Time is the denominator of existence, and bits come to be in it by Daryl Janzen

Dear John,

It seems to me what you're really proposing is that 3D space, or the Universe--which we both agree constitutes all of reality--has absolute properties relating to motion, etc., of the things in it, and that time passes when those things move.

Aside from your thinking that this motion, etc., could actually be the cause of time's passage, I agree with this, inasmuch as I think of 3D space as being real and having certain such properties relating to its existence. In fact, I'd almost be willing to say that as long as we can agree that these properties conspire to produce space-time, as the well-ordered metical description of events that occur in the Universe as it exists, then I'm less concerned about whether the measured passage of time should be chalked up to motion and all that, or absolute passage. That's not to say that I'm not interested in what the actual cause is, but that simply for practical purposes I'm glad that you seem to agree with me that the Universe must have some fundamental property that leads to consistent temporal passage, so that it's not all just willy-nilly.

But with that said, I'm only *almost* willing to agree that the motion of things through the Universe would cause time to pass in this very consistent, uniform manner, because I just can't get past feeling that nothing could ever move about and conspire to be the cause of anything if it didn't *exist* in the first place. And that sense of existence--of things in space simply enduring, regardless of whether they *remain* (in time) in one place--is what I see as a fundamental aspect of change, rest, the passage of time, and the occurrence of all events.

I'm not thinking of this as some vector projected into some aethereal dimension, but simply as an absolute passage of time that's taking place everywhere throughout space consistently, and in such a manner that the local passage of time that occurs when things move about through space in time, is less than the absolute passage, in a geometrically well-defined way.

If you think of the barograph example in my last essay, there really isn't any vector of flow through anything, but just an ordered duration of space and everything in it. And the way space-time fits into that picture, as it's being physically traced out onto a sheet of paper that scrolls along beneath the barograph pens, is very much like your idea of an uncertain future becoming a certain past. If we strip away all the unreal paper, etc., in that second dimension, leaving only the things that exist in space, there's no vector; there's just space, existing, with time passing in an ordered way.

But anyway, I think you do agree with most of this. The only difference that I'm seeing is that I think things first of all have to exist if they could ever move, etc., whereas you're wanting the motion of things to be the fundamental cause of their existence. It seems like a real chicken-and-egg problem to me.

Cheers,

Daryl

"... Like the paper, the past is physically unreal, but it is conceptually emergent."

John, I'm really glad you've understood my example so well! I think that fits in with your view so well, as that last paragraph illustrates.

I'm just not there with you on the chicken and the egg thing, but I do think it's a worthwhile problem to think about, and I think you're asking interesting questions (e.g., I do think time would pass if everything were perfectly still, but it would be impossible for everything to be perfectly still, so there's no way of verifying that. On the other hand, there's always *something* in motion, so why not suggest as you do...).

In the meantime, however, I think it's good to be mindful of the more immediate problem, that most people think there can't be an objective Now, and that reality consists of the past, present, and future, without objective distinction. I think we have to get through on that point first, and start making headway from there, before it will be possible to answer these more fundamental problems.

Ah, John that's where I have to strongly disagree. I think it's conceptually very simple to think of nothing moving, but it's impossible to imagine nothing existing. Even thinking of a single slice, an instant, in all of eternity, brings up thoughts of it as existing in my mind. I actually think that's where all the trouble in understanding the block universe model comes in--because it's impossible to think of without surreptitiously imagining it in some sense as existing. In contrast, it's incredibly simple to think of something as just existing, not moving at all through space. I can think of a rock, or whatever. I know that that rock is full of atoms and subatomic particles that *actually* are moving, but that doesn't change the fact that I'm able to naively think of it as being completely still.

The best way I think I've ever heart the passage of time expressed was by Seneca:

"Our bodies are hurried along like flowing waters; every visible object accompanies time in its flight; of the things which we see, nothing is fixed. Even I..., as I comment on this change, am changed myself. This is just what Heraclitus says: 'We go down twice into the same river, and yet into a different river.' For the stream still keeps the name, but the water has already flowed past. Of course this is much more evident in rivers than in human beings. Still, we mortals are also carried past in no less speedy a course;... the universe, too, immortal and enduring as it is, changes and never remains the same. For though it has within itself all that it has had, it has it in a different way from that in which it has had it; it keeps changing its arrangement."

It's worth reading a couple of times to understand how he's using the river metaphor. It's at best a loose comparison, because time doesn't actually flow through any existing space like a river does. The river *mostly* provides a useful means of recognising the passage of time, because the water is moving, so it's obviously changing. But the same passage is still there in all things, with the same measure, no matter whether they're moving or not.

Therefore, when you conclude with "I do think though, we can put time entirely in the category of effect, if we think of it in terms of change" I just have to completely disagree, because the passage of time lies at the heart of change. Nothing can change if it doesn't exist. As for the title, time *is* the denominator of existence, because to *exist* is to be somewhere over a period of time. Whether that "somewhere" is changing as time passes or not, the thing is existing; and in your view and mine, *absolute time* passes everywhere with the same measure, whether or not local measures of time pass differently due to a body's arbitrary motion through space. That time, *absolute time*, is the denominator of "existence", and all the events that occur just happen, and all information simply comes into existence or fades from it as time passes.

I forgot to add, at the end of the first paragraph: I can think of *something* as being completely still, and by superposition I can imagine an entire universe in which nothing at all is moving. With no photons moving about, nothing would be seen, etc., etc., but that doesn't change the fact that I can imagine it, whereas I simply can't think of anything at all without thinking of it in some sense as existing.

Actually, I can say that better--about the quote, I mean. It's worth reading a couple of times in order to see that he is using the river example in two ways. He himself is using it as a metaphor for the flow of time, and he says that's how Heraclitus uses it---but he doesn't, does he? Heraclitus is using the river as a benchmark for recognising temporal passage, because of the fact that it *is* changing. Every time we go down to the river it's obviously changed; it's different. But what Seneca notices, which was surely Heraclitus' point, although we've only got the fragment, is that *everything* is changing in the same way: it's all existing, whether it's moving or not; and that sense of "change" is uniform--the even passage, or duration, of absolute time.

A changing present; however, this "change" is not by virtue of constant rearrangement, but simply because it endures. For that reason, regardless of any possible rearrangement, each instant is already different from any other. In that sense, the present is always changing. I think this is what Joe Fisher means as well.

The alternative you suggested, that the present "moves" along the "passage of time", brings to mind a physical dimension along which the present flows. In order for the 3D present to flow along that fourth dimension, all of it would have to exist, and that's really a 5D concept.

But I think existence *is* the fourth dimension, even in the relativistic description--but the only thing that's ever real is the three-dimensional enduring present.

Daryl

John,

I've tried to discuss cosmology with you before, but you seem adamant about wanting to misunderstand the standard cosmological model. One of its basic assumptions is that there *is* a cosmic time, a cosmic frame of rest, and all the rest of what we've been talking about. In fact, George Ellis for one is far closer to agreeing with your "moving matter causes its own existence" stance than he is with my "matter can't move if it doesn't exist" one. Either way, cosmology describes space as existing, and expanding in time. The three-dimensional universe simply multiplies by a scale-factor a(t), which is a function of cosmic time.

Then how does one model this? Any scale is set by two values, so one possibility to use is that at some finite time in the past the value of the scale-factor was zero. The other value doesn't actually have to be known, but everything can be scaled relative to it. For this, we use the present value, *explicitly assuming that there is a present*, and we usually set it equal to 1 and scale the value at every other time relative to that. Redshift can be related to the change in the value of the scale factor in an expanding/contracting universe--i.e. 3D space that gets bigger or smaller as objective cosmic time passes--and can therefore be used to derive a measure of distance that relates to a change in apparent brightness. Yadda yadda. We have a means of modelling redshift and apparent brightness data. We now have really good data, and the model that tells us our Universe is now 13.8 billion years old, has expanded monotonically from a time when the scale factor was zero, and has been expanding with a very particular rate of change, fits the data very well.

Furthermore, the whole "Big Bang" idea predicted the CMB as a relic of a time when space was relatively much smaller, and energies were a lot higher than they are now, which was observed a while back. Since the initial prediction, people realised that if the CMB really were created this way, when space was a lot smaller, and that it has expanded for billions of years since, then the effects of vacuum fluctuations at that time, which would have caused tiny little anisotropies in the background radiation of space, would have expanded to huge macroscopic sizes along with space. The detailed anisotropy signature that the theory predicts also fits to the standard model. No other model has been proposed that can come close to explaining the detailed CMB anisotropy so well.

I'm not saying I agree with everything about the model, and I'm not trying to defend Big Bang cosmology here. I do have different ideas that I think explain a lot more, and they don't involve real singularities, worm holes, etc. I've been trying to defend presentism against Ken Wharton on his essay page, and I ended up going into some of the details over there. If you're interested to get an idea of what I think, you could look at that.

Regardless, I did want to defend against your claim that Big Bang cosmology is inconsistent with there being a cosmic present, but I really don't want to defend against other aspects of the theory that I disagree with.

Daryl

John,

I first of all need to apologize for the negative tone in my previous reply. I was rude, and I'm sorry. Thanks for not getting upset with me.

First point: I don't think mass actually warps space-time, but it's all a teleparallel effect due to momentum through a universe that exists with a well-defined Lorentzian background metric. I don't think stress-energy has any effect on the basic fabric of reality. (See my post to Ken Wharton). I'm also not happy with the idea of expanding space around gravitationally bound clusters of galaxies, that picks off the outliers and carries them into the Hubble flow.

Point two: A light year of intergalactic space now is not a light year of intergalactic space five minutes from now, since space is expanding. It's the speed of light through space in time that's relevant in the space-time metric. This needs to be appreciated according to the metrical description, without complicating it by thinking of space as not expanding in some places and expanding in others, etc. So: space just multiplies, right. It's everywhere expanding by the exact same amount. This is the way we model the large-scale expansion. Consider two galaxies as points in this expanding space. There are THREE relevant distances to consider when discussing the light travel from one galaxy to the other: the distance between the two points at the time of emission; the integrated distance that light travels through expanding space; and the distance between the two galaxies when the light is finally observed. When distances to galaxies, quasars, etc., are mentioned, it may be the light travel distance that's quoted. It's stated in light years, because light travels a fixed distance in a year, so quoting the light travel distance would also indicate when the light was emitted. The distance is a distance travelled, at a fixed rate, through expanding space. As I said, it's an integrated distance over the path of the photon, and not a distance that there is in space at any one time.

Point three: Number one against you is the CMB's anisotropy signature. No one's offered a reasonable proposal to explain that but Big Bang cosmology. Also, there's the fact that even the temperature was exactly predicted by Big Bang cosmology. Predictive power holds a lot of weight in physics. I suppose one can (?) contrive a theory of tired light to explain the paradox, but I don't know. I seem to recall a sky full of tired photons still having to be bright. Something to do with infinity. I could be wrong, but the possibility doesn't really interest me unless it could realistically begin to contend with the CMB and is consistent with everything else.

Point four: I'm not sure I understand. Are you now talking about aether theories? Or are you thinking that the fabric of space-time needs to be physically manifest in the standard model. I disagree with that. There's a metrical structure of the Universe; everything in the Universe is supposed to have been projected at the Big Bang so that it was all flying apart at an initially decelerating rate (yuck, IMO); and, more to that point, everything in the Universe is supposed to have henceforth been affecting that primordial rate of expansion. I personally think the apparent expansion rate has to do with an absolute background metric that was fixed before the "big bang" (again, refer to my post to Ken Wharton).

Point five: The inference that black holes exist is not justified if there is supposed to be an objective cosmic time.

See: my ideas lie outside of convention, too ;)

Cheers,

Daryl

John,

You said again here "What is the metric for that "fixed distance" light is traveling", but I keep telling you there is no fixed distance in cosmology. Space is expanding. Light travels at a fixed rate through expanding space, and the integrated distance it travels through that space in a year is a fixed amount. The fixed rate is the null rate defined by the metric.

Dylan is screaming death metal in my head, "Don't criticize what you [don't] understand!" I really don't think it's something you "can't" understand. I believe you can. But you really don't yet. And it's really important to actually understand--and understand well--the theory you want to argue against. It's the only way to do proper analysis.

Light travel through expanding space isn't the easiest concept to understand, and a lot of people do have trouble with it. I think it's an especially tricky concept for you because you want to argue that it's wrong more than you want to understand it. But please try to understand: space is constantly expanding and light travels through expanding space at a fixed rate; in a year, it can only get so far, say it goes from A to B one year; if A is a galaxy that's constantly emitting light and B is an observer, then the light A emits even a second after that last bit, that took exactly a year to get to B when it was emitted a second ago, now takes slightly longer to get to B; light still travels the same cumulative distance through space in a year, but a second later the distance between A and B was a bit more AND the eventual distance it had to cross was greater by even more than that *initial* amount because all of the space between A and B was expanding *the entire time* the light travelled.

Distances between objects aren't fixed in an expanding universe, but are expanding. Light does travel at a fixed rate described by invariant null lines in the metric. Therefore, at this fixed rate, light travels a fixed finite distance through expanding space in a year, which integrates along its path over the course of the year as the distance between two fixed endpoints grows and grows.

If you were at all trying to understand this, you would; but all you seem to be doing is looking for an error in it, and there isn't one, and that is keeping you from getting it, as far as I can tell. On this particular point, I feel we're at an impasse until you give up wanting to argue against it and first try to understand it. The question you asked to start with is already wrong, and the "unconscious assumption" you're referring to isn't remotely what anyone thinks.

Now, to move on: you said, "Big Bang cosmology did predict the background radiation, but it didn't predict its smoothness, thus the need for inflation", and I told you I don't want to defend things I don't agree with (inflation), but you've got this all wrong, too. The metric of standard cosmology--the thing that's been verified by observation--is constructed based on the observation that the Universe appears to be isotropic on the large scale, and the assumption that it should be homogeneous, so that nowhere should be special (i.e., it should thus appear isotropic from every point; this is the cosmological principle). Accordingly, the CMB should be smooth. Inflation is supposed to address the flatness and the horizon problem, but I said I don't care to defend a theory I ultimately disagree with right now, so I'm not going to get into that. The more basic issue, though, is that we have a model that assumes spatial homogeneity and isotropy, and it works empirically, but we want to explain why it should be isotropic and homogeneous. We could just go on assuming it, but that bothers people, so we try to think up reasons why that should be.

Now, to refer back to your "but it didn't predict its smoothness"--obviously yes, a signature from when an isotropic and homogeneous space was in near-thermodynamic equilibrium should be very smooth, so the theory does predict that, but what's really interesting is what I said before about the anisotropies that it predicted from tiny vacuum fluctuations occurring then, which we've also observed.

Then in your next statement you again refer to an idea I disagree with, but you again have it so wrong that I'm compelled to try to explain. You wrote: "nor the rate of redshift, so we have dark energy. It seems different standards to say it's proof when it gets it right, but when it gets it wrong, we just need a patch." The rate of the redshift is modelled very accurately by the standard model without having to change the underlying theory a lick. But accurately modelling it meant that a parameter that was previously assumed to be zero had to be allowed to be some other constant value. It's hardly a "patch" when all you're doing is saying your previous assumption seems to be wrong, because observations indicate otherwise. And by the way, in science we never ever ever say anything is proven. We say that we've verified assumptions, or falsified them. That's it. In this particular case, the assumption was falsified. But as I said, I totally disagree with the "dark energy" idea--I think there is a fundamental geometrical constant related to the metrical symmetry, which you'd know if you look at the post to Ken Wharton I keep referring to--so I don't care to defend it.

Daryl

John,

Thanks for the question. That helps. This all goes back to our presentist idea, in which space exists. At any instant, there is a certain physical distance between A and B. But because of the way in which space exists, i.e. expanding as time passes, the physical distance between A and B increases.

The fixed rate that light travels through space in time is a differential, so maybe it would be useful to take a calculus approach: rather than thinking of instantaneous velocity, start by thinking of the fixed rate as a tiny distance travelled in a moment. We can start by thinking of the expansion of space as occurring only "between" each moment, with space remaining fixed "during" each moment. Accordingly, the tiny distance that is traversed every moment is a smaller and smaller fraction of the total distance between the two endpoints, so the light initially covers a greater portion of the distance that's got to be made up. It might take only a tenth of the time to get to the half way point, because space is expanding so much by the end. But this doesn't really matter to the point that we're discussing. The point is that the physical distance that light actually crosses in a year is just given by adding up all the tiny distances travelled in an entire year, which has nothing to do with the fact that space is expanding. The latter is only important if you care to know how far in space the light actually got by travelling at that fixed rate throughout the year.

Now your mind is brimming with objections. "Inconsistent!" you cry, "Space is supposed to be continually expanding, even during those brief moments!" And that's true, but we haven't yet made this a calculus-based description. In the limit in which those moments become instants, the rate does become an instantaneous velocity, and that's what's fixed, and if you want to determine how long it will take light to travel from point A to point B when instantaneous light speed is that fixed value and space is actually continually expanding, you integrate over the path from A to B. However many years that is, tells you how many lightyears that integrated distance was. If you object to the validity of doing this, what you're really objecting to is the validity of calculus, and not the validity of the cosmological model, which simply makes use of calculus in this way.

If you don't understand calculus very well (I have no idea what level of mathematics you're comfortable with) then this isn't the easiest example to begin with. It would be better to first understand how it works in space that isn't expanding, and then complicate things with spatial expansion.

Alternatively, you could just think of the rubber band example I gave you last year. You tie one end to a post and walk slowly away, or even at a variable rate, holding the other end. You have a friend take a marker and draw a line from the fixed end over to you, walking at a fixed rate, always with the same instantaneous velocity. I think you had worried then about how this fixed rate through expanding space could be consistently defined, i.e. when space itself doesn't provide a consistent backdrop. But space really isn't enough, as I've argued above: there really does need to be a consistent four-dimensional background metric. In cosmology, that metric is defined according to comoving coordinates, so that A and B *do* remain a fixed comoving distance from each other as space expands. Galaxies all maintain their positions, and space multiplies.

Daryl