The headline seems a bit click-baity, as it refers to the Page-Wooters mechanism which was introduced 30 years ago, and as mentioned in the paper has been extensively studied.
A brief and accessible overview can be found here[2].
However this paper seeks to provide a more concrete and less constrained implementation of the Page-Wooters mechanism in order to connect it to our classical world better that previous attempts.
So while probably not a breakthrough paper, a solid step in an interesting direction.
His book From Eternity to Here on the subject of time is one of the very best science trade books I have ever read. It is chock full of end notes too which are a must read so bring two bookmarks to that party :)
I suspect though he would take issue with the description “illusion”. An illusion implies a trick, believing something that isn’t real. I think he would say emergent phenomena are real phenomena that we really experience and that time while it might not be fundamental it is very real.
The idea that time is emergent is considered unproven by most scientists. However, I personally believe there is some validity to it, even though I haven't found a single paper that convincingly supports this idea. I must admit that even some papers that are widely accepted as accurate are difficult for me to grasp and believe, as they are beyond my understanding and knowledge.
He came up with a framework where time is real (assumed), and then the laws of physics evolve with time, and then goes on to develop an evolutionary theory of universes, where universes reproduce by producing black holes, which spawn baby universes, with slightly different laws of physics. He then predicts that it should tend to produce universes that are optimized to produce black holes.
The point I heard him speak to is that when you dismiss free will, people start accepting as inevitable the kinds of global, systematic problems that face us, of which climate change is only one. It's an element of human nature.
That is an interesting point when you start taking it to different conclusions.
For example, It’s funny how often that people who claim to believe in free will often adopt the language of determinism when they say things like:
“It was meant to be”
Or, “Everything happens for a reason”
Personally, I think the general population is just confused and not particularly inquisitive when it comes to asking whether they have free will or whether their actions and language reflect their belief or lack of.
I suspect a feeling of determinism probably takes over when one feels like they’re on autopilot and lack a locus of control.
Does it correlate with being susceptible to cults, group think and parroting other people’s ideas like a consumer rather than synthesizing your own?
> Does it correlate with being susceptible to cults, group think and parroting other people’s ideas like a consumer rather than synthesizing your own?
It's known that being deluged with information tends to suspend one's own critical faculties in attempting to cope with the flow. Perhaps internet life, by tending to crowd out one's own thoughts, contributes to a sense of loss of will.
People who emerge from an "internet cleanse" seem to be refreshed in a way that might be interpreted as the regaining of will, of freedom to formulate.
I'd recommend Henri Bergson's Time and Free Will for mind opening view of time. Imo it elaborates on the distinction between space time and our temporal experience.
Philosophically, one could argue that the distinction between organic and inorganic matter is somewhat arbitrary since, at the most fundamental level, everything is simply matter. If you wanted to go in that direction, it would probably be fair to say something like it deteriorated, simply because it's programmed to.
It would also make sense evolution would choose not to change this programming.
I don't think you need to constrain that question to organic matter. Entropy applies to all forms of information including the information that organizes all known biological life out of mostly water and carbon.
Is it destroyed? does matter some how disappear or is it just it transformed from one form to another?
Why did consciousness arise from matter at all, does it disappear or is it transformed.
If you only limit yourself to what you can see then existence is rather dull and seemingly mechanically. Every time we look we see little more, and so is there really anything to suggest there is not more beyond what we can or will ever see.
Rovelli is an absolutely wonderful author - you’ll arrive at the end of that book maybe not actually understanding quantum mechanics fully, but at least feeling like you’ve been given a glimpse of them.
Fantastic book, from what I remember it was more of an autobiography with some math sprinkled in. But he's a really good writer and seems like a wonderful person.
Shook my foundations a little, I remember my partner and I were hiking for a few days at the time I was reading it and I recall having to drag myself back out of my head to experience the mountains
When they built up this physical theory, they assumed things about time, like that one thing happens after another, countless -- well -- countless times.
There is no way to not do that.
So it's pointless to say "time is an illusion". It's a basic category of thought.
But whatever to get hype for your paper, I guess...
You can "assume things about time" while writing a paper (including when it's due for sunmission), while still investigating whether the object of those assumptions has some fundamental properties, or whether it is just an emergent phenomenon from more fundamental things with no specific substance to it.
Same way we can assume things about color, but still come to the conclusion that the qualia of color are just manufactured in our brain, and that the reality behind color, as far as the universe is concerned, is electromagnetic radiation at various frequences.
Not really. The paper referenced in this article basically says "time" for a quantum system emerges from entanglement between that system and a clock. What is a clock? A system that, um, keeps time. Circular reasoning.
In colloquial use, a clock is just a set of rotating gears with some spring - or some other such contraption - from sun dials to hourglasses and quartz. It might be used for measuring time, but it's existance as a device is not based self-referentially to the concept of time anymore than a drinking glass is based on the concept of liquids to exists. What's more, in this case the "clock" is just an example of an oscillator.
> existance as a device is not based self-referentially to the concept of time
Its existence as an object is not, but its definition as a clock is. Basically the article is defining time in terms of...something that's defined as keeping time. Which, as I said, is circular.
The explanation not being possible without referencing the concept of time is not the same as time itself being a prerequisite as opposed to a product of the oscillation.
Time is a kantian a priori for us, so we can reference nothing without the concept of time anyway. Our experience of time, and our concept of time, is not the same as time.
Similar to how we can say (and some physics theories do) that the universe is a holographic set of static object where everything exists at once, and time and movement is just an illusion of our perception (like the colors we see is an mental thing, and the raw fact is "just" electromagnetic radiation).
In that case oscillation can be a property/structure of things in this static "all moments exist timeless at once", but for us it's still appears as movement in time, and when we describe it we only have this intuitive perception of it.
In general, don't try to beat down advanced physics, QM, etc with appeals to "common sense" logic, it's only merely better than "if Earth is round why don't those in the bottom part fall off".
Exactly. That's what I said. I just didn't want to drag Kant explicitly into it for various reasons.
So if you've read Kant, you understand that time is impossible to say whether it's an attribute of the world, or an attribute of us. In particular, claiming to have empirical evidence of one or the other is nonsense - yet it's what this physics paper does, at least in its clickbaity title.
> In general, don't try to beat down advanced physics, QM, etc with appeals to "common sense" logic
Don't be condescending just because you've taken physics courses. Basic category errors is something everyone's entitled to call out, you don't even have to have read Kant to understand it.
Well Detective Larson, you've come right to the scene for investigation, but the chalk lines hold no clues. If you step away from the blackboard, and go downstairs to the basement where the physical labs are, two doors down from Dr. Frankenstein's lab, you'll find some high-frequency operators who've got an atomic clock. Mrs. Frankenstein will show you the way ;)
Yes, they're using the matter itself as a clock. Who does that?
What kind of universe is it anyway when nobody's ever needed any other kind of clock since the beginning of . . . time? Oh wait . . .
> So it's pointless to say "time is an illusion". It's a basic category of thought
If you think it’s pointless, it’s going to be pointless to you whether it’s true or not
However, to give an alternative point of view. If you can model time differently and provide some predictions or enable some technology, then having a different understanding of time might be very useful. Even if we still need to use time in the models
And that’s been the case with general relativity. For a long time, and for many physical phenomena, Newton laws and models are just fine. But relativity has enabled a lot of better technologies and finer understanding of some things, through re-defining how we model time
Having to listen to a 53 minute monologue is too much, especially with the expectation that I won't agree as the podcast is subjective and non-scientific. Could you perhaps provide at least a recap when referring to someone else?
Honestly, I could not. But I can refer you to a perplexity recap. I know LLM content is not allowed, so I'll quote it as a source:
Alan Watts, in his lecture "We as Organism," eloquently explores the interconnectedness of life and consciousness. He likens living beings to the flame of a candle, a continuous flow of energy and activity, rather than static entities. Watts argues that our consciousness often overlooks the constant, harmonious processes of life, focusing instead on potential disruptions. This myopic view leads us to identify with our ego, the troubleshooter, rather than our complete organism. He emphasizes that our bodies, like candle flames or whirlpools, are patterns of the cosmos, ever-changing yet recognizable. Watts challenges the common Western notion of life as a brief flash between two darknesses, urging us to see life as a complex, continuous dance, where there is no dancer, only the dancing.
> People who don’t see their nature and try to stop their thinkings all the time are great sinful poeple and fools. They will fall into the Memoryless-Emptiness. They’re like drunks. They cannot tell good from evil. If you intend to practice non-doing, you have to see your nature before you can put an end to all states and conditions. To attain the Buddha’s Way without seeing your nature is impossible. Still others commit all sorts of evil deeds, claiming karma doesn’t exist. They erroneously maintain that since everything is empty committing evil isn’t wrong. Such persons fall into a hell of endless darkness with no hope of release.
who Zen now calls the first patriarch, but who was kicked out by many people while he was alive.
perhaps we shouldn't be so arrogant to think we're somehow immune now? but it's natural for people not to know how much more profound enlightenment is when they haven't encountered the real dharma yet.
One of the problems with following teachings that aren't right is the risk of losing oneself. It's a fact that many people spoke words under the name of Buddha, like Watts. So how on earth can we pretend that he has not introduced any % of falsehood to the right teaching while he passes it down? The alternative is that Watts is pretending to supreme enlightenment, which I have not heard of him having done.
My question as to what it means for things to happen pertains specifically to the original article talking about the meaning of "time". Instead what we've got is absolute ambiguity that amounts to "don't worry about it, just chill". That sounds like self-loss to me. Self-loss starts with loss of consciousness. That can happen when people learn the degenerated truth (it's like a rotten apple for a consciousness, shall we say).
he was an alcoholic who popularized words he didn't understand - he took the above from the diamond scripture, clearly
and Watts doesn't say much in answer my question - but rather guided people towards self-loss (after which he didn't have to worry about answering questions)
What does it mean for something to "happen"?
it goes back to the reason why the OP article suggests state evolution by time emerges from entanglement.
Thank you. Not familiar with this lecture, but I love how eloquent Alan Watts was
And it’s also great that he credits a lot of his insights to ancient Asian cultures. Essentially explaining that naturally, humans rediscover the nature of the universe, without the need for any special or modern technology, but rather through direct experience of the world
There are many hours of his talks that range from silly to esoteric to outright transcendent, poetry-like explorations and observations of the human condition
My intuitive, but not mathematical, model is that time is an illusion created by our perception “sampling reality”
It’s like when it looks like wheels are spinning backwards, or when using a stroboscopic light you see something different
“Time” is just flowing everywhere, not in any particular direction. But our perception assigns things an order, which gives us the impression of direction
We are also perceiving multiple times simultaneously. Consider that whatever is on your ears right now, will be converted to electrical signals and then loop through your brain, and potentially trigger a conscious reaction, but right now you have some other signals from some “previous” sound on your brain. So technically, your whole body is perceiving things at different times and trying to blend it all together in an illusion of “present time” that “moves forward”
My own, very personal opinion, is that there is no causality, only correlation
Well, if you believe in causality, everything that happens in a certain progression might seem as the consequence of a previous event
And that seems totally right and it’s a great model to understand our everyday life
Now imagine for a second, that the whole universe was a big cycle, and that you are going to be repeating this very same life in a “future” cycle, and maybe infinitely many times
Which one of those times is the first one? And what is happening first? Did you die first and then were born again, or were you born first before dying? If it’s a never ending cycle, would you know, or would you just be picking a point that seems convenient to you?
At another extreme, when you feel like you are hungry, what is the cause for being hungry? Is it a certain signal in your brain, is a special hormone, is it because you have a habit of eating at a certain time? When exactly do you get hungry and what is the cause? There are pretty much infinite many possible causes to choose, because there are an infinite way of understanding and modeling the meaning of the question and how to answer it
Usually we just take the fastest, “most reasonable” explanation as the reason, but it is arbitrary and subjective. Causes are agreements expressed in language and our models, they are not an absolute unbreakable order of reality
> Now imagine for a second, that the whole universe was a big cycle, and that you are going to be repeating this very same life in a “future” cycle, and maybe infinitely many times
I've heard this called 'Eternal recurrence of the same' in a past life (pun not intended). It fascinates and terrifies me at the same time.
Thank you. Hadn’t heard the name. Apparently it was a central part of Nietzche’s thought and similar to the concept of Eternal Return. Fascinating!
And yes, it’s a bit like the scene in Dune 2 when Paul’s mother, after taking the water of life, tells him he needs to drink it too, that his mind will open so he can see «the beauty and the horror»
Borrowing from signal processing, you could also call this “life aliasing”
We all share a single photon in some theories. When time has no meaning, it can run through the whole universe in a strobe.
Large correlated events need to exist because smaller correlations do. It only makes logical sense if you try to remedy the movement / distance paradoxes.
There’s probably an information density limit, which is why far away galaxies will never have their information reach us after a certain point. They might as well not exist to us, because their information will never be useable in a correlated way.
But, who/what wants to prevent everything from happening at once?
Interestingly, it seems like that might be the missing piece
Most mainstream physical models try to do away with us. To explain the world as if we weren’t in it. How things “really are”. But it’s an impossible thing to answer, because everything is mediated through our own human experience
Hence, it might be better to include our role as observers/interpreters in the models
If we can prove entanglement still exists on a per particle level, hawking radiation is just a correlation fix that uses massive black hole lifetimes to reintroduce particles when they no longer affect the time ordering. Experiments showing photons “reversing” in time stop working through a black hole most likely.
Maybe I understand it wrong, but if time is not an illusion, does that mean the past still exists? Hypothetically, if we could reverse the flow of time, would that mean we could travel into the past?
I ask this because I have a bit of a paradox regarding time travel. It's pretty simple, presumably we're all sentient beings, and our consciousness is here, now, in the present. The science fiction portrayal of time travel suggests that we could travel into the past and interact with our former selves. But if my conscious mind is here now in the year 2024, then what conscious mind are you talking to in the past? Surely my conscious mind cannot exist in two different eras simultaneously.
This little "paradox" of mine has made me ponder the true nature of time. Though more likely these are just the ramblings of a person who has a poor understanding of physics.
>Surely my conscious mind cannot exist in two different eras simultaneously.
mentally I think of it more like save/restore states.
the future-person meeting the past person would just be past person+future person as a merged state, the past person would just be a working snapshot of everything before it without the accrued knowledge of future-person.
if you're someone who believe in an untouchable intangible non-duplicable 'soul', then it breaks the framework. I see myself more as a collection of experiences, so it jibes well into that concept.
A more interesting idea is whether "you" cease to exist in the present while "you" travel back in time to meet "you" in the past. Ie, If time travel is possible, are there "yous" spread across every moment of your existence?
That asks questions of our idea of timeless self-identity or "soul" if you like. Like Trigger's Broom [1], are we the same person as we were yesterday?
The idea of "block universe" follows from special relativity and suggests that not only the past "still" exists, but also the future "already" exists. In other words, all the states of the Universe from all times are physically "there". Here is a great i troduction to this concept:
There is no past you. You travel along the time axis at one speed, other things travel at other speeds. So something could take off from earth at the speed of light and come back further ahead down your line, but nothing can go back in time.
Time is a result of entropy. Which is an inherent property of everything in the universe. From when light transmits the first existence of anything to when it returns to nothing after entropy runs its course. Time is just a measurement of degradation.
I have never understood this, it seems backwards to me. We notice that entropy tends to increase over time, and then say that entropy is a fundamental cause of time?
The increase of entropy is a statistical certainty given a causal ordering of events, no new fundamental properties required.
It is certainly true that the increase of entropy gives a measurable direction to the arrow of time, i.e. the future is where entropy is higher. But I cannot fathom how entropy is anything more than a statistical effect.
As the philosopher's say there is no past or future only present. Nothing exists outside the present. All realities(as well as memories) can only be experienced in the current moment.
Some philosophers also said that everything is made from small unsplittable parts, and even called them "atomos", meaning unsplittable in their language. Then we found them and splitted them, an then we've done that again and now we're on our third or four level of understanding world, while those philosophers try to catch up. Don't hold your breath on any particular philosophy, they are only a questions we didn't answer yet.
The fact we jumped the gun and called the first small things we found atoms doesn't mean the philosophers were wrong...
It means we were wrong to use that label for those things. We do believe there are unsplittable particles, they are just not what we called atoms. Philosophers still looking good to me.
Yes, they were not wrong, like Newton was not wrong about gravity. Philosophers are still usable as a generators of novel wild ideas, which we can then check if they are real. But don't mistake "philosopher's idea" for reality.
We know everything but the current moment only through the fragment of memory active in the current moment, so we don't even know if any past or future has or will ever exist for us to choose.
If time does not pass, chemical reactions do not proceed.
This applies to all the natural elements in our universe, and then some.
Unless you've got some chemical elements completely unlike anything in this universe, which would probably have to consist of particles that are not from around here either, you can rest assured that time isn't going anywhere anytime soon.
You could even say that all matter in the universe itself consists only of the chemical elements in existence at any one point, at their instantaneous state of pre-reaction, ongoing-reaction, or post-reaction.
What if two of these snapshots were not identical? What would the difference be attributable to?
It probably goes way back, but one day I imagine a prehistoric observer recognized that it would be impossible to get something accomplished which did not happen instantly, unless some effort was invested over a period of, you guessed it, time. Doesn't require any math at all, not even a primate observer. You just can't get something done while it's still daylight unless you start a certain period of time before the sun goes down.
So the most direct observation of time is as a celestial phenomenon, that's a no-brainer there. At least in this kind of universe.
>time is an illusion created by <insert superstition here>
Can't go forward with this since it refutes itself, the real mathematical exercise would be to back-calculate as far back as necessary to figure out where the defects arose that are incongruous with this particular universe.
What kind of person could come up with equations for that detailed of back-calculation? They would have to know more than almost all university professors. And where are you going to find them these days? Maybe what's needed is another Einstein, and people don't want to admit it.
Sometimes equations can get so off-target that it doesn't take any mathematical ability at all to call time on it.
What if there's no mathematician remaining who can calculate their way out of it realistically?
Which leaves everybody else blundering around the illogical zone :/
Illusion is just the word they try to use to explain what emergence is. I don't think illusion really fits all that well though because illusion implies it's somehow not real and that's not what emergence is about.
Emergent things are real (in the sense of Dan Dennett's real patterns) just not fundamental.
I agree. As a metaphysical ponderer, I often consider how "illusion" is fundamental to our understanding of science. Consider this: all physical laws and theories are verified through human experience on a time scale, ie: under these conditions, you will observe this result. There is always an observer and at least two points in time. Time, and observation of it, is the ground truth of all physical laws, of our very experience of the universe.
Even in your mathematical derivations, there is an implied observer and time line. Ie: "Using these axioms, performing these operations, you will observe this result". (Precondition, action, result)
A notion is an illusion when it appears to be experientially necessary but models without its structure consistently outperform models with said structure at predicting outcomes.
I've been thinking lately about whether mathematics "is" reality or whether mathematics merely represents reality, and something that I've noticed is that mathematicians and physicists seem to hold the philosophy that if one can create an isomorphism from one thing to another, then both of those things are "real" in some sense.
Take the holographic universe idea for example. There is an isomorphism mapping information within a volume to the boundary on that volume's surface; some physicists, like Leonard Susskind afaict, believe therefore that the universe is a hologram, even when there aren't any tests we can do to prove that the universe can only be a hologram because only holograms behave in such and such a way.
But when I think about it, this seems like a massive leap. We can hypothetically come up with isomorphisms that map, say, the four fundamental forces to like, four angels that work behind the scenes to orchestrate all the interactions in the universe. But that doesn't mean there really are four angels doing this. I suppose this is what someone means when they say we've "confused the map for the territory."
I can't read the text of the paper referenced by the article because I don't have a subscription, but the abstract says:
> We present an implementation of a recently proposed procedure for defining time, based on the description of the evolving system and its clock as noninteracting, entangled systems, according to the Page and Wootters approach. We study how the quantum dynamics transforms into a classical-like behavior when conditions related to macroscopicity are met by the clock alone, or by both the clock and the evolving system. In the description of this emerging behavior finds its place the classical notion of time, as well as that of phase-space and trajectories on it. This allows us to analyze and discuss the relations that must hold between quantities that characterize the system and clock separately, in order for the resulting overall picture to be that of a physical dynamics as we mean it.
Sounds to me like "we found an isomorphism between systems with internal time and systems without time that are entangled with external time..." and I just don't care, because I can come up with any isomorphism I want to. Without a prediction that contradicts our current theories, it's meaningless.
A lot of headlines in theoretical physics strike me as displaying this behavior. Listening to Sabine makes me think that this is the totality of string theory as well. Am I the crazy one?
No, you're not crazy. A ton of theoretical physics in the past several decades has gone into wild speculation about things we're able to mathematically justify and therefore imagine logically.
That doesn't inherently mean it's the only possibility, just that it is one that fits what we know about the math right now.
>mathematically justify and therefore imagine logically.
Isn't statistics a lot more of a down-to-earth branch with "theoretically" some of the most well-understood certainty determination?
I'm no expert but my odds are on having it hugely more probable for imagination to be illogical in some way, rather than logical through-and-through.
Equations can be confusing, what people really want is to draw a valid conclusion;
>one that fits what we know about the math right now.
What are the odds that right this minute there is actually anyone at all smarter than there ever was in the past? Making it very likely that this is not the highest point in math or very many other things either.
Loving this throw away comment without any context:
"the only reason that an object appears to change over time is because it is entangled with a clock
...
anyone observing the universe externally would see it as completely ... unchanging"
How is a clock unchanging? Perhaps it's needs winding, maybe somebody pulled the plug, who knows, but that's the only kind of clock I know that doesn't change.
Maybe the clock with the myriads of hands rotations is view as a whole ? All the possibles states of this clock would be seen simultaneously ? But this clock is itself made up of many parts, which are in turn composed of atoms, subatomic particles, etc. The set of all possible states of the clock also includes the set of states occupied by the different parts of the clock (down to the subatomic level) over time, before and after the clock is made and then disintegrates. The clock is, in fact, just one state among many of the atoms that make it up. These atoms were scattered before being assembled into a clock, and they will be scattered again when the clock is destroyed. So, we are not really talking about a clock, but rather a set of atoms that may have occupied very different positions in the universe, and whose supposed unity exists only transiently when a human being looks at this clock. In a certain way, considering the clock as outside of time almost turns it into a non-being, or at least a diaphanous and ephemeral being, lost in a cloud of particles randomly distributed throughout the universe.
It’s not talking about an unchanging clock. It’s saying that change depends on something that runs like a clock, that “ticks”, that alternates sequentially and in cycles
An alternative analogy would be: imagine space and time as opposites of a spectrum. If you had just 1 moment in time, with no alternation, no change, then it would be akin to having all the space together at once, nothing moving. In the other extreme, if you had as many moments in time as possible, it would be non-stop change, in a seemingly infinite space that could never be fully explored, “unknowably large”.
In a way they are saying that the universe is a sort of superposition of these extremes, and there isn’t any physical difference between them. At least in the models and experiments
What if time is a a free variable that can freely move forward and backwards, perhaps doing a random walk?
The people inside that spacetime (us) couldn't ever tell time changed directions or was going backwards because at any given time "t" the state would consistent with all prior states before t. It would also be consistent with future states of t, but the person at time t can only test for consistency with states prior to the current t, but not future states. To the person it like time is only moving forward.
> What if time is a a free variable that can freely move forward and backwards, perhaps doing a random walk?
It would have to have some measurable effects, distinguishable from "consistency with states prior to the current t". That consistency with previous states is written as t2=t1+X. If t1+X is always "previous state plus some small change", we simplify X to be 1. If you can invent HOW that random walk would manifest, you're up for a nobel prize.
I’ve thought about this as well. We really only perceive time because we have memory; with no memory (like in 50 First Dates) time stands still.
The only thing that breaks this is entropy. Even without memory, you can observe the universe and see how close we are to heat death at any moment. Thats an absolute age
I guess the word illusion is misused, as in a traffic jam is an illusion because it's just too many cars on too little road.
I don't think illusion is meant like hallucinations.
But if it is meant that way, then I guess I can't be convinced anyway, since without time I can't change my mind from not believing that to believing it.
Is the notion and the feeling of 1 second a human made up thing? Surely the speed of time isn’t invented by us so I wonder if some other beings sense time differently
That has been studied: "A comparison of 138 species finds that dragonflies perceive changes in their environment five times faster than humans and 400 times faster than starfish." [1]
The paper presents a theoretical model for understanding the concept of time in quantum mechanics. It builds upon the Page and Wootters (PaW) mechanism, a proposal that suggests time can be treated as a quantum observable.
The Problem of Time in Quantum Mechanics
In the standard formulation of quantum mechanics, time is not treated as an observable of a system, but rather as an external parameter. This means that time is not represented by an operator in the theory, unlike other physical quantities like position or momentum. This has been a long-standing issue in quantum mechanics, often referred to as the "problem of time."
The Page and Wootters (PaW) Mechanism
The PaW mechanism offers a potential solution to this problem. It proposes that time can be defined operationally by using a quantum system as a clock. The idea is that the state of the clock system is entangled with the state of the system whose evolution we want to track. By measuring the state of the clock, we can infer the time for the evolving system.
The Model
The paper presents a specific implementation of the PaW mechanism. It considers two quantum systems:
The Evolving System (Γ): This is a harmonic oscillator, a system that exhibits simple oscillatory motion.
The Clock (C): This is a magnetic system, like a spin in a magnetic field.
The two systems are assumed to be non-interacting but entangled. This means that their states are correlated in a way that cannot be described classically. The entanglement is crucial for the PaW mechanism to work.
Quantum to Classical Transition
The paper explores how the quantum description of time transitions into a classical-like behavior under certain conditions. This is done by considering the case where the clock system becomes macroscopic, meaning it behaves more like a classical object. In this limit, the quantum description of time gives way to the familiar classical notion of time as a continuous parameter.
Key Findings
The paper's key findings include:
Operational Definition of Time: The model provides an explicit way to define time operationally using a quantum clock.
Quantum to Classical Transition: The model demonstrates how the quantum description of time can transition into a classical-like behavior as the clock system becomes macroscopic.
Energy Scale of the Clock: The model highlights the importance of the energy scale of the clock in its ability to accurately describe the dynamics of the evolving system.
Implications
This work has potential implications for our understanding of time in quantum mechanics and its connection to classical physics. It could also be relevant for areas like quantum gravity, where the nature of time is a central question.
I guess if we consider ourselves, or our perception, as a quantum system, then we can be included as the clock that “drives the time” of the entangled system (the reality that we perceive)
> Cosmic coincidence that time flows in the direction our brains utilize entropy to encode and retrieve information
Memory flows in the same direction as entropic growth. If time actually moved backwards according to an "outside observer" then they would see us remembering the future and holding the past to be unknowable.
Could be our universe and timeline is a boltzman universe/boltzman timeline embedded in some large timeless crystalline state space.
That would kinda suck, because we'd be static crystals. But from the subjective perspective of a self aware sub crystal is maybe not so bad. Perhaps reality is malleable and magical.
For instance it might be possible to travel to other universes. From the global view, we have multiple atemporal subjective timelines, with subjective agents popping out of one reality and into another thanks to some crystals and magnets with special geometries. From the subjective view, you have a Rick and Morty episode
There are so many (largely metaphysical) theories for things that our universe might actually be a subjective emergent phenomenon of (a simulation, somebody's dream, a timeless static meta-universe, just to name a few) – but given that there is subjective consciousness in this universe, does it matter what substrate it's actually embedded in for our (or somebody else's, for that matter) ability to ascribe meaning to the emergent phenomenon itself?
In other words, somehow I wouldn't feel much worse about "time not being real" than I'd feel about matter, gravity etc. "not being real", being caused by the vibration of cold, unfeeling superstrings etc.
Just speculation on my part, but I think what they're concerned about is that if time doesn't actually exist and we're all just part of a static crystal, then free will can't exist because everything already happened at once.
It's the ultimate form of determinism: not only is everything predetermined but it already happened and we're just experiencing it as though it hasn't yet.
> It's the ultimate form of determinism: not only is everything predetermined but it already happened and we're just experiencing it as though it hasn't yet.
I'm not being glib or contrary when I ask this question: in what ways does this matter beyond the philosophical implications?
Determinism vs. non-determinism is indeed philosophy, so the implications of getting it wrong can be pretty significant (someone could see themselves as free from moral responsibility to not do bad things to others, because determinism).
Well, not in a way that you don't already accept for general relativity and quantum mechanics, and not for any metaphysical reasons.
But did you know that GR predicts we can build a sub light star drive that shields passengers from acceleration, just by using laser beams to hold together a Jupiter sized shell of matter. The matter shell could be accelerated at 100 Gs by massive star scaled lasers. But so long as it respects certain warp equations and energy conditions, the passengers would feel no acceleration.
That's possible with just physical matter, but GR also predicts negative energy. That allows us to theoretically build things like portals to far away portions of space, just by spinning a ring of matter and zapping it with negative energy.
The weird possibilities only seem to multiply if you add quantum states to the mix, and the potential for a larger quantum universe. Think of that a giving us many extra toe holds into the kind of spacetime fuckery that GM enables. Plus new kinds, like the idea that different realities or nonlocal regions of space could share quantum variables and allow universal travel and communication that way. Which is just amazing , and also terrifying because of the possibility of encountering very strange and dangerous places!
The strange part is not that there is some outer spacetime view where things are static and crystalline. It's that the bulk crystalline structure seems weirdly malleable and reconfigurable by subjective agents, and likely inhabited by other minds that live in portions of that crystal that are alien, and maybe even fundamentally dangerous to us. That makes these hyper determinist models a real mind trip! Okay, the structure is determined. But why is it determined in such a way that it causes such weird and disruptive potential experiences for subjective beings? And how would we cope if the structure let us build hyper technologies to, eg, contact aliens, travel to other universes, or change the laws of space and time?
Modeling reality as a static system does not eliminate free will.
When you model reality as some static crystal you observe from the outside, your intuition helpfully adds things like 1) some outside where there is time (otherwise “static” has no meaning, it’s defined in terms of time) and 2) you (the conscious observer with free will to inspect the crystal). Those things create the tension of respectively “everything already happened” and “no free will in there, surely”, but very counter-intuitively they don’t belong in that model in the first place.
I agree that the argument that there must be no free will because everything already happened is a circular argument. It simply equates determinism with the antithesis of free will, without proving why that should be the case, or even giving us a model of free will. But after eliminating that mental trap, what what is your model of how deterministic free will works? I think that unless we have one, we're still in a circular argument - it's the opposite circular argument to the one we had before, but still in circular form.
That is, just like insisting determinism must eliminate free will is begging the question, simply insisting that determinism does not eliminate free will is also insufficient.
We also need a theory of free will that is compatible with determinism. In another subthread to OP's question, I detail my idea of a protected computational substructure as the best version of free will a determinist can expect, and suggest that's enough to explain the survival benefits of what we call free will. If you are in need of a model I propose that one.
But I am also curious about your thoughts, especially if you have a very different model in mind! What kind of model do you have in mind?
I'm okay with compatibilist deterministic free will theories like those from dennet or tegmark.
Those say that free will is possible if a being establishes a computationally independent substrate and uses that to compute optimal choices for a self model.
This relative computational independence is the best we can hope for, and I believe the resulting freedom is strong enough to explain our subjective experiences of feeling like we're freely choosing. All we're doing is scoping out our possible actions, and picking one that lines up with our self models. And that matters because it's as free as we can be, and it improves our survival ability beyond than of a being with no protected internal model.
My real concern, if reality is just a bundle of all possible existence states threaded together, is that there might easily exist very scary and unpleasant states of existence, and it might be possible to subjectively encounter those states in a way that is terrifying and causes huge amounts of suffering.
The universe where things happen in different times and for clear physical reasons seems less likely to expose us to terrible irrational cosmic horror, compared to the random bundle of all possible chaotic states.
In the universe I'm proposing you might accidentally create a portal to a sub universe of hellish demonic entities. Those things exist already right now in parallel with you and they want to be where you are, like on a Rick and Morty episode!
I would honestly prefer to be in a less cosmically terrifying and alienating universe, if possible! Perhaps the universe is just very very big, but not a jumbled multiverse where everything is happening all at once.
A fantasy book that comes to mind is The Dark Tower, by King.
The universe is unraveling into a bundle of broken times and locations, falling apart because the old society "moved on" to another plane of existence...
It doesn't have this idea of the the world being a static crystal. But it's interesting to think of a static crystal spacetime that eventually seems to fall apart.
It feels as if spending too much time on Physics has some psychotic effect on the mind, not unlike psychotropic substance abuse.
There's much wrong in delegating authority over the concept of time to physicists as there is wrong in delegating authority over any concept to any science that did not create it.
But of the specific case of Physics dense conception of Time, there's more wrong to point out.
However I can only say that the heart better understands time than the mind does.
The headline seems a bit click-baity, as it refers to the Page-Wooters mechanism which was introduced 30 years ago, and as mentioned in the paper has been extensively studied.
A brief and accessible overview can be found here[2].
However this paper seeks to provide a more concrete and less constrained implementation of the Page-Wooters mechanism in order to connect it to our classical world better that previous attempts.
So while probably not a breakthrough paper, a solid step in an interesting direction.
[1]: https://arxiv.org/abs/2310.13386
[2]: https://quantum-journal.org/views/qv-2019-07-21-16/