there about this idea that
00:10:22.000 knowing everything that can be known can't possibly be about, for example,
00:10:29.840 knowing where all the astronomical bodies that orbit the sun or the stuff in the solar system,
00:10:37.840 what orbits they're going to take at any particular moment. In other words, if you ask me now,
00:10:43.200 where is Mars going to be in relation to the earth as it orbits the sun tonight at 9 p.m.
00:10:50.080 as I look into the sky, what part of the sky would I be able to tell you? I won't know that.
00:10:54.720 In fact, I won't know anything except a moon, I've got a good idea where the moon will be tonight.
00:11:00.400 But that's not the kind of knowledge we're interested in. What we're interested in
00:11:04.320 is the understanding. Could I find out? Yes, or there's a number of ways I could find out,
00:11:09.440 but could I understand the laws? Yes, I've studied those laws and anyone who wants to study those
00:11:15.440 laws can study those laws of orbital motion, of being able to predict given certain quantities,
00:11:23.360 given certain things like the mass of the sun, the distance between the sun and the object orbiting
00:11:30.080 it. These are the kind of bits of information that can go into the laws as we understand them
00:11:36.080 to enable a prediction and therefore an understanding, a deeper understanding that in fact,
00:11:40.640 all these bodies that go around the sun follow elliptical orbits. And if you have a sufficiently
00:11:46.000 powerful computer, it will do the calculation for you. You can do it with pen and paper,
00:11:49.920 you can do it with pen and paper. If you want high precision, then a computer is much better
00:11:54.720 as David says. And that's where the understanding is, just understanding that this equation represents
00:12:00.160 this particular physical entity, be it space time or in Newton's conception, the force of gravity,
00:12:05.680 then given positions of objects and masses of objects, then you can figure out what's going to
00:12:11.200 happen to them over time. This is the understanding that gives us. So far from causing the number
00:12:19.280 of things to be remembered to proliferate, understanding a simpler, deeper law that underlies all
00:12:26.720 those facts is far more illuminating and it requires less memory as well, doesn't it? Okay, back
00:12:34.160 to the book. And we're just about to get into a section where David is going to depart following
00:12:42.640 Popper from so many of the rest of physicists as they understand physics. It's specifically because
00:12:51.680 there's this debate, this debate centers around of course quantum theory as we will come to.
00:12:57.920 This is why one of the motivations for why he says what he's about to say. And what he says is,
00:13:05.760 quote, being able to predict things or to describe them, however accurately,
00:13:10.800 is not at all the same thing as understanding them. Predictions and descriptions in physics
00:13:17.040 are often expressed as mathematical formula. Suppose that I memorize the formula from which I
00:13:22.720 could if I had the time and inclination, calculate any planetary position that has been recorded
00:13:27.520 in the astronomical archives, what exactly have I gained compared with memorizing those archives
00:13:32.880 directly? The formula is easier to remember, but then looking a number up in the archives may be
00:13:39.040 even easier than calculating it from a formula. The real advantage of the formula is that it can be
00:13:43.920 used in an infinity of cases beyond the archive data. For instance, to predict the results of future
00:13:50.000 observations, it may also yield the historical positions of the planets more accurately because
00:13:55.600 the archive data contain observational errors. Yet even though the formula summarizes infinitely
00:14:02.160 more facts in the archives to knowing it does not amount to understanding planetary motions, facts
00:14:07.360 cannot be understood just by being summarized in a formula any more than being listed on paper or
00:14:12.080 committed to memory that can be understood only by being explained. Fortunately, our best theories
00:14:18.560 embody deep exponations as well as accurate predictions. For example, the general theory of relativity
00:14:23.840 explains gravity in terms of a new four-dimensional geometry of curved spacetime. It explains precisely
00:14:30.080 how this geometry affects and is affected by matter. That explanation is the entire content of the
00:14:35.200 theory. Predictions about planetary motions are merely some of the consequences we can deduce
00:14:41.360 from the explanation. Now, I think that there bears repeating. Speaking about the general theory
00:14:48.960 of relativity, David said, that explanation is the entire content of the theory. Predictions about
00:14:56.080 planetary motions are merely some of the consequences that we can deduce from the explanation.
00:15:02.560 Okay, so my reflection on that, here in the fabric of reality, David is holding up as
00:15:13.440 brightly highlighted as anywhere the centrality of explanation to the project of science.
00:15:20.960 And even more broadly. But when I first read this book in 1997, I think I appreciated
00:15:29.040 the negative aspect of David's argument, namely that science wasn't only about prediction.
00:15:36.240 I think I got that. That science wasn't just a list of facts. I think I got that.
00:15:43.440 What I don't think I really took on board was what the significance of explanation really was.
00:15:51.440 And even later when I read some pop-up for the first time, I still didn't quite understand
00:15:57.920 the centrality of explanation. It wasn't until the beginning of an infinity. When David
00:16:03.440 explained to the first time that what we're after, whether it's in science or anything else,
00:16:09.440 is not an explanation of any kind, because explanations are a dime a dozen, but hard to very
00:16:16.000 explanations, hard to vary explanations. And it's the hard to vary explanation that makes an
00:16:21.600 explanation a good explanation. But I just say that because it's an interesting personal for me,
00:16:28.640 psychological phenomena, that the concept of explanation was very much here in the fabric of reality.
00:16:36.080 But it took me a decade or more to really understand what was being said here.
00:16:42.480 And now I think I do have a much better understanding of what was going on there. As much
00:16:47.040 as I took from the fabric of reality, as fundamentally ground shifting in terms of the
00:16:53.280 perspective change that I underwent having read this book, I still didn't pick up everything.
00:16:58.480 And that's kind of a remarkable thing. And I think this is why people do go back to
00:17:03.360 great books. And this is what distinguishes great books from lesser works, let's say,
00:17:08.960 that you can keep returning to these books and figuring out that there's yet more to learn
00:17:14.720 and that you missed so much the first time around. And like I say, the importance of explanation
00:17:19.760 here that David is highlighting seemed to have escaped me. It really did escape me to a large
00:17:26.960 extent. I understood what scientific theories were not, but I don't think I really got what
00:17:32.480 scientific theories were. And I'd been reading about science and studying philosophy all this time,
00:17:41.040 all the way up to the beginning of infinity. So I think it wasn't until actually, even just
00:17:46.000 slightly prior to the beginning of infinity, it was in one of David's TED talks, a new way to
00:17:51.600 explain explanation. I think it was then that the light bulb moment happened for me the first time
00:17:56.560 I saw that. But I guess I shouldn't be too hard on myself. After all, there are professional
00:18:02.720 scientists out there, greatly accomplished physicists that I do not think appreciate what a good
00:18:09.360 explanation is, or the importance of explanation at all. Well, we know this is the case because
00:18:14.640 as we're going to come to in the fabric of reality, as we've covered somewhat in the beginning
00:18:19.680 of infinity series, or we've covered a lot in the beginning of infinity series, there is a certain kind
00:18:24.560 of theoretical physicist. And it seems to infect theoretical physics more than anything else.
00:18:29.920 A certain type of theoretical physicist specifically interested in, let's say, quantum theory that
00:18:35.840 thinks that explanation is overrated. What we're after, of course, is prediction and merely
00:18:41.520 prediction. This is the error of what's called instrumentalism, that all you want out of a theory
00:18:47.680 is to be able to predict the outcome of experiments. And this is a completely misconceived notion as
00:18:54.000 to what science is about. I mean, no one would be tempted in almost any other area of science
00:19:00.080 to think that this is what science is about. No biologist is interested in trying to predict
00:19:05.040 which species are going to evolve. They're interested in understanding the explanation of the
00:19:10.800 origin of extant species and even extinct species as well. In chemistry, we're interested in
00:19:16.480 the explanation of combustion, nor all the ways in which fires might occur in the future.
00:19:23.840 We're not trying to predict all the fires that are going to happen. In geology, we're interested
00:19:28.720 in understanding, unifying things like volcanic eruptions, earthquakes, the drift of continents.
00:19:35.600 And although we'd like to be able to predict things like earthquakes, we can't at the moment,
00:19:40.880 that's not the whole point of geology. Geology is understanding the differences between rock,
00:19:45.520 how rocks come to have the different chemistry that they have within them. The age of the earth,
00:19:50.880 how a planet can be dynamical or not. We want to understand, which is to say, we want to
00:19:56.800 explain, but it is just in certain rarefied areas of theoretical physics that, apparently,
00:20:05.520 the rules need to change because some people are uncomfortable with literal explanations,
00:20:10.560 or they simply lack an explanation. So beware, beware that kind of physicist because it seems to
00:20:19.200 be in physics alone, where explanation is pushed aside. But I shouldn't say only, of course,
00:20:26.160 we have a certain kind of scientism that's out there now as well. So there is a lack of willingness
00:20:33.360 to understand, let's say, how economic systems work, or how psychology works. And instead,
00:20:42.320 we're engaged, rather too much of the time, in attempting to predict the behavior of people,
00:20:48.720 the behavior of economic markets, rather than understanding what it takes in order to, let's say,
00:20:55.280 create wealth in economics. What are the preconditions for creating wealth? What has worked in the
00:21:00.480 past? And why has it worked in the past? Can we rule out some economic theories? Instead,
00:21:06.480 some people just want to plot graphs in an attempt to predict what is going to cause the stock
00:21:12.480 market to rise or not, and then fiddle with the knobs in some way or other. And this is an
00:21:16.960 instrumentalist view, I would suggest, within economics. And of course, we have historicism,
00:21:22.800 this idea, this false idea, this dangerously false idea, that by looking at the past,
00:21:28.480 we can extrapolate through to the future, especially in the realm of politics and history and
00:21:34.560 sociology. And this leads to some terrible political movement. So I'm probably a little bit unfair
00:21:39.760 to say that it's only the theoretical physicists that do this. Yes, it appears in psychology and
00:21:44.560 history and the humanities and the social sciences. It does appear there as well. This reluctance
00:21:50.160 to really grapple with and understanding of things and being a certain degree humble in the
00:21:56.720 face of not having an answer, of being able to say, we don't know, we are ignorant here,
00:22:02.080 but let's do the best with what we do in fact know, but not pretend that we have already
00:22:08.000 everything tied up into a nice neat little bundle where we can extrapolate off into the future.
00:22:13.680 Because the risk, of course, with extrapolation is it is an application of the false mode of
00:22:19.280 reasoning, which is induction. And there is absolutely no way that you can rule out the next observation
00:22:24.960 that you make isn't going to refute your entire linear trend or whatever other trend you think
00:22:30.000 that you have in hand. Instead, as we say here, and as David has explained here, the only way,
00:22:36.080 the only way to make predictions, reliable predictions, predictions which are genuinely logical
00:22:43.280 deductions and which allow you to assume that what you know now will happen into the future,
00:22:50.080 is to have a good hard to vary explanation. Of course, good and hard to vary do not yet appear
00:22:55.680 here in the fabric of reality, but the idea of a prediction is we're deducing it from an explanation.
00:23:02.320 And more than that, it has to be a good explanation. And specifically, the system has to
00:23:07.520 behave in such a way that you know that it has universal laws governing it, such that the extrapolation
00:23:14.480 is not going to be affected by things like, for example, knowledge creation, yet. And so this is
00:23:20.160 why general relativity allows us to predict the motion of planets. Why? Because we can,
00:23:26.480 reasonably, at this point in the history of human civilization, assume that the only thing
00:23:33.040 affecting, for example, the motion of planets in our solar system around the sun is the curvature
00:23:40.160 of spacetime, is gravity, explained by the general theory of relativity. And therefore, we can
00:23:46.800 make a deduction from that theory, which we call a prediction, and predict where any of the bodies
00:23:52.400 within the solar system are going to be for a moment to moment, using general relativity.
00:23:57.200 Now, can we make a prediction a reliable prediction for what those planets are going to be doing
00:24:02.160 a billion years from now? No. No, for a whole bunch of reasons. Because we cannot assume,
00:24:09.200 in the trivial case, that some other large cosmological body isn't going to cause a collision
00:24:15.200 with the objects within our solar system. So that's a simple thing. Our ignorance about what
00:24:19.680 else might happen to the solar system, into the distant future. A comet could come,
00:24:25.360 a strange neutron star could go wandering through the solar system, who knows? But more,
00:24:30.640 the more optimistic view is, as we learned from the beginning of infinity,
00:24:33.920 we don't know what human civilization is going to be like, a billion years from now, a billion years,
00:24:39.760 will we have the power to move planets out of there all, but will we want to do so? Perhaps,
00:24:44.560 perhaps we will have mind, Mars, such that it no longer exists basically, and we've converted it
00:24:49.920 entirely into a super colony that travels across galaxies. I don't know. But the point is, we can't just
00:24:57.600 solely rely upon something like general relativity to predict the orbital motion of planets
00:25:04.080 into the far, far distant future. We can do it for the next few years,
00:25:10.000 reach them with some reasonable accuracy. We will presume, we'll presume. Okay,
00:25:14.960 let's go back to the book, David Rites. What makes the general theory of relativity
00:25:20.560 so important is not that it can predict planetary motions a shade more accurately than Newton's
00:25:26.320 theory can. But that it reveals and explains previously unsuspected aspects of reality,
00:25:32.960 such as the curvature of space and time. This is typical of scientific explanation.
00:25:38.560 Scientific theories explain the objects and phenomena of our experience in terms of an underlying
00:25:45.040 reality, which we do not experience directly. But the ability of a theory to explain what we
00:25:50.960 experience is not its most valuable attribute. Its most valuable attribute is that it explains the
00:25:57.360 fabric of reality itself. As we shall see, one of the most valuable, significant and also useful
00:26:03.440 attributes of human thought generally is the ability to reveal and explain the fabric of reality,
00:26:10.400 posing there, just emphasizing that. So here, in the fabric of reality, we already have a hint
00:26:17.520 of the importance of people and the importance of human thought there. One of the most valuable,
00:26:23.680 significant and also useful attributes of human thought generally is its ability to reveal
00:26:28.720 and explain. Fantastic. So there we go. Are we getting the nascent beginnings of the
00:26:36.880 universality of the human mind? I think so. I think so. I think the hint to there, the ground is
00:26:43.600 being set and they're also where David writes, the underlying reality, which we do not experience
00:26:50.960 directly, is the first shot across the bow of empiricism. This great misconception that so many
00:26:59.200 scientists and philosophers and I guess man on the streets still holds, that the way in which science
00:27:04.960 works is that we go out and we observe stuff and in observing stuff, we derive knowledge from nature
00:27:11.920 in some way. This is a misconceived way of thinking about the project of science or knowledge
00:27:18.400 generally. This is not the way in which knowledge is constructed. It's a creative endeavor.
00:27:24.720 So let's continue with the book, David writes. Yet some philosophers and even some scientists
00:27:30.160 disparage the role of explanation in science. To them, the basic purpose of a scientific theory
00:27:34.880 is not to explain anything, but to predict the outcome of experiments. It's entire content lies
00:27:39.760 in its predictive formula. They consider that any consistent explanation that a theory may give for
00:27:44.800 its predictions is as good as any other or as good as no explanation at all, so long as the predictions
00:27:49.680 are true. This view is called instrumentalism because it says that a theory is no more than an
00:27:57.040 instrument for making predictions. To instrumentalists, the idea that science can enable us to
00:28:02.800 understand the underlying reality that accounts for our observations is a fallacy under conceit.
00:28:08.080 They do not see how anything a scientific theory may say beyond predicting the outcomes of
00:28:12.320 experiments can be more than empty words. Explanations, in particular, they regard as mere psychological
00:28:19.440 props, a sort of fiction which we incorporate in theories to make them more easily remembered
00:28:24.480 and entertaining. The Nobel Prize winning physicist Stephen Weinberg was in an instrumentalist mood
00:28:29.840 when he made the following extraordinary comment about Einstein's explanation of gravity.
00:28:35.120 Quote from Weinberg, quote, the important thing is to be able to make predictions about images
00:28:42.800 on the astronomers' photographic plates, frequencies of spectral lines, and so on.
00:28:47.120 And it simply doesn't matter whether we ascribe these predictions to the physical effects
00:28:51.520 of gravitational fields on the motion of planets and photons, as in pre-ion,
00:28:56.240 starting in physics, or to a curvature of space and time, gravitation, and cosmology page 147 end quote.
00:29:05.200 Weinberg and the other instrumentalists mistake, and what we ascribe the images on
00:29:09.280 astronomers' photographic plates to does matter. And it matters not only to theoretical
00:29:13.840 physicists like myself, whose very motivation for formulating and studying theories is the desire
00:29:18.720 to understand the world better. I am sure that this is Weinberg's motivation too. He is not
00:29:23.200 really driven by an urge to predict images and spectra. For even in purely practical applications,
00:29:29.360 the explanatory power of a theory is paramount and its predictive power only supplementary.
00:29:35.120 If this seems surprising, imagine that an extraterrestrial scientist has visited the earth
00:29:39.440 and given us an ultra-high technology oracle which can predict the outcome of any possible
00:29:44.000 experiment, but provides no explanations. According to instrumentalists, once we had that oracle,
00:29:50.320 we should have no further use for scientific theories except as a means of entertaining ourselves.
00:29:55.440 But is that true? How would the oracle be used in practice? In some sense, it would contain
00:30:00.480 the knowledge necessary to build, say, an interstellar spaceship. But how exactly would that help
00:30:05.680 us to build one, or to build another oracle of the same client, or even a better mouse trap?
00:30:11.040 The oracle only predicts the outcomes of experiments. Therefore, in order to use it at all,
00:30:15.280 we must first know what experiments to ask it about. If we gave it the design of a spaceship and the
00:30:21.280 details of a proposed test flight, it could tell us how the spaceship would perform on such a flight,
00:30:26.640 but it could not design the spaceship for us in the first place. And even if it predicted that
00:30:31.280 the spaceship we had designed would explode on takeoff, it could not tell us how to prevent such
00:30:35.840 an explosion. That would still be for us to work out. And before we could work it out, before we
00:30:40.960 could even begin to improve the design in any way, we should have to understand among other
00:30:45.840 things how the spaceship was supposed to work. Only then would we have any chance at discovering
00:30:51.840 what might cause an explosion on takeoff prediction. Even perfect universal prediction is simply
00:30:58.080 no substitute for explanation. Pause their my reflection. So all of this unfortunately,
00:31:05.520 unfortunately, in my view, I don't know, I can't speak for David, but it seems to all arise from
00:31:14.960 the same place. It came from quantum theory. It came from the beginnings of quantum theory, where
00:31:23.680 physicists rightly were confused, but fuddled. They didn't know what was going on. There's a whole
00:31:29.360 swag of observations they were making that just didn't comport with what they already knew about
00:31:34.880 physics. There were mysteries. And some of them simply retreated from reason. They said, well,
00:31:43.680 the project is hopeless. We're very, very good at being able to predict the outcome of experiments,
00:31:48.880 so that's all we can do. That's what science is about, which is, I would say, less arrogant and more
00:31:56.960 ignorant about science than anything else. It's as if to say, the entirety of science is theoretical
00:32:04.160 physics. And more than that, the entirety of science is those problems that you are unable to find
00:32:12.000 answers to solutions to explanations for. And so therefore, from this observation, from your failure,
00:32:18.720 from your failure as a theoretical physicist, in trying to understand this stuff. And you should
00:32:22.880 be failing all the time, the whole point of science, you're failing, you're encountering problems,
00:32:26.960 and then trying to overcome them. But because of this failure, this specific failure, this failure
00:32:32.240 in certain, rather at that time, esoteric areas of physics, you're going to extrapolate out
00:32:39.040 to the rest of the entirety of science, as if all of science is just about predicting the
00:32:44.480 outcome of experiments. It doesn't make much sense. It doesn't seem fair. It lacks consideration
00:32:51.280 for all the other interesting areas of science, where we really do want to understand what the heck
00:32:55.840 is going on. People interested in astronomy and astrophysics. We love the explanation. It's a
00:33:05.280 thrilling explanation about the evolution of stars, stars like the sun, and stars unlike the sun.
00:33:12.320 And yes, those theories, those explanations, allow us to give very rough predictions about
00:33:20.560 what might happen to the sun in the future. Absent people, of course. And we presume that what's
00:33:26.640 going to happen to the sun in the future is it's going to end its life as a, firstly, a red giant,
00:33:32.400 and then a white dwarf star, which will just slowly cool over billions of years. We know this.
00:33:38.480 It's a fascinating explanation, especially in light of the fact of what else could have happened
00:33:43.120 to the sun if it had have been larger. Namely, if it had have been a much bigger star,
00:33:47.760 many times more massive, let's say 10 times more massive, then it would explode at the end of
00:33:52.800 its life, leaving behind either a neutron star or possibly a black hole if it's bigger still.
00:33:58.240 That explanation is the point of astronomy and astrophysics. This is why people do
00:34:05.360 those kind of subjects. The fact that we can just collect light in telescopes and come to an
00:34:11.760 understanding of the universe like that and understanding of the universe is phenomenal.
00:34:15.680 That's the exciting part about science. Not predicting what's going to happen to any given star.
00:34:21.520 It's the general explanation. The big bang cosmology, cosmology still as a science is very much
00:34:29.520 in its infancy. It's only been over the last few decades. We've been able to actually gather data,
00:34:36.640 data to some extent about the behavior of the universe as a whole.
00:34:42.000 Prior to that, cosmology was well within the remit of theology only to deal with. It was
00:34:48.880 metaphysical. How could we, human beings, pathetic as we are, presume to try and understand something
00:34:56.320 like the entire universe, the entire physical universe, and yet this is what cosmologists take on.
00:35:03.040 And by gathering these scant amounts of evidence, it's not like the most crucial part of
00:35:08.720 cosmology is about predicting what's going to happen to the universe in the future. That's part
00:35:13.840 of it. But the only way in which we can make any kind of guess about what's going to happen
00:35:19.600 into the future, a scientific guess, a scientific prediction, conjecture about the possibility
00:35:25.360 of what will happen into the distant future is by having an explanation in the first place that
00:35:29.600 relies on our understanding of what's causing the evidence that we gather. Evidence like the 2.3
00:35:37.040 Kelvin, or 2.7 Kelvin, temperature of the cosmic microwave background. The heat left over
00:35:43.040 after the big bang, which we've only recently be able to collect these photons, these very low
00:35:48.400 energy photons, and wonder about the origins of them and explain, therefore, the origins of them.
00:35:54.000 And so that's all the fun stuff. Putting together all the different,
00:35:58.560 we're triangulating really with this heat that permeates through out the entire universe,
00:36:04.480 along with the fact that wherever you point your telescope at very distant galaxies, you find
00:36:09.120 they're moving away, not only from us, but from each other. And trying to understand why
00:36:14.240 is the amount of hydrogen out there, an intergalactic space, this amount compared to the amount of
00:36:20.160 helium that's in intergalactic space, compared to everything else that's out there as well.
00:36:24.000 Why is it this ratio, this disstrangulation of evidence that enables us to then come with the
00:36:30.880 grand explanation that we call the big bang, and then inflationary theory is phenomenal.
00:36:36.960 That's the phenomenal part in the exciting part of the story of science, not predicting.
00:36:42.880 And anyway, predicting these really distant things in cosmology, again, we're still in the
00:36:49.520 infancy. And so whenever you hear science popularizes, it's kind of fun. I think it's about as
00:36:55.440 fun as a science fiction movie at this point. There are the predictions about what's going to
00:37:01.600 happen to the universe on timescales of hundreds of millions, billions, even trillions of years,
00:37:07.920 some of these predictions. People make them very, very confidently. But the evidence is limited,
00:37:14.720 that would be the first thing. And the timescales that we're talking about are just so ridiculous,
00:37:18.720 that it would seem to me that it's going to be the case that we're going to find far better
00:37:26.000 cosmological theories. So at the moment, of course, we think that the universe is undergoing
00:37:32.640 this dark energy accelerating expansion. And if we take that seriously through to the absolute
00:37:38.880 limits of what we could possibly know, then we think, well, eventually all the galaxies that
00:37:45.600 we can observe are going to wink out of existence, because they're going to be accelerated along
00:37:50.720 with space time beyond the horizon of what we can see. Eventually, only our galaxies will be left
00:37:56.000 like a lonely island. And then it will start to expand itself as space begins to expand. And then,
00:38:01.760 you know, even the solar system will expand. And then, you know, the planet will expand probably
00:38:05.760 by this time, by the way, of course, the sun has long since extinguished itself. But if any people are
00:38:10.560 left here in the region, that is the solar system, even eventually they will start to expand
00:38:16.160 as well. Their bodies will start to expand apart because of this accelerating expansion of space
00:38:20.880 time. But this is all predicated on the fact that our theory, our present theory, the best theory
00:38:27.360 that we currently currently have about the behavior of the universe, won't be overturned. And
00:38:34.080 I would, if I was a betting person, I would think that that observation is going to be
00:38:40.240 overturned in some way, in some significant way. And one possible way is that, you know, even
00:38:48.240 thousands of years from now, even if that explanation hasn't been overturned, that people might
00:38:54.000 be able to harness the energy in some way and reverse it. Because at the moment, that accelerating
00:38:59.440 expansion is actually quite a weak force. And that gets us very far away from the book here,
00:39:06.560 except to say, it's clearly not the case that science in any field at all is primarily about
00:39:13.760 prediction. It's about understanding physical reality and reality more broadly. And therefore,
00:39:19.280 it's about explanations. So even even an oracle that's able to make all the predictions in the
00:39:24.960 world doesn't allow you to really understand the world that you're in, even if you can predict
00:39:30.320 the outcome of experiments. As David goes on to write, the Oracle would be very useful in many
00:39:35.760 situations, but its usefulness would always depend on people's ability to solve scientific problems
00:39:41.600 in just the way they have to now, namely by devising explanatory theories. It would not even
00:39:48.000 replace all experimentation because its ability to predict the outcome of a particular experiment
00:39:52.160 would impract us to depend on how easy it was to describe the experiment accurately enough
00:39:56.640 for the oracle to give a useful answer compared with doing the experiment in reality.
00:40:01.360 After all, the oracle would have to have some sort of user interface. Perhaps a description of
00:40:06.400 the experiment would have to be entered into it in some standard language. In that language,
00:40:10.560 some experiments would be harder to specify than others. In practice for many experiments,
00:40:14.880 the specification would be too complex to be entered. Thus, the oracle would have the same
00:40:19.760 general advantages and disadvantages as any other source of experimental data. And it would be
00:40:25.840 useful only in cases where consulting it happened to be more convenient than using other sources.
00:40:32.480 To put that another way, there is already one such oracle out there. Namely, the physical world
00:40:38.080 tells us the result of any possible experiment if we ask it in the right language.
00:40:42.640 If we do the experiment, though in some cases it is impractical for us to enter a description
00:40:47.920 of the experiment in the required form, I to build and operate the apparatus, but it provides
00:40:53.680 no explanations. Isn't that fantastic? Very much in David Deutsch fashion. Just eviscerating
00:41:03.280 what might be regarded as a knockdown argument against people who are saying that science is about
00:41:10.480 predictions. It's almost like the super AI, not AGI, but a super AI, narrow intelligence,
00:41:20.480 but it's a super intelligence. And this super intelligence can predict the outcome of any experiment
00:41:25.680 that you like. And so this is what some of the early quantum physicists were about some quantum
00:41:30.400 physicists today talk about being instrumentalists or the shut up and calculate type people.
00:41:36.240 And if this is all that science is about, then this oracle would make, wouldn't it, science
00:41:42.960 redundant? But the problem is, if you want it to predict the outcome of experiment,
00:41:49.120 then you have to first specify the experiment. That takes a heck of a lot of explanatory work to
00:41:54.320 do. After all, why are you doing this experiment in the first place? What is the theory that you're
00:41:59.440 testing? Have we thought about that yet? How do we input this in? How do we tell the oracle what
00:42:04.480 the experiment is precisely? What is the instrumentation that you're using? How did you figure
00:42:09.120 out what that instrumentation was? What is the problem that the instrumentation is trying to solve
00:42:13.200 in the first place? And as David says here, we've got this oracle, don't we? We've got this
00:42:18.720 oracle. It's called physical reality. Physical reality is the oracle. It will give you the
00:42:23.040 answer to any experiment that you ask it. The hard part is not asking the question, the hard part
00:42:28.560 is figuring out what the question is in the first place, asking what you're testing,
00:42:34.720 what exactly is this theory you're testing? Why are you doing this experiment? This is not what
00:42:38.640 science is about, okay? We learn these terrible lessons in school science class. What an experiment
00:42:46.000 is is, oh, well, we're doing an experiment today class. We're going to take a test tube of these
00:42:52.800 chemicals and a test tube of these chemicals and we're going to mix them together into a
00:42:56.240 beaker and see what happens. That's an experiment, isn't it? And in fact, this enters culture,
00:43:02.960 this is what experiments are supposed to be. Just a random mixing of ideas, trying something where
00:43:09.200 you've got absolutely no idea why you're doing it, why you're doing it in the first place,
00:43:14.560 let alone what is going to happen. And having found something new happening, something unexpected,
00:43:19.760 which of course will happen in any case. You just don't know what's going to happen. You take your
00:43:23.680 two test tubes, you mix them together. If nothing happens, that's surprising. You didn't know
00:43:27.840 that that's what was going to happen. If you get an explosion, that's surprising, you didn't know
00:43:31.600 that was going to happen. If you get a color change and whatever the color is, it's going to be
00:43:34.880 surprising. But the point is, you had no theory to begin with. Did you? What were you testing? Why
00:43:40.880 were you doing this experiment? This is not what an experiment is. I wouldn't call that an experiment.
00:43:45.760 There is no sense in which that's an experiment. An experiment is a test of a theory. And there are
00:43:51.520 two kinds of experiments in the world. There's an experiment where you literally have two good
00:43:56.800 theories on offer and you don't know which one is true. It's almost impossible to think of cases in
00:44:02.400 science where there were three reasonable, viable explanations for a given phenomena. It doesn't
00:44:08.720 happen. In science, just think about it yourself. The usually is identically one explanation,
00:44:16.640 and we call it the scientific theory of. For so long, as far as the origins of the universe went,
00:44:23.440 something that many people were interested in, there really were no viable explanations at all.
00:44:29.040 There were supernatural ones. God did it, which kind of raises the question as to where did God come
00:44:35.200 from and if people answer, well, God is that entity that's outside of space and time and whatever
00:44:40.560 else. Well, why move the problem one step back? Why not just say, well, the origin of the universe,
00:44:45.840 whatever that thing was, is outside of space and time and gave origin to the universe. We don't
00:44:50.400 need an intelligent creator being. Whatever the case, there would not really any good scientific
00:44:57.520 explanations. At the turn of the 1900s, the turn of the 20th century, we had this idea of an
00:45:05.040 eternal universe that was just always there or infinite and all spatial directions. Maybe God clicked
00:45:11.920 these fingers and a universe that was spatially infinite just popped into existence at some point.
00:45:17.840 You know, whatever the Bible said, however long, six thousand years or something. But this makes
00:45:23.040 no testable scientific predictions. It's not experiment that we can do to test whether or not
00:45:28.800 that is a better theory than something else. It's not observation that we can make.
00:45:32.320 An experiment has to be able to compare two different competing scientific theories. And eventually
00:45:38.800 we did have two, eventually we did. We had the idea of the Big Bang, you know, the Big Bang sort
00:45:44.640 of, well, it's an interesting part of the history of cosmology as to who came up with the Big
00:45:50.640 Bang. You know, was it the priest George LaMartre was at Alexander Friedman, there was an Einstein
00:45:56.160 as well. They all had seemingly had had something to do with coming up with the Big Bang. I don't
00:46:01.200 know where you would actually place the credit for the Big Bang itself. It was just a, this really
00:46:06.880 was a case of the slow accumulation of problems and evidence in cosmology, which then all pointed to
00:46:15.520 this common origin in the space and time, the universe was smaller in the past.
00:46:21.680 But there was, there was a time where it was quite reasonable to subscribe to Fred Hoyle's idea
00:46:27.680 of a steady state universe, of the universe that just perpetually existed. So there, there was a
00:46:33.360 genuine split in the scientific community. Was it an origin in space and time, the Big Bang,
00:46:38.320 or was it a universe that had always been there, the steady state. And the purpose of an experiment,
00:46:43.360 a cosmological experiment of a kind of being able to observe, observe things like
00:46:49.520 the cosmic microwave background that constitutes an experiment setting up a big antenna that can
00:46:54.160 collect microwave radiation. And to notice, it is homogenous in all directions, more or less,
00:47:00.400 which means that the universe was permeated with heat. What was the origin of the heat? Well,
00:47:03.760 the steady state can't really account for that. Nor can steady state of course properly
00:47:09.200 account for the red shift of distant galaxies in all directions as well.
00:47:14.240 And then the ratio of hydrogen to helium, okay, all of this stuff is explained by
00:47:18.560 the Big Bang theory and not explained by adequately by the steady state theory. And so these
00:47:24.640 things, these observations constitute experiments of a kind that rule out one particular theory
00:47:30.880 in favor of another. Now, this is the ideal kind of experiment. The ideal kind of experiment is
00:47:37.520 called a crucial experiment. It decides between two competing theories. Now, the only other kind
00:47:44.160 of experiment is an experiment that makes the theory problematic. Well, maybe it doesn't even make
00:47:49.040 the theory problematic. It's just a problem. You know, the measurement of the speed of neutrinos
00:47:56.000 back in the day, whenever that was, when the large hydrogen clatter was switched on. And they thought
00:48:01.440 that the neutrinos were traveling faster than the speed of light. This is an experiment,
00:48:07.760 I did this experiment. That experiment was problematic in the true sense of the word, not the
00:48:13.520 woke sense of the word. In the true sense of the word, it raised a problem. Now, did it raise a
00:48:18.720 problem for relativity? Well, it might have. It might have. As it turned out, no, it was problematic
00:48:23.760 for another reason. Namely, the experiment itself was faulty, flawed. It suffered from something
00:48:28.320 called systematic error. Okay, there was an error in the method, the way in which the experiment
00:48:32.480 was conducted. A cable was loose or something or other. And so this is a legitimate experiment,
00:48:38.640 in a sense. It revealed something about the nature of experimentation of that kind. Careful with
00:48:44.480 your cables. But that's the only other kind of experiment. Well, you already have a theory. You have a
00:48:48.960 theory about neutrinos and the speed with which things can move and the way in which an experimental
00:48:55.600 apparatus should be set up. Okay. And you're testing all of this stuff. You're testing this
00:49:00.560 by conducting the actual experiment, collecting the data. But my example of, you know, the random
00:49:05.920 mixing of chemicals in a school science laboratory when you have no clue what's going on.
00:49:12.560 Well, that's not really an experiment. Now, to be fair, I don't think any science teacher
00:49:16.640 actually really does this. Okay. Most science teachers have some conception at least of what's
00:49:23.920 going on with the underlying chemistry or science. And they do try and explain this to the children.
00:49:29.520 And the children are, you know, testing things. They are testing hypotheses. This does indeed go
00:49:36.320 on. But the extent to which you're really getting a genuine understanding of what's going on is
00:49:41.760 anyone's guess. That's a whole other topic. However, okay. So I'm going to go back to the book.
00:49:46.000 I'm going to skip a section there, which is more detail about instrumentalism. This idea that
00:49:52.240 the entire purpose of science is just about making predictions. And I'll skip to the point where
00:49:56.640 David writes, quote, an extreme form of instrumentalism called positivism or logical positivism
00:50:04.400 holds that all statements other than those describing or predicting observations are not only
00:50:08.720 superfluous, but meaningless. Although this doctrine is itself meaningless, according to its
00:50:14.800 own criterion, it was nevertheless the prevailing theory of scientific knowledge during the first
00:50:20.080 half of the 20th century, even today instrumentalist and positivist ideas still have currency.
00:50:26.800 One reason why they are superficially plausible is that although prediction is not the purpose of science,
00:50:32.720 it is part of the characteristic method of science. The scientific method involves postulating
00:50:38.640 a new theory to explain some class of phenomena and then performing a crucial experimental test,
00:50:44.080 an experiment for which the old theory predicts one observable outcome and the new theory another.
00:50:50.000 One then rejects the theory whose predictions turn out to be false, thus the outcome of a
00:50:54.480 crucial experimental test to decide between two theories does depend on the theory's predictions
00:51:00.240 and not directly on their explanations. This is the source of the misconception that there is
00:51:04.560 nothing more to a scientific theory than its predictions, but experimental testing is by no means
00:51:08.960 the only process involved in the growth of scientific knowledge. The overwhelming majority of theories
00:51:12.960 rejected because they contain bad explanations, not because they fail experimental tests,
00:51:18.400 we reject them without ever bothering to test them, pausing their my reflection.
00:51:24.080 Wow, there's just so much there and I think this is again why or possible explanation for myself,
00:51:30.240 possible explanation for myself is to why I didn't get it the first time around, even though I read
00:51:34.400 this book, you know, over and again and I was engaged even in the late 90s in online email
00:51:41.600 discussions about the book. I still failed to take on boards so much, you know, there's the
00:51:47.520 concept of a crucial experimental test. This took me all the way until, well, 2016, 2016 when
00:51:56.240 David published his paper, the logic of experimental tests, particularly of ever retying quantum theory,
00:52:03.440 and it was then that I think I finally appreciated what a crucial experimental test was.
00:52:09.920 But there's a difference between a crucial experimental test and any other kind of experiment
00:52:13.920 that happens in science. And again, the crucial experimental test is the one which is able to
00:52:19.440 decide between a theory and its rivals. And so it leaves one theory standing, ruling out the
00:52:26.560 others, you know, in most cases, certainly in physics, at best you've got two competing theories,
00:52:33.760 at best, usually only have one. And if you do have one and you're testing that theory by doing
00:52:39.520 experiments and the experiment time to bring with the theory, then you've got this problem in
00:52:44.640 preparing epistemology, sometimes known as a joupham coin thesis of how do you know what's wrong?
00:52:50.880 Is it the theory that's wrong when it disagrees with the experiment? Or is it that you're
00:52:57.360 experiment is wrong? You know, there's that saying many a beautiful theory has been slain by an ugly
00:53:02.480 fact. Well, it's not quite true. You can't slay a theory with an ugly fact. Unless you've got
00:53:08.720 another theory to jump to, unless you have a better idea of what to do. If we did 10 experiments
00:53:15.280 tomorrow and they all disagreed with general relativity, there's literally nothing for it, but to
00:53:19.760 rely on general relativity, because no one's got a better theory of general relativity,
00:53:23.600 they're better than general relativity. Namely, a theory that can do everything that general
00:53:28.880 relativity can do, and more, and more is the key thing. And they're at the end of this section
00:53:36.400 here, we get the idea that the overall majority of theories are rejected because they can
00:53:42.160 tame bad explanations. Now, now this part I got back in the fabric of reality, and this is one of
00:53:47.520 those thrilling passages, because here we get to the grass cure for the common cold. This is the
00:53:55.760 first time I encountered that argument. And this idea that you need an explanation. It's the
00:54:04.400 explanation that you're testing, not the predictions. Let's just read it. Okay, and this is where
00:54:09.440 I'll end today, because I think it's a great way to end things. And if you haven't heard this before,
00:54:14.160 strap yourself in. Okay, the importance of explanations in testing, in experimental testing,
00:54:21.280 rather than just predictions, David writes. For example, consider the theory that eating a
00:54:25.920 kilogram of grass is a cure for the common cold. That theory makes experimentally testable
00:54:31.600 predictions. If people tried the grass cure and found it ineffective, the theory would be
00:54:36.560 proved false. But it has never been tested and probably never will be, because it contains no
00:54:42.160 explanation, either of how the cure would work or of anything else. We rightly presume it to be
00:54:47.760 false. There are always infinitely many possible theories of that sort, compatible with existing
00:54:52.560 observations and making new predictions, so we could never have the time or resources to test them
00:54:57.840 at all. What we test our new theories that seem to show promise of explaining things better
00:55:03.440 than the prevailing ones do, pausing their ending it for today. But just notice there,
00:55:10.080 anyone can come along and make a testable prediction, a testable claim. That doesn't mean they've
00:55:17.040 got a scientific explanation. It doesn't mean they're doing science at all. David's other example is,
00:55:22.160 you know, any person with a sandwich board standing on the street corner saying that the
00:55:27.200 world is going to come to an end in fiery bombardment from the heavens next Tuesday,
00:55:34.400 June the 18th or whatever, has a testable prediction. And when the day comes and goes without
00:55:41.600 incident, does anyone learn anything? Well, they might, or they might not. They might just go back
00:55:47.440 to their religious texts, reinterpret it in some way, and say, oh, I was out by a year just
00:55:52.640 you wait until next year, but there is no explanation there. It's testable, but without the
00:55:58.720 explanation, we have no reason to assume why that prediction should be the way that it is. So if
00:56:06.160 if you say grass is going to cure the common cold for eating one kilo of grass is going to cure
00:56:12.400 the common cold, why should we believe you? What is the mechanism? And so this works for any
00:56:20.080 area of science, and especially any area of pseudoscience, okay? Anyone who has the crazy nostrum,
00:56:30.400 the claim about what alternative medical intervention is going to cure you with your disease.
00:56:38.320 The key thing is to ask why and how. Now, it's absolutely the case that there are still places
00:56:44.560 within medicine, where there isn't a fantastic explanation of why the particular thing works,
00:56:52.560 but in traditional Western medicine, certainly at least what we have is a tradition of rules of
00:57:00.400 thumb. In other words, this thing has been shown to work in many cases, and we don't know why.
00:57:07.120 We don't know why yet, but we're working on it. We're trying to figure out what the explanation is,
00:57:12.720 okay? And I can easily, and we can, you know, the community of doctors can show that the thing
00:57:21.200 causes little harm and has some benefit for reasons they don't know. But this is because the
00:57:27.600 gradual evolution, the hard one evolution of that kind of knowledge, which you might even call
00:57:34.720 in explicit medical knowledge that's been passed down. Even if we don't have a fully explicit
00:57:40.000 scientific explanation of how some of these treatments work. Okay, so this is the first
00:57:46.960 of what I presume will be many episodes about the fabric of reality. We're barely through chapter
00:57:54.000 one yet, and so next time I think I will read more, speak less, but until then, bye-bye.
00:58:02.000 Now, of course, many people may well notice that if you're watching this for the first time,
00:58:06.000 I have another series on the beginning of infinity, and importantly, alongside this, I have a series
00:58:11.600 on the science of canon cards, Chiarama letters, new book that has only been released over the last
00:58:19.040 few weeks. This is in 2021. And so I would encourage people to go out and get that book as well
00:58:25.360 as, of course, the fabric of reality. And if you're so inclined, you can find me on Patreon.
00:58:30.800 You can do a Google search for top cast Patreon, T-O-K, C-A-S-T, Patreon, and you'll find me there,
00:58:37.840 or Brett R. Hall at Patreon as well. Or you can just go to www.brethall.org and on the front
00:58:46.720 there there's a little button that says donate, and I would appreciate any kind of assistance with my
00:58:52.720 ongoing work here in understanding the worldview of David Deutsch, Car Popper, Chiarama letter,
00:59:01.840 and various other people who are interested in the optimistic future and the centrality of people
00:59:08.640 to understanding the universe, the cosmological significance. Until next time, bye-bye.
