00:00:00.000 Welcome to Topcast, the penultimate beginning of infinity episode.
00:00:25.960 And last time we covered, summarized a lot of the themes that are in the end of science
00:00:34.720 by John Horgan and contrasted it with the vision that we are given of science and knowledge
00:00:44.720 And I think I concluded there with some of my own favourite reasons why we should think
00:00:51.400 this is not the end of science at all, that there are so many really interesting unanswered
00:00:57.240 questions right now that we are on the precipice, we're always on the precipice, but
00:01:01.760 on the precipice of yet another bunch of grand fundamental discoveries in physics.
00:01:09.160 Now this idea that we are at the very beginning of infinity, the beginning of discovery
00:01:14.640 and science that there are just so many things we don't know has been born in upon me
00:01:20.600 in a really fortunate way because presently my job involves almost daily conversations
00:01:27.160 with physicists working in very fundamental areas of theoretical physics to ask them about
00:01:34.840 what areas of physics need additional attention.
00:01:37.960 Just today I was speaking to a very accomplished physicist working on the question of fine
00:01:46.480 Why is it that the contents of nature and the laws are just such that we get complex chemistry
00:01:56.840 Well, in speaking to this person, yes indeed it could have been otherwise and there's
00:02:01.680 a really interesting set of possible solutions but really none of them seem viable to
00:02:07.120 Another route is of course, Kyra and David's Constructa theory which might give a new lens
00:02:13.680 through which we can view this problem and perhaps find solutions as well.
00:02:18.160 And this is just within theoretical physics, just theoretical physics, never mind biology
00:02:26.280 How could anyone think we're at nearly the end of science when something like the coronavirus
00:02:38.120 Even if the fundamental physics theory could be found beyond the standard model, beyond
00:02:45.160 quantum theory and we stopped there, I don't think that's the case.
00:02:51.040 There would still be scientific problems to solve.
00:02:54.120 Every single physical problem that we encounter asteroids from the sky, volcanoes from
00:03:00.000 the earth, viruses from the sea and who knows where else, are going to require scientists
00:03:07.600 So it's not possible to reach the end of science unless we reach an unproblematic state.
00:03:14.080 Which of course, as David says, is another word for death.
00:03:17.880 Otherwise we're going to continue to be confronted by problems, ever more interesting
00:03:22.280 When we solve problems, we find more interesting problems arising from the solutions.
00:03:32.520 I've been talking to people at working at the foundations of quantum theory, open questions.
00:03:38.320 People working at the frontier of quantum computation, open questions.
00:03:42.480 People working in various disparate areas of astronomy, from cosmology, open questions,
00:03:47.280 the formation of galaxies, open questions, the formation of the solar system, open questions.
00:03:51.560 How stars actually work when they've got high or low metallicity, open questions?
00:03:57.280 Unanswered questions with the big bang are really interesting.
00:04:00.120 I remember going to talk with Roger Penrose, who has this wonderful idea.
00:04:07.680 It's like it's a Hindu cosmology almost that he mathematically figures out that towards
00:04:14.720 the end of the universe, if the universe keeps on expanding, that's the current best theory
00:04:19.200 seems to suggest the universe will keep on expanding, at an accelerating rate we're
00:04:22.560 going to talk about that a little bit more today, that eventually not only do all galaxies
00:04:28.440 fly apart and the material within the galaxy's fly apart, but all matter flies apart
00:04:32.240 and eventually all you're left with is a completely and utterly featureless universe of
00:04:39.560 They're the only things that then exist in that universe, trillions and trillions and trillions
00:04:43.840 And at that point, the universe cannot keep time in the regular way because to keep time
00:04:48.280 in it a clock and in such a universe in the far distant future, there is no such material
00:04:54.200 out of which the universe can keep a record of its own time, its own age and so it kind
00:04:59.440 of forgets in Roger Penrose's words exactly how old it is.
00:05:03.360 So it may as well be the beginning of the universe again and so maybe that's how a big
00:05:07.880 The end of the universe is a mirror image of the very beginning of the universe and this
00:05:12.480 is kind of this Hindu idea of our cyclical universes.
00:05:16.040 Anyway, that could be mere metaphysical, mathematical musings, but we still don't know
00:05:23.200 what went on a certain fraction of a second after the instant in time at which time and
00:05:32.800 What was the thing that precipitated the origins of the universe?
00:05:39.760 This is probably always going to remain an open question.
00:05:42.480 We'll just keep pushing it back, pushing it back, pushing it back a little bit further
00:05:50.520 But even then, we will still ask, what caused that thing to happen?
00:05:54.920 And again, this is just this is just fundamental cosmology.
00:05:59.400 We have unanswered questions in every area of science.
00:06:04.840 But let's go to the beginning of infinity, we're up to the point where David is talking
00:06:08.760 directly about cosmology and he writes, quote, in cosmology, there has been revolutionary
00:06:14.800 progress even in the few years since the end of science was written and also since I wrote
00:06:22.320 At the time, all viable cosmological theories had the expansion of the universe gradually
00:06:26.200 slowing down due to gravity ever since the initial explosion at the Big Bang and forever
00:06:32.960 Cosmologists were trying to determine weather, despite slowing down, its expansion rate
00:06:37.040 was sufficient to make the universe expand forever, like a projectile that has exceeded
00:06:42.320 escape velocity or whether it would eventually recollect in a big crunch.
00:06:47.800 Cosmologists were believed to be the only two possibilities.
00:06:51.520 I discussed them in the fabric of reality because they were relevant to the question, is
00:06:55.200 there a bound on the number of computational steps that a computer can execute during
00:07:01.160 If there is, then physics will also impose a bound on the amount of knowledge that can
00:07:06.400 Knowledge creation being a form of computation, just quickly pausing there, going back, very
00:07:13.160 last phrase there, knowledge creation being a form of computation.
00:07:18.040 The sina conon, the essential part of what a human is without being an essentialist,
00:07:25.000 the essential part of being of what a person is, our explanation for a person is, is a knowledge
00:07:31.320 In particular, an explanation, creator, an explanatory knowledge creator.
00:07:41.920 At least it is a lot of progress beyond anything that has come before.
00:07:46.440 Is a person, a creature that's able to understand morality?
00:07:55.880 Is a person, a creature that is able to do mathematics and art?
00:07:59.760 These were all circling the true, best explanation that we now have, which is that people
00:08:08.800 What David says there is just so important, knowledge creation being a form of computation.
00:08:13.080 I think a few of us have said over the years, the mind is performing computations.
00:08:19.720 It's not an analogy that we know now about the universality of computation.
00:08:25.400 All physical systems out there can be modeled by a universal computer, and that includes
00:08:30.560 I won't go into it again now, but here we have it again in clear black and white, knowledge
00:08:39.080 Everyone's first thought was that unbounded knowledge creation is possible only in a universe
00:08:51.160 However, on analysis it turned out that the reverse is true.
00:08:55.280 In universes that expand forever, the inhabitants would run out of energy, but the cosmologist
00:09:00.040 Frank Tippler discovered that in certain types of reclapsing universes, the big crunch singularity
00:09:05.600 is suitable for performing the faster and faster trick that we used in infinity hotel.
00:09:11.280 An infinite sequence of computational steps could be executed in a finite time before
00:09:15.000 the singularity powered by the ever-increasing title effects of the gravitational collapse itself.
00:09:19.800 To the inhabitants who would eventually have to upload their personalities into computers
00:09:23.800 made of something like pure tides, the universe would last forever because they would be
00:09:27.880 thinking faster and faster without limit as it collapsed and storing their memories in
00:09:31.680 an ever-small of volumes so that access times can be reduced to that limit.
00:09:35.920 Tippler called such universes omega point universes, at the time the observational evidence
00:09:40.000 was consistent with the real universe being of that type, posing their mind reflection.
00:09:43.600 I'm sort of smiling as I read that because this is one of those areas of theoretical
00:09:48.320 physics that it's fun, it's lots of fun, but always in the back of my mind I think well
00:09:54.960 what we're talking about here is literally at least at the time this was written, at
00:10:00.360 least some billions of years hence and these days we're thinking more like trillions of
00:10:04.800 years hence and we talk about the ultimate ends of the universe, whatever that might
00:10:09.960 And we don't know what knowledge is going to be created tomorrow or the next day to overturn
00:10:15.840 So when we're making these grand predictions about such vastly distant times, it kind
00:10:24.960 of is like science fiction because we just don't know what errors have been assumed
00:10:35.520 So fun as it is, I mean every single one of these theories suffers from the same flaw
00:10:42.360 that it cannot possibly be refuted by anyone alive today.
00:10:48.760 This is what Jeremy Lenny here says, well if not anyone alive today, it cannot possibly
00:10:53.680 be refuted by anyone doing an experiment within the next few billion years.
00:10:58.840 So all of them can be on the table, I guess they can be refuted by other observations
00:11:03.600 that we make, but this is the point about making prophecies about the far distant future.
00:11:09.720 They're just fun, they're fun to play with physically mathematically, I guess, as David says
00:11:14.760 in the very next paragraph, quote, a small part of the revolution that is currently overtaking
00:11:20.200 cosmology is that the omega point models have been ruled out by observation, evidence,
00:11:25.760 including a remarkable series of studies of supernovae in distant galaxies, has forced cosmologists
00:11:31.720 to the unexpected conclusion that the universe not only will expand forever, but has been
00:11:36.520 expanding at an accelerating rate, something has been counteracting its gravity, pausing
00:11:43.080 So this is one of the ways that we now talk about a precision cosmology, which is exciting
00:11:51.680 for those of us who kind of studied this, because at the very beginning of my interest
00:11:57.880 in this cosmology, well, we had an understanding of the Big Bang, but that was a bad
00:12:04.800 I mean, we were talking about the grandest scales of the universe were still somewhat
00:12:11.240 That would really happen to the end of the universe, it was very difficult to gather the
00:12:14.560 data needed to be able to constrain the various competing theories.
00:12:22.040 And this particular event, this particular discovery of the accelerating expansion of the
00:12:27.760 universe is burned into my own mind anyway, because I remember it quite clearly being
00:12:33.400 talked about, the buzz that arose at the university and the astronomy department at the
00:12:40.000 University of New South Wales, about 1998, 1999, because prior to everyone sort of had an
00:12:45.920 idea, as David just said, of what should have happened after the Big Bang, namely the
00:12:55.760 And so what happened in 1989, well, there were two competing groups, researchers that
00:13:03.560 were working on high redshift supernova, supernovas that occurred in galaxies, very, very
00:13:12.880 And why were they looking for these things at all?
00:13:15.440 Well, to constrain these models, to figure out what was going to happen to the universe
00:13:21.880 The thing about these kinds of supernova, supernova, one A, and supernova one A are
00:13:27.680 these very rare kind of supernova, where you have some kind of large star, maybe a red
00:13:34.040 giant, in mutual orbit with a white dwarf star, which is much smaller.
00:13:42.000 And the white dwarf stars have an upper limit on their mass.
00:13:46.400 Once you exceed that upper limit, which is called the Chandrasekal limit, the Chandrasekal
00:13:50.680 limit being named after the physicist who calculated it, I think it's 1.38 times the
00:13:57.640 Once the white dwarf star exceeds that number, 1.38 times the mass of the sun.
00:14:03.280 And the repulsion forces of the electrons that are holding the star up, so in other words,
00:14:10.240 you've got atoms buttressed up against other atoms.
00:14:14.040 And the electrons are the only thing, the electron repulsion is the only thing preventing
00:14:19.080 I suppose the quantum physicists were picking up on that and say, well, it's a poly-exclusive
00:14:24.600 But whatever the case, you've got one force outwards trying to prevent the collapse,
00:14:29.000 and gravity inwards trying to cause the collapse.
00:14:35.440 And there is a very sudden collapse of that star via complicated processes.
00:14:42.360 We don't need to go into that then results in a massive explosion, basically because the
00:14:50.160 Now this happens at precisely that 1.38 times the mass of the sun.
00:14:57.880 So as one star, the white dwarf is a creating, collecting matter from that other larger star,
00:15:04.280 it passes that limit and explodes, and these things all explode at the same time.
00:15:09.880 So within our own galaxy, we're not going to see one more than likely, okay?
00:15:15.320 These are so rare that I'm not even sure that we've ever seen one within our galaxy.
00:15:20.760 I think even the supernovae that have hitherto been seen by the unaided human eye that
00:15:27.320 have occurred within a Milky Way weren't even of this sort.
00:15:31.840 So how on earth are these researchers studying these supernovae actually able to see any?
00:15:38.120 And in fact, they did see quite a number of them.
00:15:43.560 Well, rare as they are, galaxies are just so numerous that even if they only happen on
00:15:48.920 average once every million years to a galaxy, well, there are trillions of galaxies out
00:15:54.040 of well, hundreds of billions that we can actually observe.
00:15:57.280 And so if you have the right technology and the right computers and you're scanning large
00:16:01.880 portions of the sky, then you will pick these things up.
00:16:05.240 And this is what these two competing groups of astronomers did.
00:16:09.400 One of the groups was the high-z supernovae project led by Brian Schmidt, who's an Australian,
00:16:16.040 well, at least we can't even as an Australian because he won the Nobel Prize for this,
00:16:20.320 but actually he was born in America, naturalized to be an Australian.
00:16:23.720 He led one group, a very large group of astronomers actually.
00:16:27.240 And they were competing against the supernova cosmology project led by Saul Perlmutter.
00:16:33.160 And both of them were doing basically the same thing, making observations of these supernova,
00:16:39.040 competing in a friendly way, because I think sometimes when cloud cover, obscured the view
00:16:45.720 of the telescopes for one team, the other team would pick up the slack for them.
00:16:52.240 And they knew what to expect to some extent from the results.
00:16:57.160 And what they expected was completely unlike what the results were.
00:17:01.040 And so this was a classic experiment of the kind, a classic experiment of the kind.
00:17:07.080 Because it's an experiment that disagrees with the known theory, the best known theory.
00:17:12.880 And there is no explanation for what is going on.
00:17:15.360 So what was the problem just in very brief what the problem was, was when they looked
00:17:21.280 at these supernovae at the distances they were, at the red shifts that they were, using
00:17:27.360 In other words, you collect the light and then you break up the light into what it's
00:17:32.480 And what it's made out of is called its spectra.
00:17:34.840 The spectra is a consequence of the kind of elements that are in the explosion of the supernova.
00:17:40.840 And so if you burn copper, you get this kind of characteristic bluey green flame.
00:17:44.680 And if you burn iron, you get a red flame, if you get a carbon, you get this characteristic
00:17:49.680 All the same sort of thing happens with stellar spectra.
00:17:52.000 And so you collect the light with a telescope and then you put it through this thing called
00:17:56.640 the spectroscope, which then goes into a computer.
00:17:59.120 And it tells you what the star is made of, that's the first thing.
00:18:02.720 And the second thing is that you can figure out the red shift, which tells you how far away
00:18:07.080 The problem is once they did that and found out how far away the star was using the stellar
00:18:11.920 spectra, the luminosity, the brightness of these high red shift type 1A supernova were
00:18:24.160 But the thing is, the understanding of the astrophysics of the luminosity of type 1A supernova
00:18:29.920 says that it should be extremely reliable and extremely good standard candle, something
00:18:36.800 that has a fixed luminosity, no matter what the distances or anything like that now.
00:18:44.080 Any of us did question the results at first, because of things like, well, the metallicity,
00:18:53.960 in other words, how much material that is heavier than in the very distant universe would
00:19:02.680 have been different, because in the very distant universe, you're talking about the universe
00:19:09.360 And when the universe was much, much, much younger, it hadn't yet had the time to produce stars
00:19:15.320 that contained within them the same kind of elements that we find in our local universe.
00:19:21.520 In other words, what the sun is made out of or what the other stars within the Milky Way
00:19:26.000 galaxy is made out of, these have higher amounts of metal, why?
00:19:30.440 Because the stars have exploded during the explosion, they release the material that's
00:19:36.720 So the next generation of stars then collects up that material and can then burn using
00:19:42.920 And when you look at those stars, you can see the material, you know, contains metals.
00:19:45.840 Now, these very, very distant type 1A supernovas are happening with stars that have
00:19:50.240 appeared much, much, much earlier in the universe.
00:19:53.720 The light is much, much older, which means it was produced so many billions of years earlier.
00:19:59.560 So maybe just maybe the physics of what's going on there, not the physical laws, but what's
00:20:05.080 happening with the kind of material out of which those supernovas are created.
00:20:09.640 Maybe that's a little bit different to what is happening here closer to us.
00:20:15.120 It still could be the case, who knows, and that would be called a systematic error.
00:20:18.720 I think that we don't understand about the astrophysics of stars and in particular type
00:20:27.160 Maybe more distant type 1A supernovas behave differently to closer supernovas, but we
00:20:32.960 can rule that out now because there's a lot of other evidence also pointing out an accelerating
00:20:39.920 expansion of the universe, not least of which is the cosmic microwave background radiation
00:20:44.040 analysis as well, which clever astrophysics can figure out looking at the anisotropies and
00:20:49.880 how large those anisotropies are and so on, to explain those in terms of an accelerating
00:20:57.680 So it's not only a type 1A supernova data that we're relying on right now.
00:21:02.360 And as Saul Perlmutter himself says in an article that he wrote, those high redshift
00:21:09.560 supernova are finer than we would expect, even if the universe was completely empty.
00:21:16.000 So the mathematical models are strongly in agreement with the idea, the hypothesis, that
00:21:28.120 The reasons that we have next to no clue about, and as David says, let's go back to
00:21:34.240 He writes, quote, something has been counteracting its gravity, the gravity of the universe.
00:21:39.160 We do not know what, pending the discovery of a good explanation, the unknown course has
00:21:47.480 There are several proposals for what it might be, including effects that merely give
00:21:50.760 the appearance of acceleration, but the best working hypothesis at present is that in
00:21:56.880 the equations for gravity, there is an additional term of a form first mooted by Einstein
00:22:02.720 in 1915, and then dropped because he realized that his explanation for it was bad.
00:22:07.440 It was proposed again in the 1980s as a possible effect of quantum field theory, but again,
00:22:12.160 there is no theory of the physical meaning of such a term that is good enough to predict,
00:22:16.040 for instance, its magnitude, the problem of the nature and effects of dark energy is
00:22:20.400 no minor detail, nor does anything about it suggest a perpetually unfathomable mystery.
00:22:26.640 So much because knowledge is being a fundamentally completed science, depending on what
00:22:30.560 dark energy turns out to be, it may well be possible to harness it in the distant future
00:22:35.400 to provide energy for knowledge creation to continue forever.
00:22:39.280 Because this energy would have to be collected over ever greater distances, the computation
00:22:45.160 In a mirror image of what would happen in a mega point cosmologies, the inhabitants of
00:22:48.880 the universe would notice no slowdown, because again, they would be instantiated as computer
00:22:52.760 programs whose total number of steps would be unbounded, thus dark energy, which is ruled
00:22:57.280 out one scenario for the unlimited growth of knowledge, would provide the literal driving
00:23:03.240 The new cosmological models describe universes that are infinite in their spatial dimensions,
00:23:08.320 because the big bang happened to finite time ago, and because of the finiteness of the
00:23:11.840 speed of light, we shall only ever see a finite portion of infinite space.
00:23:17.840 But that portion will continue to grow forever, thus, eventually, ever more unlikely phenomena
00:23:25.440 When the total volume that we can see is a million times larger than it is now, we shall
00:23:29.200 see things that have a probability of one and a million existing spaces we see it today.
00:23:34.280 Everything physically possible will eventually be revealed, watches that come into existence
00:23:38.360 spontaneously, asteroids that happen to be good lightnesses of William Hayley, everything.
00:23:43.880 According to the prevailing theory, all those things exist today, but many times too far away
00:23:49.520 for light who have reached us from them yet, pausing their myreflection.
00:23:53.800 So this is, on the assumption that everything that physically possibly can happen, indeed
00:23:59.840 will happen, which is one way of understanding, for example, the multiverse, could be one
00:24:14.000 This assumes, of course, this argument that David has just made there about watches
00:24:19.400 popping into existence and good lightnesses of William Hayley assumes the cosmological
00:24:24.680 principle, the cosmological principle being, on very large scales, the universe is homogenous
00:24:39.880 I don't know that it's something we can derive from more fundamental theories of physics.
00:24:47.520 I think we just assume it logically needs to be the case, and so then this would follow.
00:24:53.920 Constructed theory, of course, may have some new light to shed upon things like this,
00:24:59.480 and the idea that anything that can happen, indeed, will happen.
00:25:04.360 Now, everything might happen just by chance, that's one thing.
00:25:08.920 But then some things might need to be made to happen, even though they're possible we
00:25:16.080 And for more on that, you'll have to go to my series on the Physics of Can and Count, and
00:25:21.240 before that, by the book, the Physics of Can and Count, by Caram, I'll let her.
00:25:25.520 But for now, let's go back to the cosmology here, David writes.
00:25:29.760 Light becomes fainter as it spreads out, there are a few of photons per unit area.
00:25:34.440 That means that ever larger telescopes are needed to detect a given object at ever larger
00:25:40.800 So there may be a limit to how distant and therefore how unlikely a phenomenon we shall
00:25:48.160 Except that is, for one type of phenomenon, a beginning of infinity.
00:25:51.920 Specifically, any civilization that is colonising the universe in an unbounded way will eventually
00:25:58.480 This is a single infinite space, could play the role of the infinitely many universes
00:26:03.160 postulated by anthropic explanations of the fine-tuning coincidences.
00:26:10.720 If the probability that such a civilization could form is not zero, there must be infinitely
00:26:15.720 many such civilizations in space, and they will eventually encounter each other.
00:26:20.800 If they could estimate that probability from theory, they could test the anthropic explanation.
00:26:25.760 Furthermore, anthropic arguments could not only dispense with all those parallel universes
00:26:30.040 that could dispense with the variant laws of physics too, just causing that, David does
00:26:34.320 have a note here that when he says, those parallel universes, he's talking about universes
00:26:39.920 This is not the quantum multiverse, completely different, completely different.
00:26:46.400 The multiverse in the quantum theory explanation is, all the universes are by exactly the
00:27:00.600 But this is kind of megaverse idea used in anthropic arguments where we have the concept
00:27:13.040 And as I say, I'll speak into a researcher today who does simulations of this kind of thing.
00:27:19.640 And has very interesting ideas about, for example, fiddling with the knobs of the constants
00:27:27.160 So for example, the gravitational constant G, the fine structure constant, the cosmological
00:27:32.600 constant, these things, you can fiddle with the values of these things, and then see
00:27:38.080 And most fiddling of the constants result in featureless universes.
00:27:44.880 Some he was saying don't cause the extinguishing of life very easily, but some do cosmological
00:27:53.720 constant gravitational constant, for example, have huge effects on either formation of galaxies
00:28:00.160 Now, the interesting thing then, which I wasn't aware of, because I know these simulations
00:28:04.320 done simulating entire universes, universes with different laws in a sense, namely the
00:28:11.520 values of the constants are different, but keeping everything else the same.
00:28:16.160 What the researchers cannot yet do, which I asked about, can you simulate universes with
00:28:25.040 entirely different laws of physics in the sense that, well, let's not have general relativity,
00:28:33.160 Let's not have quantum theory, let's have something completely different.
00:28:37.520 This is not possible at the moment, it's not feasible at all.
00:28:42.920 He was saying, well, if you wanted to change the law of gravity, then you would need
00:28:47.600 to redo stellar physics, stellar nuclear synthesis, for example, using that new theory.
00:28:55.600 So that's a whole other thing that the simulation would need to be able to cope with.
00:28:59.360 So they're not even there, the best they can do now, clearly this is really just merely
00:29:04.560 scratching the surface, of trying to figure out could life exist in universes with
00:29:11.040 All they're doing is fiddling with the constants of nature and keeping everything else
00:29:16.400 In other words, the laws of physics have exactly the same form, it's just the coupling
00:29:23.840 And so getting interesting results out of that.
00:29:26.680 The interesting result is almost all choices, other than the selection of constants that
00:29:32.640 we do have, result in a sterile universe, that's an interesting enough result.
00:29:36.680 But it's certainly not putting paid to this idea that if there is a megaverse out there,
00:29:41.360 there could be infinite civilizations out there, there could be.
00:29:46.360 I don't believe this, I don't think anyone should believe this.
00:29:49.680 No one knows this, it's just completely conjectural right now.
00:29:54.760 We have no way of constraining any of these theories, really.
00:29:59.680 We don't have an answer to the fine-tuning problem.
00:30:03.200 This is why we're very much at the beginning of infinity as far as this question is concerned.
00:30:07.720 Okay, so I'm skipping a bit that David writes here, you'll have to go to the book yourself
00:30:14.440 And I'll skip to where he talks about the Fermi problem.
00:30:17.400 So he's just finished describing some aspects of the issue with fine-tuning and we've
00:30:22.840 reported solutions to fine-tuning and namely the Antropic argument.
00:30:31.240 Nor therefore can it solve the Fermi problem, where are they?
00:30:35.200 It may turn out to be a necessary part of the explanation, but it can never explain anything
00:30:40.120 Also, as I have explained in chapter 8, any theory involving an Antropic argument must
00:30:45.400 provide a measure for defining probabilities in an infinite set of things.
00:30:50.640 It is unknown how to do that in the spatially infinite universe that cosmologists currently
00:30:58.960 For example, there is the so-called quantum suicide argument in regard to the multiverse.
00:31:07.160 You buy a ticket and set up a machine that will automatically kill you in your sleep
00:31:10.520 if you lose, then in all the histories in which you do wake up, you are a winner.
00:31:15.640 If you do not have loved ones to warn you, there are other reasons to prefer that most
00:31:18.960 histories not be affected by your premature death.
00:31:21.600 You have a range to get something for nothing with what proponents of this argument call
00:31:26.840 However, that way of applying probabilities does not follow directly from quantum theory
00:31:33.720 It requires an additional assumption, namely that when making decisions, one should ignore
00:31:38.200 the histories in which the decision maker is absent.
00:31:43.680 Again, the theory of probability for such cases is not well understood, but my guess
00:31:48.280 is the assumption is false, pausing their myreflection.
00:31:51.800 Yes, so this quantum suicide idea that if you commit suicide, you should expect as a
00:31:58.240 matter of probability within the multiverse that you will wake up tomorrow.
00:32:05.480 My way of understanding this is, no, a version of you will wake up, but that is not you.
00:32:11.960 We have talked about this before, and I did recently an episode called the Nexus, which
00:32:18.600 is where I think that the strength of the fabric of reality, everything that is in the
00:32:23.440 beginning of your infinity, really, brought together really our best to provide the
00:32:29.760 best explanation for what a person is, and that is why I called the Nexus, this mixing
00:32:33.280 of the threads of the fabric of reality give us a better understanding of what a person
00:32:38.840 And in that, I was trying to understand the nature of personhood in the context of the
00:32:43.560 multiverse, knowing that we consist of infinitely many fungible instances right now.
00:32:49.960 So sitting here right now, continuing to speak to you, many fungible instances of myself.
00:32:56.760 And right now, some portion of them, some measure of them, have gone off to get a cup
00:33:03.840 of tea and do a variety of other things as well, but there remains a set of fungible
00:33:10.960 Now, I'm not conscious of those other versions, right?
00:33:16.080 Now, if I arrange to have myself killed in my sleep, how does consciousness deal with
00:33:24.880 Are you extinguishing a particular consciousness forever and for good and allowing another
00:33:31.000 There's no guarantee that it's you and this is why David says, you can't ignore the
00:33:34.960 histories in which the decision maker is absent, okay?
00:33:41.880 We know, as a matter of fact, that people die in our universal the time, we can see them
00:33:47.280 Now, some versions of them then go on to exist, all right, but we're not observing those.
00:33:51.880 Why should you think that you're going to be the observer of the version that survives?
00:33:57.120 There is no good argument for this is why I think that something also survives.
00:34:00.920 Something will survive, possibly given our best understanding of quantum theory now.
00:34:09.920 I think the quantum immortality thing, quantum suicide thing, it doesn't run through.
00:34:15.360 And I think all it says that we've got a lot that we don't understand here.
00:34:20.800 This is another flag like dark energy for a problem.
00:34:29.560 So given that, you know, we shouldn't, we shouldn't go trying to play the lottery in this
00:34:35.440 Okay, let's go back to the book because we're about to talk about one of my favorite
00:34:43.040 A related assumption occurs in the so-called simulation argument, his most cogent proponent
00:34:49.880 It's premises that in the distant future, the whole universe, as we know, it is going to
00:34:53.800 be simulated in computers, perhaps for scientific or historical research.
00:34:58.160 Many times, perhaps infinitely many times, therefore virtually all instances of us are in
00:35:04.560 those simulations and not in the original world.
00:35:06.920 And therefore, we are almost certainly living in a simulation.
00:35:10.880 So the argument goes, but is it really valid to equate most instances with near certainty
00:35:17.640 For an inkling of why it might not be, consider a thought experiment.
00:35:21.920 Imagine that physicists discovered that space is actually many layered like puff pastry.
00:35:27.000 The number of layers varies from place to place.
00:35:30.120 The layers split in some places, and they're content split with them.
00:35:37.040 Hence although we do not feel it, instances of us split and merge as we move around.
00:35:42.480 Supposed in London, space has a million layers while an Oxford only has one.
00:35:46.840 I travel frequently between the two cities, and one day I wake up from having forgotten
00:35:54.160 When I bet I am much more likely to be in London, just because a million times as many instances
00:35:59.120 of me ever wake up in London as in Oxford, I think not.
00:36:03.440 In that situation, it is clear that counting the number of instances of oneself is no
00:36:07.120 guide to the probability one ought to use in decision making.
00:36:10.760 We should be counting histories, not instances.
00:36:13.760 In quantum theory, the laws of physics tell us how to count histories by measure.
00:36:18.120 In the case of multiple simulations, I know I've no good argument for any way of counting
00:36:22.600 One question, but I do not see why repeating the same simulation of me a million times
00:36:27.960 should in any sense make it more likely that I am a simulation rather than the original.
00:36:32.400 What if one computer uses a million times as many electrons as another to represent each bit
00:36:38.520 Am I more likely to be in the form of computer than in the latter?
00:36:41.880 A different issue raised by the simulation argument is this, will the universe as we know
00:36:51.360 The world as it exists today contains an enormous amount of suffering.
00:36:55.800 And whoever ran such a simulation would be responsible for recreating it.
00:37:00.440 A two identical instances of a quaille, the same thing as one, if so, then creating
00:37:04.880 the simulation would not be immoral, no more than reading a book about past suffering
00:37:09.520 But in that case, how different do two simulations of people have to be before they
00:37:15.800 Again, I know I've no good answer to these questions.
00:37:19.080 I suspect that they will be answered only by the explanatory theory from which AI will also
00:37:28.080 Yes, so David has mentioned this before, all the way back in a window on infinity and
00:37:33.760 the earlier chapter, the problem with trying to count infinities.
00:37:39.200 And then if you have these universes with different physical laws, you have an uncountable
00:37:46.240 infinity. And if you're thinking of this fractal type situation, where in the distant
00:37:51.080 future, there's going to be civilizations that will have computers in which there will
00:37:55.160 be simulations of people who have computers, in which there are going to be simulations
00:37:59.880 and so on and so on and so on, just fractally expanding out.
00:38:03.560 There's no way of counting these and so we don't even know what the nature of consciousness
00:38:08.200 And by the way, our best understanding of physical reality that we occupy right now, as we've
00:38:12.000 already said, is that you are infinitely many fungible instances already, which can't
00:38:18.000 And so in what sense are those more numerous and you, what are you, like David's giving
00:38:24.200 a hint here, if the simulated versions of you are not infinitely many fungible instances,
00:38:29.960 but are based upon some other kind of simulations of laws of physics, which nevertheless
00:38:36.640 Well, we've done experiments here to show that we live in a universe that is governed
00:38:42.600 by the laws of quantum theory, which mean that you, as a person, aren't a single instance.
00:38:48.680 But maybe those simulated, the most efficient way, the most efficient way of simulating
00:38:54.240 people in those computers, is single instance people.
00:39:02.760 But we know that we're not single instance people, we're uncountably infinitely many.
00:39:07.040 So maybe we already outnumber even that number of infinitely many people being simulated.
00:39:13.080 I wonder why, well, he wouldn't have known, Nick Bostrom didn't take into account this
00:39:17.840 idea of the multi-verse already that we live in a multi-plus, of course, not many people
00:39:24.640 And philosophers should, analytic philosophers should, okay, skipping a little, and let's
00:39:29.640 go to a little bit more about Bostrom and David Wright here.
00:39:34.320 And even more dubious example of anthropic type reasoning is the doomsday argument, it
00:39:39.640 attempts to estimate the life expectancy of our species by assuming that the typical human
00:39:44.960 is roughly half way through the sequence of all humans.
00:39:49.080 Hence we should expect the total number who will ever live to be about twice the number
00:39:57.280 And for that reason alone can it possibly be a valid argument, but let me briefly pursue
00:40:03.080 First, it does not apply at all if the total number of humans is going to be infinite.
00:40:08.440 For in that case, every human who ever lives will live unusually early in the sequence.
00:40:13.520 So if anything, it suggests that we are at the beginning of infinity.
00:40:19.520 Illness and old age are going to be cured soon, certainly within the next few lifetimes,
00:40:24.080 and technology will also be able to prevent deaths through homicide or accidents by creating
00:40:28.480 backups of the states of brains, which could be uploaded into new blank brains in identical
00:40:35.280 Once that technology exists, people will consider it considerably more foolish, not to
00:40:40.200 make frequent backups of themselves than they do today in regard to their computers.
00:40:44.560 If nothing else, evolution alone will ensure that because those who do not back themselves
00:40:50.400 So there can be only one outcome, effective immortality for the whole human population, with
00:40:55.280 the present generation being one of the last that will have short lives.
00:40:59.320 That being so, if our species will nevertheless have a finite lifetime, then knowing the
00:41:04.200 total number of humans will ever live, provides no upper bound on that lifetime, because
00:41:09.040 it cannot tell us how long the potentially immortal humans of the future will live before
00:41:16.440 In 1993, the mathematician Werner Vinci wrote an influential essay entitled The Coming
00:41:22.840 Technological Singularity, in which he estimated that, within about 30 years, predicting the
00:41:28.040 future of technology will become impossible, an event that is now known simply as the
00:41:34.000 Vinci associated the approaching Singularity with the achievement of AI and subsequent discussions
00:41:39.800 I certainly hope that AI, for which David means AGI, is achieved by then, but they see
00:41:45.960 no sign yet of the theoretic progress that I have argued must come first.
00:41:50.560 On the other hand, I see no reason to single out AI as a mold-breaking technology.
00:41:58.600 Most advocates of the Singularity believe that, soon after the AGI breakthrough, super-human
00:42:04.040 minds will be constructed, and that then, as Vinci put it, the human era will be over.
00:42:09.560 But my discussion of the universality of human minds rules out that possibility.
00:42:15.360 And humans are already universal explainers and constructors.
00:42:18.480 They can already transcend their parochial origins, so there can be no such thing as a superhuman
00:42:24.640 They can only be further automation, allowing the existing kind of human thinking to be
00:42:29.120 carried out faster, and with more working memory, and delegating perspiration phases to
00:42:35.560 A great deal of this has already happened with computers and other machinery, as well
00:42:39.040 as with the general increase in wealth, which has multiplied the number of humans who are
00:42:47.840 For instance, there will be evermore efficient human computer interfaces, no doubt culminating
00:42:54.480 But tasks like internet searching will never be carried out by superfast AI as scanning
00:42:59.440 billions of documents creatively for meaning, because they will not want to perform
00:43:05.040 Any more than humans do, nor will artificial scientists, mathematicians, and philosophers
00:43:09.040 ever wield concepts or arguments that humans are inherently incapable of understanding,
00:43:14.000 universality implies that in every important sense humans and AI's will never be
00:43:20.840 Similarly, the singularity is often assumed to be a moment of unprecedented upheaval and
00:43:24.920 danger as the rate of innovation becomes too rapid for humans to cope with, but this is
00:43:31.200 During the first few centuries of the Enlightenment, there has been a constant feeling that
00:43:34.520 rapid and accelerating innovation is getting out of hand, but our capacitor to cope with and
00:43:38.640 enjoy changes in our technology, lifestyle, and ethical norms, and so on, has been increasing
00:43:42.960 too, with the weakening and extinction of some of the anti-rational memes that used to
00:43:48.000 In future, when the rate of innovation will also increase due to the sheer increasing
00:43:51.840 clock rate and throughput of brain add-ons and AI computers, then our capacity to cope
00:43:56.640 with that will increase at the same rate or faster.
00:44:00.280 If everyone was suddenly to think a million times as fast, no one would feel hurried as
00:44:05.200 Hence, I think that the concept of the singularity as a sort of discontinuity is a mistake.
00:44:10.200 Knowledge will continue to grow exponentially or even faster, and that is astounding
00:44:14.040 enough, pausing there, ending the reading there for today because it's a wonderfully positive
00:44:21.520 This singularity, by the way, if you want some more eviscerating critique of it, I think
00:44:28.000 that's as strong as you can get anywhere, but a slightly different approach to it, the
00:44:31.480 computer scientist, Jaron Lanier, J-A-R-O-N-L-A-N-I-E-R.
00:44:38.920 He is far too unknown, he's known amongst a certain community of people, but he deserves
00:44:47.160 to be like David Deutsch, far more well-known than what he is, and the German Lanier
00:44:51.960 has an additional kind of handicap in that he doesn't like social media, and so he refused
00:44:59.440 He finally has wonderful talks that he gives on YouTube, and his books are absolutely brilliant,
00:45:04.560 and he similarly doesn't agree with the bostromes and the Ray Kurzweils and the Vernavinges
00:45:12.320 of the World on this point about Doomsday and Singularity, and we're going to upload ourselves
00:45:20.760 He admits of the mystery of human consciousness, for example, in a slightly different way
00:45:28.560 I think we're going to hear them have a conversation, but here, this whole idea, the singularity,
00:45:33.240 there's going to be this sudden take-off of technology.
00:45:38.360 And like David says, the psychological impact of this is, well, apart from the doomsday
00:45:43.160 as the naysayers, the pessimists have always been with this, you know, they've complained
00:45:46.400 about the invention of the motor vehicle, the television, or the telephone, the book, okay.
00:45:53.680 It's a great Twitter account, pessimists archive where they reproduce very old newspaper articles
00:46:01.320 of people complaining about things like books, and how books are ruining children, ruining
00:46:07.320 their lives, and then of course that moved on to radio is ruining children's lives, and
00:46:11.000 television is ruining children's lives, and of course today it's not just computers, but
00:46:15.280 in any piece of technology is ruining children's lives.
00:46:18.440 We've always had the pessimists trying to tell us that technology is bad for us, but we can't
00:46:23.600 handle it, and there is this zeitgeist now that people aren't handling the technology
00:46:28.840 particularly well, but, you know, with every solution comes new problems, would you rather
00:46:33.960 be out in the field scratching the existence out of the dirt as, you know, Neanderthal people
00:46:41.080 We have some problems with technology today, but there are a heck of a lot better than
00:46:44.880 the dealing with the problems that they solved.
00:46:48.000 Also mentioned there is you can't have AI being super intelligent and taking over all
00:46:51.920 of our tasks, especially not the creative ones, because they'll be people, super intelligent
00:46:58.400 narrow AI, you know, AI that's super intelligent in the sense that it can beat us at
00:47:04.040 Never wants to choose to do anything other than chess, and so it's not a threat to us.
00:47:08.880 For more on this, see my articles at www.brethall.org about super intelligence, where I
00:47:15.720 take Nick Boschtrim's view of super intelligence, whose book, super intelligence, I think
00:47:21.400 it's, I was disappointed in it, more than the fact I didn't like it, since I kind of
00:47:31.560 liked it because it read like a science fiction book, and I listened to the audio, and whoever
00:47:35.600 reads the audio, they sound a bit like a robot, so it's a little bit scary, but they're
00:47:39.640 in that uncanny valley where they're quite they're human, but just a little bit like Nick
00:47:45.300 Boschtrim decides to, that's very cruel, no, Nick Boschtrim's obviously extremely
00:47:50.640 intelligent, but the book for me was disappointing because I was expecting to be blown
00:47:55.400 away by the precision of the philosophy, but in fact it was the philosophy in the epistemology
00:48:01.840 that was the weakest part of the book, and it was upon this foundation that rested all
00:48:06.760 the pessimism, so once you get the epistemology wrong, the pessimism just flows naturally
00:48:11.440 from these ridiculous ideas about how Bayesianism, and this is what really turned to me
00:48:16.040 off Bayesianism, I think it was, so I had to credit Nick Boschtrim for inspiring me to
00:48:19.960 really research the depth of Bayesianism and realizing the poverty that the epistemology at
00:48:25.360 the heart of what Bayesianism is all about, and so if you just take on Popper's conception
00:48:31.160 of epistemology, you don't get these pessimistic ideas about AI and doomsday and so on
00:48:37.080 It's no accident that the pessimists are prophets with bad epistemology, it's an awful
00:48:44.680 trinity of misconceptions that go together there to all self-support one another, just take
00:48:53.440 on the right epistemology, and you'll no longer be tempted to make prophecies, you'll
00:48:59.360 admit of your ignorance, on the one hand, and then realize that there's hope for the future
00:49:04.320 in being able to solve any problem using creativity.
00:49:08.240 Okay, next time we'll be, sadly to some extent, the final episode on the beginning of
00:49:15.680 infinity, I'll probably do that from somewhere else, a slightly nicer different location,
00:49:20.960 I think, I'll have to think of ways in which I can make the final episode, something different,
