An Infinite Time's Arrow is Impossible and Incompatible with Scientific Theory

In summary, zhermes argues that the concept of infinity is controversial and that there is no reason why future infinite time cannot exist. However, he does not provide any evidence to support this claim.
  • #1
james.goetz
45
0
Anthony Aquirre and Steven Gratton in 2003 developed a speculative physics hypothesis that includes a timeless generation of time. [1] However, Aquirre in 2007 argued against his 2003 hypothesis of timeless origins while hypothesizing the notion of a past infinite time's arrow. [2] This post briefly examines the possibility of an infinite time's arrow and concludes that an infinite time's arrow is impossible, which was first proposed in the sixth century AD by John Philoponus [3]. Similarly, an infinite time's arrow is incompatible with scientific theory.

The conundrum of time's beginning involves the controversial notion of infinity because an infinite sequence of events would never end in at least one direction. For example, assuming the observed spacetime continuum began fourteen billion years ago and the continuum never ends with a Big Crunch or Big Rip, [4] then the continuum always continues with an ever-increasing finite age.

Similarly, there could not have been an infinite past time's arrow. For example, if there was infinite past time, then an infinite past time would precede every point in continuum history while an infinite sequence could never pass for any point in history to exist. Likewise, there was no (1) infinite past sequence of vacuum fluctuations or (2) infinite past cycles in a cyclic universe.

Some scholars stated to me in personal communication that infinite past time is possible because of different theories of time. For example, various philosophers challenge all empirical observations of cause and effect while proposing that all appearance of such sequences is essentially an illusion in an eternalist/block universe. Such eternalist theories ultimately propose radical simultaneousness of all supposedly past, present and future events while denying all distinction between the past, present, and future. [5] This rejection of sequences disputes the proposed impossibility of infinite past time, but at the expense of rejecting the notion of time's arrow. Also, rejecting the notion of time's arrow incidentally disputes every theory involving cause and effect, which includes all scientific theory. In this case, nobody can possibly disprove that the universe is an eternal block while the appearance of time is merely an illusion, but such philosophical theories are incompatible with the notion of science.

1. Aquirre, Anthony, and Steven Gratton. 2003. "Inflation without a beginning: a null boundary proposal." http://arxiv.org/abs/gr-qc/0301042.
2. Aquirre, Anthony. 2007. "Eternal Inflation, past and future." http://arxiv.org/abs/0712.0571.
3. Wildberg, Christian. 2007. "John Philoponus." Stanford Encyclopedia of Philosophy. http://plato.stanford.edu/entries/philoponus/.
4. See Big Crunch and Big Rip in Caldwell, Robert R., Marc Kamionkowski and Nevin N. Weinberg. 2003. "Phantom Energy and Cosmic Doomsday." http://arxiv.org/abs/astro-ph/0302506.
5. See Markosian, Ned. 2008. "Time." Stanford Encyclopedia of Philosophy. http://plato.stanford.edu/entries/time/.
 
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  • #2
Welcome to PhysicsForums james.goetz; very provocative title, and excellent post!

james.goetz said:
The conundrum of time's beginning involves the controversial notion of infinity because an infinite sequence of events would never end in at least one direction. For example, assuming the observed spacetime continuum began fourteen billion years ago and the continuum never ends with a Big Crunch or Big Rip, [4] then the continuum always continues with an ever-increasing finite age.
Why do you call this controversial?

james.goetz said:
Similarly, there could not have been an infinite past time's arrow
You haven't established any reason why there can't be future infinite time.

james.goetz said:
For example, if there was infinite past time, then an infinite past time would precede every point in continuum history while an infinite sequence could never pass for any point in history to exist.
No. This is false. Its basically the same idea as Hilbert's verdical Paradox (of the 'Grand Hotel'); and similarly analogous to Zeno's Dichotomy (verdical) Paradox. Both of these are resolved with calculus. The concept of confined infinites is very tricky, and completely non-intuitive. I think the underlying problem is a linguistic association between the mathematical concept of 'infinity' and an idea of 'insurmountability' --- which is not accurate. Anyway, there are an infinite number of real-numbers between 0 and 1, yet 2 can be reached :) Consider choosing a random number between 0 and 2. There are an infinite number of choices between 0 and 1, but the probability of choosing one of those numbers is finite (only a half).
 
  • #3
zhermes said:
Welcome to PhysicsForums james.goetz; very provocative title, and excellent post!
Thank you, zhermes.
zhermes said:
Why do you call this controversial?
I now see I was unclear. I tried to say that the concept of infinity is controversial. But that might not be needed in that paragraph. Here is a better way to recast that paragraph:

"The conundrum of time's arrow is comparable to a never-ending clock. For example, assuming the observed spacetime continuum began fourteen billion years ago and the continuum never ends with a Big Crunch or Big Rip, [4] then the continuum always continues with an ever-increasing finite age."
zhermes said:
You haven't established any reason why there can't be future infinite time.
Before I can go farther with this, I need to know the following. Do you agree or disagree with the above recast?
 
  • #4
Okay, yeah. But I still don't really see where you're going.
But yeah, big-bang, finite-time ago, goes on indefinitely, always at a finite age.

Side-note, "time's arrow" per se refers specifically to the unwavering unidirectionality of time's passage---just want to make sure we aren't/don't stumble upon that semantic issue.
 
  • #5
When you say an Infinite Time's Arrow is Impossible, are you saying that time can’t be an independent variable and can’t range from – infinity to + infinity?
 
  • #6
James,

You are so on target.
 
  • #7
zhermes said:
Okay, yeah. But I still don't really see where you're going.
But yeah, big-bang, finite-time ago, goes on indefinitely, always at a finite age.

Side-note, "time's arrow" per se refers specifically to the unwavering unidirectionality of time's passage---just want to make sure we aren't/don't stumble upon that semantic issue.
Hi zhermes, I'm glad that we clarified these details. You said in post #2:
You haven't established any reason why there can't be future infinite time.
These semantics could be tricky. For example, my revised second paragraph established that no spacetime continuum with a finite beginning and an expansion that never ceases will never have an infinitely long time's arrow. Given that I established that the observed universe could expand forever with a finite time's arrow, do you agree or disagree with my proposal that an infinite time's arrow is impossible?
 
  • #8
Imax said:
When you say an Infinite Time's Arrow is Impossible, are you saying that time can’t be an independent variable and can’t range from – infinity to + infinity?
Hi Imax, I apologize because I'm unsure of what you mean by "are you saying that time can’t be an independent variable and can’t range from – infinity to + infinity?" But I'll clarify that I'm specifically talking about time's arrow and that there could never be an infinite lapse of time's arrow, past or future.
 
  • #9
bobsmith76 said:
James,

You are so on target.
Thank you bobsmith76.
 
  • #10
james.goetz said:
...For example, my revised second paragraph established that no spacetime continuum with a finite beginning and an expansion that never ceases will never have an infinitely long time's arrow. Given that I established that the observed universe could expand forever with a finite time's arrow, do you agree or disagree with my proposal that an infinite time's arrow is impossible?

Okay. I think i follow what you're saying. The problem is in your premise of what infinity is. Given a start-time of the universe, any future point in time will have a finite age. That doesn't mean this makes time finite. Something is infinite if it is unbounded. For any given time in the future, it has a finite-time (this means its a 'countable set', but the future time dimension is still unbounded, and thus infinite.

You should revisit my link about Hilbert's grand-hotel paradox---it might clarify how countability is not mutually exclusive with infinity.

And again, its not 'time's arrow' in this context, its just time.
 
  • #11
zhermes said:
Okay. I think i follow what you're saying. The problem is in your premise of what infinity is. Given a start-time of the universe, any future point in time will have a finite age. That doesn't mean this makes time finite. Something is infinite if it is unbounded. For any given time in the future, it has a finite-time (this means its a 'countable set', but the future time dimension is still unbounded, and thus infinite.

You should revisit my link about Hilbert's grand-hotel paradox---it might clarify how countability is not mutually exclusive with infinity.

And again, its not 'time's arrow' in this context, its just time.
You are evading the context of my argument, which is time's arrow. Could we please stick to the subject of my argument that is clearly stated in the title?
 
  • #12
james.goetz said:
You are evading the context of my argument, which is time's arrow. Could we please stick to the subject of my argument that is clearly stated in the title?

Except for my final comment, in my last response, that's exactly what I was responding to. You're argument, as I understand it, can be summarized as follows: because every future time will be separated from the big-bang by a finite time, time is not infinite.

This is false, for the above reasons.
 
  • #13
zhermes said:
Except for my final comment, in my last response, that's exactly what I was responding to. You're argument, as I understand it, can be summarized as follows: because every future time will be separated from the big-bang by a finite time, time is not infinite.

This is false, for the above reasons.
No, that is a misunderstanding of one point in my argument. This point of my argument is summarized as follows: because every future time in the observed spacetime continuum will be separated from the "big-bang" by a finite time, then time's arrow will never be infinite.

I'll also add that time's arrow is bounded by the present. However, if somebody supposes that the future already exists, then perhaps they're an eternalist who rejects the existence of time's arrow. In case of eternalist theory, as stated in the fourth paragraph of my original post, there's no time's arrow and no sequences of events but a mere illusion of sequential events. Likewise, there would be no observations of cause and effect that are foundational to scientific observation.
 
  • #14
zhermes said:
You're argument, as I understand it, can be summarized as follows: because every future time will be separated from the big-bang by a finite time, time is not infinite.
This is false, for the above reasons.

james.goetz said:
No, that is a misunderstanding of one point in my argument. This point of my argument is summarized as follows: because every future time in the observed spacetime continuum will be separated from the "big-bang" by a finite time, then time's arrow will never be infinite.

What exactly is the 'misunderstanding'? What is the difference between the bolded statements? The argument is false, for the above reasons. Read the article on countable sets (http://en.wikipedia.org/wiki/Countable_set) and Hilbert's[/PLAIN] [Broken] grand hotel (http://en.wikipedia.org/wiki/Hilbert's_paradox_of_the_Grand_Hotel)[/URL]. [Broken]

james.goetz said:
I'll also add that time's arrow is bounded by the present. However, if somebody supposes that the future already exists, then perhaps they're an eternalist who rejects the existence of time's arrow. ...
  1. The philosophical concept of eternalism or presentism is subjective, speculative, and irrelevant.
  2. "Time's arrow", per se is a term used to describe the unidirectionality of time. You are using that term incorrectly. The arrow of time is in no way "bounded" by the present. It behaves the same in the past, the present, and the future. If you mean just 'time', as suggested by the context of all of your posts, 'time' is still not bounded by the present, as it existed in the past, exists in the present, and will exist in the future. Time can be conceptually segmented based on the present, and time relative to observers or events can be described relative to the present.
  3. For semantic reasons, the future (i.e. events yet to come) cannot "already exist". Quantum mechanics also suggests that events in the future are indeterminate. Time, per se---which is a direction of freedom---is a dimension like any other: it exists everywhere in the space, regardless of particular location (e.g. 'present').
 
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  • #15
zhermes said:

I reread the articles that you cited. The misunderstanding has nothing to with any disagreement about countable sets and Hilbert's paradox. For example, those articles offer no insight about a never-ending clock that never lapses an infinite duration of time .

Perhaps, as you say, I misused the term "time's arrow." I supposed time's arrow refers to the unidirectional lapse of time, but if time's arrow does not refer to unidirectional lapse of time, then I will recast my brief article. Please see the recast below:

"An Infinite Lapse of Time is Impossible and Incompatible with Scientific Theory"

Anthony Aquirre and Steven Gratton in 2003 developed a speculative physics hypothesis that includes a timeless generation of time. [1] However, Aquirre in 2007 argued against his 2003 hypothesis of timeless origins while hypothesizing a past infinite lapse of time. [2] This post briefly examines the possibility for an infinite lapse of time and concludes that an infinite lapse of time is impossible, which was first proposed in the sixth century AD by John Philoponus [3]. Similarly, an infinite lapse of time is incompatible with scientific theory.

This conundrum of time is comparable to a never-ending clock. For example, assuming the observed spacetime continuum began fourteen billion years ago and the continuum never ends with a Big Crunch or Big Rip, [4] then the lapse of time in the continuum always continues with an ever-increasing finite age."

Similarly, there could not have been a past infinite lapse of time. For example, a past infinite lapse of time would indicate that an infinite lapse of time preceded every point in continuum history while an infinite lapse of time could never pass for any point in history to exist. Likewise, there was no (1) past infinite lapse of time with vacuum fluctuations or (2) infinite past cycles in a cyclic universe.

Alternatively, various scholars propose the philosophical concept called eternalism, which proposes a radical simultaneousness of all supposedly past, present and future events while denying all distinction between the past, present, and future. [5] This rejection of sequential events appears to dispute the impossibility of a past infinite lapse of time. But this rejection includes the expense of rejecting the possibility for a lapse of time. Also, rejecting the possibility for a lapse of time incidentally disputes every theory involving cause and effect, which includes all scientific theory. In this case, nobody can possibly disprove eternalism while the appearance of sequential events is merely an illusion, but such philosophical theories are incompatible with the notion of science.

1. Aquirre, Anthony, and Steven Gratton. 2003. "Inflation without a beginning: a null boundary proposal." [url]http://arxiv.org/abs/gr-qc/0301042
.
2. Aquirre, Anthony. 2007. "Eternal Inflation, past and future." http://arxiv.org/abs/0712.0571.
3. Wildberg, Christian. 2007. "John Philoponus." Stanford Encyclopedia of Philosophy. http://plato.stanford.edu/entries/philoponus/.
4. See Big Crunch and Big Rip in Caldwell, Robert R., Marc Kamionkowski and Nevin N. Weinberg. 2003. "Phantom Energy and Cosmic Doomsday." http://arxiv.org/abs/astro-ph/0302506.
5. See Markosian, Ned. 2008. "Time." Stanford Encyclopedia of Philosophy. http://plato.stanford.edu/entries/time/.
 
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  • #16
Throughout the course of the last 15 posts, you have yet to offer a response to a single one of my responses, critiques, or complaints. Changing every term from "time's arrow" to "lapse of time" is negligible.

If you're simply looking for a place to publish your musings, PhysicsForums is not it.
 
  • #17
I have found this conversation very interesting and insightful. :)

I feel like you both have valid points, but neither one has the true answer, which is that "times arrow" must have a beginning and an end, but it is infinite in the amount of cycles that occur.

I E a big bang occurs and the universe expands along with time moving forward and continues for a finite amount of time of "infinite cycles" and once the Dark matter cannot be overcome by the expansion of the universe it starts collapsing. At the moment of collapse "times arrow" ends. Then another big bang occurs, but and here is the doozy, because the laws of physics have collapsed it can't be that time has continued, restarted, or ended, but that the "new" universe is completely different and a separate new "time's arrow" begins. The real question is will the laws of physics be the same when the next big bang occurs, and I laugh asking myself that question because the idea humors me so much.
 
  • #18
My view is that being mathematical concepts only, infinite and infinitessimal are equally impossible in the real world.
 
  • #19
I guess in someways my view doesn't allow for infinity if the "time's arrow" ends, and a new big bang begins where the laws of physics have broken down, than it will not be infinite cycles, but a different event, where the previous event ceased to exist. :) Oh that is just so funny to think about.
 
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  • #20
zhermes said:
Throughout the course of the last 15 posts, you have yet to offer a response to a single one of my responses, critiques, or complaints. Changing every term from "time's arrow" to "lapse of time" is negligible.

If you're simply looking for a place to publish your musings, PhysicsForums is not it.
Sorry, I never saw you address my primary point that an infinitely long lapse of time can never pass, but you described (1) geometric concepts of unbounded time independent of empirically observable sequential events and (2) various paradoxes of infinity that say nothing about the sequential counting of an infinite number of real numbers. But since I better understand you and you say that I never responded to one of your responses, then I will review your first response:
zhermes said:
No. This is false. Its basically the same idea as Hilbert's verdical Paradox (of the 'Grand Hotel'); and similarly analogous to Zeno's Dichotomy (verdical) Paradox. Both of these are resolved with calculus. The concept of confined infinites is very tricky, and completely non-intuitive. I think the underlying problem is a linguistic association between the mathematical concept of 'infinity' and an idea of 'insurmountability' --- which is not accurate. Anyway, there are an infinite number of real-numbers between 0 and 1, yet 2 can be reached :) Consider choosing a random number between 0 and 2. There are an infinite number of choices between 0 and 1, but the probability of choosing one of those numbers is finite (only a half).

I agree that there is an infinite number of real numbers between 0 and 1, between 0 and .1, between 0 and .01, and ad infinitum. And if I count .1, .2, .3, .4, .5, .6, .7, .8, .9, 1, then my counting included an infinite number of infinite numbers, but that says nothing about sequential counting of a countable infinite set. And that says nothing about identifying say the first three real numbers after 0 or after .1 or so on. And the probability of randomly picking an infinitely improbable number from an infinite set says nothing about an infinite lapse of time. In sum, I see you say nothing [directly] relevant about the passage of an infinitely long sequence of events.
 
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  • #21
james.goetz said:
Sorry, I never saw you address my primary point that an infinitely long lapse of time can never pass
This was your main point. I showed that the only reason you presented for it was wrong. Once again, you suggested that if every future time is of a finite-age, time cannot be infinite. Over the entire course of this post, that is the only reasoning you have done. And it is plainly, manifestly false.
james.goetz said:
In sum, I see you say nothing [directly] relevant about the passage of an infinitely long sequence of events.
That is the point I have repeated responded to---and thus have responded to the body of your argument, and your post.

james.goetz said:
you described (1) geometric concepts of unbounded time independent of empirically observable sequential events and (2) various paradoxes of infinity that say nothing about the sequential counting of an infinite number of real numbers.

Observations show that the universe is flat, and accelerating in expansion---suggesting it will expand indefinitely, and there will be infinite time. Those are the 'empirical observations'. The verdical paradoxes I presented deal with exactly that issue---the basis of your argument.

james.goetz said:
I agree that there is an infinite number of real numbers between 0 and 1, between 0 and .1, between 0 and .01, and ad infinitum. And if I count .1, .2, .3, .4, .5, .6, .7, .8, .9, 1, then my counting included an infinite number of infinite numbers, but that says nothing about sequential counting of a countable infinite set. And that says nothing about identifying say the first three real numbers after 0 or after .1 or so on. And the probability of randomly picking an infinitely improbable number from an infinite set says nothing about an infinite lapse of time.
You're right. These couple of concepts, out of the many I've presented, do not directly refute your point. They were meant to help elucidate the nature of 'finite vs. infinite' and how countability is a separate issue. Both of these points you still seem to struggle with.
 
  • #22
Dan81 said:
I have found this conversation very interesting and insightful. :)
Excellent, and thanks for joining in!

Dan81 said:
I feel like you both have valid points, but neither one has the true answer, which is that "times arrow" must have a beginning and an end, but it is infinite in the amount of cycles that occur.

This is an interesting proposition, and it is not only appealing but the basis for many theories in cosmology. None-the-less, there is nothing either theoretical or observational to negate the possibility that time is infinite.

Tanelorn said:
My view is that being mathematical concepts only, infinite and infinitessimal are equally impossible in the real world.

I think I might agree with you Tanelorn; but the problem is that such an idea could be entirely founded on our day-to-day experiences in which such a proposition seems appealing, if not obvious. It might be that not only are particles/energy/etc quantized, but also space-time itself---creating a minimum size-scale of the universe, and thus no true 'infinitesimal'. It could similarly be true that the universe is bounded and finite in all respects, and thus there is no true 'infinite'. But again, none-the-less, this need not be the case.
 
  • #23
If infinite past time is impossible, then why would infinite space at your left or right side be possible? The current model of the universe is a universe of infinite size. If you are going to argue that it would be impossible to arrive in the now if there is an infinite amount of preceding time, than I wonder why it would be possible to arrive in the here if there's an infinite amount of space left or right of us.

I've heard about the idea of the direction of time being defined by the direction in which entropy increases. If the universe truly is infinite in size, then there ought to be places in the universe where the entropy is steadily decreasing and the beings living there would consider it as a factor they could depend on.
 
  • #24
The observable universe is temporally finite, I trust we all agree on that point. We know nothing about the unobservable parts of the universe, and probably never will. This renders the argument unfalsifiable, which is a polite way of saying it is unscientific.
 
  • #25
I'm fully aware of that, but I'm not trying to prove anything based on that. I'd like to carry the model of the universe which is based on the observable universe a little further and see what it implies about our universe beyond the borders which we are able to observe. It may lead to insights which might be testable and help us get a better understanding of the world we live in.

Whoever came up with the idea of a Calabi-Yau manifold must be fully aware of the fact that is, at least for the moment, absolutely unfalsifiable. Still it does not stop physicists from talking about the idea and wandering about what that means about the world we live in.
 
  • #26
zhermes said:
This was your main point. I showed that the only reason you presented for it was wrong. Once again, you suggested that if every future time is of a finite-age, time cannot be infinite. Over the entire course of this post, that is the only reasoning you have done. And it is plainly, manifestly false.

That is the point I have repeated responded to---and thus have responded to the body of your argument, and your post.



Observations show that the universe is flat, and accelerating in expansion---suggesting it will expand indefinitely, and there will be infinite time. Those are the 'empirical observations'. The verdical paradoxes I presented deal with exactly that issue---the basis of your argument.


You're right. These couple of concepts, out of the many I've presented, do not directly refute your point. They were meant to help elucidate the nature of 'finite vs. infinite' and how countability is a separate issue. Both of these points you still seem to struggle with.

Hi zhermes, I needed to break for another project.

One main problem that I see is that you could brush up on your informal logic and avoid fallacies. For example, we both provide anecdotal examples of surmountable infinities. However, it's a logical fallacy to insist that since some infinities are surmountable then all infinities must be surmountable.

Also, my original post clearly described the observed universe with unlimited expansion. And here you tell me that the observed universe is flat with indefinite expansion as if I was unaware of that. And then you completely contradicted a previous statement of yours because you earlier agreed with me that the spacetime continuum will always expand and will always be finite.

I'll clarify that I'm not objecting to the existence of infinite past and future time independent of sequential events.
 
  • #27
luitzen said:
If infinite past time is impossible, then why would infinite space at your left or right side be possible? The current model of the universe is a universe of infinite size. If you are going to argue that it would be impossible to arrive in the now if there is an infinite amount of preceding time, than I wonder why it would be possible to arrive in the here if there's an infinite amount of space left or right of us.

I've heard about the idea of the direction of time being defined by the direction in which entropy increases. If the universe truly is infinite in size, then there ought to be places in the universe where the entropy is steadily decreasing and the beings living there would consider it as a factor they could depend on.
Hi luitzen, there is a difference between unlimited potential expansion and current infinite size. The entire idea of science saying that space with physical laws is expanding indicates that space is finite. And I have no doubts about infinite nothingness (no physical laws) beyond the observed universe.
 
  • #28
james.goetz said:
we both provide anecdotal examples of surmountable infinities. However, it's a logical fallacy to insist that since some infinities are surmountable then all infinities must be surmountable.
I made no such claim. And once again, to draw you back to Hilbert's Hotel---the entire point of that 'paradox' is establishing that there are degrees of infinite, some larger than others---and thus some which contain contain the others.

At no point did I even suggest that all infinities are 'surmountable' --- presuming that you mean something about countability, or a finite range containing an infinite set...

The fact is that, in theory, the span of time can be directly mapped to the real-numbers. The real-numbers are infinite in range. Thus time, can be infinite in range. Period. As I've said repeatedly, your fundamental point suggests that because every time is finite (i.e. every corresponding real number is finite), the full range of time (or real numbers) cannot be infinite. This is plainly false. And you have yet to offer a refutation, only redirections.

This isn't a debate on the validity of your arguments. I'm explaining why they're wrong - and I've thoroughly lost interest. The purpose of PhysicsForums is to learn and educate; not to share one's personal theories on the universe.

My FINAL comments on this thread:

james.goetz said:
Also, my original post clearly described the observed universe with unlimited expansion. And here you tell me that the observed universe is flat with indefinite expansion as if I was unaware of that.
'You keep saying that word. I do not think it means what you think it means.'
You're using the terms "un-limited" and "in-definite" yet claiming the same things are NOT "in-finite". ?!

james.goetz said:
And then you completely contradicted a previous statement of yours because you earlier agreed with me that the spacetime continuum will always expand and will always be finite.
Again, you don't understand the language. At any given time in the future, a time may be finite, but it is possible that time is still infinite.

james.goetz said:
I'll clarify that I'm not objecting to the existence of infinite past and future time independent of sequential events.
Really?! To quote from the title of the thread "An Infinite Time's Arrow is Impossible".

Or from previous posts:
#7 "[the spacetime continuum] will never have an infinitely long time's arrow"
#8 "I'm specifically talking about time's arrow and that there could never be an infinite lapse of time's arrow, past or future."
#11 "Could we please stick to the subject of my argument that is clearly stated in the title?"
#13 "time's arrow will never be infinite."
#15 The restated title of your post "An Infinite Lapse of Time is Impossible"
#20 "my primary point that an infinitely long lapse of time can never pass"

And with that, I unsubscribe.
 
  • #29
zhermes said:
I made no such claim. And once again, to draw you back to Hilbert's Hotel---the entire point of that 'paradox' is establishing that there are degrees of infinite, some larger than others---and thus some which contain contain the others.

At no point did I even suggest that all infinities are 'surmountable' --- presuming that you mean something about countability, or a finite range containing an infinite set...

The fact is that, in theory, the span of time can be directly mapped to the real-numbers. The real-numbers are infinite in range. Thus time, can be infinite in range. Period. As I've said repeatedly, your fundamental point suggests that because every time is finite (i.e. every corresponding real number is finite), the full range of time (or real numbers) cannot be infinite. This is plainly false. And you have yet to offer a refutation, only redirections.

This isn't a debate on the validity of your arguments. I'm explaining why they're wrong - and I've thoroughly lost interest. The purpose of PhysicsForums is to learn and educate; not to share one's personal theories on the universe.

My FINAL comments on this thread:


'You keep saying that word. I do not think it means what you think it means.'
You're using the terms "un-limited" and "in-definite" yet claiming the same things are NOT "in-finite". ?!


Again, you don't understand the language. At any given time in the future, a time may be finite, but it is possible that time is still infinite.


Really?! To quote from the title of the thread "An Infinite Time's Arrow is Impossible".

Or from previous posts:
#7 "[the spacetime continuum] will never have an infinitely long time's arrow"
#8 "I'm specifically talking about time's arrow and that there could never be an infinite lapse of time's arrow, past or future."
#11 "Could we please stick to the subject of my argument that is clearly stated in the title?"
#13 "time's arrow will never be infinite."
#15 The restated title of your post "An Infinite Lapse of Time is Impossible"
#20 "my primary point that an infinitely long lapse of time can never pass"

And with that, I unsubscribe.

I understand that zhermes unsubscribed from this thread, but I wish to respond to distortions in his parting comments since others might read this thread.

First, he says that my view of a finite universe is a personal view. I suppose that would be the case in the nineteenth century but not since the 1920s.

Second, he possibly assumes that unlimited potential is equivalent to unlimited actualization. I definitely mean that "unlimited" potential is not "infinite" actualization.

Third, I apparently originally miss-used the term "time's arrow" and thought that it meant the unidirectional passage/lapse of time. So my original title could look misleading. But in post #15, I responded to education from this forum and said the title should be "An Infinite Lapse of Time is Impossible and Incompatible with Scientific Theory."

Fourth, he implies that "an infinite lapse in time" is exactly the same thing as "the existence of infinite past and future time independent of sequential events." For example, in post 14, he acknowledged that future events do not yet exist. And he always refers to infinite future time. But given infinite future time and the nonexistence of future events, then logically infinite future time is independent of sequential events.

Fifth, I kept clarifying my argument, but he kept twisting my argument into a straw man and finally accused me of unwillingness to learn.
 
  • #30
James, Infinities of any kind in nature create problems and paradoxes. For example, most scientists consider the classical singularity of GR as unphysical and expect it will be resolved by a working version of quantum gravity. An infinite arrow of time is really not much different from a gravitational singularity which pretty much implies the same thing, just on a smaller scale. We know the observable universe is temporally finite, which appears to immunizes us residents against 'sins of the father' invoked by an infinite arrow of time. If we assume all other universes [if any] are temporally finite and causally disconnected, an infinite number of temporally finite universes does not appear to create a paradox.
 
  • #31
Chronos said:
James, Infinities of any kind in nature create problems and paradoxes. For example, most scientists consider the classical singularity of GR as unphysical and expect it will be resolved by a working version of quantum gravity. An infinite arrow of time is really not much different from a gravitational singularity which pretty much implies the same thing, just on a smaller scale. We know the observable universe is temporally finite, which appears to immunizes us residents against 'sins of the father' invoked by an infinite arrow of time. If we assume all other universes [if any] are temporally finite and causally disconnected, an infinite number of temporally finite universes does not appear to create a paradox.
Chronos, Good point. I agree. I never wrote a word against the possibility of an infinite number of disjointed, finite space-time continuums. Do you have a particular favorite model along these lines?
 
  • #32
I'm not partial to any vast / infinite number of 'universes' model, but, nearly all of them, AFAIK, at least imply they are causally disconnected - which means we can, at best, only infer any of them actually exist. I've always felt that places the whole idea on equal footing with creationism, which I find unappealing.

And yes, I agree you did not rule out the possibility of causally disconnected universes. What you assert, IMO, is a paradox that arises in any universe that is infinitely old. In my mind this has already been done - e.g., Olber's paradox. This problem does not arise in a temporally finite universe.
 
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  • #33
Chronos said:
I'm not partial to any vast / infinite number of 'universes' model, but, nearly all of them, AFAIK, at least imply they are causally disconnected - which means we can, at best, only infer any of them actually exist. I've always felt that places the whole idea on equal footing with creationism, which I find unappealing.

And yes, I agree you did not rule out the possibility of causally disconnected universes. What you assert, IMO, is a paradox that arises in any universe that is infinitely old. In my mind this has already been done - e.g., Olber's paradox. This problem does not arise in a temporally finite universe.
Thank you. I'll take a close look Olber's paradox. Do you know of any other examples?
 
  • #34
Chronos said:
I'm not partial to any vast / infinite number of 'universes' model, but, nearly all of them, AFAIK, at least imply they are causally disconnected - which means we can, at best, only infer any of them actually exist.
Chronos, I took a second look at this and disagree that most multiverse models imply causal disconnection. For example, most multiverse models of inflation imply that there was no first inflation event or first vacuum fluctuation. And a cyclic universe by definition implies that there has been an infinite number of past cycles. Some of the papers on twenty-first century cyclic models include a side note that there might have been a beginning (which means it is not a true cyclic model) and make no attempt to explain the beginning, but these papers need to insist that an infinite past sequence of expansions and crunches is imposable for reasons that have been known since the sixth century while there had to be a beginning. I have no doubts of the possibility of infinite past sequences in geometry but not in nature.

I'm in no way opposed to inference in science, but any inference of an infinite past sequence of any type of events is impossible and likewise should be incompatible with scientific theory.

Also, per your comment on creationism, we need to clarify that this in no way supports young Earth creationism. And conjectures about theism are philosophical and I already got a warning about that in this forum, so I am sticking to the limits of science here.
 
  • #35
james.goetz said:
Chronos, I took a second look at this and disagree that most multiverse models imply causal disconnection. For example, most multiverse models of inflation imply that there was no first inflation event or first vacuum fluctuation.

James, this is not true. The concept of a multiverse arising from inflation is based off of the fact that the doubling time of the space occupied by the inflaton field is larger than the half-life of the inflaton field. Some models of inflation imply that the universe has been inflating forever, but there are many that allow for a first vacuum fluctuation/inflation event, and still give rise to a multiverse. Eternal inflation's predictions of the fluctuation level in the CMB have been precisely confirmed by WMAP.
 
<h2>1. Why is an infinite time's arrow impossible?</h2><p>An infinite time's arrow is impossible because it goes against the fundamental laws of thermodynamics, specifically the second law which states that entropy (disorder) in a closed system will always increase over time. An infinite time's arrow would mean that entropy would eventually reach a maximum, which is not possible according to this law.</p><h2>2. How is an infinite time's arrow incompatible with scientific theory?</h2><p>An infinite time's arrow is incompatible with scientific theory because it contradicts the concept of causality, which is a fundamental principle in science. An infinite time's arrow would mean that there is no beginning or end, making it impossible to determine the cause and effect of events.</p><h2>3. Can't the concept of an infinite time's arrow be explained by the concept of eternal recurrence?</h2><p>No, the concept of eternal recurrence is a philosophical idea and not a scientific theory. It suggests that the universe and all events within it will repeat infinitely. However, this goes against the concept of entropy and causality, making it incompatible with scientific theory.</p><h2>4. What evidence do we have to support the idea that an infinite time's arrow is impossible?</h2><p>There is no direct evidence to support the impossibility of an infinite time's arrow. However, the second law of thermodynamics and the concept of causality have been extensively tested and supported by scientific experiments and observations. These laws are fundamental to our understanding of the universe and its behavior.</p><h2>5. Could future scientific advancements change our understanding of time and make an infinite time's arrow possible?</h2><p>It is possible that future scientific advancements could lead to a better understanding of time and potentially challenge our current understanding. However, it is highly unlikely that an infinite time's arrow would become possible as it would require a complete overhaul of our understanding of the fundamental laws of the universe.</p>

1. Why is an infinite time's arrow impossible?

An infinite time's arrow is impossible because it goes against the fundamental laws of thermodynamics, specifically the second law which states that entropy (disorder) in a closed system will always increase over time. An infinite time's arrow would mean that entropy would eventually reach a maximum, which is not possible according to this law.

2. How is an infinite time's arrow incompatible with scientific theory?

An infinite time's arrow is incompatible with scientific theory because it contradicts the concept of causality, which is a fundamental principle in science. An infinite time's arrow would mean that there is no beginning or end, making it impossible to determine the cause and effect of events.

3. Can't the concept of an infinite time's arrow be explained by the concept of eternal recurrence?

No, the concept of eternal recurrence is a philosophical idea and not a scientific theory. It suggests that the universe and all events within it will repeat infinitely. However, this goes against the concept of entropy and causality, making it incompatible with scientific theory.

4. What evidence do we have to support the idea that an infinite time's arrow is impossible?

There is no direct evidence to support the impossibility of an infinite time's arrow. However, the second law of thermodynamics and the concept of causality have been extensively tested and supported by scientific experiments and observations. These laws are fundamental to our understanding of the universe and its behavior.

5. Could future scientific advancements change our understanding of time and make an infinite time's arrow possible?

It is possible that future scientific advancements could lead to a better understanding of time and potentially challenge our current understanding. However, it is highly unlikely that an infinite time's arrow would become possible as it would require a complete overhaul of our understanding of the fundamental laws of the universe.

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