My brain sputters out when I try to go from timeless relations (which assume spatial dimensionality as a given) to a timeless universe within which I sit with the illusion of time! I can't get my mind around anything that doesn't also assume time as a given -- all I end up with is a load of geometry sitting around doing nothing.
No one actually has a working model of consciousness so that programme has a long way to go. But if the only evidence for time is change as Barbour likes to say, and change basically boils down the relative motion of particles, why not describe the whole thing as a timeless table of coordinates essentially? And let psychologists build sensation and a perception of a flow of time from that.
It's a tempting view due to its simplicity and the importance of math. But it is extreme, but so is every other theory or metaphysics trying to explain the same stuff!
This is a circular argument since motion is a change in position. So a change is a motion and a motion is a change. This implicitly refers to personal experience of perception of time flow, but nobody has figured out how to describe it with equations or model without references to that perception.
It can be that this is even impossible since as with equations the words of language are static and can only refer to the perception of time without capacity to describe it.
It is kind of circular - which suggests there is nothing unique about time. "The only evidence for time is change". Not "change (of particle position say) is one evidence of time passing". No - the ONLY evidence is change - the change in particle position for Barbour's simple examples. Therefore, do away with this extra baggage of time, and just look at particle positions. After all, we tell time (and motion) by the position of hands of a clock, the position or angle of stars, or the oscillation in position/momentum of atoms.
What no one has done is understand consciousness or reduce biology to physics much at all. The math behind the above is extremely well known and ironed out. That is why some physicists now put the challenge on biologists and psychologists. The personal or subjective flow of time we all experience is theorized to be recreatable from this (timeless) framework. After all, all you have access to is a single snapshot and memories. Sensorial data and brain states. Registering and firing of nerves and neurons. Momenta of particles...why not? Just particle momementa in a table in some kind of sequential form (e.g. worldines in 4D spacetime block universe).
I completely agree this may end up being an impossible challenge, or that it's later shown to be misguided. But there are accomplished philosophers and physicists behind it, or at least sympathetic to it.
> It is kind of circular - which suggests there is nothing unique about time. "The only evidence for time is change". Not "change (of particle position say) is one evidence of time passing". No - the ONLY evidence is change - the change in particle position for Barbour's simple examples. Therefore, do away with this extra baggage of time, and just look at particle positions.
Well, you've eliminated one step: you can't just look at particle positions, you need to measure change in particle positions in relation to X if you are to explain the world. Simply saying "static state 1", "static state 2" doesn't explain anything, unless you have some kind of relation between state 1 and state 2.
In the end, the very basic purpose of physics is to be able to tell, given state 1, what state 2 will be.
> In the end, the very basic purpose of physics is to be able to tell, given state 1, what state 2 will be.
Totally. But I would say your idea of predicting is still unnecessarily involving a "flow of time"; of things "becoming" or changing in themselves. Relations can hold without this notion of change or "becoming". A carpet with a regular pattern does not evolve in time, yet it has patterns. The patterns could be analogues to the laws of physics. The pattern tells you what can be in adjacent portions of the carpet, just like the laws of physics take input and tell you what will or can happen next. The carpet never changes though. You can imagine a separate observer tracing out a line in the pattern from one section to another and seeing it "change", but again the carpet never changed.
Fitting consciousness into this model is very hard I admit. There would be no outside observer tracing out lines in the carpet seeing them change. Instead, the flow of time (the feeling of us persisting from one moment to the next; not being entirely new objects at each instantaneous slice) would have to be a conscious illusion. But so is redness and warmth I could say. Maybe a brainstate is just your memories. And having a sequence of memories gives the illusion you existed prior to this instant. And this process* is done at every instant.
*Process as in timeless patterns on a carpet or timeless laws of physics. This process does not "take time", it's just action of particles behaving the laws of physics - in a timeless/carpet sense. Consiousness is given at every instant by the relation of particles, like the imagine on a movie screen is given at each instant from the photons of the projector. It's just that our screen "consciousness" feels persistent due to having memories.
If anyone wants a more cogent explanation read Tegmark, Barbour, and Harvey Brown. Here is Harvey https://youtu.be/CA-YsWXRSHU
The problem is that there is no change or any notion of time flow in physical models. They describe a static 4-D universe. So there is no particle but there is a one-dimensional world line in the equations with no difference between points. Surely time has a particular property that is reflected in the equations that one can predict across time and not space. The notion of that world line reflects this. But this does not tell why we perceive those world lines point by point.
I.e. a physical model is like a set of frames for a movie with particular relations between frames. But it does not tell why if we see the movie we perceive the motion and not, for example the whole movie at once. Or why the perception is across time and not space.
And since these being discussed in various forms since at least Parmenides and Buddha I doubt this will be resolved any time soon.
> The problem is that there is no change or any notion of time flow in physical models.
What do you mean by this?
When I write x(t) = x0 + (dx/dt) * t + (d2x/d2t) * t^2, time is right there in the equation.
In relativity, it is even self-evidently different from the 3 spatial dimensions: s = sqrt(x^2 + y^2 + z^2 - (ct)^2).
There is even a somewhat intuitive interpretation for the special-ness of the time dimension: all matter is constantly moving along the ct axis of space time at speed c, unless acted on by some force, trying to follow the shortest distance between the past and the future (so the trajectory bends towards the center of mass of any other matter it finds on the way).
That equation describes a curve in 2 dimensional space with no differences between points with each point having particular time and space coordinates. And you can even resolve it to express time as a function of space. But we do not interpret that as a flow of space.
Sure, but you still can't explain it without adding an extra dimension to your model, and that extra dimension is not symmetrical with the space dimensions. In fact, there is no physical model that I am aware of that makes time and any space dimension interchangeable.
The fact that our mathematical models generally seem to allow movement backwards and forwards in time is in stark opposition to observed physics. This obviously suggests that the models are wrong, and there is something about time we are not capturing well enough. Relativity does somewhat fix this, by essentially postulating that everything is moving with speed c in space-time, but that is a somewhat unsatisfying explanation, since it seems natural to ask why.
The extra dimension does not explain the movement or change. The world line corresponding to the equation is static. It does not show at all why when one looks at a particle, one perceive the movement and change in the position, and not, for example, the whole world line at once.
I am not saying that time and space are the same in physical equations. The point is that they do not describe the perception of time flow, not that there is no difference between time and space.
As I wrote the structure of equations (equations are parabolic or hyperbolic, not elliptical, the sign of the time dimension in the metric tensor is opposite to the space coordinates) reflects that one can predict across time but not space. I.e. the equations reflects that from a picture of a room one can tell what will happen in one hour or what did happen one hour ago. Shadows from the Sun will move, a sleeping cat will not be there, but things will be mostly the same. But try to tell what is in the rest of the room from a one-hour long video of the wall. It is not possible.
But this difference tells nothing about perception of “now” or the time flow.
In a sense the equations reflects how memory operates. We remember a sequence of events and we can focus on a particular moment or select events in an arbitrary order similar how we can select a point or points on the world line of a particle. But the memory does not have “now” and so the equations reflecting the notion of the world line tell nothing about the time flow.
The problem is even worse, because without some time-like process, that geometry can't even be observed. The problem here isn't mathematics, it's the practical aspects of the universe.
> timeless universe within which I sit with the illusion of time
I'm not sure what the definition of illusion is here, but the universe does have an evolving state and that's not an illusion according to any meaning of the word I can think of. Time as a general measure of the speed of this evolution is not a human concept either, there is no difference in the way living matter is subjected to time vs how "dead" matter is.
Where there's room for interpretation in my opinion is whether time is a real dimension, or if it's just a dimension-like phenomenon. It may in the end well boil down to something like "time is just the local tick rate of matter", which is a position that may only be provable if we could somehow discern whether the past actually exists physically (as opposed to being destroyed as the universe's state evolves like an array of cellular automata would).
There's a bouncy ball in a box with pressure sensing walls. Each wall feeds the pressure data to HDD physical storage. The ball is released from the top wall at some random angle toward the bottom. The storage devices spin at 100prm and in sync.
Looking at the data from the 6 storage devices, I would see the first entry is from wall_ceiling, recorded at plate rotational angle 0pi. Then the next entry in the collection is from wall_floor say at 1pi. Then wall_left at 1.5pi then wall_ceiling again at 2.1pi, then wall_right at 3pi.
The ball-sensor-storage system alone never needed a "flow of time". The data printout at the end is just a piece of paper with a few columns of numbers. A function is also a column of numbers. And so is a circle or any other polygon.
You may think the printout went from 1 entry to 2 entries to 3 entries...that surely was a flow of time. No. A flow of time is the subjective feeling of a continuous you "flowing" through time. It is entirely internal. The printout system does not have a flow of time. It has time, but again, Barbour is arguing time is extra baggage which is unneeded when you have the motion of the particles - as above. It adds nothing. At each step the printout is entirely given by the behavior of the other particles in the system. Why not our brain states too? When you see "blue" you are seeing 480nm wavelength photons hitting your retina and cones. When you feel continuous, each brain state of yours is kind of a running average of your previous brain states (memories). Or something like that. Maybe some kind of recursive build up of memories at each instant.
But you say you must "flow" even for brief moments to perceive something. Even if it's in discrete steps that's fine with you. But you have to be willing to go one step further to get their arguments. There is only assemblages of particles. And somehow certain assemblages lead to self-reference and awareness, of which we call conscious experience and "flow of time".
Can a function "feel" something? Who knows. But the course of human scientific endeavor has taken us very far from where we started.
> It has time, but again, Barbour is arguing time is extra baggage which is unneeded when you have the motion of the particles - as above. It adds nothing.
This is the part that seems suspect: it seems like motion is taken to be fundamental, but time is not. This seems just as arbitrary as taking time as fundamental, and motion as derived (simply the totality of positions at different points in time).
But overall, given the position and momentum of a particle at step 1, can you predict its position at step 6 without knowing some quantity that is equivalent to the length of time between step 1 and step 6? And if you do require such a quantity, does it matter whether we use time or something else?
> A flow of time is the subjective feeling of a continuous you "flowing" through time.
Sure, but there is much more to time than this human subjective experience. A lot of our knowledge of physics relies on the notion of time to actually function. It's true that we already know that some of our fundamental physical theories are flawed (since they are currently incompatible with each other), and perhaps removing time from them COULD be a necessity for unifying them, but this is far from a given.
I very much doubt you could reformulate special relativity without ending up with a concept that is completely isomorphic to what we think of as time.
Note that a physical representation of a continuous "you" is a much more dubious concept than time itself, and I think it is one that is anyway incompatible with most physical theories/interpretations, as arguments like the Ship of Theseus or teleportation have shown forever.
I appreciate the effort, but it doesn't matter how many times I read your post, I don't see what's being accomplished there and it honestly feels both condescending and unneccessarily complex at the same time. Even in your example, there is clearly state change (how could there not be).
In particular it's the casual anthropocentrism that doesn't sit right with me, but it's so much more. You're mostly concerned with human perception and philosophical aspects that have roots in human feelings. If your main objection to the existence of time is that it doesn't fit in with your definition of consciousness, that means we're not even remotely talking about the same thing. We might use overlapping words, but that's it.
Consciousness is not a scientific concept.
Penrose did a lot of damage trying to legitimize it with his quantum woo, but it's fundamentally incompatible with scientific considerations outside of psychology.
I appreciate your criticism! I never read much of Penrose, and find a lot of what he says outside of mathematics to be questionable. I also think I have an incredibly loose idea of consciousness and remain fairly uncommitted. I actually have little interest in making great claims about consciousness, I just have to use it because the idea of the flow of time is made to be a "conscious" (experiential) illusion instead of ontologically, mind-independently real by this very interpretation of the maths of physics. This is hardly my idea though, and I have been paraphrasing people like Harvey Brown, Tegmark, and Barbour the whole time. And the idea of a static block universe dates back to early 1900's, and eternalism back to antiquity. If I have failed and come off pretentious, that's my fault and not theirs. I apologize for that.
Of course there is state change. Of course the sun will rise tomorrow. Of course a state machine will evolve deterministically based on some inputs.
Those are all described mathematically. But the mathematical laws of physics alone must then be interpreted in some way to describe reality. I mean look at the debate over which interpretation to apply to the same maths of QM for an example. Physics is not mathematics, it applies explanations.
And what these physicists above argue is that the math of the laws of physics does not necessitate an ontological, mind-independent flow of time to the universe. That we do experience a flow of time is not under question. We do. What is under question is that since the laws of physics (i.e. the math) works without an ontological flow of time (note: flow of time is a different idea than "time" or "arrow of time", neither of which I am arguing about here. We are only talking about the flow of time), why and how do we experience/perceive one?. Well, they say, through the sequentialism of memories and physical, sensorial data. Nothing woo. And if you are worried about physicists talking about experience - don't we experience a photon registering on a detector or a magnet deflecting electrons up vs down? Those come through empirical experiences. The flow of time would be an experience in a similar form as redness is. It has an empirical origin (e.g. photons on our cones) that leads to an experience.
So no one is denying the flow of time as experience. Just like you can't deny "redness" or "hotness". They are experienced by us, but some also think we can explain them in naturalistic, scientific ways. And that will require a neuroscience perspective on some level. I only bring in consciousness to the extent needed, as it is intimately connected to our perceived "flow of time".
We have to keep clear, "time", "flow of time", and "arrow of time". In earlier posts I did say Barbour thinks "time" is a redundant term; needless baggage on top of just caring about particles and relations to other particles. That in turn morphed into how we can recreate the experience we all have of time-flowing if there really are only particles and forces - no magic of the mind. To explain that, I had to talk about how the flow of time might not be ontologically real. And neuroscientists and physicists will then have to show how our experience is reducible to particles and forces (or fields). A tall task but a totally naturalistic, scientific one no? No woo. Put off defining consciousness and the mind and how they emerge from particles, but allow for it to be what ultimately is responsible for experience, within a "timeless" universe.
Is this not a justifiable position? If you disagree, I would be interested where you feel it goes wrong (if you feel like sharing). If you think we can do physics without referencing to experience I would also be interested.
