I’m reading Our Mathematical Universe (2014), by Max Tegmark, and I’ll post about the book when I finish. However he got my attention early with the topic of eternal inflation. That got me thinking about how there are some key unanswered questions regarding the Big Bang and inflation of the non-eternal sort.
Inflation certainly does need some explaining. It may be related to dark energy, as both seem to do the same sort of thing (push space apart). The putative physics of inflation is bad enough; eternal inflation is (in my view) fairy tale physics.
For one thing, eternal? Seriously? Infinite something from nothing?
It’s hard enough to justify something from nothing in the first place. The idea this entire universe sprang from nothing is hard to swallow, but appears to be a fait accompli.
Infinite universes we can’t observe is a whole other level of story telling.
The inflation story makes some sense once one accepts an axiom: A smaller-than-an-atom speck of, as Tegmark puts it, hard to dilute matter came to exist.
The consequence of such matter, once it exists, is enormous pressure driving the matter to expand. The hard to dilute part means it quickly doubles in size without noticeably reducing its density.
This means it will double again. And again. Until it reaches the point it finally does dilute enough that density drops, and the period of rapid inflation ends.
If we can accept such magic matter, inflation makes sense. Note this special matter doesn’t expand into space, it expands to become space and everything in it.
Which you can see leaves a lot of unanswered questions and unknown physics. Not everyone agrees inflation is correct, although it does answer some questions the Big Bang alone cannot. I’ll come back to that.
Eternal inflation says that inflation never stops, it continues forever outside our universe where it creates an infinite number of new “bubble” universes (Tegmark’s Type II multiverse).
In this scenario, specks of “inflatronium” (my term, not Tegmark’s) freeze out and turn into expanding bubble universes. It’s perhaps a bit like how yeast creates air bubbles in rising bread dough.
Effectively, normal inflation involves a bit of weird matter appearing and blowing up into a universe, whereas eternal inflation involves infinite weird matter already existing and spawning infinite universes.
If any of that offends your sensibility, you’re certainly not alone, but sensibility can’t be our guide. We can certainly wonder about some things, though.
Question: Was there a Big Big Bang that created the inflatronium? Tegmark seems to suggest so, but doesn’t go into details. Are there two things: the BB Bang and an infinite number of B Bangs?
Question: In the bubble, there is a brief time of inflation, which ends. Outside the bubble, there is eternal inflation, which doesn’t. Two things again?
Question: Why does a bubble universe form from expanding inflatronium? What causes the speck to freeze out? Is the speck different from the base?
Question: What is the difference between the physics of the greater spacetime inflatronium inhabits and the physics in our bubble?
Question: Is this inflatronium a perpetual motion machine? Not just running forever, but creating an infinite number of new things?
There now seem two creation events to account for: The creation of inflatronium and the creation of bubble universes. There are also a number of infinities to account for: eternal inflatronium and the infinite space it’s creating, an infinite number of universe bubbles, and (apparently) infinite space inside each bubble.
My point is that it’s one thing to accept the idea of a speck of über-matter springing into existence, blowing up until it dilutes, and then coasting thereafter on the energy of the bang.
It raises a lot of questions, but there are observational facts about the universe that need a story explaining them, and the Big Bang story does fit the bill rather well.
(And I’m certainly not the first to observe the parallels with Genesis 1 in the Bible. As a childhood astronomy and physics geek, I always thought “Let there be light!” sounded an awful lot like the Big Bang story.)
It’s another proposition entirely to accept infinitely expanding matter spawning an infinite number of infinite universes. Not saying it’s wrong, just that, at least in my view, it’s a much bigger ask.
(As an aside, Tegmark’s Type I universe requires our bubble universe be infinite in size, and I’m just not sure that’s right. Give how much of his argument rests on [A] our infinite Type I universe, [B] infinite Type II universes from eternal inflation, and [C] infinite universes from MWI, his arguments seem on a superposition of shaky ground and thin ice. I’m not a believer in infinite.)
((All this infinite stuff seems to violate the rule of parsimony. The Type I and Type II infinities don’t even have the Everett Excuse of “just following the math, boss!”))
One thing that makes inflation attractive is that it explains why the Cosmic Microwave Background (CMB) is so uniform.
Under a non-inflationary Big Bang scenario, there isn’t time for energy in the universe to equalize, so under such a scenario, it’s thought there should be much more variation in the temperature of the CMB. This is called the horizon problem.
It’s also hard to understand why observations indicate space seems to be extremely flat. But theory indicates that level of flatness is like balancing on a razor — it requires forces cancelling to 120 decimal points to balance. This is called the flatness problem.
The notion that the universe underwent a brief period of rapid expansion solves both problems rather neatly.
In the first case, the universe was much smaller and able to equalize before it blew up hugely fixing that even temperature. In the second case, the rapid expansion flattened space just like the surface of an expanding balloon seems flatter and flatter to an ant on its surface.
I wonder if the first case gets it slightly wrong. I wonder if the evenness of the CMB is simply from the universe being very uniform at first.
There is a perception the universe must have started with very low entropy, because our observation is that entropy always increases. Therefore it had to be lower in the past and lowest at the beginning.
Perhaps the assumption things needed to mix in the beginning is incorrect. Perhaps the original speck of matter was as uniform, as low in entropy, as matter can be. So it’s not at all surprising the CMB is so even.
In fact, it was only in the expansion of space that quantum uncertainty allowed variation — variation that ultimately led to stars and galaxies.
Bottom line, this undermines the notion that inflation is needed to account for the evenness of the CMB — which, in turn, undermines the notion of inflation.
If the observed flatness of the universe can be otherwise accounted for (maybe it just is that way), the notion of inflation is further undermined. It’s important to understand that inflation is a story about the past that accounts for what we see now. Another story might be more correct.
Which is all to say that, if inflation is not demonstrable fact, then eternal inflation is on even shakier ground. And given its (literally) expansive nature, it has to be seen as a whole other proposition.
All of which is very idle speculation on my part. What’s interesting is how it connects with another idea I’ve read about recently.
I’ve written before about the stark difference between countable numbers and uncountable numbers. I’ve also written about how it’s possible reality doesn’t use the real numbers (the uncountable ones).
If that were true, it would eliminate strict determinism. It would make the future definitely and truly unknowable.
I’ll blog about this in the future, but I read an article about a mathematician exploring the idea that the real numbers aren’t real — that reality uses rational numbers.
A core idea here is that infinite precision of a numeric value represents infinite information — which is questionable. There is only so much information that can be contained in a given area.
I need to read the article again and maybe look deeper into the idea, but I was really struck by how it fit in with the ideas I’ve played with recently.
Stay banging big, my friends!
April 26th, 2020 at 9:13 am
I’ll say that, especially after reading Baggott’s book, Tegmark’s book is hard for me to read because of all the hand-waving. It’s bad enough his full embrace of MWI without addressing any of its big questions, but he’s talking about how he’s unified Type I (infinite visible horizon bubbles in our universe) and Type III (MWI) multiverses. He apparently thinks it solves the probability problem.
It’s taken me quite a few sittings to get halfway through. It might be a while before I can post on it.
April 26th, 2020 at 9:23 am
Great post 😁
April 26th, 2020 at 9:26 am
Thank you! 😉
April 26th, 2020 at 3:26 pm
I’m surprised to see you reading this book. Tegmark is definitely not in the Baggott, Woit, Hossenfelder camp. He’s definitely willing to put on his speculation hat. And I do think he exudes far too much certitude in those speculations.
It’s been several years since I read it. I recall levels 1-3 each being plausible extrapolations of accepted assumptions. For example, if space is flat and infinite, then Level 1 seems to fall out. If inflation is true and didn’t just start before the big bang, then Level 2 can be a consequence. And, of course, Level 3 is MWI along with all its controversies. All of these assume that the purported structures continue unchanged beyond our observable horizons, any of which could be thrown by future discoveries.
But I found his explanation of how Levels 1 and 2 were compatible confusing. I had to dig up Brian Greene’s book on multiverses to get it straight.
Level 4 didn’t really work for me. He just assumes that mathematical platonism is reality. He’s free to do that, but it seems like I’m free not to. I see no real necessity. It seems like metaphysics without even a tenuous connection to science.
Still, I found it interesting reading.
April 26th, 2020 at 4:51 pm
“I’m surprised to see you reading this book.”
Ha! 🙂 It’s just that I like to fully understand all sides of an issue. (Put it this way: I won’t rejected something unless I know exactly what I’m rejecting. 😉 )
That’s why I got a copy of Everett’s paper that started the whole MWI thing. I want to know what he really said. (What’s funny is that people go on about how Everett didn’t really say there were multiple worlds, and yet his paper is titled The Many-Worlds Interpretation of Quantum Mechanics, so I’m not sure why people go on like that.)
“I do think he exudes far too much certitude in those speculations.”
That is exactly the problem, and it’s certainly Baggott’s point. (I think Hossenfelder and Woit take it a step further in pointing to how this happens, this getting “lost in math” or fantasy. (I was going to buy Sabine’s book, but then I realized I’d heard all her arguments repeatedly on her blog. 😮 ))
“For example, if space is flat and infinite, then Level 1 seems to fall out.”
Yes, if space is infinite, then Level I is a direct consequence. If is the key word there. And it has to be truly infinite, not infinite but bounded like the surface of a sphere or torus.
“If inflation is true and didn’t just start before the big bang, then Level 2 can be a consequence.”
If inflation is  true,  existed before our BB,  presumably had a BBB of its own,  is eternal in time and  infinite in space… then there could be other bubble universes, sure, you betcha.
Which, despite starting from the same stuff with meta-laws applicable to all universes, can have emergent laws that differ between bubbles. The physics constants, the “dials” of the bubble universe can vary between bubbles. (Whereas all Type I universes have the same laws.)
As you say, these are, almost by definition, out of reach to us. (Except that some Type III universes interfere with each other until they don’t anymore.)
“But I found his explanation of how Levels 1 and 2 were compatible confusing.”
It’s Types I and III that he unifies. There being (supposedly) infinite copies of us in worlds with similar laws, so any MWI splitting can be viewed as happening in two distinct universes separated by (lots and lots of) space. Those worlds just happened to be identical up to the point they “split”.
Note this requires true infinity. The odds of identical parallel universes are numbers we really can’t wrap our heads around. The size required to guarantee finding duplicates is even harder to visualize.
As an illustration, I have a file with 10,000,000 digits of pi. There’s a formula that gives the max length of a digit string guaranteed to be found given X number of random digits. If I recall, it’s five here, and I’ve tested and found all possible five-digit strings in those digits of pi.
So the math is right in that, if you have enough universes, you will have duplicates, and you will have duplicates up to any given point where they’ll branch as if in an MWI split. But you have to have an truly infinite number of distinct worlds in the infinite realms of our Type I universe.
“He just assumes that mathematical platonism is reality.”
Yep. Funny thing is, it’s the only way MWI really makes any sense because MWI says essentially the same thing: the wave-function isn’t just real, it’s the only reality. MWI really is a Tegmarkian view to begin with.
(I met a guy long ago who believed in MWI before it was popular. He said I’d figure he was crazy, but I’d already heard of MWI by then. But his argument to the energy problem was saying how SQRT(4) has two answers and other math has lots of answers to one equation. No one blinks an eye at that. Which was a quintessentially Tegmarkian argument.)
April 26th, 2020 at 6:11 pm
On Everett’s paper, my understanding is that the “Many Worlds” name was coined by Bryce DeWitt several years later. There are multiple versions of Everett’s paper, some of which might have the “Many Worlds” title appended to it. But the original title was something like “A Theory of the Universal Wave Function”.
Everett’s advisor, John Wheeler, was trying to get Niels Bohr’s approval, so the original published version had a lot of controversial aspects pulled from it. I think Everett put out a “director’s cut” several years later which included the parts Bohr couldn’t tolerate. (In the end, Bohr couldn’t tolerate any of it anyway.)
Anyway, I’ll be curious what you find in it. (I’ve never dug it up since I assume it would be greek to me.)
On Levels 1 and 2, my confusion was how there was room for Level 2 if Level 1 was reality. The answer involves some weird topological stuff that I only recall Tegmark alluding to, but that Greene explained much more clearly.
I do remember Tegmark saying he’d reconciled Levels 1 and 3 mathematically. What I was talking about is separate from that. Interestingly, I also recall him saying he tried to reconcile 2 and 3 but couldn’t. I read this with interest, because it occurred to me that MWI could be what happens in a bubble when inflation stops, that the inflation ends up being redirected or transformed. I figured it was just amateur speculation on my part, but I’ve since read some physicists think the same thing, although I haven’t heard of anyone finding actual mathematics for it.
I actually don’t think the MWI requires Tegmark’s ideas to be true. It only requires that the Schrodinger equation is a complete description of the quantum system. Admittedly there are affinities between the ideas.
April 26th, 2020 at 6:51 pm
Ha! Good call, you’re right, I was fooled by the cover sheet. You hit it almost exactly: The Theory of the Universal Wave Function I searched, and the phrase “many-worlds” appears only in that cover sheet. 😀
(I think it turns out it’s still an inescapable conclusion, though.)
I’m aware of much of the history. As I understand it, Wheeler ultimately turned away from the idea, and it’s hard to know what to make of what happened to Everett. I’ve only just started on his paper, but if anything strikes me I’ll post about it.
“The answer involves some weird topological stuff…”
Yeah, for something so central to his argument Tegmark doesn’t do much to support how there’s room for infinite size bubbles in infinite inflating meta-space. It’s been a while since I read Greene (whom I now find equally uncritical and even evangelical), but it wouldn’t surprise me he gets more into the topological stuff. For a mathematician, Tegmark can be weirdly un-mathy. Maybe just because it’s a pop science book.
Tegmark does say both Type I and Type II universes share the same spacetime, so it’s hard to understand how some weird topology works in that context. Our universe, at least, seems flat, so if it’s infinite…
“I do remember Tegmark saying he’d reconciled Levels 1 and 3 mathematically.”
Yeah, he says mathematically, but it apparently involves a calculation of the Schrödinger equation for the entire macro system of that quantum card experiment. I didn’t think we understood macro systems at that level such that would could write Schrödinger equations for them.
And his argument is based on both Type I and III being infinite.
The whole thing is an answer to the probability problem, but I don’t see that it does answer it (and Tegmark ignores this aspect). It’s still true under (any form of) MWI that even the most improbable events always happen to someone. There is a reality where everything does happen. Somewhere someone is always really surprised.
In a single world, highly improbable events only happen rarely.
You’re right he tried to reconcile Types II and III but failed. I assume one issue is the potential for different emergent laws. Any splitting has to occur at the beginning of time.
“I actually don’t think the MWI requires Tegmark’s ideas to be true. It only requires that the Schrodinger equation is a complete description of the quantum system.”
Well, a big bullet point in the MWI argument is: “We take the Schrödinger equation seriously!” 😀
What I’ve said is that MWI makes sense in a Tegmarkian universe. That would answer a lot of the physical objections (energy, probability, etc) to the theory. That was how that guy I knew justified his belief in something part of his own thinking told him was irrational.
April 26th, 2020 at 7:50 pm
You made me fish out Everett’s paper, just out of curiosity. Scanning it, it does like look it gets very mathematical, but I saw readable sections. The opening section, and the chapter on observation look interesting. I might have to look at them.
On how Type I fits within Type II multiverses, I actually once took a shot at it.
(Scanning it now, the key thing is how time is different inside the bubble vs outside in inflationary space.)
On MWI and Tegmarkian universe, sorry, I missed some nuance there.
April 26th, 2020 at 8:01 pm
Missed some nuance in the connection? Still missing?
April 26th, 2020 at 8:14 pm
I responded as if you had said that MWI required a Tegmarkian universe, but you noted you only said it made sense in that universe, a personal judgment rather than the statement of logical necessity I took it to be.
April 26th, 2020 at 8:28 pm
MWI doesn’t absolutely require a Type IV universe, but it raises serious questions without it. (Serious enough that neither Sean Carroll nor Max Tegmark have answers. At the very least, that means the theory isn’t fully fleshed out.) On the other hand, MWI seems almost a consequence of a Type IV universe if the Schrödinger equation is a part of that mathematical framework.
Which, to the reductionist extent quantum physics governs all, implies it has to exist. If it’s all QM, it’s almost the only thing that has to exist, which directly equates Type IV and MWI. I think this strongly implies the reverse relationship, that MWI begs for a Type IV universe to make sense.
Or,… neither is a correct view of reality. 😀
(BTW, FWIW: I think the phrase “personal judgement” directs more towards the person rather than the judgement, which is what I think should be argued.)
April 27th, 2020 at 11:21 am
In any event, we’re off on a tangent here, anyway. We have an unfinished conversation on my recent MWI post if we want to discuss MWI. This post was intended to be about inflation and eternal inflation.
(I may post about MWI again when, or if, I get through Everett’s paper. The text sections are interesting, but most of the math is above my head. He goes into information theory, which surprised me. A lot of the paper seems oriented towards probability. It’ll take a while to absorb.)
April 27th, 2020 at 2:54 pm
Sounds good. On that post I linked to explaining the relationship between Tegmark’s Level I and II multiverse, it’s worth noting that that particular conception of how the bubble works isn’t universal among physicists who are eternal inflation enthusiasts. Some do see the bubble as finite with an edge, although we still couldn’t approach it, since there would be a boundary that kept receding away from us faster than the speed of light.
April 27th, 2020 at 4:01 pm
To the extent I take eternal inflation seriously I definitely lean towards the bubble universes being, as they say, “infinite yet bounded” — like the surface of a sphere. That means if it were possible to traverse the universe in a straight line, you would end up back where you started. As such there’s no edge, per se.
It’s not possible to make that trip due to the expansion, of course. Even light can’t make that trip, which is why we don’t see copies. I imagine there is room for many other visible horizon bubbles, but I’m skeptical our Type I universe is infinite. I haven’t found explanations of how we could be both a bubble and infinite creditable. It’s all very speculative.
You mentioned your 2014 post; one thing I wanted to ask about:
The bubble universe is constantly growing into inflationary space, bringing in new regions of space where inflation is coming to an end.
The idea that our bubble was consuming the meta-space outside it is new to me. My understanding was space was created by the expansion — there’s nothing “outside” to expand into. Can you clarify?
If I understand Tegmark, (from our point of view) first there is eternally expanding “inflatronium” — an “infinitely” dense form of über-matter that’s inflating due to being so dense. It’s not explained why, but I gather some speck of it reaches a point of not being inflatronium and it “freezes out” and becomes a bubble universe.
All the points around the bubble keep expanding at eternal inflation rates — i.e. super fast. The bubble maintains that inflation rate for that brief time, for about 10^-32 seconds, in which the bubble universe grows from a speck smaller than a nucleon to “about the size of a grapefruit.” What we see as a Big Bang with a period of inflation is actually a slowing down, almost like throwing a ball out the window of a speeding car.
Meanwhile the points around the bubble speed away as the bubble’s expansion slows down. (And then speeds up a little much later on.) So I definitely have questions about what, if anything, is between the bubble and outside the bubble. Where exactly are we in relation to the eternally inflating stuff?
And what created eternal inflation in the first place? It seems our Big Bang isn’t the same, although there are theories that “(our) inflation never stopped” and that became eternal inflation. Except what privileged us to be in the first universe? It makes far more sense we’re one of the infinite number of bubbles with many before us and many to come after us.
April 27th, 2020 at 4:49 pm
For me, an infinite universe and one with any kind of edge both seem absurd. I don’t think curved space helps, because in reifying the curvature metaphor, it then implies that space is curved inside of something, and the question then becomes whether that something is itself infinite or bounded.
The idea of consuming inflationary space was my interpretation of Greene’s description, but looking back at it, I’m not sure it’s right or necessary. All we need is an expanding bubble. But the boundary isn’t sharp. From the perspective of inflationary space, there are regions where inflation continues apace, there are adjacent regions where it’s showed down slightly along the edges of the bubble. There are regions deeper in the bubble where it’s slowed down more.
The degree of change represents how far each region is along its big bang trajectory. From outside the bubble, it’s all simultaneous. But from within the bubble, only the regions with equivalent levels of change represent the simultaneous state. (Greene has diagrams in his book which make this far more clear than I can in a brief description.)
To your question, it makes the big bang the boundary between our universe and inflationary space, which we obviously can’t traverse, except by traveling back in time.
I think most bubble universe variations see us as just one of the bubbles, not the first or last by any measure.
As I understand it, what started the inflation moves beyond the boundaries of the theories. (Just as the original big bang theory couldn’t address what caused the bang.) Maybe the turtles ate something that gave them gas. 🙂
April 27th, 2020 at 7:10 pm
Okay, here’s a thought I just had: could dark energy actually be the influence of the inflatronium surrounding our universe? Because I have to wonder what all that external mass means for us. I suppose if space is expanding FTL its gravity wouldn’t have time to reach us.
“I don’t think curved space helps,”
As I understand it, space be can both infinite and curved. The curvature has to do with the lines light would follow (the geodesics) if unaffected by nearby mass. It’s that triangle thing where the angles are 180 in flat space but larger or smaller if space is curved.
The idea of an “edge” seems more absurd to me than infinite universe mostly on the premise that space looks infinite. (My alternate is the infinite-but-bounded universe.)
“To your question, it makes the big bang the boundary between our universe and inflationary space,”
Right, and it’s at the heart of what I’m questioning. We have our pre-Type II view that the Big Bang occurred and the universe expanded. The edge of our universe, 300,000 LY beyond the CMB is the edge of the expansion. The BB caused everything to happen.
In the Type II view, the BB is the inner “edge” (surface) of inflatronium. It’s almost like we’re being pulled into existence rather than pushed. (Hence my sudden flash wondering about dark energy. Is our bubble being pulled apart?)
It also suggests our Big Bang was different from the Big Big Bang that got all this going. Because…
“I think most bubble universe variations see us as just one of the bubbles, not the first or last by any measure.”
Exactly, that’s my perception, too. So what got this all started?
Yeah, it’s outside the theory, but the whole eternal inflation thing seems outside our theories, so either speculation is fair game or we should stick to the universe we’re pretty sure actually exists.
It’s always those damn turtles.
April 27th, 2020 at 7:46 pm
I don’t really understand the infinite and curved topology, unless it’s maybe curving along one axis but not another, with the non-curving axis being the infinite one, sort of like an infinitely long cylinder. But it brings me back to wondering what the cylinder is in. (If it’s in nothing, then that itself is a very strange boundary.)
On the dark energy point, the big rip cosmology strikes me as maybe dark energy simply being inflation re-asserting itself. Our bubble might have an expiration date. I think I read somewhere that if true, the universe as we know it might end in a few tens of billions of years. Which makes the heat death future positively optimistic in comparison.
I can see how eternal inflation might fall out of some models of inflation. The question for me is the status of inflation. When I wrote that 2014 post, we thought we had evidence for it, but it later evaporated. Some physicists think inflation generates as many questions as it answers.
On the turtles:
April 27th, 2020 at 8:14 pm
It’s not really possible to visualize; only by bad analogy (hence why it’s hard for you to see it). You’re in a curved space right now (because of the Earth’s gravity). You could demonstrate that curvature by shining a laser beam for a long enough distance. It would curve downwards.
A lot of people wonder about the connection between inflation and dark energy. The latter is much weaker — it’ll never tear apart galaxies, let alone (as I once heard) atoms. But once the local galaxies merge with us, we’ll truly be the island universe early astronomers thought we were.
I think the current view is trillions of years before galaxies finally consume themselves. Then all the star ash eventually falls into the black hole. And once the CMB finally drops to low enough energy, black holes will be able to emit more than they suck down (currently photons from the CMB far outweigh Hawking radiation). Finally the black holes evaporate, and that’s pretty much it. Space will keep expanding with only some very low frequency photons.
“I can see how eternal inflation might fall out of some models of inflation.”
Yeah, and that’s another point. There are models in which our inflation, parts of it, doesn’t stop and becomes eternal, so… does that become the inflation, or is there eternal inflation inside the eternal inflation, or are these just different theories?
By which I mean wild ass guesses. (Albeit informed by math.)
“When I wrote that 2014 post, we thought we had evidence for it, but it later evaporated.”
😀 Yeah, I noticed you mentioned BICEP2. Oh, well.
Quite agree inflation isn’t a universal view; that’s why I pointed to an alternate idea about the horizon problem. Inflation, like dark matter and dark energy, is a putative answer to an observed problem. If we’ve misunderstood the problem, the answer isn’t likely to be right.
April 27th, 2020 at 8:21 pm
I forgot to mention, re Douglas Adams, I’ve got The Salmon of Doubt in my Cloud Library save list, but I’m already bogged down reading Neal Gaiman’s biography of Adams, Don’t Panic: The Official Hitchhiker’s Guide to the Galaxy Companion, so I’ve been putting it off.
I’m just not big on “lives of authors” I guess. Got bogged down in an autobiographical book of Terry Pratchett essays about his life that I put down more than a year ago and never picked up. (And Pratchett is one of my favorite authors in any genre.) Just not my cuppa.
April 27th, 2020 at 8:32 pm
Can’t say I’m big on author biographies myself. I do sometimes enjoy the collected letters of authors, which ends up giving insights into their biography, but more because of what it reveals about their creative processes. I learned a lot about Heinlein in Grumbles from the Grave, as well as Tolkien from The Letters of J. R. R. Tolkien.
But the lives of most authors, even ones who wrote awesome stuff, are usually far from the most interesting stuff around.
April 27th, 2020 at 9:21 pm
Yeah, people are people. Some people are more into what other people are up to. (It still floors me all the interest people have in the private lives of David Tennet and his wife. I love Doctor Who as much as the next guy, but I have no interest in the lives of the actors.)
I lean strongly towards art standing on its own, but there is a Yin-Yang tension between standing alone and the richness that comes from being informed about the context, era, creator, etc. There’s also a tension between art accessible to anyone and art it requires extra knowledge to fully enjoy. Bach’s fugues, for example, are a lot more than musical ditties, they’re exercises in mathematical permutations. (So is the old art of church bell ringing.)
Science fiction is by no means the first art to require educated consumers!
April 28th, 2020 at 9:23 pm
Well, I’m to the part Tegmark is going to start talking about his MUH. He prefaces it with a story about how a paper about this prompted an email from the editor of a major journal. The email suggested in no uncertain terms that he should cut out the fantasy crap and stick to his physics day job. 😮
He also prefaces this section with a chapter about our intuition and internal reality model, which seems to be the preferred preface to any number of crackpot theories.
Absolutely our internal model of reality is but a wireframe of the real thing, and absolutely our intuitions are based on the low-speed, low-energy macro world of our perceptions, and absolutely those perceptions can’t be fully trusted. But that doesn’t me we throw out the baby with the bathwater. Reality does shine through in our perceptions, and our intuitions are based on an apparently factual, consistent, lawful and casual reality (whatever that amounts to).
So two points these intuition screeds always ignore:  While unreliable, my perceptions and intuitions still have some value.  The OMG constantly cited examples of how shitty our intuition is all bear one common trait: It was hard evidence or unassailable argument that caused us to look past our intuitions.
That second point applies to Tegmark and all these other fantasists spinning yarns about maybes. And make no mistake: I’m not at all opposed to the yarns. I’ve been a science fiction fan all my life. It’s strictly a matter of labeling and perception.
That editor had a point: There is a divide, Max, between your day job as a physicist, in which you have a responsibility to not be part of the growing storm of science bullshit, and you freedom as a thinker to speculate about ideas.
I do gotta give Max full props for being pretty upfront all along about what is real physics and what is his speculation. He even has a chart in front of the book. (That said, I do think his dividing line and mine aren’t the same, which is a motivator for this post.)
May 1st, 2020 at 9:56 am
Tegmark is playing the hits. He deals with the “what about change” and “what about the present moment” questions his MUH invokes by citing the block universe and, explicitly, how Special Relativity makes it true.
All I can say is, see Blocking the Universe for a counter-argument.
I’ve been taken aback quite a few times now by what seems a strange sloppiness on Tegmark’s part. Perhaps it’s due to writing a book for general consumption, but there are omissions and papering over things to a level of almost being errors that surprise me from a professional mathematician.
One personal hot-button: He uses “begs the question” to mean “raises the question” which, yes, it does, but the phrase “begs the question” has a specific meaning in rhetoric and the dialectic — one I’d expect Tegmark to both know and respect. It seems sloppy to use the phrase in the casual manner, but it’s admittedly a hot-button of mine.
But it got me sensitive to other things he does that seem surprising sloppy, and I don’t know if it’s intentional and he knows better or if his thinking really is that sloppy. (He’s never impressed me and his book is utterly failing to do so. But I’m determined to finish.)