So I love the idea of black holes as a reproduction mechanism for universes, and all that that implies - but have you (or other theorists working in this area) addressed anywhere the conservation of energy / conservation of mass? As it appears to me that even a supermassive black hole (never mind a "regular" supernova black hole) contains many orders of magnitude less matter and energy than our universe, pre or post inflation. That said, I only studied physics to twelfth grade, so am very likely missing some important aspect.
This is a fun blog! Everyone in the comments seems to be making a recommendation, so here's mine: have you discussed somewhere the anthropic principle? In my opinion it's key to the universe evolution idea.
BTW I'm based in your old stomping ground of UCG (now U Galway).
Thanks! As for the anthropic principle, I haven't discussed it yet, but I will! Yes, I agree. Very important. Evolution of universes makes for a far more parsimonious explanation of why this universe generates, and suits, intelligent life than do the broader every-single-version-is-equally-likely multiverse theories.
I've just come across your blog and am enjoying it hugely, thank you!
Quick question: have you read "What Does A Martian Look Like" by Jack Cohen and Ian Stewart? It has some fascinating arguments about the universality (and possible diversity) of life which I feel goes beyond what you've included here.
Depending on how strongly deterministic physics is - say, if superdeterminism is correct - and if the new universes created in black holes vary only slightly - then does it suggest we might have lived lives very much like these, over and over again?
Well, I don't think physics IS that strongly deterministic. Certainly not deterministic enough to generate lives just like ours, but with only very slight variations, 13.8 billion years after the Big Bang! That doesn't really make sense to me. If there are ANY small variations at this point, they will soon have cascading consequences that will quickly split this universe off from the one it initially resembled. They very quickly diverge once there is any small variation. (I mean, we know from chaos theory that very small variations in the initial conditions can have huge downstream consequences.) And that has been true at every point in the last 13.8 billion years. So either they are identical, or they diverge wildly from very early on. And changing one or more of the basic parameters of matter, even slightly... that's a pretty big initial change! I don't think you can do that to a universe and get a copy of that universe that is identical down to the individual human beings-but-they-are-slightly-different 13.8 billion years later. And that's leaving out the whole idea that living organisms might have agency and make meaningful, complex, non-determined choices (which I think is the case). So, TL;DR: nope, is my guess. But... similar creatures on similar worlds might well end up in similar situations, in an extremely similar universe, sure. If that makes sense. There is a logic to DNA evolution that is probably replicated in other universes if the basic parameters are close enough to ours, and leads to similar-looking outcomes, though down (at a more granular level) very different paths...
I'm way out of my league to conclude anything but:
* Dr Hossenfelder is a researcher at a serious research institution, working on quantum gravity so she's got to be somewhat credible on this subject
*. She believes that a theory called 'superdeterminism' which says the entire evolution of the universe is 100% determined given the state of the universe at the big bang and the laws of physics
I'm obviously out of my league to conclude whether she's right or wrong.
I agree with what seems like a restatement of chaos theory, but extreme sensitivity to initial conditions doesn't role out precise calibration of a system with exactly specified initial conditions.
I have no idea whether that's possible from an engineering PoV. If it is, we might imagine a future civilization really confirming Hossenfelder's theory by intentionally two black holes with matching initial states and laws of physics, carefully controlling the flow of hawking radiation, and observing that the states follow similar trajectories over time.
> leaving out the whole idea that living organisms might have agency and make meaningful, complex, non-determined choices
Hossenfelder argues this specific belief has caused physicists to reject superdeterminism. I initially rejected her theory for exactly that reason; i want to believe in choice, i can't help but believe that choices are a real thing. The theory of cosmological evolution seems to supply an out: superdeterminism is true, but there is new information coming into the universe all the time.
Suppose hawking radiation enables freewill because there's always this thing called 'now' which is the same in all universes, and is continually generating new signals which go into all of the universes at once. Universes that started on pre-determined courses eventually diverge from them once they progress enough to 'catch up to' a mainline sequence of 'now.' For example, imagine a theory that says 'all of history was pre-determined up until the end of the mayan long count, i.e. late 2012, at which point we caught up to mainline and from that point on, choices have existed and been meaningful determinants of causal outcomes. All pre-2012 memories were encoded in the state of the universe at the start of the big bang. We were automata that _felt_ like we were choosing, and we weren't until we started doing so.
If superdeterminism is true, we should expect evolution of the initial set of conditions to be chosen for that which _also_ creates more universes. What i imagine a lot of civilizations doing would be trying to capture as much of their own history as possible, so that there's a simultaneous process of creating child universes while computationally re-creating their own history, by trying to precisely measure as much as possible of the cosmic microwave background radiation.
Kind of an insane theory, of course, but i just like to explore the space of possible theories. Also, there's a beautiful symmetry because this concept and the transition in human brains, around age 25 or so. Before we turn 25, neuroplasticity is the default and the prefrontal cortex (the seat of executive function!) is not fully formed. Around age 25, the prefrontal cortext is fully formed, so we can use executive function, but neuroplasticity requires effort from then on. So our brains exhibit this "first, learn by default, choices are more or less out of your control ,then comes a time where learning requires effort and choices are possible" pattern, similar to that of a universe where superdeterminism and cosmological evolution are both true.
Oh man, Mark, that's an epic comment! Thanks for getting so deeply involved in the conversation. You made a lot of interesting points, so I may not have time to answer them all tonight (it's my bedtime here in Berlin; with a three-year-old, you have to grab your sleep when you can).
Yes, I love Sabine Hossenfelder (I think I quoted her in one of my first posts, and I hugely enjoyed her book, Lost in Math), though I don't always agree with her. Her critiques of theoretical physics, and its obsession with symmetry and beauty, are terrific, though! I haven't watched that particular video. Let me watch it, and I will get back to you with a more thoughtful reply, tomorrow...
Okay, that book sounds fabulous, and no, I haven't read it. Thanks for the tip!
So I love the idea of black holes as a reproduction mechanism for universes, and all that that implies - but have you (or other theorists working in this area) addressed anywhere the conservation of energy / conservation of mass? As it appears to me that even a supermassive black hole (never mind a "regular" supernova black hole) contains many orders of magnitude less matter and energy than our universe, pre or post inflation. That said, I only studied physics to twelfth grade, so am very likely missing some important aspect.
This is a fun blog! Everyone in the comments seems to be making a recommendation, so here's mine: have you discussed somewhere the anthropic principle? In my opinion it's key to the universe evolution idea.
BTW I'm based in your old stomping ground of UCG (now U Galway).
Thanks! As for the anthropic principle, I haven't discussed it yet, but I will! Yes, I agree. Very important. Evolution of universes makes for a far more parsimonious explanation of why this universe generates, and suits, intelligent life than do the broader every-single-version-is-equally-likely multiverse theories.
Oh, and give Galway a hug from me! I am hoping to get back there next year.
I've just come across your blog and am enjoying it hugely, thank you!
Quick question: have you read "What Does A Martian Look Like" by Jack Cohen and Ian Stewart? It has some fascinating arguments about the universality (and possible diversity) of life which I feel goes beyond what you've included here.
Depending on how strongly deterministic physics is - say, if superdeterminism is correct - and if the new universes created in black holes vary only slightly - then does it suggest we might have lived lives very much like these, over and over again?
Well, I don't think physics IS that strongly deterministic. Certainly not deterministic enough to generate lives just like ours, but with only very slight variations, 13.8 billion years after the Big Bang! That doesn't really make sense to me. If there are ANY small variations at this point, they will soon have cascading consequences that will quickly split this universe off from the one it initially resembled. They very quickly diverge once there is any small variation. (I mean, we know from chaos theory that very small variations in the initial conditions can have huge downstream consequences.) And that has been true at every point in the last 13.8 billion years. So either they are identical, or they diverge wildly from very early on. And changing one or more of the basic parameters of matter, even slightly... that's a pretty big initial change! I don't think you can do that to a universe and get a copy of that universe that is identical down to the individual human beings-but-they-are-slightly-different 13.8 billion years later. And that's leaving out the whole idea that living organisms might have agency and make meaningful, complex, non-determined choices (which I think is the case). So, TL;DR: nope, is my guess. But... similar creatures on similar worlds might well end up in similar situations, in an extremely similar universe, sure. If that makes sense. There is a logic to DNA evolution that is probably replicated in other universes if the basic parameters are close enough to ours, and leads to similar-looking outcomes, though down (at a more granular level) very different paths...
Are you familar with Sabine Hossenfelder's theory of superdeterminism?
https://backreaction.blogspot.com/2021/12/does-superdeterminism-save-quantum.html
I'm way out of my league to conclude anything but:
* Dr Hossenfelder is a researcher at a serious research institution, working on quantum gravity so she's got to be somewhat credible on this subject
*. She believes that a theory called 'superdeterminism' which says the entire evolution of the universe is 100% determined given the state of the universe at the big bang and the laws of physics
I'm obviously out of my league to conclude whether she's right or wrong.
I agree with what seems like a restatement of chaos theory, but extreme sensitivity to initial conditions doesn't role out precise calibration of a system with exactly specified initial conditions.
I have no idea whether that's possible from an engineering PoV. If it is, we might imagine a future civilization really confirming Hossenfelder's theory by intentionally two black holes with matching initial states and laws of physics, carefully controlling the flow of hawking radiation, and observing that the states follow similar trajectories over time.
> leaving out the whole idea that living organisms might have agency and make meaningful, complex, non-determined choices
Hossenfelder argues this specific belief has caused physicists to reject superdeterminism. I initially rejected her theory for exactly that reason; i want to believe in choice, i can't help but believe that choices are a real thing. The theory of cosmological evolution seems to supply an out: superdeterminism is true, but there is new information coming into the universe all the time.
Suppose hawking radiation enables freewill because there's always this thing called 'now' which is the same in all universes, and is continually generating new signals which go into all of the universes at once. Universes that started on pre-determined courses eventually diverge from them once they progress enough to 'catch up to' a mainline sequence of 'now.' For example, imagine a theory that says 'all of history was pre-determined up until the end of the mayan long count, i.e. late 2012, at which point we caught up to mainline and from that point on, choices have existed and been meaningful determinants of causal outcomes. All pre-2012 memories were encoded in the state of the universe at the start of the big bang. We were automata that _felt_ like we were choosing, and we weren't until we started doing so.
If superdeterminism is true, we should expect evolution of the initial set of conditions to be chosen for that which _also_ creates more universes. What i imagine a lot of civilizations doing would be trying to capture as much of their own history as possible, so that there's a simultaneous process of creating child universes while computationally re-creating their own history, by trying to precisely measure as much as possible of the cosmic microwave background radiation.
Kind of an insane theory, of course, but i just like to explore the space of possible theories. Also, there's a beautiful symmetry because this concept and the transition in human brains, around age 25 or so. Before we turn 25, neuroplasticity is the default and the prefrontal cortex (the seat of executive function!) is not fully formed. Around age 25, the prefrontal cortext is fully formed, so we can use executive function, but neuroplasticity requires effort from then on. So our brains exhibit this "first, learn by default, choices are more or less out of your control ,then comes a time where learning requires effort and choices are possible" pattern, similar to that of a universe where superdeterminism and cosmological evolution are both true.
Oh man, Mark, that's an epic comment! Thanks for getting so deeply involved in the conversation. You made a lot of interesting points, so I may not have time to answer them all tonight (it's my bedtime here in Berlin; with a three-year-old, you have to grab your sleep when you can).
Yes, I love Sabine Hossenfelder (I think I quoted her in one of my first posts, and I hugely enjoyed her book, Lost in Math), though I don't always agree with her. Her critiques of theoretical physics, and its obsession with symmetry and beauty, are terrific, though! I haven't watched that particular video. Let me watch it, and I will get back to you with a more thoughtful reply, tomorrow...