I'm surprised Sabine did not cite the foremost authority on retro-causality - the White Queen: 'I don't understand you,' said Alice, 'It's dreadfully confusing!' 'That's the effect of living backwards,' the Queen said kindly: 'it always makes one a little giddy at first --- but there's one great advantage in it, that one's memory works both ways' . . . 'What sort of things do you remember best?' Alice ventured to ask. 'Oh, things that happened the week after next,' the Queen replied in a careless tone . . . Alice was just beginning to say, 'there's a mistake somewhere -- ' when the Queen began screaming so loud that she had to leave the sentence unfinished. 'Oh, oh, oh!' shouted the Queen, shaking her hand about as if she wanted to shake it off. 'My finger's bleeding! Oh, oh, oh oh!' . . . 'What is the matter?' Alice said, as soon as there was a chance of making herself heard. 'Have you pricked your finger?' 'I haven't pricked it yet,' the Queen said, 'but I soon shall.' 'When do you expect to do it?' Alice asked, feeling very much inclined to laugh. 'When I fasten my shawl again,' the poor Queen groaned out: 'the brooch will come undone directly. Oh, oh!' As she said the words the brooch flew open and the Queen clutched wildly at it, and tried to clasp it again. 'Take care!' cried Alice. 'You're holding it all crooked!' And she caught at the brooch: but it was too late: the pin had slipped, and the Queen had pricked her finger . . . 'But why don't you scream now?' Alice asked . . . 'Why, I've done all the screaming already,' said the Queen. 'What would be the good of having it all over again?' Lewis Carroll, Through the Looking-Glass and What Alice found there (1872)
Wonder-full, indeed. As much more of a philosopher and logician than a physicist (while quite handy with the math and arguments), i am frustrated by the inflexibility, and irresolution, of these sorts of ideas and explanations. Well, first off, there are never any explanations, really. The whole thing starts to sound like a scientific circle of great Egos vying for recognition in an obscurity of meaningless, mind-numbing "gamesmanship". The simplest concept, for me, turns on a simple, obvious reversal of our terms: One is born into a world imbued with "future" possibilities, while all about, in every conceivable corner, crack, and crevice, there exists evidence of a rich, full, resonant "past". (Yes, I know that this thesis is not directly relevant to an "effect to cause'" inversion argument, but the parallels are more in the nature of "substance" in change as a metaphor for "the arrow of time" conventions, etc.) Of course, this notion of a dualism in the very "direction" of the temporal IS THE WORLD, at the quantum level too; but the theorists have other commitments, and are seriously baffled by much of the mathematics that is literally coming apart right before their eyes. They love their "clock" time, but seem to have invested in the rather disturbing misconception that they have, unconsciously, gotten rid of "lived" time. I don't know: Whatever your position, I am giving up on the convoluted rationality that guides a great deal of this sort of theorizing today. ...Regards
I was shocked when my philosophy of science professor recommended Lost in Math to the class a few weeks ago. It says a lot about the quality of your work. It’s crazy that we have you, a high-quality resource, explaining these things to us for free on RU-vid.
One of the many wonderful effects your videos has on me is that even when I don’t fully comprehend the topic, you leave me wanting to know more, to better understand, to ask questions. In short, you leave me with genuine curiosity, wonder and awe. These are very precious gifts, Sabine. Thank you.
I believe the future is already written, we may have free will, but it's limited and our future actions help decide what we do today. I have felt this several times in my life. Now this does not reverse cause and effect, but it makes you think...
Another work of fiction that uses a consistent history is the German series "Dark". It does so masterfully in my opinion (even though the intertwinning storylines and characters might get a bit tiresome for some after a while). What I love the most about this series is the fact that certain occurences might seem outright paradoxical at first glance (I won't go into detail as to not spoil it for anyone who hasn't seen it), but are actually perfectly consistent with the structure of time and causality established within its world.
Ahh .. was hoping you'd still do these types of videos! I love the "news" bits you do too, but I was concerned you'd stop doing single topic videos in place for them. Thanks for doing both! And for all of the great work you do.
I think that Dr. Hossenfelder misses the point of the Transactional Interpretation. Yes, of course it gives the same answer as conventional quantum mechanics (QM), but with a difference. QM gives an answer without a logical mechanism. Cramer's approach gives a logic to it. This comes out brilliantly in Costa de Beauregard's explanation for quantum entanglement, that similarly invokes forward and backward-going waves. It resolves Einstein's consternation with "spooky action at a distance" since there is no longer instantaneous action at a distance, but instead traveling waves. Furthermore (getting a little more technical here), in traditional QM the probably density is the product of a wavefunction and its complex conjugate. That complex conjugate is precisely the mathematic description of a wave going backwards in time. Therefore, the QM itself is telling us that there is a backwards-going wave. There's more, but I'll stop here to save digital ink.....
I appreciate how you can disagree with the interpretation but also admit that it's fine for others to adopt it since it's not contradictory. While I personally prefer Copenhagen for its simplicity, I think we need to think about alternatives until we find something better
Indeed. There is a way of understanding retro causality I write about which makes it the only interpretation which meets all the standards of science-especially parsimony. Thanks 👍🏻
Premonitory dreams on which you acted and those actions not being possible had the premonitory dreams predicting them not happened? Yeah me too. This taught me that the linearity of time was just an illusion to us. More or less related, I remember some people who believed in the Mandela effect and who believed that it was caused by the "timeline righting itself" and some people remembering the former timeline.
@@Th3BigBoy I was at a night club and encountered two gentleman on the dance floor they looked very familiar to me. I talked to one of them briefly, can't remember about what. But I invited them back to my table where I was with a bunch of my coworkers. I sat down and he put his jacket on the back of a chair and flicked his index finger my way I did the same back. He went back to the dance floor and I followed him and encountered the second guy standing on the dance floor. He said "I swear this has happened before" a couple of times. That's when my mind went🤯🤯🤯🤯🤯🤯🤯🤯🤯🤯🤯🤯😱😱😱😱. Because I had dreamt that whole situation when I was 15. What's even more startling is the other person. Because I think it may have happened to him too.
Another way to view backwards time travel is to view time as always moving forward but the time traveler can reverse their perception of whether time moves forward and backwards using a time machine or w/e method. So the time traveler can interact like normal but the rest of the universe is moving backwards, their actions or inaction effecting the world around them in the same way but cause and effect are reversed. This would create a butterfly like effect backwards in the time, the further back you travel, the more changes. For example if you used a time machine and traveled backwards in time, you and everything in the time machine is no longer taking the same path it took to get to the point of time traveling. All the interactions would changed, the air molecules, your conversations, objects you moved, materials used to build the time machine, breaks in cause and effect would create a different past. This could lead to some interesting phenomenon such as objects seemingly moving on their own, people having precognition or deja vu, and "ghosts". This would effect things and people closer to the time traveler as they have more interactions with each other. The more complex or chaotic something is, the more likely it will change or not happen as you expect. This sadly could also lead to some issues like the time traveler's dead loved one not reverting back to life. Would love to see people talk about this and making movies of.
My life is quite a trip... As a 73 yr young "info maniac" Sabine's discussions always make me smile... As we're flummoxing through this Nexus MOMENT... Chaos all around. ❤️😢🤔😊
Aside from the interesting topics and fantastic explanations, can we all just take a moment and recognize Sabine’s incredible wit and sense of humor? The matter of fact tone, and the dry delivery makes it even funnier. There are definitely some gems in this one… 😂🤣🤣
I've always really liked the transactional interpretation. Especially since it doesn't arbitrarily throw out half the wave function for being "unphysical" like pretty much every other interpretation of quantum mechanics does.
I think it's the right ansatz, and that the back-and-forward outside physical time should be replaced with something like interference of both timeflows that both happen "simultaneously".
Imagine you shine laser pointer into the sky. It now makes "transactions" with unfathomable amounts of matter even billions of light years away (both in space and time). So I don't find this much more satisfying than the other interpretations.
@@jurajvariny6034 Why is that a problem? Those transactions would happen over billions of years, so locality is still preserved. Or do you dislike the number of transactions? That seems like a weird problem given that all modern physics models involve stupid amounts of interactions. The only change is that the interactions are happening in both temporal directions rather than 'jumping' across large distances.
@@slicedtoad if i understood this interpretation correctly it follows that everything we observe depends not only on backward light cone, but also on forward one. And unless the universe collapses in finite time (does not seem to be the case), our forward light cone can even have infinite time span. I find it hard to wrap my head up around - how present can depend on transactions in future which stretches to infinity.
@@jurajvariny6034 I agree it's weird. But it's an alternative is the Copenhagen interpretation which, to me, is so much worse. The math works and makes sense in QM. Trying to translate the math into understandable concepts and analogies is, as far as I can tell, impossible with the Copenhagen interpretation. "A particle exists in all possible states at once" is a nonsense statement. You can fuzz your brain and pretend it almost makes sense, but you're mostly just lying to yourself. The transactional interpretation requires the strange idea of signals travelling backwards in time. Which is weird. But it's not incomprehensible. The backwards travel is strictly limited in such a way that paradoxes don't arise and that information can't be sent back by an observer. We already think of time as a dimension that we travel in one dimension. Adding the idea that certain things travel in the opposite direction isn't that much of a jump. That's my take, anyway. I'm not a physicist, though.
My mother who is the ultimate pragmatist and not given to any sort of exaggeration on one occasion only foresaw a minor bus accident of a church youth bus that my father was on heading to church camp in which one girl was moderately injured. She thought it odd but said nothing of it at the time. About 6 hours later she received a call from my father letting her know they had arrived (pre -cell phone days) and the details matched to the slightest detail. Never happened to her prior or since. She rarely mentioned it because it was unnerving to her. I have never experienced this and have only experienced deja vu as many have I believe. Since she was the last person I would have expected to fabricate such a happening and wished that it hasn't happened, I take this as firm evidence not for physical time travel but some phenomenon of the mind that MAY relate to QM processes that out brains utilize that we have yet to fully understand although there is more research in this area for several reasons; one of which is that classical physics can not explain how a brain can function as it does while consuming only approximately 8 Watts. Sorry for the long post; I have thought of my mother's experience again when I watched this and added the part about the brain for those who may want to explore that further.
Precognition, presumably. Some people experience this regularly, although many people are not aware of it. There is some scientific literature about it, but most physicists ignore it because it doesn't fit with their "world view".
Since you mentioned about time travel in science fiction, I’m slightly surprised that you didn’t mention John Cramer is also a science-fiction writer. Seems like an interesting side note, at least.
Very interesting, thank you Sabine! I worked on this issues and I made two videos on retrocausality, one on "Transtemporal quantum entanglement" and other on "Receiving messages from the future" (both in spanish, sorry)
The novel Recursion (in german: Gestohlene Erinnerung) from Blake Crouch has another time travel concept: time travel creates a new version of the past and all different versions of the past collapse at the point of departure into a common future because of causality (with consequences). Perhaps you could call it Retro-Superdeterminism. So far this novel has not been made into a movie (sadly, the novel is cleverly written and a nail biter). It also has a physicist as the heroine. You might like it. And of course Heinlein's classic All you Zombies (filmed as "Predestination") for a consistent time paradox enclosed in a time loop.
@@HansLemurson That's not exactly what happens in the novel. The future is changed by the past but it is kind of merged. Therefore the time travelers are instructed to keep the changes as small (as local) as possible. Time traveler also is a bit of a stretch since there is no physical time travel. It's only information that can travel. Like memories. Questions are: What is your biggest regret in your life? What if your former self suddenly would know the outcome of a decision that transformed into your biggest regret because it is a memory of the future? Would you like to have a second chance? I don't want to spoil the novel completely so I want to leave it at that. I heartily recommend the novel.
02:55 - Only my German friends might want to revisit their "Latin exams". My British "public school" friends just want Latin and Ancient Greek to sound "more English"!
Sabine, I've been watching your videos for years and they're so good. Just heard your podcast interview on Breaking Math and enjoyed it a lot. Please keep putting out the great videos :)
@@hansburch3700 why a comment in 'cryptic' german? Too afraid, someone could prove your statement wrong? As long as I follow this channel, it is the most objective and honest depiction of science, I know. But perhaps you like Doc Sabine's books to read. I recommend. Both available in german now. Or her papers, if you're a math man or working in the fields of quantum mechanics.
Since you buy a new notebook it is pretty clear where it came from :D The riddle is: from where come the instructions for building the time microwave? I wonder, is this a Stein's gate reference or are microwaves just the next closest thing to a time machine in term of how much magic is involved in its functioning?
@@ref8893 Either you don't get me or I don't get you. Of course there are two notebooks, but for each one it is compltely clear where it came from. I bought one in the store, and the other one is from the time machine and was bought by my time-travel clone in the store.
How can we (or do we even need to?) talk about a "second time internal to the wave" when we know the wave does not experience time? I'd like to see some discussion of why we talk about spooky action at a distance when the photon experiences neither time nor distance.
Photons don't, but fermionic matter (like electrons and atoms) do have a kind of internal 'clock' related to their spin. However, I agree that at the quantum level there is no real 'distance' and so the 'nonlocal' influences are not really 'action at a distance'.
The idea of people receiving your emails before you've written them makes me think of one of Terry Pratchett's characters. She's a clairvoyant who answers people's questions before they've asked them. You have to be careful to always ask the question she's just answered, though, or she gets a headache.
I think no matter how hard you try to parse this, in the end the paradoxes just kill it dead. People talk about entropy setting the direction of the arrow of time. But if you think about, even if you could reverse time, entropy would STILL increase, because that's the most probable thing to have happen. Remember - you don't get to cheat. The only way to get entropy to decrease as time flowed backward would be to keep a log of all of the "states of the universe" and use that log as you went back in time to choose which of the possible (probabilistic) states to go to each instant. There is no such log. Entropy increase as things randomly change - it doesn't MATTER which way time is running. No - the arrow of time is established by OUR MEMORIES. When time t comes along, we REMEMBER time t-dt, but we don't remember time t+dt. So it's all bound up with consciousness, and we don't understand consciousness well enough to have the conversation in any rigorous way. And if you want to claim that we would remember time t+dt instead of t-dt, then... all you've done is change the sign of the time coordinate. And it's arbitrary to start with. So you've changed nothing. If you want to insist on a classical universe, then sure - we all know that if you could set up the initial conditions of a system precisely enough, it would run toward lower entropy. But we have NO way of doing that. So if you try to say you'll "just reverse the direction of time" and have the universe retrace its path backward, you're essentially demanding an unobtainable set of initial conditions. An EXTREMELY RARE AND SPECIAL set of initial conditions.
I did read this piece 12 years ago , I will read this , and judge this 16 years ago , traveling with almost the speed of light , you will look back in time , and say , God I look old now
Best approach to time travel paradoxes is shown in Futurama. Rather than trying to work around them they embrace them. Time exists as a whole, so Fry being his own grandfather does not cause a paradox. I love that version, same with Fry and Lars. 🚀
The Time Traveler's Wife is full of bootstrap paradoxes. SPOILER ALERT: . . . . . . For example, in the past, the time traveler dictates to his 6 years old future wife a list of 152 dates of his encounters with her, which she writes in a notebook. He'd learned the list by reading & memorizing her notebook. And yet, he often says he can't change history, for example he failed each time he tried to prevent his mother's death. I haven't entirely figured out the rules of time travel in that tv series, but my assumption is that he can change history only in ways that don't change his memory of history, and much of his behavior is predestined. I don't understand how the universe enforces that restriction and the predestination, though. He taught himself the rules of time travel, as he understood them, by tutoring his younger self instead of consulting with physicists, because he expected that if he revealed that he travels in time he would become a lab rat for the rest of his life. There's a scene where he's a passenger in a car driven by his 16 years old future wife, who's driving like a maniac because she "knows" from what he's told her about their future that neither of them can be killed that day. He's alarmed by her driving and warns her that, even though the two of them are invulnerable, people in other cars could be victims of her reckless driving and if that happened she would always regret it. This might be a plot hole, because if that had happened it's hard to believe that he wouldn't have been told about it by his future self or by his "regretful" wife. There's also a scene where he's a passenger in a car traveling at 60 mph and is concerned that if he were to time travel away from that moment he would find himself traveling at 60 mph unprotected by the car... but he ought to know he's invulnerable until he reaches the age of the oldest version of himself that he or his wife have met. Still, despite these plot holes, this tv series has a lot of convoluted time travel interactions that are fun to scrutinize for paradoxes. For example, the real reason he didn't consult with physicists must have been that he'd been told by a future version of himself that he didn't; otherwise he should expect from his memorie of his future self that he's invulnerable to the possibility of becoming a lab rat for the rest of his life... at least up until the age of his oldest self that he ever encountered.
Hi Sabine! Other paradox solutions: (1) your time ship only goes back in jumps of a great many millennia: so changes "wash out" over time (Stargate SG1). There is a paradox compensator (delay) machine used by an evil Time Lord (Doctor Who). (3) You can go back to watch but cannot make lasting changes (The Time Machine, 2002 film), yet if you go to the future and return to your original time, you can change your present to alter the future you saw (I like this one).
I'm not quite sure how to explain this. But, what if.... entangled particles are not only entangled with one another but with the same plane of reality (meaning the same timeline or "world" of multiple worlds)? So let's say if the two particles always have opposite spins, when we observe one, of course, the other always shows the opposite spin, but NOT because information has passed from one to the other but because the plane that the first has collapsed within will always contain the opposite particle with the opposite spin. It would mean that we have chosen (observed) the first one and in doing so we have chosen the plane of reality within which the other one demonstrates the expected spin, always. So it's not that any information has passed from one to the other it's that we have observed the first particle and since it is entangled with the same plane of reality as the other particle it means just that we have chosen the plane within which the spins are associated. It does not mean that any information has passed from one to the other. I know that sounds confusing. I'm sorry. But I hope it's understandable what I'm trying to say. And please forgive my redundancy.
The grandfather paradox is resolved when you realize that the new information - granddad is dead and never bore your mother or father - only propogates into the future at the speed of light. Since you, and everything in your vicinity (your personal past light cone) are also traveling at most the speed of light, the new information will never reach you. I don't know if it will ever reach anyone else; maybe with more time shenanigans? But you keep on keeping on, all your memories and, probably, even your parentage intact.
However, if you travel back in time, you can break the speed limit of light - It is simple. Travel under speed of light, and go back in time so to arrive before light arrives. Woooh - you break the record and outrace the light!
Careful with that: I received one of these in Anton's "What da Math" channel - different number sometimes related to some "spooky" investments and similar scams
@@possibledog If a particle becomes deterministic to some observer then does the next observer still has the particle in superposition? Then, when the two observers meet to talk about the particle they observed would their observations match?
I wrote a story as a teenager about time travel and you might like the model in the story. In the story, any changes made in the past would update into the future at one second per second and the universe just keeps going on, not really caring about the changes you make. So if you went back in time to assassinated Hitler before he came into power, and you went back to your own time, you wouldn't witness any changes. In order to be in your original time with no Hitler, you would need to stay alive for hundred or so years for things to update. The model in the story does imply that there is a "true" time that the entire universe moves forward through. I know that's not the popular theory, but it's still a unique take on time travel and dealing with paradoxes.
Ive have for a long time thought that our notion of time that flows forwards is problematic given the mental gymnastics we end up with trying to come up with physical interpretations like Copenhagen or many worlds. It makes more sense that linear time is an emergent outcome of a different set of rules. I am thus, rather entranced by this idea.
Entropy drives time forward. Each point in time has sequentially less free energy available to do work. Time isn't simply a necessary dimension for space travel, it is the increasingly diffuse distribution of energy. Time is the evolution of free energy.
@@obsidian9537 oh its absolutely necessary to include entropy because of what it means to travel backwards in time. if you isolate a system like a child's play pin and throw a bunch of blocks on the ground, how would you travel backwards? You'd have to rearrange everything back to how it was before the blocks were thrown around, and that takes energy. To actually travel back in time, one would have to revert every particle to its previous position and energy. This isn't time travel as we think about it in movies because we know it's just another configuration making use of time going forward. This brings into question the notion of time as something that flows and is ridden like a wave. There is no time, just your memory of previous states contrasted with information on new states, plus the cost of changing states. The net cost to changing states is diffusion of energy in the universe. This is where you will understand why time travel back is not possible. How do you revert the state of the universe without expending energy and making it more diffuse? Time is nowhere to be found, just the impracticality of utilizing energy to reverse entropy of the universe. A system can reverse entropy at the cost of the entropy for outside of the system, so maybe time travel can exist for fundamental particles on a very short time scale. But that's a far cry from rearranging every electron in your body and in the world.
Sabine, here's what you need to do: Set up a double slit quantum eraser experiment, send the signal to the pattern right after the splitter, but bounce the switched signal off the moon and back so that there is a 1 to 2 second delay. If you see the interference pattern, turn on the observer. If you see the discrete pattern, turn off the observer. Viola! You've just invented a time machine and/or broken reality -- the universe will now shut down. So long and thanks for all the fish! #ItchyFeet
Can you ELI5? How would you set this up, and how would you even measure it from the moon. I'm obsessed with retrocausality, and would love to see a legit experiment, or evidence in my lifetime. Keep hearing quantum erasers, Shrodinger's cat thought experiment, etc but never do we really see anyone do these things.
This is awesome. On the subject of time travel in movies, I'd love to hear how you would break down the movie "Primer". It's got a really unique interpretation of time travel and causality, but it's one of the lesser known time travel movies.
Primer is just classic "parallel reality" time travel, except with two extra twists 1. the traveler ages the same amount of time he's traveling, 2. the traveler cannot travel to a time before the machine was switched on. Both of those twists are effectively just limitations on the classic "parallel reality" time travel, and also, in Primer, the entire plot is ridiculously convoluted, which perhaps makes the time travel bits more confusing than it really is.
@@therflash Technically, you're right, but I think those "twists" change the "rules" of time travel significantly enough that the result is qualitatively different, and made the resulting movie far more interesting than the typical time travel yarn.
@@waltonsimons12 That is true, but fundamentally, whenever they use the time machine, the timelines split and a parallel timeline is created, which means it was included in the "parallel timeline" type. The extra twists are just limitations on top of the "parallel timeline" trope, there's nothing extra that the Primer timetravel is capable of.
@@therflash Sure, but again, I'm speaking qualitatively. As an analogy, consider rock music. Thrash metal, grindcore, crustpunk, and surf music all fall within the genre of rock music. But surf music is very different from thrash metal, grindcore, or crustpunk. Similarly, I think "Primer" is very different from other stories in the "Parallel Timelines" genre of time travel stories.
The arrow of time points forward in time because of the wave function collapse. Because causality has a speed limit every point in space sees itself as the closest to the present moment. When we look out into the universe, we see the past which is made of particles. When we try to look at smaller and smaller sizes and distances, we are actually looking closer and closer to the present moment. The wave property of particles appears when we start looking into the future of that particle. It is a probability wave because the future is probabilistic. Wave function collapse happens when we bring a particle into the present/past.
it makes sense if you don't think of the wave function as a cloud of possibilities, instead as a pressure wave going down the drain, driven by the en-tropic pressure, when it collapses it's flashed, seizes to exist and becomes more or less defined structure, subject to further entropy pressure. It spans distances because it's an expanded boiling liquid(one way of looking at it). I've posted hypothesis on F, find it under quantum mechanical universe hypothesis group.
The Bootstrap Paradox is known in DwarfFortress circles as The Mystery of the First Anvil. Making an anvil is easy. You just need some iron, a forge, and ... an anvil.
Careful with that: I received one of these in Anton's "What da Math" channel - different number sometimes related to some "spooky" investments and similar scams
The Bootstrap Paradox is known in Everyday Life circles as the Mystery of the First Egg. Making an egg is easy. You just need a chicken… which comes from an egg.
Anvils are cast, and casting only required some suitable cohesive foundry sand and an anvil-shaped pattern for the mold carved out of wood - for which one can use flaked flint stone tools - so no anvils, or forged tools requiring an anvil like knives or axes are needed to make an anvil.
@@robertbutsch1802 Overtime, something, with every cycle of birth, eventually became the system of "egg birthes a chicken". Imagine like, with every generation, something in the chicken's dna is changing, and it eventually starts laying eggs.
I didn’t particularly care for the novel. It was really more about “relationships” than about the time travel, and I found the romance smugly anti-romantic. The very best time-travel novel ever written, unlikely ever to be surpassed is the first, H. G. Wells’s “The Time Machine”-brilliant, evocative, haunting. The novel with the most time-travel tropes packed into a single story is probably Isaac Asimov’s “The End of Eternity”.
@Bassotronics - Actually, I think she's pretty good at explaining physics - which most people (in my experience) mistakenly believe is *_complicated_* - in a way that is more accessible to those who aren't familiar with it. But _complicated_ and _complex_ are not the same thing...at least not in my lexicon. Complicated things are messy, convoluted, highly detailed, but not necessarily incomprehensible or unknowable. Complex things (and here I'm referring to the property of *_complexity_* - as in complex systems) are not merely complicated. A complex system is one whose behavior cannot be modeled by finite algorithms. IOW, you can't just explain it or predict its behavior with simple equations. In that sense, physics isn't complex at all; in fact, physics is the science of simple systems. We can model their behavior with statements like F = ma and E = mc^2. Works great for that stuff. But complex systems - like the human body, or the weather (...or the climate), or human. behavior, or the economy...nope. We can create models, and they're useful for certain purposes, but they have limitations. We can't cure the common cold, or cancer, or prevent arthritis, or aging. In a sense, physicists have taken on the easy stuff...well, OK - maybe it's not the easy stuff, but it's the simple stuff. I'm a physicist and an engineer; the problems I tackle are solvable; the systems I deal with are simple. I would not want to be a medical doctor, or a meteorologist, or a psychologist, or an economist. That's the really complex stuff.
Retrocausality could be the most significant aid for evolution. It is suggested that sheer randomness of gene errors would present far too many possibilities than could be useful in any meaningful way to contribute to attribute evolution. However, retrocausality could theoretically pass information of those attributes which are useful from the future to the past which would then support the appearance and adoption of successful attribute change. That would imply that the evolution of all creatures and cellular life on this planet depends upon retrocausality to adopt successful evolutionary attributes.
I'm curious about how the delayed-choice quantum eraser experiment is explained in the transactional interpretation. Another wonderful video. Your explanation of Einstein's "spooky action at a distance" was the most clear and concise I've ever heard. Par for you.
Id def check her old video on it because its not retrocausal as usually presented. Once the specifics of how an actual experiment is conducted is know i dont treat it that way
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The best academic dis I've read was, "If this paper were published, it would only serve to confuse non-experts while being refuted by experts [or so we've been told]". ...i added that last part for effect.
On the Microwave example: Wouldn't that mean that there are 2 seperate 'worldlines' in this case? - There is a certain starting point where you did not have a prepared notebook, and something spurred you into action into developing this time machine in the first place. Let's call this line Alpha. - You developed the machine, and sent back the notebook. This splits the "causality path" at the point where you receive the instructions to build the machine. - From this point forward, you already have the notebook, so in no way will the future play out like the initial path. This is line Beta. - When you send back the information in the machine, you will only ever arrive back at Beta, because: You already had the information. It is different from Alpha. The only way to change Alpha is to ensure you never develop the first machine - which would then fully destroy Beta, as it 'never would have existed'? Which then again requires you to change Alpha, in order to preserve Alpha. Time travel is confusing. :')
LIGHT CONE: At 1:00 you talk about the Light Cone. This was the first decent explanation I've ever seen anyone give of the Light Cone. Others attempted, especially when speaking about Black Holes and the way the roles of Space and Time shift inside a Black Hole. I realize you are saying all actions in this universe (outside of a Black Hole) must exist within the Light Cone towards the Future and the Light Cone towards the Past. But what do the Light Cones to the side represent? Are those Light Cones the things that occur within Dark Matter and the Quantum level?
There is fairly famous american novel by the brilliant Thomas Pynchon (who wrote V), called "Gravity's Rainbow", which goes deep into Pavlov's theories, and one of the key plot points in the book is the hero Tyrone Slothrop, sleeps with a woman in London, exactly where the next german buzz bomb hits... anyway there are various intelligence operatives studying Tyrone trying to figure out how this all works... It's a tragicomical novel that takes place during WW2. A fairly difficult book to finish, but the ending is terrific.
I may never know exactly what you're talking about but I just really like you and the sound of your voice. And perhaps one day something may just sink in .
Sabine, bubele, it's probably called "The bootstrapping paradox" simply because the expression "pull oneself up by ones bootstraps" is a paradoxical misnomer (you you can't lift your feet off the ground by pulling up your bootstraps)
I think you are correct. It may be that there is no observed without an observer, and the cause is just constantly being spontaneously generated as we travel outward.
On interventionist causality, do we need to assume the cause (one if we intervene with, both events fail) always exists? Lets say we have two events A and B but no knowledge of time order. when we intervene with A, both A and B don't happen. but when we intervene with B, both A and B *also* don't happen. there's no way to determine which one is the cause. Does this case translate to timelike closed curve in spacetime causality?
A feedback loop; a speaker next to a microphone, can't see into the future or past. But after the initial input sound, the amplification perpetually increases the power of that sound. This is akin to the assumption you can "see the past" (or future) with a plane that loops light in such a way. There's no feedback, until there's feedback, and then you need to cut the feedback to cut the sound.
I think somewhere in all this business the way we form memories comes into play. The micro laws of physics largely don't care about time direction. But here's the thing - when the light comes on, we have a memory of someone having just flipped the switch. So it's easy for us to correlate those things. But when we see the switch flipped, we have no memory of the light coming on. So the structure of our memory has to do with how we form causal chains.
It seems to me that retro-causality could definitely exist, but on our macro-level we wouldn't experience it directly anyway. Even if time were traveling backward, we would perceive it the same way as we do now simply because everything would be identical... if I am making sense which I doubt
To make Retrocausality to work, right here, right now, just reverse a few axioms and assume we perceive everything backward. 1) entropy always tends to decrease. 2) the effect necessitates the cause. 3) it's the end state of the universe that is determined, not the beginning (from our perception of time). This has the end result that if we know the end state of the universe, we can predict and calculate with absolute precision everything that must have happened to get there, and also allow many things that may have happened but have been cancelled out so as to have no effect on the end state of the universe. That said, there's still no way to truly test the theory, and it really can't help us, since we can't perceive the end state yet anyway.
Faster than light does not mean time travel. It means we give up relativistic assumption as universal to all physical phenomena. It means we will have discorvered a field in which information *does* travel faster than light, or a particle which travels faster than light, but which interacts so weakly with normal matter, we have yet to detect it. It would enable a new (narrower) definition of "simultaneous" for spacelike separated events.
If the effect happens before the cause it means that you have inadequate perspective. Something happened that you couldn't see which created a paradox. That happens to be a cause btw.
This "transactional protocol" and "second time" just means that we live in a simulation, and there exists a "processor" responsible for those "transactions" and clocked by it's own clock mechanism.
Thank you very much, very very informative on so many levels. But let me point out that what stood out for me was the following observation I became aware of while trying to follow all the mental acrobatics about echo waves etc.. It reminded me, without being an "expert" in any (of this) while my interest is growing with time, of the mental acrobatics to which astronomers back in time had to go at length in order to make the observations/ facts fit the theory they had been brought up with or have risen within. To sum up my ramblings by the following quote: If your mind is empty, it is always ready for anything, it is open to everything. In the beginner's mind there are many possibilities, but in the expert's mind there are few. Shunryu Suzuki
I am no physics major but it seems the line moving forward in time from object to object should be the same line traveling backwards separate in direction only so that it is the same path but also the opposite. of course, that is my simplistic view. in other words the two paths are only separate by read. this probably wildly ignores things i am unaware of but professors are trying to take into account. read one end before the message is recieved and it still works unitarily- cause before effect like you need because the reverse works the other way.
this conserves classically and can still be read before you get there.i guess what i am hinting at is that it is easy to view it going forward when we have already decided to look in the other direction entropy-wise.
I predict retrocausality is impossible. This is based on a mathematical solution which eliminates the QM "infinities" problem. However, I have not yet proven consistency (of course may never), so a complete paper is years off. Thanks for this video. Well done as always.
Cause and effect (If there is to be a cause and effect) must have a 'product.' (Sum) A thought experiment: Now, given the timeline perspective in observation of this Sum in 'now' it would be unavoidable to have to 'look back.' * And in looking back to earlier nows (effects***), on our timeline, we see a connection to a series of pasts*(causes) to presents (effects) in increasing order of magnitude the farther back we look. (Sum of causes in this timeline leading back to now.) A good cognitive effect in understanding retrocausality. [* A series of observations starting from effect (outcomè) [** At the outcome (product) that backtracks further to the effect, and even further back yet to their cause.] [*** summed up to this product (singular now)]
Thanks for helping demonstrate retrocausality, on Saturday (Australian Time) I was pondering fusion power processes needing to be embedded with AI and QC, then Sunday you posted the Fusion video and today, my favourite topic.
Wow, I just started watching this. Thank you Sabine for covering this very interesting topic. As soon as I get chores done I'll get back to watching the entire video.
