00:00:00.000 Welcome to Topcast and episode 2 of The Science of Canon Can't Buy Chiara My Little
00:00:29.720 or rather my commentary on The Science of Canon Can't Buy Chiara My Little.
00:00:35.920 And last time in the first episode I gave a broad overview of what The Science of Canon
00:00:41.680 Can't Was About and plucked out a few bits and pieces from Chapter 1.
00:00:47.280 It was much broader than what today is going to be about.
00:00:50.040 I'm still on Chapter 1, however I'm just going to be focusing on the physics content
00:00:58.280 And that Chapter 1 is of course such stuff as Dreams Are Made On.
00:01:02.920 And in the previous episode about this book it was about the some of the ways in which
00:01:09.120 constructive theory might be applied to many different areas of science.
00:01:14.040 And why this way of conceiving of science as being about what could possibly occur and
00:01:21.800 what could not possibly occur is a new mode of explanation.
00:01:25.600 That might have useful applications not only to things like science and biology but
00:01:32.080 even to aspects of our knowledge like art and literature.
00:01:36.840 But today really the focus is going to be on the physics.
00:01:41.000 So I'm just going to dive straight into the book part way through the chapter.
00:01:47.080 And Chiara writes, quote, a boundary has been generated that affects and constrains the
00:01:53.360 way criticism and conjecture can occur, a boundary that is keeping out certain kinds of
00:02:02.320 These are explanations that involve counterfactuals.
00:02:05.840 The boundary grew up because of a phenomenon that has been going on for some time.
00:02:10.800 Silently, largely unnoticed like water seeping into a ship whose hull has a hidden hole
00:02:16.320 below the waterline to see what it is we must start where it all began.
00:02:24.640 It is perhaps ironic that this boundary generating phenomenon started in physics because
00:02:28.520 physics is one of the clearest examples of how thinking can produce knowledge and make
00:02:34.320 At a glance from what one is taught in elementary courses at school, physics may appear
00:02:39.080 like a collection of tools to solve irrelevant problems of the kinds you get in weekly
00:02:45.000 What is the time of flight of an apple that falls from a tree of a certain height?
00:02:49.200 How long will it take a bathtub of such a volume to be filled with water if the water
00:02:55.960 Compared with other disciplines such as literature or philosophy, physics may not seem to
00:03:08.240 This first impression is very far from the truth.
00:03:13.960 It is profound, beautiful and illuminating, a source of never-ending delight.
00:03:19.760 Physics is about solving problems in our understanding of reality by formulating explanations
00:03:27.080 The point of physics is not the particular calculation about the fall of an apple.
00:03:32.240 It is the explanation behind it which unifies all motions, that of the apple, with that
00:03:40.760 The dazzling stuff consists of explanations for they surprise us by revealing things
00:03:45.720 that were previously unknown and very distant from our intuition, with the aim of solving
00:03:52.960 As I said, problems always consist of a contrast or clash between ideas about the world.
00:03:58.560 For example, in the past, people believed that the earth was at the centre of the universe,
00:04:02.720 but that notion clashed irredeemably with observations, such as those about the apparent
00:04:07.720 movement of the stars, of the other planets, end of the moon.
00:04:11.960 This led Copernicus and Galileo to conjecture that the sun, not the earth, was at the centre
00:04:17.560 The Copernican Revolution was an astonishing change of perspective which allowed us to make
00:04:22.000 formidable progress in understanding astronomy and celestial mechanics, and eventually
00:04:26.360 led via a series of further steps to our current space exploration enterprises pausing
00:04:35.600 Now it might be if you're paying careful attention to some of my podcasts, it might seem
00:04:42.000 that there is a contradiction in what I say about this kind of thing here.
00:04:47.960 What Chiara refers to as the Copernican Revolution.
00:04:51.600 What historians refer to as the Copernican Revolution, what many people refer to as the
00:04:57.480 But one of the reasons why it's referred to as the Copernican Revolution is because it
00:05:05.960 But I wouldn't take the word revolution too seriously.
00:05:10.600 The sociologist philosopher of science, scientist, and physicist, Thomas Kuhn wrote a book
00:05:16.680 called The Structure of Scientific Revolutions, where he sought to explain that progress
00:05:23.120 in science, progress in scare quotes to some extent, was a story of revolutions.
00:05:30.280 The overturning of particular frameworks, and if you're in one framework or paradigm,
00:05:36.040 one way of understanding the world, then it was very difficult for you to understand any
00:05:39.440 other way of conceiving that the world could operate.
00:05:43.000 In other words, science was always a sociological battle, this battle between the old
00:05:50.560 And there's no real objective way of determining who is correct on this account, but rather
00:05:57.520 it is a political battle between the old and the young lions battling it out and just
00:06:03.120 having arguments that are filled with emotion and filled with politics, rather than objectively
00:06:08.160 looking at the facts and coming to a deeper understanding of the world.
00:06:12.880 The Copernican Revolution, as Kiera says there, is certainly an astonishing change of perspective,
00:06:18.760 because we went from conceiving of ourselves as human beings, occupying a planet at the
00:06:26.200 center of the universe, every other celestial body orbiting around us.
00:06:31.560 What Copernicus and others saw was that the better explanation, the better scientific explanation,
00:06:39.160 was to shift the earth from the center to having the sun at the center, heliocentrism.
00:06:44.520 Now on one hand, this isn't an astonishing change of perspective, certainly mentally
00:06:49.360 for people. However, the scientific theory that goes on to explain orbital motions of
00:06:57.840 celestial objects didn't change that much, because we still had orbits, things were still
00:07:04.560 moving in approximate circles or ellipses, there was still relative motion between these
00:07:10.560 The difference was an incremental change from having one object at the center to having
00:07:15.600 a different object at the center. On the one hand, the earth then the sun. Now, we can
00:07:22.240 debate about what it would mean for that to be revolutionary. But the usual understanding
00:07:28.200 of revolution is a complete overturning of everything, but not everything was overturned.
00:07:33.960 And so we could make a pretty strong counter argument that this wasn't really a revolution.
00:07:40.120 It was a component, an incremental change, the existing understanding of the universe,
00:07:46.480 but it still was an astonishing change of perspective. But scientifically speaking, it allowed
00:07:52.200 us to correct certain errors in the way in which eventually allowed us to correct certain
00:07:55.800 errors in the way in which planetary motions operated. But people who follow in the intellectual
00:08:03.160 tradition of Thomas Kuhn liked to make a big deal about changes like this. They formulate
00:08:10.240 an entire view of science, which is there are those who believed in the Copernican idea,
00:08:15.440 and those who believe in the Ptolemaic idea, and there was just no way that these two
00:08:19.400 groups of people could communicate with one other, operating in completely different paradigms.
00:08:24.680 But were they really operating in completely different paradigms? After all, the content
00:08:30.680 of both theories remained relatively unchanged. It was just the object that center was
00:08:37.880 the thing that changed. It was an incremental change, I would suggest, following in
00:08:42.920 Popper's intellectual tradition. If on the other hand, we had have gone from a Ptolemaic
00:08:48.000 view to a Copernican view where there were no such things as orbits. There were no such
00:08:53.240 things as planets. There was no relative motion between the celestial objects. If all of
00:08:58.400 it was utterly overturned, then I could get it. Then I could understand that maybe this
00:09:02.840 would be revolutionary. But in fact, so much of the theory was maintained. And this is
00:09:08.840 true between classical mechanics and quantum mechanics as well. That's a bigger change.
00:09:14.520 That's a much bigger change of perspective and much more of the content actually changes
00:09:18.320 as well. But much, much is preserved. And as Kiara says in exactly the same sentence
00:09:24.960 where she says that the Copernican Revolution was an astonishing change of perspective,
00:09:29.400 it then led via a series of further steps to our current space exploration enterprises.
00:09:35.920 So it's always this story of steps, these incremental steps. It's very hard to leap to
00:09:42.000 something utterly different where you're just giving up everything that you knew previously
00:09:48.680 and coming up with a theory that in no way contains any of the content of the previous
00:09:53.400 theory, it typically does. It typically does. We go from having a force of gravity to no
00:09:59.320 force of gravity. But lots of stuff still remains the same. Mass is still involved, for
00:10:05.640 example. Energy is still involved, for example. Or but still happened, for example, back
00:10:10.880 to the book, Kiara writes, quote, by solving problems of that kind, physicists have gradually
00:10:17.720 uncovered entirely unsuspected worlds. Telling us a deeper layer of the story of how things
00:10:23.480 are, these layers are beyond the immediate reach of our senses, but our mind can visualize
00:10:28.800 them in the light of explanations. In existing physics, all explanations have some primitive
00:10:34.720 elements, in terms of which the physical reality to be explained is expressed. The appearance
00:10:40.200 of the dark sky at night is a perfect example of that. It can be explained in terms of the
00:10:44.560 unexpected underlying phenomena involving things like photons, the remarkable fact that
00:10:50.000 the universe is expanding and so on. None of those elements is apparent in the sky itself,
00:10:54.880 but they are all part of the explanation for why it looks the way it does in terms of what
00:10:59.200 is really out there. Explanations are accounts of what is seen in terms of mostly unseen
00:11:05.840 elements, pausing their my reflection. So this is a common thread now that runs through
00:11:13.760 the work of Karl Popper, David Deutsch, Kiara Miletta, that we have this conception of science,
00:11:20.880 almost everything, as I like to say, interesting that we know about science, is the scene,
00:11:26.720 what we can observe in terms of the unseen, what we cannot observe. And I've been at pains in
00:11:32.960 my conversations on that other podcast in various other places with Naval Revocant to explain
00:11:38.400 and try and promote this idea that almost everything in science is not about what we can observe
00:11:46.160 directly. And it is very well encapsulated by this idea of explaining the scene in terms of the
00:11:51.920 unseen. And so if we can go through the standard examples again, David's favorite example being
00:11:58.800 that of dinosaurs, we do not observe dinosaurs. They're unseen. What we observe are fossils in the
00:12:07.280 ground. Those fossils in the ground that exist in rocks are essentially patterns in rocks that we
00:12:12.800 have to interpret. And then a chain of explanatory interpretations leads us to the conclusion that once
00:12:20.560 upon a time, more than 62 million years ago, walk the earth, these huge creatures that we call
00:12:26.480 dinosaurs, that we do not observe. And then unless we build time machines or we have significantly
00:12:32.080 more advanced genetic engineering, we will not see with our eyes. Instead, we must imagine this is
00:12:38.240 part of the explanatory theory that explains why fossils exist. The cause of the fossils is these
00:12:46.880 unseen things. And so now we can change that to, I like to use, stellar nucleosynthesis,
00:12:55.040 stellar nucleophusion. We cannot travel to the center of a star, to the core of a star like
00:13:02.640 the sun. In fact, there are good physical reasons why it is impossible for us to directly observe
00:13:09.360 anything at the core of the sun. We cannot send a probe there. There is no material that can
00:13:13.760 survive the journey to the center of the sun. We can't even send things to the center of the earth,
00:13:17.920 much less the center of the sun. Any material out of which you think you could make a probe,
00:13:22.080 the most strongest titanium, tungsten alloy, isn't going to make it even to the surface of the sun
00:13:27.760 before the thing entirely melts and then vaporizes. We're not going to get to the center of the sun,
00:13:32.640 but we know what's going on there. We cannot see what's going on there directly. All we do
00:13:39.440 is collect photons of light here at earth and interpret those photons of light. And by a chain
00:13:46.240 of explanation and interpretation, we conclude, oh, there's hydrogen there at the center of the sun.
00:13:53.120 Protons, those protons, those hydrogen nuclei are being smashed together with sufficient energy
00:13:59.040 that they fuse forming helium. And that process releases heat and light, and that's what we detect,
00:14:05.360 and the explanation of the light here at earth is because of that process going on in the core of
00:14:10.720 the sun, which we cannot see. The Big Bang is another fantastic one that we will never see
00:14:15.520 the Big Bang. We cannot be there to observe it. No one was there to observe it. No one ever will be
00:14:22.000 there to observe it, but it happened. So we are explaining what we see now, the cosmic microwave
00:14:29.120 background, the so-called Hubble expansion of the universe, the redshift of galaxies,
00:14:35.920 and the ratio of hydrogen to helium. And indeed the dark night sky, all of these things are explained
00:14:41.600 by this unseen thing, the Big Bang. Choose your favorite example from science, from modern science,
00:14:49.920 and you will quickly realize that there is a part of the explanation which relies upon
00:14:56.400 unseen things going on. The problem, of course, is in the scene. We end up observing something,
00:15:04.960 and we can't explain this observation, what is going on here? The observation causes us to think,
00:15:10.320 well, that doesn't make sense in light of this. So let's try to come up with an explanation.
00:15:14.880 And the explanation falls back towards things that we cannot observe. It's a very fascinating
00:15:21.200 part of science. It's a different way of conceiving of science, by the way. Anyone who describes
00:15:25.760 and self as an empiricist would have to explain what's going on here because empiricism
00:15:30.640 is the misconception that science is only about the things that we can observe.
00:15:36.720 They can need to prove the scientific theory by recourse to observations in the world.
00:15:44.240 But that's not the way that science works, because again, the vast majority of interesting
00:15:48.720 stuff in science is about the unseen or the unobserved. Okay, let's go back to the book,
00:15:54.480 and cure our rights. There is no limitation in principle to how deep one can go in finding
00:16:00.000 even more primitive elements. The primitive elements of an explanation can always be explained
00:16:05.120 further in terms of other entities, and so on going deeper and deeper.
00:16:09.920 Deeper levels of explanation may look very different from the shallower ones. For instance,
00:16:14.960 there was a time in physics when particles were thought to be the ultimate elements of reality.
00:16:19.840 These are discrete lumps of matter interacting with each other via forces at a distance.
00:16:25.600 That view was then overturned by the idea of fields. A field in physics is a thing that permeates
00:16:31.280 everything there is in a continuous way. Particles are now understood as excitations,
00:16:36.720 ripples of fields. But fields themselves could, in principle,
00:16:40.960 we've broken down further into more primitive elements of explanation,
00:16:44.160 opening up a novel and even more fundamental explanation of reality.
00:16:48.400 This may be hard to imagine for us, but we must be prepared to imagine more fundamental entities
00:16:52.880 than fields. Given that physics is open to further, more fundamental explanations.
00:16:57.520 The resulting picture of scientific knowledge is that there are different levels of explanation
00:17:01.040 about reality. Each of these levels may sometimes be autonomous.
00:17:04.400 In the sense that it does not need to refer to the others to make sense of its own internal
00:17:09.120 rules. For example, it is still fine to think of particles without referring to fields of
00:17:12.880 view which to describe certain simple mechanical interactions such as the collision of two rigid
00:17:17.440 spheres. None of these levels is exhaustive. All the levels are essential to understanding what is
00:17:22.960 out there, pausing that is my quick reflection on this. So when it comes to a word like particles,
00:17:30.000 I like to think that we just continue to understand the nature of particle with ever more precision
00:17:36.640 over time. And there'll be no end to how well we can understand particles. Take, for example,
00:17:42.880 the electron. Now, it used to be thought that the electron, well, sorry for the fact that it used
00:17:50.160 to be thought the electron didn't exist, that there were just these things called atoms and they
00:17:53.840 were just spheres that were just individual spheres. We can go back to democritus in ancient Greece
00:17:59.760 for that. It took some time later until we thought that, well, the electron is actually this
00:18:05.680 charged particle that orbits the nucleus in an atom. The atom now being something that is indeed
00:18:11.360 divisible made up of other simpler components. And then we realized, well, the electron might be
00:18:17.600 the excitation of the field. But it didn't change the fact the electrons in electron. And I don't
00:18:21.680 think it changed the fact that a particle is a particle. Unless one is to insist that particle must
00:18:26.400 mean something other than excitation of the field. In the same way that we do not need to agree
00:18:32.640 with the ancient Greeks, democritus doesn't get to claim the word atom and keep it for all time.
00:18:38.240 We can refine our understanding of the word atom over time and come to a better, deeper
00:18:44.080 understanding of what an atom genuinely is. It's not something that's indivisible. Even if the
00:18:48.960 Greek word means indivisible. So too with an electron. And now we know an electron excitation of
00:18:54.880 the field, but also consisting of lots of fungible instances of itself throughout the multiverse,
00:19:01.200 we should expect that this understanding of the electron would just continue to be refined.
00:19:05.440 Could it ever be the case that we would find an explanation where the electron was entirely
00:19:10.320 able to be done away with? I doubt it, but it's possible. It's possible. Are we wrong about
00:19:16.000 the electron right now? I would certainly expect that to be the case, that we can find out something
00:19:21.280 new about the electron, namely some new properties that we didn't know about before.
00:19:25.440 All of these things are true. But I emphasize that because certainly in episodes that I've done
00:19:30.640 on the multiverse, I've said categorically that the electron is not a wave in a single universe
00:19:37.840 that I refuse to go down the path of saying an electron is both a particle and a wave.
00:19:43.200 I say it to particle. Then of course we get into this idea that it's an excitation of the field.
00:19:47.760 The field being a continuous thing across a universe. Does that then mean that the electron is a
00:19:54.480 particle and a wave? Only if I would suggest, only if you take into account a God's eye view of the
00:20:00.560 entire multiverse. Singing across the entire multiverse, the electron might seem to be a continuous
00:20:06.880 thing of a kind. At the same time, in any given universe, it is going to be a discrete thing
00:20:14.000 as well. I think we need to be precise about what level of explanation we're talking about.
00:20:21.680 Within the single approximately single universe, or across the entire multiverse.
00:20:27.200 Anyways, that is just to give my little opinion that electrons are particles, but we can come
00:20:32.640 to understand what the word particle means, to a deeper, more refined way over time.
00:20:41.040 Back to the book, you're right, quote. The usual output of knowledge creation in physics is a
00:20:46.640 piece of knowledge that addresses a particular problem. For example, the explanation for why the
00:20:51.040 sky appears dark at night. The explanation for why the sun appears to move in the sky from east
00:20:55.760 to west every day, and so on. From time to time, such problem-solving leads to an entirely
00:21:00.720 new physical theory, such as Newtonian mechanics, general relativity, or quantum theory.
00:21:06.400 These rare events have momentous consequences, resulting in a radical change in the way we look
00:21:12.080 at the world, which may take several decades to be assimilated. Often, a new physical theory's
00:21:17.600 practical and theoretical implications can be worked out only after a long while. For example,
00:21:23.360 nothing in Einstein's theory of general relativity even hinted at GPS, the global positioning system,
00:21:28.800 which provides information about location and time to our phones and cars using a network of
00:21:33.520 satellites orbiting Earth. Yet, GPS relies directly on the phenomena described by general
00:21:39.280 relativity. The possibility of GPS is a counterfactual, allowed by general relativity.
00:21:45.840 That's why a new physical theory is much more than a solution to a particular problem.
00:21:51.840 It is a conjectured explanation that attempts to approximate the actual laws of physics,
00:21:57.840 the rules that constrain everything in our universe. If you ask the physicists to write down what we
00:22:03.280 currently know about the laws of physics, they would probably start writing a bunch of equations.
00:22:07.840 For example, E equals MC squared. But then they would think again, they would start adding words
00:22:12.800 to explain what those various symbols mean. E is energy, M is mass, C is the speed of light and so
00:22:18.000 on, and they would explain in words what energy, mass, speed, and light are. All those words
00:22:23.760 constitute the explanation that is the core content of the physical theory that those equations
00:22:28.480 express. The two ingredients are indissoluble with that explanation and equation is empty and
00:22:33.920 has no meaning. Without formula, the explanation is too vague to be applied. A physical theory,
00:22:39.360 therefore, is not just the set of its formula, such as E equals MC squared, nor is it the collection
00:22:44.960 of its testable predictions. It is a conjectured explanation, which includes, for example, the
00:22:50.560 informal descriptions of what E, M, and C are in that formula, and why they are related in that way.
00:22:56.480 This will also apply to things that, unlike the speed of light, cannot be directly measured,
00:23:01.360 such as the geometry spacetime, which are nevertheless crucial to explain why that formula,
00:23:07.200 which is then relevant to make predictions, is as it is. In practice, physical theories about the
00:23:13.120 universe that count as viable explanations must at least have certain traits that guarantee
00:23:18.560 they are free of basic flaws, just pausing their more reflections. Here, the idea that
00:23:25.760 a theory is just a solution to a problem, or a solution to a particular problem,
00:23:31.920 hit rigs of the instrumentalist idea. That's as long as you have equations, then what you can do
00:23:38.960 is predict the outcome of experiments. This is what's being hinted at here. But in fact,
00:23:44.320 if you're not an instrumentalist, if you are a realist, then what you say is that the theories we
00:23:49.840 have are approximations too, what is really out there, in some sense. In the case of physics,
00:23:56.000 the conjectured explanations we have are approximations too, the ultimate laws of physics,
00:24:00.880 that are definitely there governing the universe in some way. Now, if you're an instrumentalist
00:24:04.880 again, then what you would say is, well, E equals M, C squared just allows you to predict
00:24:10.240 the outcome of, I don't know, a nuclear bomb explosion, how much energy you'll get.
00:24:16.640 Without ever worrying about, well, how do you then even talk about energy? You then have to
00:24:22.720 explain what energy is. A realist wants to explain what energy actually is, would actually say,
00:24:27.440 well, M means mass, and I'll tell you what mass is, and C means the speed of light, and I'll tell you
00:24:31.120 what that means as well. This entire grand theory, the general and special theory of relativity,
00:24:36.640 are actually describing stuff that's out there in the real world. It's not just to generate
00:24:42.480 equations, which then allow us to predict the outcome of an experiment. We need to have
00:24:47.680 something more than that. We need to have contact with physical entities in the real world.
00:24:54.000 That is how the explanation is cashed out. We need both as Kiara says, we need both the
00:25:00.640 formula, the equations, because that gives us precision in being able to make some predictions.
00:25:05.680 That's very, very crucially important. But we also need an explanation in words of what the different
00:25:11.760 parts of the equation actually refer to, and in that case, we have energy being referred to,
00:25:17.360 mass being referred to, speed of light being referred to. Now we're about to get into
00:25:22.080 something a little new, a little piece of terminology, and this is exciting for me because it's
00:25:27.920 in epistemology, and it's about the nature of an exact theory. So let's go to that
00:25:34.560 Kiara writes, quote, in practice, physical theories about the universe that count as viable
00:25:40.880 explanations must at least have certain traits that guarantee they are free of basic flaws.
00:25:48.240 In the first place, they must be exact. By exact theory, I do not mean expressible precisely
00:25:54.320 in mathematical terms or anything like that. I mean a theory that does not include any limitation
00:26:00.080 as to the accuracy of its statements. In short, one that does not include any approximation,
00:26:05.600 think of two recipes for a cake, one requiring that you put approximately 100 grams of sugar
00:26:11.680 in a bowl, the other requiring that you put in exactly 100 grams of sugar. The first is an
00:26:17.520 approximate recipe. In that 99 grams or 101 grams will probably do, the second is an exact one,
00:26:24.880 just as with recipes, approximations in physical theories are vague as to what they say about
00:26:30.400 physical reality. And for that reason, they're problematic. For example, in regard to those recipes,
00:26:35.520 one could ask why approximately 100 grams of sugar and not exactly 99. An example of an exact
00:26:41.520 physical theory is Newtonian physics, which allows one to predict the exact place and time of
00:26:46.560 an apple's landing on the ground once we know when and where it comes off the tree. And it's
00:26:52.240 initial velocity. Newtonian physics is also an example of the most general kind of theory in that
00:26:57.600 it is universal. A universal theory is one that is not subject to any limitation about its
00:27:02.800 domain of applicability. Newton's theory applies to apples on earth and on Mars and in any
00:27:08.400 upper alley in place in the universe, pausing their my reflection. Let's do an example. Let's do this
00:27:14.960 one. Let's figure out, you know, in a science book like this, I think it's recommended by editors
00:27:21.600 or something like this. There's this saying that goes around for every equation that you put into
00:27:27.280 a book like this. Your number of readers is reduced by half or something like that. I don't know.
00:27:32.800 Anyways, I don't care. I'm making a YouTube or a podcast. And so I can, I can put
00:27:39.680 a quasency and I can do a little bit of baby level physics. So let's do that. Let's actually do
00:27:46.320 the upper one. But before before we get to the upper one, I'll do something even simpler. So
00:27:51.760 let me put something up on the screen here. Here's an equation. Okay. So this equation here is
00:27:57.200 v equals u plus a t. And let me explain what each of the parts you mean. This is one of the
00:28:02.720 so called sovat equations, s u v a t, which high school physics students are unfortunately
00:28:09.520 forced to learn. Oh, you know, if they're in high enough years, they can elect to learn.
00:28:13.920 The sovat equations are part of Newtonian classical mechanics. They don't work universally
00:28:21.600 as it turns out. Now, they're purported to be universal and Newton would have thought they were
00:28:25.280 universal. But in fact, they don't apply because we have this thing called relativity and there's
00:28:31.040 an upper limit on how high v can be. V is your final velocity. V is your final velocity.
00:28:37.040 u stands for your initial velocity. A stands for your acceleration. And t is the time over which you
00:28:44.320 are accelerating. Now, we don't know if this comes from. Well, on the one hand, you might think it's
00:28:48.400 common sense, depending upon how mathematically minded you are. You might look at that and think,
00:28:52.400 well, of course, my final velocity v is going to be how fast I'm now traveling u plus how long
00:28:59.360 I'm going to accelerate for. So that can be common sense. But in fact, it comes from here, the
00:29:05.040 definition of what acceleration is. Acceleration is the change in the velocity over the
00:29:12.320 change in time. So it's about the change in velocity. That's what acceleration is. It's how
00:29:16.720 much you are speeding up, slowing down, changing your direction, that kind of thing. Now, we can,
00:29:21.360 but that way of writing it there is a equals delta v over delta t. The delta is just the Greek
00:29:27.200 letter, which means change in. So I'm changing velocity over a change in time. Change in velocity
00:29:33.680 is the takeaway u, your final velocity, take where your initial velocity. And that's all over
00:29:40.000 your delta t. How long, but duration of time, you're, you're having to be accelerating for.
00:29:45.040 So let's, let's consider an example. Let's say that right now you're in a car and you're traveling
00:29:50.160 at 10 meters per second. Now, I know that most people don't talk in terms of meters per second.
00:29:55.200 But physicists, they like to talk in meters per second, rather than miles per hour or kilometer's
00:30:00.240 per hour. We talk in meters per second. Let's, so we're traveling at 10 meters per second. Let's
00:30:05.120 assume that we to press the accelerator now car and we accelerate at a rate of two meters per second
00:30:12.560 as reasonable for a car. And we're going to accelerate. We're going to leave our foot on the accelerator
00:30:17.440 at a constant rate of acceleration. That's the important thing as well. Many cars don't accelerate
00:30:21.680 at a constant rate, but we're going to presume constant rate. And we're going to do that for a time
00:30:26.960 of five seconds. So we're going to put the accelerator down for five seconds. We're going to be
00:30:31.120 moving at initially 10 meters per second and accelerating for two meters per second. Then how fast
00:30:36.720 are we going at the end of this five seconds? Well, this is the math that we do. We want to figure
00:30:40.880 out what V is. So V is going to equal U plus AT. And knowing that U is 10. And I'm going to add to
00:30:50.800 that two times five. Two times five is 10. So the acceleration over those five seconds has added
00:30:59.120 another 10 meters a second to my initial velocity. So I've got 10 meters a second plus another 10
00:31:05.920 meters a second altogether. V, my final velocity is 20 meters a second. So this is what we would
00:31:14.160 call an example of a kind of dynamical law where we've got some initial conditions,
00:31:20.240 my initial conditions were 10 meters a second. Two meters per second per second was my acceleration.
00:31:27.920 Over a time period of five seconds, putting all of those initial conditions together,
00:31:33.280 I can then make a prediction of what my final velocity is going to be. So this is a way of
00:31:38.640 conceiving of how physics is done. And almost all physics is little more than an example of this,
00:31:45.600 hitherto, by the way, without constructor theory. So hitherto, we have equations, we plug in the
00:31:51.680 initial conditions. And then we can predict whatever future state of the system that you want.
00:31:57.360 So in this case, our very simple system of the car, presuming that relativity doesn't exist
00:32:02.160 in the universe, presuming we live in a universe governed by Newtonian physics,
00:32:08.400 then I can tell you what your final velocity of V is going to be. If only you can tell me
00:32:13.040 what the initial conditions are, what you is, what A is, and what T is. So this is supposedly
00:32:18.480 how physics is done. Give me a law of physics like V equals u plus a t. Tell me what the initial
00:32:23.840 conditions are. And then I will tell you, if I will predict any future state of the system
00:32:29.040 at whatever time you like. Now let's have a look at Chiara's example there. An example of an exact
00:32:34.960 physical theory she says is one like Newtonian physics, which allows one to predict the exact
00:32:40.640 place and time of an apples landing on the ground. Once we know when and where it comes off the
00:32:45.680 tree and its initial velocity. Okay, so in this case, I'll use a different equation. It's another
00:32:52.160 one of these pseudo equations. If you're interested, then you can look up where you get an equation
00:32:57.840 like this. It's a little bit more complicated than the previous one. But the equation is this,
00:33:02.800 S equals u t plus half a t squared. And all those symbols mean exactly the same as what they did
00:33:09.280 in the previous one with the addition of S. S is the displacement or where something is happening.
00:33:15.360 So S is the displacement. You just like before is the initial speed of the object. T is the time
00:33:20.480 taken and A is the acceleration. Now if we have an object like an apple sitting on a tree,
00:33:26.800 then its initial speed is u, which is just sitting there. And what we're interested in is finding
00:33:31.680 out S, how far it's going to fall. Now if you tell me T, if you time, you're standing there with
00:33:38.320 a stopwatch or something next to the apple tree, timing how long it takes for that apple to hit
00:33:44.640 the ground, then I'll be able to tell you S, how far it has fallen, where it's going to hit the
00:33:49.040 ground. Now it's going to hit the ground of course, immediately beneath the tree, but where exactly
00:33:53.760 is the ground? Well, that's the problem that we can set out. So let's, let's make a guess.
00:33:58.400 Let's presume you're standing there with your stopwatch. And it takes precisely one second,
00:34:03.760 one second, four, that apple to hit the ground. Then what do we predict for S? Well, S is going to
00:34:10.160 be S equals U T plus half A T squared. But in this case, our U is zero. Our U is zero. So that term U
00:34:18.800 times T is going to also be zero because it doesn't matter what T is. T in this case happens to be
00:34:23.520 one. Zero times anything is zero. So we've got S equals zero plus a half A T squared. Now what's A?
00:34:31.360 A is the acceleration. Now, the acceleration in this case is the acceleration due to gravity,
00:34:37.360 the acceleration due to gravity on Earth, which is taken as roughly speaking a constant all over the
00:34:42.960 surface of the Earth. Let's presume we're at sea level. And the acceleration due to gravity there
00:34:47.040 is approximately 9.81 meters per second squared. And by the way, this changes around the world,
00:34:54.000 just ever so slightly, and you can use the fact that it changes around the world to do something
00:34:57.840 called gravity analysis. This is what geophysicist do, and you can find things in the ground,
00:35:01.680 and that's a whole area of science. But let's go back to this. S equals U T plus half A T squared.
00:35:07.520 We've got S equals zero plus a half times 9.81. Now we know plus a half times 9.81 times T squared.
00:35:16.320 Times, how long did we say? One times one squared. So now we've got S equals zero plus a half,
00:35:23.760 nine point eight, one times one squared, which is one. So that's half of 9.81. Call it half of 10.
00:35:31.680 So it's a little bit under five. It's actually about 4.9. So the tree must have been 4.9 meters high.
00:35:39.440 That's how far the apple fell. So 4.9 S equals 4.9. So we found out where the apple fell.
00:35:45.920 So you can play around with that yourself. If you've never seen anything like this before,
00:35:49.280 that too is a kind, well, that equation has derived from the laws of physics, the
00:35:55.840 Newtonian laws of physics. As we presume the laws of physics would be, if we lived in the universe
00:36:02.000 governed by, for example, Newton's law of gravity. But now we know that we're not in that kind of
00:36:07.440 universe. That, by the way, that that worked perfectly well. And the reason why Newtonian mechanics
00:36:12.720 is still taught, still learned, is because for almost all engineering purposes, Newtonian physics
00:36:19.360 works perfectly well. You can get to the moon with Newtonian physics like this. It is precise
00:36:24.400 enough to be able to approximately get the right answer. When I say approximately, I mean,
00:36:29.760 with high precision, once you start to get to really high velocities, close to the speed of light,
00:36:34.800 then the thing starts to break down. Then it doesn't work so well. Then you want to rely upon
00:36:38.880 relativity, Einstein's relativity. But that is beyond the scope of even my podcast here. Okay,
00:36:45.920 so just to summarize all of this, all I'm doing here is just showing you the traditional way in
00:36:50.800 which physics has always been done. You have an explanation, an explanation of how the world works
00:36:59.680 in terms of forces, perhaps, things like quantities like acceleration and time, gravity,
00:37:07.200 and so on. And from this explanation, a scientist, someone like Newton, is able to
00:37:13.440 derive from certain principles, from certain things that he understands about reality, assumes
00:37:17.920 about reality, guesses to be approximately correct about reality. He then is able to derive from
00:37:24.640 that explanation, certain equations, which represent some aspect of those physical laws,
00:37:29.760 v equals u plus a t, s equals u t plus half a t squared. And we can regard that s equals u t plus
00:37:36.480 half a t squared, for example, or v equals u plus a t, as a dynamical law. Certainly as an equation
00:37:42.560 representing a dynamical law of some kind. And if we know the initial conditions, the numbers
00:37:49.040 that we plug into the equation, we were able to make a prediction of what will happen in the future.
00:37:54.640 This is the sense in which physics has always been done. And even if you get into
00:38:00.400 relativity, it's the same idea, the equations change, but it's the same idea. If you get into
00:38:05.280 quantum theory, it's the same idea. Things get more complicated in terms of the formalism,
00:38:10.400 as we say, the mathematical equations become more complicated. We have all sorts of weird and
00:38:16.880 interesting calculus going on, and matrices going on, and in certain cases, statistics happening.
00:38:23.200 But it's the same. It is where we have an equation of some kind, and we take some numbers that
00:38:29.520 we know, the initial conditions, and we predict what is going to happen in the future. We're
00:38:34.240 finding our v, given our u, our a, and our t. Basically, that idea. Until now, back to the book,
00:38:42.960 the Chiararites. Again, physical theories that are not universal and apply only to some scales,
00:38:48.880 all domains, are by themselves problematic, because one still has to explain what they hold only
00:38:54.880 at that scale and not elsewhere. So, by tentatively solving problems in our understanding of physical
00:38:59.840 reality, physics ends up seeking universal and exact physical theories. These theories, as I shall
00:39:06.400 explain in chapter two and seven, must also be testable, so that they can be checked against reality
00:39:12.320 to find potential errors. Because of fallibleism, it is important to note here that exact
00:39:18.400 does not at all mean true. Any conjectured explanation which seems to be working may be found to be
00:39:24.560 false at any time. As I said, this happened with Newton's theory of gravitation when it was
00:39:29.920 superseded by quantum gravity and general relativity. We can never know whether a physical theory
00:39:34.800 that we have formulated is true. All we can say is that it has so far not been found to be false.
00:39:40.800 This may seem a little unsettling, but it is an extremely interesting fact about how knowledge is
00:39:45.440 created. And as I said, it is central to the possibility of making progress via criticism. Here,
00:39:52.560 we get closer to the origin of the pernicious boundary to exclude counterfactuals.
00:39:58.240 As one can imagine, there are different ways in which explanations can be formulated.
00:40:02.560 How many? We do not know, infinitely, many presumably. The mode of explanation of Newton's theory
00:40:08.640 has a distinctive feature. Its scope is confined to explaining what happens in the universe,
00:40:14.240 given two primitive elements. One includes what in physics jargon are called laws of motion.
00:40:20.960 The rules that tell us how the motion of systems, what physicists call the dynamics,
00:40:26.480 unfold in space and time. The other are the specific initial conditions of the motion.
00:40:31.840 For example, Newton's laws of motion can be applied to say what happens to an apple given
00:40:36.240 the initial conditions, the particular place where the apple started its motion, and its initial
00:40:40.240 velocity. The set of points that a system goes through as it moves is called a trajectory.
00:40:45.840 Hit a tennis ball with a racket against the wall. The trajectory is the imaginary line one can
00:40:50.320 draw to describe where the ball goes after it leaves your racket. The laws of motion and the
00:40:54.880 initial condition give us a way to predict that trajectory without actually having to observe
00:41:00.320 any actual ball being hit. Given the initial position and velocity of the ball,
00:41:04.800 one can predict precisely where its motion will bring it, just computing the trajectory
00:41:08.960 from the laws of motion. This mode of explaining things in terms of what happens has proved
00:41:14.480 extremely successful and far-reaching. It allows for powerful predictions, which can be tested
00:41:19.840 with experiments to enable conjecture and criticism. The mode continued to be successful even
00:41:25.520 when Newton's theory was found to be inadequate. By, for instance, failing to describe the
00:41:30.400 procession of the planet Mercury, it delivered theories like quantum theory and general relativity,
00:41:35.440 which are our current best theories to explain physical reality. Both of these subtle theories
00:41:40.480 are formulated as laws of motion. It is the very same mode of explanation that Newton adopted
00:41:46.800 informing his laws. Along with much progress, this mode of explanation has, perversely,
00:41:53.040 generated the wretched boundaries that could stand in the way of future successes.
00:41:57.840 An unspoken stipulation was made. What I shall call the traditional conception of fundamental
00:42:03.600 physics, that all fundamental physical theories must be formulated in terms of predictions about
00:42:09.200 what happens in the universe given the initial or more generally supplementary conditions and laws
00:42:14.480 of motion. In this conception, physics is no longer an open-ended enterprise. It has been
00:42:19.760 infinitely narrowed to the project of finding theories that can be expressed only in terms of
00:42:23.600 what happens in the universe given the laws of motion of all its constituents and a particular
00:42:28.240 initial condition. So the ultimate theory about physical reality would consist of a collection
00:42:32.800 of the trajectories of all elementary particles in the universe given where and when they started.
00:42:38.480 We do not have such a theory yet, but it is traditionally regarded hypothetically as the
00:42:44.480 ultimate explanation of everything important about the universe pausing their just my reflection.
00:42:49.280 Okay, so in my very baby example of vehicles u plus a t, for example,
00:42:55.840 you could apply this to in theory, okay, if you're this oracle or a god or some sort of
00:43:02.080 super intelligence, whatever you want to call it, that's got access to some kind of system where
00:43:07.760 you know the current velocity of any particular particle throughout the entire universe,
00:43:14.320 you know what its acceleration might be, which is a consequence of the forces that might be
00:43:18.320 applied to it, then if you just pick some time t in the future, then you will know what
00:43:24.320 v is going to be. Now of course, there are lots of complications here, namely that you won't
00:43:28.720 have a constant acceleration, let's say, putting aside the fact that, of course, the universe
00:43:34.960 doesn't even obey v equals u plus a t because we know that relativity and quantum theory.
00:43:40.640 For two examples, contradict what is being said here, but in principle, you get the idea that if
00:43:46.640 you accept the notion that there are these dynamical laws, that if you have the initial conditions,
00:43:52.080 dynamical laws such as vehicles u plus a t, then if you just plug in these initial conditions,
00:43:57.920 you allow for the prediction at any point in the future, at any time t in the future of the
00:44:03.760 state that it evolves to, this is the concept of determinism. And so this leads to all sorts of
00:44:11.680 poor philosophical arguments, I would suggest, as well as this narrowing of the conception of what
00:44:16.960 physics could potentially be about. And it seems to insofar as we regard this as being a universal
00:44:23.200 truth about physical reality. It rules out all sorts of things. And this is why it leads to this
00:44:30.480 poverty of philosophical explanations and other kinds of explanations. We can't get beneath
00:44:35.440 this notion of this kind of determinism. So we rule out things like free will, for example,
00:44:43.200 some people rule it, choose to rule out free will. And we're going to come to this at various
00:44:47.360 points throughout the discussion of this book. It's a pet peeve of mine, because free will, to me,
00:44:54.160 apart from just describing what humans do, what people do, people make choices in the world.
00:44:59.120 But it's also a label for a certain kind of mystery. And there is a mystery. There really are
00:45:04.000 mysteries out there in the universe. There are so many things we don't know at the beginning of
00:45:07.360 infinity. But if you think that we already have everything wrapped up neatly in terms of
00:45:12.800 dynamical laws and initial conditions, which allows to predict at any any point in the future what's
00:45:17.280 going to happen, then we have a deterministic universe that rules out all other possible mysteries
00:45:23.600 in the universe. After all, isn't everything already predetermined? Therefore, there are no
00:45:27.440 mysteries in the universe. There are no open questions. All we need to do is to plug into some super
00:45:31.600 computer of the future or consult some article about what's going to happen. And that apparently
00:45:36.320 solves everything. Know that merely predicts everything and prediction is not the purpose of science
00:45:41.120 or knowledge production in general. What we're after are explanations. And even if this
00:45:45.840 conception of physics, this dynamical laws and initial conditions thing was true, which we're
00:45:51.280 about to say isn't the best way of conceiving of science? Not the best way of conceiving of
00:45:57.680 physics, let alone science. And I would say probably knowledge more broadly, even if we were to
00:46:02.320 conceive of science being like this, it it presumes far too much. It presumes everything can be
00:46:09.680 explained in terms of physics. Well, it doesn't even explain it. It dismisses explanation.
00:46:15.920 It says that everything's about prediction. And this is not the purpose of science. And it's
00:46:20.160 an unfortunate thing that's entered the culture, the intellectual culture, one would say that
00:46:27.120 commented, people who commented on Newton thought that it revealed a clockwork universe. And
00:46:32.720 therefore ruled out every other interesting emergent aspect of reality. After all, if it's just a
00:46:39.760 clockwork universe, then there's no place in it for mysteries like consciousness and free will,
00:46:45.920 things that might not easily sit within this framework of determinism. Many of us say it does.
00:46:53.840 It does anyway. Free will isn't at all affected by determinism. But anyway, what we're about to
00:47:00.400 get to here one reason I love constructor theory is because all of this argument about determinism
00:47:08.480 is predicated very much on the idea that it's true anyway, that dynamical laws and initial
00:47:15.200 conditions are the whole truth of the matter, that there isn't a misconception lurking there,
00:47:21.120 that there isn't a deeper way of understanding physics. And there is, and we're about to find out
00:47:24.960 what it is. And besides that, besides that, and we're about to come to this presently, the initial
00:47:32.240 conditions dynamical laws thing doesn't explain why the initial conditions are the way that they are,
00:47:38.240 why the initial conditions are the way that they are. Look, how do we, how did we get to the state
00:47:42.640 in the first place? And if you just say the big bang, well, why is the big bang the way that it is or
00:47:46.800 was? There's no explanation. There's no way of even conceiving of that within the present framework,
00:47:54.000 nothing within that present framework of dynamical laws of initial conditions can explain why
00:47:59.200 the initial conditions should be the way that they are. You can't refer to anything within
00:48:05.120 that framework to give you the bits of the framework. Why are the physical laws the way that they are?
00:48:10.800 Silent on that. These just are the physical laws. Why are the initial conditions the way that they are?
00:48:15.200 Silent on that. That's just the way things are. Constructed theory is the first time, as far as I can tell,
00:48:20.640 that we've got an area in physics, which is going to provide a window into allowing us to peer into
00:48:29.120 answers, possible answers about that. Let's go back to the book, where Chiara is. That traditional
00:48:36.320 conception has created the barriers against counterfactual explanations and its project, if taken
00:48:41.200 literally appears impossible. In the first place, it is not possible to explain literally everything
00:48:46.800 in terms of initial conditions and laws of motion. For example, even if we had a decent theory
00:48:51.520 of what the initial conditions of the universe are, it could not itself be explained in terms
00:48:56.240 of initial conditions. For a start, it would have to contemplate what would happen if other
00:49:01.920 initial conditions were chosen. A counterfactual explanation. How to explain the choice of the
00:49:07.680 initial conditions is indeed an open problem in fundamental physics. There are also other
00:49:12.640 related open issues that require that counterfactuals be addressed, such as the problem of fine
00:49:18.240 tuning the laws of physics, about why dynamical laws are as they are. For an excellent exposition
00:49:24.320 of this problem, see Paul Davies, the Goldilocks and Ingmar. The fine tuning problem cannot be
00:49:29.120 addressed by stating only what happens. One has necessarily to look at what might have happened if
00:49:34.480 the laws had been different. And how can one do that without counterfactuals? In addition,
00:49:39.600 explaining what we see now in the universe around us, in terms of a story that starts with
00:49:44.240 initial conditions is itself arbitrary. One could describe everything that happens, including what
00:49:48.960 we see now, given the final conditions of the universe, and then use the laws of motion backwards
00:49:54.400 by retrodicting, instead of predicting the current state of affairs, pausing now by reflection.
00:50:00.640 Yeah, this retrodicting versus predicting very true, given any state of motion, you can predict
00:50:06.720 what the conditions are using dynamical laws at any point in the future of the past.
00:50:12.720 Many of us just choose the word predicting to, as a general term, even predicting what happened
00:50:19.200 in the past is still a form of prediction, you know, that predicting, for example, what the conditions
00:50:24.560 at the Big Bang would like, rather than saying, will retrodict what it was like at the Big Bang,
00:50:28.880 just predict, even though we're talking about the past. Now, that aside, fine tuning. Yes,
00:50:34.800 Paul Davies did write this excellent book, The Goldilocks in England. Since then, they have been
00:50:41.520 other books. One book was a fallacy, the fallacy of fine tuning by Victor Stanger, who was a
00:50:48.240 particleist, and he does very well to explain aspects of fine tuning, but then he dismisses
00:50:54.560 the moral and says that this is not a problem. That's a very interesting book. In response to that
00:50:59.360 book, largely in response to that book, not only, but largely in response to that book. A couple of
00:51:04.480 Ozzie physicists. Now, one is a theoretical physicist who moved into cosmology, his name is
00:51:09.280 Gerant Lewis, and another is an astrophysicist in cosmologists who are Luke Barnes,
00:51:16.080 and they wrote a book called A Fortune at Universe, Life in a Finally-tuned Cosmos. And that's
00:51:21.280 really interesting book because the two authors there are coming at the issue from very different
00:51:26.720 positions. Gerant Lewis is an atheist. Luke Barnes is not an atheist. I think he comes from a Christian
00:51:34.800 tradition. And they're both trying nut out the debate in a very friendly, good-natured, humorous way,
00:51:42.080 and they explain all the modern problems. I think it's one of the more very, very recent books written
00:51:47.440 on this 2016. It was published. You can get the audio book as well. Or just look up,
00:51:52.400 especially Luke Barnes, but also Gerant Lewis. On YouTube, there's just some really fascinating
00:52:00.240 lectures they give. Both of them have been on closer to truth that wonderful
00:52:05.520 series of interviews with Robert Lawrence Kuhn. So you can find that here. And so I personally,
00:52:12.960 I love I'm fascinated by this fine-tuning issue, basically because we know nothing. We know so
00:52:21.760 little. And in Lewis and Barnes, they don't push a particular perspective. Even I say,
00:52:29.360 you know, Barnes comes from this Christian tradition. He uses it as a way of critiquing,
00:52:37.360 other ways of trying to explain or explain away the fine-tuning problem, namely via a
00:52:41.760 megiverse. And Gerant Lewis uses his arguments to try and explain away the supernatural explanation.
00:52:49.200 So they're using, they're very much in, even though they wouldn't call themselves
00:52:52.720 Papurians. I'm almost certain of that. I think they're basing. That's hard. They use their ideas
00:52:59.520 as very much as critiques of one another. And ultimately comes with inclusion that,
00:53:04.160 well, there are just many, many, many open questions when it comes to this whole area of fine-tuning
00:53:09.920 and the physical constants. Much, much less to say, well, you could have different physical laws
00:53:15.920 as well. Now in the next part, we're going to bring this new theory of physics which shows
00:53:22.160 promise in providing new avenues within physics to answer age-old problems in physics
00:53:28.880 with an appeal to epistemology. Let's go back to the book, Gerantz. The traditional conception is
00:53:37.280 also perverse because it clashes with the pillars of rational thinking, which I mentioned early on,
00:53:43.200 that have been changeable and improveable via conjecture and criticism. Physics aims at solving
00:53:49.920 problems. As a consequence, it seeks, if possible, universal and exact, testable laws formulated
00:53:57.520 in whatever mode of explanation happens to be appropriate. In contrast, the traditional conception
00:54:02.880 forces theories to come only in one form, thus narrowing down the space available for thinking
00:54:09.040 it introduces a boundary, which impedes progress. It confines physics only to things that can be
00:54:14.720 described exactly in terms of statements about what happens given the initial conditions and laws
00:54:19.680 of motion, but not about other phenomena, which thus remain only imperfectly explained. There is more.
00:54:26.800 The traditional conception of physics has inspired an approach that is now spread to other parts
00:54:32.640 of science too, via an approach that has been called reductionism. The idea that there is only
00:54:39.760 one level of explanation that is both fundamental and admissible, and everything else can be reduced
00:54:45.040 to that, such a level of explanation is, presumably, that of elementary particles or fields
00:54:51.360 and their trajectories, given their initial conditions, that this take on physical reality is,
00:54:56.160 again, to narrow. There are questions that this approach cannot answer, questions that are deep and
00:55:01.920 important for understanding the full reality of a physical phenomenon. For instance, the question,
00:55:06.960 why is a given transistor in a computer on, at the end of the given computation,
00:55:11.360 has at least two answers? One is that it is on because the electrons in the computer were set in
00:55:17.360 such and such initial conditions. The other is that it is on because the computer performed
00:55:21.840 the computation to find the factors of, say, the number 15. And the on transistor is part of the
00:55:27.520 encoding of the output, 3 and 5. The reductionists would discard the latter explanation as
00:55:32.400 less fundamental, because, after all, factoring a number is nothing but the electric
00:55:35.920 currents in the computer. Reductionism ultimately denies that the computational description is
00:55:40.960 necessary, though some reductions may accept that it is helpful as a matter of discourse.
00:55:45.840 But this is, of course, nonsense. Both explanations are necessary to understand what is happening.
00:55:51.920 They refer to different autonomous levels of explanation, which do not implicate one another,
00:55:56.880 by ignoring one of them. One misses something crucial about reality. Reductionism impedes
00:56:01.760 progress in physics and science in general because it requires all explanations to conform
00:56:06.320 to certain arbitrarily predefined criteria. For instance, that they refer exclusively to
00:56:10.960 microscopic particles in their trajectories. In the example I gave earlier about computations,
00:56:15.200 the explanation in terms of microscopic particles in their initial conditions,
00:56:18.560 a electron current in the computer is not enough to capture the full picture of what is going on,
00:56:22.720 a factoring a given number. Yet reductionists insist on dismissing whatever does not fit into
00:56:27.360 those criteria, from information and thermodynamics to creativity and consciousness as approximate,
00:56:32.240 and thus, outside the scope of science. The result is a narrow, limited view of science,
00:56:36.560 posing near my reflection. That might even undersell things. The result is a narrow,
00:56:40.240 unlimited view of science. It completely dismisses the entire corpus of science aside from
00:56:47.680 fundamental physics. It's everything else is utterly useless, like there is no understanding there
00:56:53.600 in, for example, evolution by natural selection. That if you want to explain the origin of species,
00:56:59.040 the only legitimate, true explanation that underlies everything is the equations of motion,
00:57:05.920 the laws of physics and the initial conditions. That's absurd, it's absolutely absurd.
00:57:11.600 That conception of science allows us to solve almost no problems. If we want to find a vaccine
00:57:16.960 for the next virus, no one should be tempted to think what are the physical laws and initial
00:57:23.440 conditions, even in the five distant future, because we have emergence simplicity. It won't be
00:57:27.760 the most efficient way to figure out vaccines, even if we have a supercomputer of the future.
00:57:32.000 We're going to want to understand the nature of viruses and how we can reduce their impact upon
00:57:39.680 people over time. As for what makes science rich and interesting as well as useful,
00:57:45.440 you know, these grand ideas about how cosmology plays out over time, we want to understand the
00:57:51.040 evidence of that, that's out there, almost simultaneous with this episode, or released one on
00:57:55.920 quasars. Even something within physics, even something within relatively fundamental physics,
00:58:02.640 cosmology, we want to understand the origin of the emergent physical phenomena as well.
00:58:08.880 And sometimes this requires more than just the trajectory of the elementary particles.
00:58:12.880 Sometimes it requires the elementary particles, but sometimes it requires more than that,
00:58:15.920 the gathering of evidence that goes beyond merely what the fundamental particles are doing.
00:58:21.520 Okay, going back to the book because Chiara talks about precisely this and she writes,
00:58:27.120 There are phenomena that cannot be fully expressed by the traditional conception.
00:58:31.920 By this I mean that physical theories and explanations about those phenomena can take only
00:58:36.320 approximate non-exact forms when expressed using the traditional conceptions approach.
00:58:40.640 So by restricting oneself to that approach, one cannot adequately explain them within science.
00:58:46.800 One important example of things the traditional conception cannot adequately capture
00:58:51.280 includes thermodynamic entities such as those associated to particular kinds of energy transfers.
00:58:57.040 In physics, they are called work and heat. The laws stating how work can be turned into heat,
00:59:03.280 and vice versa, are central to things like heat engines, which which made possible the
00:59:07.280 industrial revolution, yet thermodynamics is often regarded as only a useful approximation,
00:59:13.040 not a fundamental physical theory. So heat and worker regarded as not worthy of further
00:59:18.320 explanation, because an exact physical theory about them cannot be cast in terms of statements
00:59:22.720 about what happens given in initial conditions and laws of motion. The traditional conception has
00:59:28.160 thus given up on an exact understanding of work and heat and similar entities and claims to be
00:59:32.800 content with the existing problematic approximate theories. These theories, as you will see,
00:59:39.200 are highly effective, but only in certain limited domains. For example, to design heat engines
00:59:44.480 such as those used in cars and locomotives, however, they appear to rely on various approximations
00:59:49.840 which, when we consider these laws as fundamental, become inadequate. I shall explain these laws
00:59:55.440 and how to solve them with counterfactuals in Chapter 6, just pausing their myreflection.
1:00:00.320 There's lots of interesting books out there on thermodynamics, if you're interested in pursuing this
1:00:06.480 in greater detail. Anything by Peter Atkins is fantastic. I particularly enjoy this book,
1:00:12.080 an introduction to thermodynamics, but he's also written very complicated books about this.
1:00:16.160 It's a standard part of anyone's physics degree as to study thermodynamics. Work and heat
1:00:22.960 is, these are very interesting concepts, and I'm looking forward to going through that part of
1:00:28.800 the book where Keira explains in greater precision what work and heat really are. But I can give you
1:00:35.440 the general up until now, physics idea of these concepts. Work is just a technical term for the
1:00:44.720 product of the force and distance. If a force is applied over a particular distance, in the
1:00:50.640 direction that the force is applied, as long as the force and the distance are in the same direction,
1:00:56.800 then you've got work. This is the product of these two things. If you're pushing something further
1:01:01.280 applying a force, then you're doing work in physics. So that, to some extent, that makes a certain
1:01:06.960 amount of common sense, that's what work is. When you have a heat engine, when you have a cylinder
1:01:12.160 of some sort, then it's doing work because the gas is producing a force on the parts of the piston
1:01:19.760 over some distance, and that's the amount of work that happens to be done. Heat is a complicated
1:01:25.040 process as well. It's a complicated concept, and we can get right into it, but Peter Atkins has this
1:01:30.000 wonderful idea that heat is not the name of an entity. So it's not a fluid of some kind. If he says
1:01:35.760 it's not anything of any kind, it's the name of a process. So it is where energy is being transferred
1:01:41.360 from something that's hot to something that's cooler, and so you're heating it. This is causing
1:01:46.160 something to heat up, and so heat properly construed should be used as a verb. But of course,
1:01:51.760 Keira is going to sharpen all these concepts up in light of constructive theory, but we'll get there
1:01:57.600 in chapter six. And I'm going to skip a bit here where Keira mentions what and what emergence means,
1:02:06.160 the concept of emergent, where you have something appearing in an explanation at a higher level,
1:02:14.640 beyond the laws of motion and initial conditions, beyond basic particle physics. So once an entity
1:02:21.040 starts to appear, for example, a cat is emergent. It's emerged out of the physical laws in some way
1:02:27.360 shape or form. And cats appear in explanations. Animals appear in explanations. They genes appear in
1:02:32.960 explanations as well. The chemicals appear in explanations. These things become emerging phenomena.
1:02:38.480 And all this emergent phenomena results in levels of explanation. So I'll just read a final
1:02:44.160 part here about this idea of levels of explanation and privileging certain levels of explanation.
1:02:50.320 And that we shouldn't presume that emergent levels of explanation are any less important or even
1:02:54.800 fundamental as compared to the ones about particle physics, namely that the emergent
1:03:01.920 things, the emergent concepts, objects that are out there, as Keira says, quote, declaring those
1:03:08.400 entities as not really of interest to fundamental physics. The problem with this take is that all
1:03:14.240 levels of explanations are necessary to grasp a given situation. Remember the example with
1:03:20.800 computation and factoring, levels of explanation work together like layers in a cake. It is
1:03:26.640 impossible to get the cakes full flavor by ignoring the top layers and just sticking to the base.
1:03:32.160 In this book, you'll be able to grasp the flavor of the full cake by being introduced to
1:03:37.760 counterfactuals, end quote, fantastic way to end today. So we're going to grasp the flavor of the
1:03:45.360 full cake by this concept of counterfactuals. And it's a wonderful way of conceiving a physics that
1:03:51.760 is no longer being about, as I said in the last episode, this single string that stretches
1:03:58.240 throughout time. This string is very, very narrow. It's a single thread that is just an aspect
1:04:07.440 of the greater whole of reality, the greater whole of reality being, all the things that could
1:04:12.880 have happened rather than just looking at what did happen and what will happen. Science should be
1:04:19.520 about trying to figure out what could have happened. And indeed, what could happen if only we have
1:04:24.320 the right knowledge? So it is a grand, broader vision of science, of physics, bringing together
1:04:33.920 these strands in the fabric of reality, truly speaking, so that we can have a much, again,
1:04:40.880 broader view of how to go about solving problems, generating explanations, especially in physics,
1:04:48.480 but also in other areas of science. That's where we'll end it for today. Until next time, bye bye.
