Can causality exist without time?

[Perpetual Student]

It is claimed by some physicists that, before the big bang, time did not exist. It seems to me that if that were the case, then there would have been no causality before the big bang and (in plain English) nothing could happen. Consequently, there would have been no big bang, there would still be no time and nothing would ever have happened, and nothing would be happening today or ever.
Playing with coordinate changes for time is merely an irrelevant exercise, since, as I attempted to point out above, there would be a time for the big bang and a time (or not) before the big bang in whatever coordinate system were chosen. For example, in the T discussed above, the big bang would presumably occur at T = 1? However, I'm not sure that's what s. i. intended but it really doesn't matter at this point and I don't believe it’s worth pursuing further.
So, if there were no time before the big bang, there would have been no big bang, or anything else, now or ever. It appears to me that is an inescapable conclusion. Therefore, since there was a big bang, there was "time" before the big bang!
Physicists say their models say nothing about t = 0 or t < 0, so it is left for philosophers, and all other people (including physicists) who love to think and speculate about the universe and its origins to think about it, speculate about it, discuss it, and, as best they can, come to whatever conclusions may be reached about it.

BTW, when I am shown to be wrong, I readily and quickly come to terms with it and move on. I have found out that learning often involves a sequence of false starts and corrections. There is no shame and there should be no remorse for being wrong along the way to gaining more knowledge and understanding.

 

[dasmiller]

Playing with coordinate changes for time is merely an irrelevant exercise, since, as I attempted to point out above, there would be a time for the big bang and a time (or not) before the big bang in whatever coordinate system were chosen. For example, in the T discussed above, the big bang would presumably occur at T = 1? However, I'm not sure that's what s. i. intended but it really doesn't matter at this point and I don't believe it’s worth pursuing further.

I wouldn't dismiss the significance of the coordinate transforms so quickly. Yes, if you measure time by the vibrations of cesium atoms (the second is defined in terms of cesium state transitions), and project that scheme backwards to a period before there were any cesium atoms, eventually your time scale would go past the big bang. But in other ways of mapping time, the big bang is infinitely far back.

The vibrations-of-cesium-atoms metric has a lot of practical applications, but (and I say this as someone who worked for years on a system that assumed that cesium clocks were the preferred reality) why is the #@$*&%# vibrations-of-cesium-atoms way of measuring time so much more important than, say, a measurement that relates time interval to the apparent size of the universe? Or Sol's exponential time? Or any of an infinite number of other ways to measure time? Taking a subset of those ways (those that have 0 <= T < infinity) and saying that they're the "real" ones and thus causality has a problem is . . . well, it's not immediately obvious to me that it's the only correct approach.

This doesn't necessarily mean that it's wrong. In some domains, that trick works just fine. Engineers routinely pick special coordinate transforms to simplify problems and it's a perfectly valid approach because in those domains, if a thing is true in one coordinate system, then it's true in all. For other kinds of problems (relativity springs to mind), that sort of logic can get you into deep trouble.

So, what kind of domain is this question in? I honestly don't know. But I don't think it's fair to simply assume that the time-measurement system that you're accustomed to has some special status that can be used for assessing the origin of the universe.

 

[sol invictus]

So - let's say I define my own "special" time interval - the T100, which is the time it takes for there to be a total of 10^100 interactions among the particles & photons in the universe. (yes, I can come up a bunch of reasons that this isn't a very usable defintion, starting with the argument about whether we're in an infinite universe, then the fact that the definition assumes a meaningful concept of simultaneity across the universe, then- oh, nevermind). Nowadays, a T100 interval takes a few femtoseconds or millenia of 'normal' time.
As we go back closer to the big bang, particles were closer together and moving faster so they interacted more often, and the T100 interval was shorter.
Does the T100 interval go to zero proper time as we approach the big bang? And does it go there quickly enough that there have been infinite number of T100 intervals since the Big Bang? (which stops looking like a bang in this perspective) Or is T100 too flawed to make any such assertions?

Well, interaction rates tend to go at least as the square of the density. The density times the volume is some total number of particles which we'll take to be fixed (it actually could increase, so that's conservative). So then the number of interactions would increase like the density, which for a standard big bang is something like t^{-3/2}. That diverges when you integrate, so yes - by that rough reasoning there are an infinite number of T100s.

It is claimed by some physicists that, before the big bang, time did not exist. It seems to me that if that were the case, then there would have been no causality before the big bang and (in plain English) nothing could happen. Consequently, there would have been no big bang, there would still be no time and nothing would ever have happened, and nothing would be happening today or ever.

That reasoning is flat-out wrong - my -infinity<t<infinity ---> 0<T<infinity is an explicit counterexample.

The truth is, there are a number of proposals for how to "resolve" the big bang. Some imply that there is no time before t=0 - and they are perfectly self-consistent - and some that there was.

In theories of quantum gravity the situation can be really murky. In many such theories, our spacetime is an approximation (it's a local maximum in the wavefunction). There are other such approximations, and they may be present in the wavefunction as well. Each would have its own time and space. When these begin to mix, the whole notion of causality becomes very problematic.

 

[Perpetual Student]

...
The truth is, there are a number of proposals for how to "resolve" the big bang. Some imply that there is no time before t=0 - and they are perfectly self-consistent - and some that there was.

In theories of quantum gravity the situation can be really murky. In many such theories, our spacetime is an approximation (it's a local maximum in the wavefunction). There are other such approximations, and they may be present in the wavefunction as well. Each would have its own time and space. When these begin to mix, the whole notion of causality becomes very problematic.

And there are proposals that the universe is eternally existing, and thus does not require a unique beginning and a beginning of time. The chaotic inflation theory or eternal inflation model of Andrei Linde is a prominent example. There are other such proposals of a universe with an infinite past time. I guess the point here is that these are proposals made by serious theorists as are the proposals you mention above. In the absence of solid evidence, we poor laymen are stuck with our limited wits to come to our own conclusions.

 

[quarky]

A single photon not bound by C is all that is required.

 

[sol invictus]

And there are proposals that the universe is eternally existing, and thus does not require a unique beginning and a beginning of time. The chaotic inflation theory or eternal inflation model of Andrei Linde is a prominent example.

http://prola.aps.org/abstract/PRL/v90/i15/e151301

Many inflating spacetimes are likely to violate the weak energy condition, a key assumption of singularity theorems. Here we offer a simple kinematical argument, requiring no energy condition, that a cosmological model which is inflating—or just expanding sufficiently fast—must be incomplete in null and timelike past directions. Specifically, we obtain a bound on the integral of the Hubble parameter over a past-directed timelike or null geodesic. Thus inflationary models require physics other than inflation to describe the past boundary of the inflating region of spacetime.

There are other such proposals of a universe with an infinite past time.

That is true.

I guess the point here is that these are proposals made by serious theorists as are the proposals you mention above. In the absence of solid evidence, we poor laymen are stuck with our limited wits to make up our own minds.

It's one thing to acknowledge the existence of various possibilities. It's another to claim that an entire class of them are impossible due to some trivial (and invalid) logical syllogism.

 

[Perpetual Student]

...
It's one thing to acknowledge the existence of various possibilities. It's another to claim that an entire class of them are impossible due to some trivial (and invalid) logical syllogism.

OK, let's say we have a situation (one cannot use terms like era or epoch) of no time and no causality. Tell me how the big bang or anything happens.

 

[sol invictus]

OK, let's say we have a situation (one cannot use terms like era or epoch) of no time and no causality. Tell me how the big bang or anything happens.

It's simply not a sensible question (in that situation). It's - rather precisely - like asking what happened before t=-infinity.

 

[Perpetual Student]

It's simply not a sensible question (in that situation). It's - rather precisely - like asking what happened before t=-infinity.

The question is quite sensible in the context of the situation described, namely the claim that there was no time before the big bang. It's the situation that is not sensible and leads to contradictions and absurdities, which has been my point all along.

 

[69dodge]

If there were no t < 0, then there must have been a causeless event, namely, the universe, which would have to incorporate the creation of space and time. I find that illogical.

And if there were times t < 0, extending back infinitely far? What caused the universe in that case?

The universe as a whole has no cause, either way.

Why is one more logical than the other?

If there was once "no time," and no causality, then there would still be "no time." and no causality.

Doesn't saying "there was once x" implicitly assert the existence of a time at which there was x?

It seems to me that it does. So, "there was once no time" is a contradiction in terms.

Don't think, "there was once no time." Think, "there never was any time t <= 0."

 

[The Man]

The question is quite sensible in the context of the situation described, namely the claim that there was no time before the big bang. It's the situation that is not sensible and leads to contradictions and absurdities, which has been my point all along.

You keep coming back to the assertion of “no time before the big bang” whereas as all one can really assert is that time like geodesics have no extension past that singularity (since the question was being moved that way anyway). All that means is that currently we can assert no definitive casual relationship between T < 0 and T > 0 even if we consider a T < 0. Certainly that lack of causality, as I tried to point out before, does not mean that time can not or does not exist before T = 0, but from just a relativistic standpoint we have no way of demonstrating that causality (or even time) extends past that singularity. We know that relativity is not a complete description and from a quantum standpoint we lose our normal consideration of causality at the Planck time even before getting back to T = 0 and the singularity (perhaps even avoiding the problems inherent with a singularity). When we have a more complete theory that encompasses both we will most likely have a better understanding of time going back to and perhaps even before T = 0. It just does not seem constructive to focus on an assertion of a lack of time before the big bang when it is really just our lack of understanding about the big bang around T = 0 where time and casualty are just some of our basic concepts that we simply can not currently effectively apply to that singularity or to get around it.

 

[Perpetual Student]

You keep coming back to the assertion of “no time before the big bang” whereas as all one can really assert is that time like geodesics have no extension past that singularity (since the question was being moved that way anyway). All that means is that currently we can assert no definitive casual relationship between T < 0 and T > 0 even if we consider a T < 0. Certainly that lack of causality, as I tried to point out before, does not mean that time can not or does not exist before T = 0, but from just a relativistic standpoint we have no way of demonstrating that causality (or even time) extends past that singularity. We know that relativity is not a complete description and from a quantum standpoint we lose our normal consideration of causality at the Planck time even before getting back to T = 0 and the singularity (perhaps even avoiding the problems inherent with a singularity). When we have a more complete theory that encompasses both we will most likely have a better understanding of time going back to and perhaps even before T = 0. It just does not seem constructive to focus on an assertion of a lack of time before the big bang when it is really just our lack of understanding about the big bang around T = 0 where time and casualty are just some of our basic concepts that we simply can not currently effectively apply to that singularity or to get around it.

I am quite comfortable with the reality that current models cannot deal with questions about t <(=) 0. The target of my objections has been confined to dogmatic assertions that there was no time before t = 0. Such assertions seem to be based on the fact that the current models are inadequate. The logic seems to be something like: "Our current models do not account for t <(=) 0, hence there was no t <(=) 0." I find those assertions logically inconsistent for the reasons I have stated (too) many times already.

 

[Perpetual Student]

And if there were times t < 0, extending back infinitely far? What caused the universe in that case?

The universe as a whole has no cause, either way.

Why is one more logical than the other?



Doesn't saying "there was once x" implicitly assert the existence of a time at which there was x?

It seems to me that it does. So, "there was once no time" is a contradiction in terms.

Don't think, "there was once no time." Think, "there never was any time t <= 0."

I don't get the point about "there was once no time” or "there never was any time." "There never was any time" is just as tautological since the word "never" implies time. Nevertheless, if you think you have a better way of saying it, that's OK.

I am not looking for a "cause of the universe." I find a universe that goes back in time infinitely as logically acceptable. A universe that goes back to a finite point in time and simply stops or ceases to exist is not logical.

 

[Moochie]

A question for those who know a lot more about physics, cosmology and philosophy than I do.

I'm engaged in a discussion on another forum, and the topic has drifted to the idea of causality. My erstwhile opponent (who is a religious moderate with fundamental leanings, if that makes any sense - he is also not stupid and a very good debating partner, so please don't underestimate him) is suggesting that causality can exist without time. Otherwise, how could the universe have begun? Since time began at the instant of the universe's creation, then the creation's cause must have existed outside of time. Of course, this "cause" is God.

My contention is that causality cannot exist without time, because any sequence of events requires the existence of time. Otherwise, how can any one event even be said to occur "after" another, let alone be caused by it. My contention is also that there can be uncaused events (qv. the Kalam Cosmological Argument).

Is he right? Can one event cause another in the absence of time?

I think "time" is about as meaningful as "meridians" in acupuncture.


M.

 

[sol invictus]

A universe that goes back to a finite point in time and simply stops or ceases to exist is not logical.

For the fifth time, going back to "a finite point in time" and then stopping is an utterly meaningless statement. In order to give it meaning, you must specify the metric on time.

To try to make that easy for you to see I've shown you how to map infinite intervals to finite, and finite to infinite, with coordinate transformations. You can map any interval (finite or infinite) to any other (modulo boundary points) and so if you don't keep track of the metric factors, you can't draw any conclusions at all from the nature of the interval.

So your claims about this are patently absurd - they're like saying "it's logically impossible to measure time using seconds, but hours are fine". If you want to say something less completely stupid, give us a metric you think is logically inconsistent.

 

[69dodge]

For the fifth time, going back to "a finite point in time" and then stopping is an utterly meaningless statement. In order to give it meaning, you must specify the metric on time.

To try to make that easy for you to see I've shown you how to map infinite intervals to finite, and finite to infinite, with coordinate transformations. You can map any interval (finite or infinite) to any other (modulo boundary points) and so if you don't keep track of the metric factors, you can't draw any conclusions at all from the nature of the interval.

So your claims about this are patently absurd - they're like saying "it's logically impossible to measure time using seconds, but hours are fine". If you want to say something less completely stupid, give us a metric you think is logically inconsistent.

I think you're way over his head. (No offense intended, Perpetual Student.) Don't you agree? Over my head too, though perhaps by less.

If he didn't understand the point of your t -> e^t transformation, just repeating it, more or less verbatim, isn't going to help.

Anyway, saying that the universe is x billion years old is really different from saying that it's infinitely old. No? The difference is not just a mere relabeling of events, as by t -> e^t.

Can you describe the difference in simple terms? Can you explain why, even though there is some difference, that difference doesn't invalidate the analogy between a universe in which time goes back to infinity and one in which time goes back only to 0?

Leaving aside questions of strict logical consistency or inconsistency, it certainly feels stranger for the universe to have existed for a finite amount of time without anything having existed "before" it, than for it to have existed forever without anything having existed "before" it. If it existed forever, of course nothing existed before it---there was no opportunity for anything to exist before it, because it always existed---whereas if it existed for x billion years, one could at least imagine that something might have existed x + 1 billion years ago, even though in fact nothing did.

Presumably, that's wrong. But why?

In summary, dumb it down for us, please.

 

[Perpetual Student]

OK, I'll try this one more time. Our current estimate is that the universe we know is approximately 13.5 billion years old. We can ask and get answers to the question, "what was the universe like 12 billion years ago?" Similarly, we can ask about 13.4 billion years ago. Because of the uncertainty of the 13.5 figure when going back in time further, we rephrase our questions to "what was the universe like, say, 100,000 years after the big bang," or 10^-15 seconds after
the big bang.

So, I am now asking the question, "what was the universe like 16 billion years ago?" (years are defined as we all know, ultimately using the cesium atom.)

Now, the answer to that question may be among the following:

1. Our current models do not tell us; we do not know.

2. Our current bubble had not yet started in an endless, number of bubble universes. (The Linde proposal)

3. The universe consisted of Swiss cheese, made by God, which he later changed to the singularity leading to the big bang.

4. There was no universe and no time.

OK, now #1. seems like a reasonable answer. #2. although highly speculative, is interesting. #3. and #4. are absurd. #4. is absurd because there is no basis for such a statement and it leads to all the contradictions I have already amply described. If the universe were nothing with no time 16 billion years ago, then there would still be nothing.

 

[Vorpal]

From my understanding an open interval is one where that interval does not include the endpoints as interior points, but I’m always willing to be wrong. Certainly an interval is dependent on the set which it is a subset of and the interval [0,∞] (in the proper notation) in this consideration is a subset of the set of real numbers defining the set of positive real numbers. However, since the set of positive real numbers is the whole space being considered for T (negative T being before the big bang singularity) would it not be clopen in that regard?

If you're using it that way, then it's true but without content--every space is clopen in itself, no matter what topology or other structure is defined on it. It's also extremely confusing, since in the same breath we're discussing differences of [0,inf) and (0,inf), so if they're both clopen in themselves (and neither is in the reals), what's the point of introducing topological distinctions? The word you're looking for as it applies to intervals is "half-open" (or "half-closed").

You seem to be making the same augment as Perpetual S.

I've been consistently making the exact opposite of his argument in various forms throughout this thread, including in the part you've just quoted.

Funny, I did not see Prpetual S. “moving the question to talk about extensible geodesics instead”.

Well, that explains why he's slowly driving Sol insane (j/k). I made no claims about what PS has or hasn't done in that post, but since doing so would be a direct way to meet Sol's objection to him, so it was relevant.

 

[sol invictus]

I think you're way over his head. (No offense intended, Perpetual Student.) Don't you agree? Over my head too, though perhaps by less.

Probably - be he claims to know some math, so that's why I took that approach.

Anyway, saying that the universe is x billion years old is really different from saying that it's infinitely old. No? The difference is not just a mere relabeling of events, as by t -> e^t.

That's correct. As I said somewhere above, a good definition is what's called "proper time", which is invariant under these coordinate transformations. The amount of proper time back to the big bang in our universe is approximately 13.7 billion years.

Can you describe the difference in simple terms? Can you explain why, even though there is some difference, that difference doesn't invalidate the analogy between a universe in which time goes back to infinity and one in which time goes back only to 0?

I never said that, exactly - I simply objected to PS's naive and wrong arguments about causality. One relevant point is that even in a universe that has existed for a finite proper time, there are still an infinite number of events in any arbitrary interval near 0. That was Vorpal's point, and my coordinate transform simply makes it more apparent (or at least I thought so). So even there, all events have a cause - in fact, an infinite chain of causes (at least if we exclude the single point at t=0).

Leaving aside questions of strict logical consistency or inconsistency, it certainly feels stranger for the universe to have existed for a finite amount of time without anything having existed "before" it, than for it to have existed forever without anything having existed "before" it.

It may feel that way, but I'm not sure that intuition has much validity. In physics one deals with this kind of question by asking what initial or boundary conditions are necessary. In other words, you have some equations that describe the system, but they generally have many solutions - so you ask what is necessary to specify a particular one. Usually that's a boundary condition.

Now, in an eternal universe you'll still have to specify a "boundary" condition everywhere at some specific time. Once that is done you can evolve forward or back as long as you want. In a future-eternal universe (i.e. one with a big bang) you'll have to do precisely the same, but when you evolve back something different happens: the equations become singular. Except that it sometimes happens that for a very special class of solutions they don't become singular, and one might prefer such solutions - in which case a finite universe of that type requires less outside input, and is in some sense more unique and perhaps more natural.

If it existed forever, of course nothing existed before it---there was no opportunity for anything to exist before it, because it always existed---whereas if it existed for x billion years, one could at least imagine that something might have existed x + 1 billion years ago, even though in fact nothing did.

Presumably, that's wrong. But why?

Well.... what's one mile north of the north pole? (The class of solutions I mentioned above are quite a bit like that - they "round off" smoothly at t=0 just like a sphere.)

Actually dasmiller provided another interesting possibility above. Even if the proper time is finite, it might be that whatever kind of clock you care most about ticks faster and faster as you approach the big bang, in such a way that it ticks an infinite number of times "before" you arrive there. In that case, the universe is effectively eternal.

 

[Vorpal]

I am quite comfortable with the reality that current models cannot deal with questions about t <(=) 0. The target of my objections has been confined to dogmatic assertions that there was no time before t = 0.

Slow down a bit. What "dogmatic assertions" to that effect? No one here has claimed such in any absolute terms, and even you make no mention of this motivation until now. It's quite plain in (your) post #11 of this thread that this sub-discussion started with the claim that no times t≤0 logically contradicts causality. It doesn't. In fact, the core of the matter isn't even empirical in the ordinary sense--it's just a question of whether X is logically consistent with Y.

Imagine A and B talking about their favorite models of the universe. They're mathematicians, so they leave most of the empirical work to the physicists and concentrate on internal properties instead.
A: I've this model in which there's a cosmological time t takes only positive values.
B: Doesn't that contradict causality? I mean, every event should be preceded by a cause.
A: Well, the state of the universe at every t has a prior state that determines it, which is as strong a sense of "cause" as it gets.
B: But what about t≤0? What happens then?
A: That makes no sense in this model; the entire universe has t>0. That's all there is.
B: I still think there's a contradiction. I like the idea of t in (-inf,inf) better, since it avoids it. Your model has nothing before t = 0; this one does!
A: What are you talking about? The model satisfies causality as you defined it. If you've some version of causality in mind, what is it?

The question is quite sensible in the context of the situation described, namely the claim that there was no time before the big bang. It's the situation that is not sensible and leads to contradictions and absurdities, which has been my point all along.

At no point have you exhibited the contradiction, merely claimed there is one. You gave a criterion of causality that's essentially "prior to any stuff, there's other stuff [that fully determines it?]", and this is fully consistent with a universe that only has t>0.

I don't understand why you think there's a contradiction; I can only speculate. If it has something to do with the treatment of times as real numbers and that one can talk about negatives ones too (as your post #77 is coached in those lines), well, one can always find contraptions to do that (e.g., the long line^WP to include "before" t=-inf) directly, or indirectly just by applying a suitable transformation.