Naked Science Forum
General Science => General Science => Topic started by: Devans99 on 26/06/2020 12:24:49
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The Big Bang seems like it could be the start of time. I thought of another way to look at the same problem:
1) Assume no start of time, then the length of the past must be greater than any finite number of days (if its finite, time has a start)
2) But finite numbers increase forever without bound - it is not possible for the length of the past to be greater than all finite numbers (nothing can be greater than something unbounded)
3) So the length of the past must be finite
4) So time must have a start
5) Also, you can say time passing is just adding one to the day count - so its impossible for the past to be non-finite.
Just for completeness, I'll give my definition of 'time':
Motion requires a degree of freedom in which to express itself - if the universe was composed of 3 spacial dimensions only then there would be no motion at all - everything would be statuesque. So there must be something else in addition to the 3 spacial dimensions that allows motion and this degree of freedom is called time. So time cannot possibly be motion but we do measure time by measuring motion.
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Not a problem since nobody seems to be suggesting a length of time greater than some unbounded value.
If the length of time of the past is not 'greater than some unbounded value' then its a bounded value - IE a finite number, which implies time has a start.
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Our only useful definition of time is "what separates sequential events". If there were no events before BB, there was no time.
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Our only useful definition of time is "what separates sequential events". If there were no events before BB, there was no time.
Can we prove that though? Another way of looking at it is:
1) The first time period (eg first second) of time, causes the 2nd time period (2nd second)
2) If the first time period (the first second of time) does not exist, then the second time period cannot exist because it is defined by and dependant on the first time period.
3) If the nth time period does not exist, then the nth+1 time period cannot exist.
4) So by mathematical induction, time cannot exist at all if it has no initial time period
5) But time does exist, so time must have a start.
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Ridiculous axioms lead, by induction, to ridiculous conclusions. QED.
The second lump of glump depends on the first lump of glump. Discuss, without defining glump.
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1) Assume no start of time, then the length of the past must be greater than any finite number of days (if its finite, time has a start)
ok
2) But finite numbers increase forever without bound - it is not possible for the length of the past to be greater than all finite numbers (nothing can be greater than something unbounded)
Here is where the proof falls apart. This is precisely what unbounded and infinite mean. If there is no starting point, as assumed in point 1, then no finite number of days will span from now until this nonexistent point. This doesn't mean that the number of days must be greater than infinity, it means that it is infinite (ie not finite). There is a distinction, and confusing the two is the source of the contradiction you identified.
For example I have never eaten a black hole. If we look through the entire history of my past day, we will never find a point in time when I ate a black hole. Nor in the last two days, or 200 days, or 200,000,000,000,000 days. There is no finite number of days that we can look back to and find a point in time where the event occurred. If your proof were valid, the same logic would dictate that I must have, at some point, eaten a black hole.
3) So the length of the past must be finite
4) So time must have a start
5) Also, you can say time passing is just adding one to the day count - so its impossible for the past to be non-finite.
Having broken down at point 2, it is impossible to continue.
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Ridiculous axioms lead, by induction, to ridiculous conclusions. QED.
The second lump of glump depends on the first lump of glump. Discuss, without defining glump.
Earlier periods of time depend on later times. For example, if you had not been born, would you exist now?
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If there is no starting point, as assumed in point 1, then no finite number of days will span from now until this nonexistent point. This doesn't mean that the number of days must be greater than infinity, it means that it is infinite (ie not finite)
Yet days pass and we can count them - so the past clearly has a length.
And length = end - start
If we say the past has no start, IE
length of past = NOW - UNDEFINED = UNDEFINED
Well that contradicts our finding that the past has a length. Hence time has a start.
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If there is no starting point, as assumed in point 1, then no finite number of days will span from now until this nonexistent point. This doesn't mean that the number of days must be greater than infinity, it means that it is infinite (ie not finite)
Yet days pass and we can count them - so the past clearly has a length.
And length = end - start
If we say the past has no start, IE
length of past = NOW - UNDEFINED = UNDEFINED
Well that contradicts our finding that the past has a length. Hence time has a start.
yes: (now – undefined = undefined)
but the fact that (now – yesterday = 1 day) is true has nothing to do with whether there can be an undefined time.
ie tell me when I ate a black hole.
or, we all agree that we can do addition and subtraction with finite numbers (we can even stick with integers to keep things simple). Please, tell me, what is the lowest integer? I can count down from 0 to –1, –2, –3, –4... etc. If we follow your logic (quoted above), then there must be a first one, otherwise, how could we tell that –8 was 5 less than –3?
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yes: (now – undefined = undefined)
but the fact that (now – yesterday = 1 day) is true has nothing to do with whether there can be an undefined time.
ie tell me when I ate a black hole.
or, we all agree that we can do addition and subtraction with finite numbers (we can even stick with integers to keep things simple). Please, tell me, what is the lowest integer? I can count down from 0 to –1, –2, –3, –4... etc. If we follow your logic (quoted above), then there must be a first one, otherwise, how could we tell that –8 was 5 less than –3?
'Now' is defined - we exist do we not?
But if time has no start, the the length of the past is:
end of time (now) - start of time = length of past
IE
NOW - UNDEFINED = UNDEFINED
That can't be right, so time must have a start.
There is no lowest integer, but the integers only exist in our minds; I'm talking about what can exist in reality. Real things need both a start and end else they have an UNDEFINED length - so nothing with the structure of the whole set of integers could ever exist in reality.
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There is no lowest integer, but the integers only exist in our minds; I'm talking about what can exist in reality. Real things need both a start and end else they have an UNDEFINED length - so nothing with the structure of the whole set of integers could ever exist in reality.
So you must also hold that the universe has spatial edges too, right?
Like, if we travel North on the surface of the Earth, the farthest we can go is the North pole, but if we then define an axis that connects the North pole and South pole of the Earth, then we could imagine going 100 km North of the North pole (up, or more positive on the axis), or 100 km South of the South pole (down, or more negative on the axis). We are obviously here, on earth: at 0 km ± a few thousand km. But where is the Southernmost part of the universe? (or the Northernmost, for that matter?)
NB: I'm not saying that the answer to these questions is easy, I'm just trying to point out that logic you have presented doesn't hold.
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So you must also hold that the universe has spatial edges too, right?
Think of space being measured by a ruler which goes on forever - every possible finite number x is inscribed on the ruler and it goes on forever - so the ruler must be longer than all finite numbers x, but finite numbers go on forever, so that’s impossible (how can something be longer than a thing with no end?).
Space is expanding and ‘nothing’ cannot expand, so space must be something (substantivalism) rather than nothing (relationism).
I imagine spacetime as maybe something (something physical) within a sea of 'nothingness'.
'Nothingness' is absence of space, time and everything - it is dimensionless - it is absolute lack of existence. 'Nothingness' cannot be said to be infinite because it does not exist.
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So, that's a "yes"?
If I understand correctly, you believe that space and time are both finite (and maybe bounded too?)
And that's ok (my understanding of what is known of cosmology doesn't prohibit either.)
All I'm saying is that, even if this is actually true, the proof you are holding up to establish this is not valid.
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So, that's a "yes"?
If I understand correctly, you believe that space and time are both finite (and maybe bounded too?)
And that's ok (my understanding of what is known of cosmology doesn't prohibit either.)
All I'm saying is that, even if this is actually true, the proof you are holding up to establish this is not valid.
Yes you have my views correct - finite and bounded space and time.
Please indicate why you think my proof of the start of time is not valid.
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1) Assume no start of time, then the length of the past must be greater than any finite number of days (if its finite, time has a start)
ok
2) But finite numbers increase forever without bound - it is not possible for the length of the past to be greater than all finite numbers (nothing can be greater than something unbounded)
Here is where the proof falls apart. This is precisely what unbounded and infinite mean. If there is no starting point, as assumed in point 1, then no finite number of days will span from now until this nonexistent point. This doesn't mean that the number of days must be greater than infinity, it means that it is infinite (ie not finite). There is a distinction, and confusing the two is the source of the contradiction you identified.
For example I have never eaten a black hole. If we look through the entire history of my past day, we will never find a point in time when I ate a black hole. Nor in the last two days, or 200 days, or 200,000,000,000,000 days. There is no finite number of days that we can look back to and find a point in time where the event occurred. If your proof were valid, the same logic would dictate that I must have, at some point, eaten a black hole.
3) So the length of the past must be finite
4) So time must have a start
5) Also, you can say time passing is just adding one to the day count - so its impossible for the past to be non-finite.
Having broken down at point 2, it is impossible to continue.
You are implicitly using your assumption of bounded time to invalidate the assumption of no starting point.
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You are implicitly using your assumption of bounded time to invalidate the assumption of no starting point.
Unbounded time seems impossible. It implies that the length of the past is greater than any number of finite days.
But finite numbers go on forever so it is not possible for the length of the past to be greater than all finite numbers.
So the length of the past must be a finite number of days long - time has a start.
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1) assume time is finite
2) time must have a starting point
QED
When put in this form, your argument is now valid, but also pure tautology...
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1) assume time is finite
2) time must have a starting point
QED
When put in this form, your argument is now valid, but also pure tautology...
Where exactly did I 'assume time is finite'?
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You are implicitly using your assumption of bounded time to invalidate the assumption of no starting point.
Sorry, I'm a bit new to unbounded time. My limited understanding:
We imagine spacetime as a surface of a sphere - then it sort of seems unbounded.
But you can set co-ordinates in an arbitrary way (chose 0,0 - the origin), then all points are relative to the origin and spacetime has a definite, finite, start and end in all dimensions.
So you could say that unbounded spacetime is sort of bounded?
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Earlier periods of time depend on later times. For example, if you had not been born, would you exist now?
A complete inversion of logic, as I hope you realise.
From birth to writing this, is a sequence of events, separated by time. If I stop writing, I will not be unborn. Later events depend on former events, not the other way around. The length of time between now and my going to bed will not affect the number of years that elapsed between birth and now.
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A complete inversion of logic, as I hope you realise.
From birth to writing this, is a sequence of events, separated by time. If I stop writing, I will not be unborn. Later events depend on former events, not the other way around. The length of time between now and my going to bed will not affect the number of years that elapsed between birth and now.
I think you need to reread my argument.
My argument relies on 'Later events depend on former events'.
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A complete inversion of logic, as I hope you realise.
Sorry, you are correct, what I mean to say in my original argument was 'later times depend on earlier time'.
So the argument was meant to read:
1) the first time period (eg first second), causes the 2nd time period (2nd second)
2) if the first time period (the first second of time) does not exist, then the second time period cannot exist because it is defined by and dependant on the first time period.
3) If the nth time period does not exist, then the nth+1 time period cannot exist.
4) So by mathematical induction, time cannot exist at all if it has no initial time period - a start of time is required else the rest of time is undefined and cannot exist.
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You are implicitly using your assumption of bounded time to invalidate the assumption of no starting point.
Sorry, I'm a bit new to unbounded time.
Thank you for acknowledging this :-) It is the key to learning more.
My limited understanding:
We imagine spacetime as a surface of a sphere - then it sort of seems unbounded.
But you can set co-ordinates in an arbitrary way (chose 0,0 - the origin), then all points are relative to the origin and spacetime has a definite, finite, start and end in all dimensions.
So you could say that unbounded spacetime is sort of bounded?
Yes, you can have non-bounded but still finite surfaces (and spaces) if there is curvature.
I'm not sure that the surface of a sphere really applies to time though (and one can go directly East on the Earth indefinitely, they just wouldn't actually leave the boundary). It could be reasonable to model time like the radial component of polar coordinates, where the origin is actually a meaningful 0, and there isn't any meaningful interpretation of negative values.
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So the argument was meant to read:
1) the first time period (eg first second), causes the 2nd time period (2nd second)
2) if the first time period (the first second of time) does not exist, then the second time period cannot exist because it is defined by and dependant on the first time period.
3) If the nth time period does not exist, then the nth+1 time period cannot exist.
4) So by mathematical induction, time cannot exist at all if it has no initial time period - a start of time is required else the rest of time is undefined and cannot exist.
The conclusion is still invalid and is not a logical conclusion.
The definition and numbering of time periods is arbitrary. Take our Western year numbering system which defines an arbitrary start time, but this does not imply there are no years before 0AD. Similarly we can define other arbitrary start times eg start of lockdown and count the days forward, but again it does not imply there is nothing that goes before.
The same applies to what is misleadingly called Big Bang. This is the earliest event we are able to detect and we can take it as an arbitrary zero, however, just because we measure from this point does not mean time did not exist prior to BB. It may be that the phenomenon we call time started at BB, but there are other hypotheses; a previous universe may have collapsed leading to a sudden re-expansion, or there may have been an infinite time with nothing before a spontaneous event, we really do not know because any evidence was destroyed at BB.
As @chiralSPO points out, there are ways of modelling spacetime which have a definite 0 and other ways where it does not. Personally I suspect ±∞ centred on the current instant of time ;)
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1) the first time period (eg first second), causes the 2nd time period (2nd second)
No. The first event causes the second event. Time period is what lies between* them. It is an effect, not a cause.
*obnoxious phrase, but "separates" can be misinterpreted as an action.
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Yes, you can have non-bounded but still finite surfaces (and spaces) if there is curvature.
I'm not sure that the surface of a sphere really applies to time though (and one can go directly East on the Earth indefinitely, they just wouldn't actually leave the boundary). It could be reasonable to model time like the radial component of polar coordinates, where the origin is actually a meaningful 0, and there isn't any meaningful interpretation of negative values.
With polar coordinates, the time dimension would have an arbitrary start/end. We could choose it to be 0 degrees for example.
Even simpler than polar you could imagine 2d spacetime (1 space, 1 time) as the latitude and longitude of the earth. If time was represented by longitude, the we could choose the meridian line as the start/end of time.
The choice of the start/end of time for an unbounded but finite universe can be arbitrary, but I think there would have to be a real, physical, start of time in such universes - time is built up sequentially (1st day defines the 2nd, 2nd the 3rd, etc...) - so this sequential building up of time would have to have a starting point (eg the meridian line)
A simple interpretation of the unbounded but finite universe option suggests to me that time meets itself (at the meridian line) - so time has to be in the same state at the start and end of time - so that would be a closed type of universe - a big bang that coincides with a big crunch - both events being at the start/end of time (the meridian line).
But I think it gets more complex than this. Hawking represented time as a complex number with his 'no boundary proposal'. That strikes me as wrong: time is a single, linear, degree of freedom - time absolutely does not have a real and imaginary component.
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No. The first event causes the second event. Time period is what lies between* them. It is an effect, not a cause.
*obnoxious phrase, but "separates" can be misinterpreted as an action.
If we have a week: mon, tues, wens, thurs, fri, sat, sun.
Then you remove Monday from existence, does the rest of the week still exist?
No it does not. Say I flew to Paris on Monday. But Monday no longer exists. Where exactly I am on Tuesday?
BTW The argument for the start of time works with causation just fine to:
If the chains of cause and effect stretch back forever, then there cannot be a first cause. The first cause would cause the 2nd cause - without the first cause, the second cause cannot be. Likewise, the nth cause would cause the nth+1 cause, so by mathematical induction, causality cannot exist at all if there is no first cause. But causality does exist, so there must be a first cause. Because it is uncaused, it must be outside of time, which implies time has a start.
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Sorry, I'm a bit new to unbounded time.
You seem to have opened over say 50 threads on various forums, all more or less on this topic, and all committing the same fallacies over and over. You're not new to it, you're just acting that way for whatever purpose you have in doing this. Learning to avoid your logic mistakes does not seem to be this purpose. I can think of only two other reasons.
2) If the first time period (the first second of time) does not exist, then the second time period cannot exist because it is defined by and dependant on the first time period.
Presentism denies this assertion, and is still considered a logically valid view. I offer it as counterexample to your assertion here.
3) If the nth time period does not exist, then the nth+1 time period cannot exist.
4) So by mathematical induction, time cannot exist at all if it has no initial time period
By induction, this logic (if better worded) leads to no end of time. If you want to draw some conclusion about the past, you need to talk about the nth-1 period, not the nth+1. Such logic (typically asserting any moment requires a prior moment) is used to conclude a lack of an initial time period since it would violate such a premise.
Yet days pass and we can count them - so the past clearly has a length.
You've learned absolutely nothing from all the prior identical threads. I can count the negative integers, yet the set of negative integers does not have a size (a beginning). There's no most-negative integer. Your logic here actually leads to the opposite conclusion than the one you draw, but that doesn't stop you from just asserting a conclusion that doesn't follow at all.
Mind you, I'm not asserting an infinite past. I'm just pointing out that your logic is invalid.
Well that contradicts our finding that the past has a length.
You've not established that the past has a finite length except to assert it, which is begging the question, a different fallacy.
Think of space being measured by a ruler which goes on forever - every possible finite number x is inscribed on the ruler and it goes on forever - so the ruler must be longer than all finite numbers x but finite numbers go on forever, so that’s impossible (how can something be longer than a thing with no end?).
You didn't establish that it was longer than a thing with no end. You established that it was longer than any particular finite value along the ruler, but none of those values are the length of the ruler.
I imagine spacetime as maybe something (something physical) within a sea of 'nothingness'.
That would be space being contained by other space.
'Nothingness' cannot be said to be infinite because it does not exist.
So you're saying that our spacetime is something within a sea of something nonexistent, which is pretty close to asserting the nonexistence of the universe.
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The definition and numbering of time periods is arbitrary.
Sure, but you can use any measuring system for time (eg Planck units) and reach the same conclusion.
As time enables motion, time and motion are equivalent, so any regular motion allows us to measure time. So we can always break time down into units of different times.
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2) If the first time period (the first second of time) does not exist, then the second time period cannot exist because it is defined by and dependant on the first time period.
Presentism denies this assertion, and is still considered a logically valid view. I offer it as counterexample to your assertion here.
How exactly does presentism deny this assertion?
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I flew to Paris on Monday. But Monday no longer exists. Where exactly I am on Tuesday?
Of course it no longer exists - Monday (and every other Monday before 29 June 2020) was a time period in the past. You are in Paris, and it is Tuesday.
Monday is not a cause. And even if it were, your great-grandparents probably no longer exist. Do you? Press the big red button, bomb disappears, hole appears in the ground. The disappearance of the cause was essential to the effect!
Moral: beware of -isms. Use your eyes and brain, the tools of science.
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I flew to Paris on Monday. But Monday no longer exists. Where exactly I am on Tuesday?
Of course it no longer exists - Monday (and every other Monday before 29 June 2020) was a time period in the past. You are in Paris, and it is Tuesday.
So you were in London on Sunday.
You flew to Paris on Monday.
Now it is Tuesday and you are in Paris.
But Monday does not exist (by the argument we are using) - so you never flew to Paris.
So how can you be in Paris when you are in London?
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But Monday does not exist (by the argument we are using) - so you never flew to Paris.
That’s a non sequitur.
I’m breathing, as hopefully are you, I take a breath, I exhale and it is gone; like all my former breaths, it no longer exists. As I take my next breath, I know that that would not be possible without the foregoing succession of breaths I’ve been taking for the past 80 years. All of those years, and all of those breaths, no longer exist, but their influence certainly does, or I would not be posting this.
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But Monday does not exist (by the argument we are using) - so you never flew to Paris.
That’s a non sequitur.
I’m breathing, as hopefully are you, I take a breath, I exhale and it is gone; like all my former breaths, it no longer exists. As I take my next breath, I know that that would not be possible without the foregoing succession of breaths I’ve been taking for the past 80 years. All of those years, and all of those breaths, no longer exist, but their influence certainly does, or I would not be posting this.
Why is it a 'non sequitur'?
Later time periods are dependant upon earlier time periods. Take this example:
1. A particle is at position 1 at time 1
2. The particle is at position 2 at time 2
3. The particle is at position 3 at time 3
If we remove [2], then the particle jumps discontinuously from position 1 to 3 - so [3] can only exist if [2] exists - [3] depends upon [2].
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Why is it a 'non sequitur'?
What planet are you from?
Take this example:
Interesting that you expect me to take your example, when you have totally ignored mine.
If we remove [2],
By your logic, you can't; it doesn't exist, once you've reached [3].
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Why is it a 'non sequitur'?
What planet are you from?
But you have not said why it is a 'non sequitur'?
You can't just say somethings wrong and then refuse to say why!
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You can't just say somethings wrong and then refuse to say why!
Where, exactly, did I refuse to do anything?
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You can't just say somethings wrong and then refuse to say why!
Where, exactly, did I refuse to do anything?
I'll go through it again for you. I stated that later times are dependent on earlier times and gave as justification an arguments involving removing the day Monday:
1) So you were in London on Sunday.
2) You flew to Paris on Monday.
3) Now it is Tuesday and you are in Paris.
4) But Monday does not exist (we've removed it from existence) - so you never flew to Paris.
5) So how can you be in Paris when you are in London?
You said 4 is ‘a non sequitur’.
Why?
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But Monday does not exist (by the argument we are using) - so you never flew to Paris.
Irrelevant. Monday did exist, as the interval of time during which I flew from London (before) to Paris (after).
Unless you are very special (and I mean physically, not educationally), your great grandparents probably don't exist, but you seem to, because they once did.
You didn't need to remove Monday from existence. It disappeared all by itself, just like every other day in the past.
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But Monday does not exist (by the argument we are using) - so you never flew to Paris.
Irrelevant. Monday did exist, as the interval of time during which I flew from London (before) to Paris (after).
Unless you are very special (and I mean physically, not educationally), your great grandparents probably don't exist, but you seem to, because they once did.
You didn't need to remove Monday from existence. It disappeared all by itself, just like every other day in the past.
But would I exist if we erase the time period my great grandparents lived? No.
So later times are really dependant upon earlier times.
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You said 4 is ‘a non sequitur’.
Why?
That still doesn’t tell me where I refused anything.
I think Alan has very adequately answered your question. However, I will add that you cannot remove Monday; by your own logic it is not there to be removed. What you did on Monday is done and cannot be undone.
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You said 4 is ‘a non sequitur’.
Why?
That still doesn’t tell me where I refused anything.
I think Alan has very adequately answered your question. However, I will add that you cannot remove Monday; by your own logic it is not there to be removed. What you did on Monday is done and cannot be undone.
If the day on which you were born never happened, would you be here now?
So your birthday defines and determines all your later times - without your birthday, you cannot be.
So earlier times do indeed define/determine/cause later times.
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If the day on which you were born never happened, would you be here now?
I consider it a matter of courtesy to try to answer all questions. I consider it a matter of common sense to do my best to understand the questions. Would you care to explain how a spacetime event which, manifestly, occurred could, somehow, “unoccur”?
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If the day on which you were born never happened, would you be here now?
I consider it a matter of courtesy to try to answer all questions. I consider it a matter of common sense to do my best to understand the questions. Would you care to explain how a spacetime event which, manifestly, occurred could, somehow, “unoccur”?
The spacetime event in question is the start of time - is there such an event or does time stretch back forever?
It appears time cannot exist unless there is a start of time:
The first time period (eg first second), causes the 2nd time period (2nd second) - if the first time period (the first second of time) does not exist, then the second time period cannot exist because it is defined by and dependant on the first time period. If the nth time period does not exist, then the nth+1 time period cannot exist. So by mathematical induction, time cannot exist at all if it has no initial time period - a start of time is required else the rest of time is undefined and cannot exist.
So to explain this another way, time without a start is like a system with no initial state. Because the system has no initial state, it has no subsequent states (because later states are defined by earlier states). So the system does not exist at all without an initial state, but we said it did - contradiction - hence all systems require an initial state.
Think of your initial state - your birth - would you be here if you had not been born.
So this is the whole problem with time not having a start - it implies the whole universe has no initial state - therefore no subsequent states - the universe cannot exist, but the universe does exist - contradiction - time must have a start.
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Would you care to explain how a spacetime event which, manifestly, occurred could, somehow, “unoccur”?
In what way does #44 answer this question?
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Would you care to explain how a spacetime event which, manifestly, occurred could, somehow, “unoccur”?
In what way does #44 answer this question?
I am not saying that events "unoccur", I am saying did the start of time event occur or not? I think you need to re-read #44.
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I think you need to re-read #44.
Thank you,’ I’ve taken your advice.
If the day on which you were born never happened, would you be here now?
It did happen. I am here. An event occurred which you chose to cite as an example, it was an immutable spacetime event. You ask me to contemplate the possibility of its not having occurred. Then you say “I am not saying that events "unoccur”. Please explain how this is not self contradictory.
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If the day on which you were born never happened, would you be here now?
It did happen. I am here. An event occurred which you chose to cite as an example, it was an immutable spacetime event. You ask me to contemplate the possibility of its not having occurred. Then you say “I am not saying that events "unoccur”. Please explain how this is not self contradictory.
I am using your birth as an analogy for the start of time:
- If you were not born, would you exist now?
- If there was no start of time, would the now (the present day) exist?
The answer to both questions is no - all systems require an initial state, else there are no subsequent states - IE the system cannot exist.
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Later time periods are dependant upon earlier time periods. Take this example:
1. A particle is at position 1 at time 1
2. The particle is at position 2 at time 2
3. The particle is at position 3 at time 3
If we remove [2], then the particle jumps discontinuously from position 1 to 3 - so [3] can only exist if [2] exists - [3] depends upon [2].
*opens can of worms*
Do you hold that time must be continuous then?
How could the object ever get to point 2 (time 2) if it had to jump discontinuously from point 1 to point 2?
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I am using your birth as an analogy for the start of time:
I'm flattered, but your insistence that you are not implying the removal of a spacetime event makes it a poor analogy.
- If there was no start of time, would the now (the present day) exist?
Before you can ask anyone to answer that question, you will have to explain how the event of time's starting could occur without pre-existing time in which the change could happen.
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Sorry, this is a repost--I didn't want it to get lost at the end of the last page...
Later time periods are dependant upon earlier time periods. Take this example:
1. A particle is at position 1 at time 1
2. The particle is at position 2 at time 2
3. The particle is at position 3 at time 3
If we remove [2], then the particle jumps discontinuously from position 1 to 3 - so [3] can only exist if [2] exists - [3] depends upon [2].
*opens can of worms*
Do you hold that time must be continuous then?
How could the object ever get to point 2 (time 2) if it had to jump discontinuously from point 1 to point 2?
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Before you can ask anyone to answer that question, you will have to explain how the event of time's starting could occur without pre-existing time in which the change could happen.
That's an interesting question.
Time having a start seems to tie in with the sparse physical evidence we have (the Big Bang), but it leads to problems. It seems something external to spacetime must be responsible for the start of time. The thing that is responsible for the start of our time (call it time1), could possibly exist in another, inclosing form of time (call it time2). But by the arguments given in the OP/above, time2 must also have a start, implying a time3 is required too, and so-on into an infinite regress of different types of time.
All infinite regresses are impossible, so an infinite regress of time1, started by time2, started by time3, etc… is not possible. That implies there must exist something that is external to all forms of time - something timeless and permanent - this is the thing that maybe the root cause of everything.
The problem is we then have this state of timelessness - that must support change. So I'm not quite sure what it could be? Something of a non-sequential nature maybe?
The only type of change we know is the type that occurs in time. So timelessness is a bit of a challenge.
But it seems that timelessness - as bizarre as it sounds - probably does exist. Another way to look at the same issue is causally:
1. Everything in time has a cause
2. Nothing can be the cause for itself
3. (From 1 and 2) At least one cause must be outside of time
Can you see any way out of the above reasoning that does not involve 'timelessness'?
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*opens can of worms*
Do you hold that time must be continuous then?
How could the object ever get to point 2 (time 2) if it had to jump discontinuously from point 1 to point 2?
That's quite a can!
I believe that spacetime is discrete, but I feel it might be better discussed on a separate thread?
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Whilst some events in spacetime proceed via discrete steps, or at least are only metastable in discrete positions, there is nothing inherently discontinuous in the concept of spacetime.
Much of the rest of the argument presupposes that time can somehow be reversed - the business of "erasing" past days, for instance, can only be done retrospectively by definition. Nikita Kruschev's famous example (eggs -> omelette) shows why this is inconceivable: you would have to unscramble all that has happened since your chosen erasure point, but this would take time (so you could never finish the job) and would necessarily include unscrambling the process of unscrambling itself (because if Monday never happened, you wouldn't need to erase it) so you could never start the job.
Since time is what separates sequential events, if there were no events before the Big Bang, you could sensibly call that t = 0. However the more intellectually satisfying concept of a cyclic universe allows all sorts of change before the present BB and t = 0 has no more cosmic significance than the birthday of anyone or anything else.
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Since time is what separates sequential events, if there were no events before the Big Bang, you could sensibly call that t = 0. However the more intellectually satisfying concept of a cyclic universe allows all sorts of change before the present BB and t = 0 has no more cosmic significance than the birthday of anyone or anything else.
Does this not still involve the problem of infinite regression?
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Does this not still involve the problem of infinite regression?
Yes, and the question of what came before, and what caused this evolution is one of the arguments for the idea of "no beginning". A universe with no beginning has always existed, no first cause, no creation, just an endless playing out of the mechanics of big bangs, big crunches, big bangs, forever backward, forever forward, and across infinite space.
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The question cannot be answered without answering another fundamental question: What is time? In short it is simply a function of distance which brings a more fundamental question: What is distance? Well distance is the measure of space relative to some arbitrary reference point with some arbitrary scale. I will try to explain things as simple as possible in the following discussion.
Imagine now the entire space to be composed of a discrete fine grid of lines just like some sort of knitting or fabric where energy and matter can only exist on those lines and not in between. So measuring distance is actually counting those lines or threads relative to some arbitrary starting point. Thus if we take the reference point to be some singularity that existed (many threads away) in the fabric then there will be no meaning for negative distance at all since we are only counting how many threads we are away from that singularity.
Of course sometimes the threads get pulled away or deformed due to gravity or acceleration. However measuring local distance is still counting threads so if we were only meant to exist on this fabric then we will never feel the difference that the distances between the fabric threads have changed. We can only know that those distances have changed by comparing them to other fabric threads in some distant points from the information carried with the light or energy coming from those distant points.
With this setup imagine that the number of threads is the only thing related to our space fabric that we can measure. So if we were travelling through this fabric or if this fabric was travelling through us at some speed then time will be the distance covered between counting one thread and the other. Therefore by definition it can only be positive and passing forward. If you come to think about it in this context, time has no meaning at all. It is simply the interval taken between the appearance of one thread and the next so it depends on speed, acceleration and deformation of the fabric.
Now let’s get back to the fundamental questions: Is this fabric limited or infinite in extent? Well at some point in the past many many threads back it was limited or at least much smaller. With the big bang the whole fabric stretched from one singularity and the distances between the compressed threads increased orders or magnitude in infinitesimal parts of the second.
Your question was when did the time begin? In our context we can put it as when did the first thread come along? Simply it came with the big bang. But what was before that or what was outside that infinitesimal singularity that formed the universe is the same as asking what is there between the threads of our current space fabric. Is it nothing as opposed to something? But what is nothing and does this nothing have any measurable properties? We know that energy, light, matter and time can only exist on the threads and not in between.
Our entire measurements exist only on the threads of the space fabric. The question of what’s in between is quite difficult to answer. We simply do not know and probably can never know. It is just like asking two dimensional beings that lived and existed entirely at the surface of a balloon what is inside your balloon?
Of course the above is not the only definition of time. There is another definition of time that is based on entropy. Entropy is a measure of the degree of randomness. Imagine a closed room and you break a bottle of red gas in one of its corners. At the begging there is some order in the room meaning that the red gas is in one place while the rest of the room is not affected by it so to some degree you can divide the atmosphere into particles belonging to red gas or outside the red gas. As the time passes the red gas spreads throughout the room increasing the randomness in its atmosphere. Simply we can no longer decide where each particle is. Thus, as time moves on, the degree of randomness increases and therefore entropy increases. This appears to be a fundamental law of our universe. We can thus define time by measuring the degree of randomness in the observable universe.
If you have a closed room or a closed finite system then the degree of randomness will always increase as the time passes by. But if the room is not closed and energy can be put to it then we can filter out the air in the room and restore order to its atmosphere. So entropy only decreases if the system is not closed or is infinite.
Simply if the universe is a closed system just like a bubble of matter and energy then this means the entropy of the universe is always increasing as time passes. Since the increase of entropy is related to change in momentum and energy of the macrostate, this means the macrostate of the universe thermal energy or temperature is always constant. However if the observed universe temperature is always cooling down then this means it is not a closed system. In other words it must be either infinite in extent or interacting with other universes where it can exchange energy. This may give you many ideas about what is really between the threads of our universe or space.
However, the idea of infinite universe or multiple universes exchanging energies is one theory and there are too many theories to count in one answer but they all remain theories and my guess we will never know what’s inside our balloon.
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Much of the rest of the argument presupposes that time can somehow be reversed - the business of "erasing" past days, for instance, can only be done retrospectively by definition.
My argument does not 'presupposes that time can somehow be reversed'. It is an argument about whether time needs a start or not.
To recap what I've been saying, all systems need a initial state, else there are no subsequent states and the system cannot exist. The universe is a system, so it needs an initial state - IE the start of time.
Since time is what separates sequential events, if there were no events before the Big Bang, you could sensibly call that t = 0. However the more intellectually satisfying concept of a cyclic universe allows all sorts of change before the present BB and t = 0 has no more cosmic significance than the birthday of anyone or anything else.
The problem with cyclic universes is cycles are not stable - you loose energy which each cycle. So for example, say the universe had been in a pattern of expanding-contracting-expanding-etc... forever. Then it would loose energy on each cycle, and by now it would have stopped cycling - all the matter would be in one big black hole.
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The question cannot be answered without answering another fundamental question: What is time? In short it is simply a function of distance which brings a more fundamental question: What is distance? Well distance is the measure of space relative to some arbitrary reference point with some arbitrary scale. I will try to explain things as simple as possible in the following discussion.
I have a slightly different definition of time:
Motion requires a degree of freedom in which to express itself - if the universe was composed of 3 spacial dimensions only then there would be no motion at all - everything would be statuesque. So there must be something else in addition to the 3 spacial dimensions that allows motion and this degree of freedom is called time. So time cannot possibly be motion but we do measure time by measuring motion.
So time is a dimension-like degree of freedom, that allows motion.
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To recap what I've been saying, all systems need a initial state, else there are no subsequent states and the system cannot exist. The universe is a system, so it needs an initial state - IE the start of time.
Inversion of cause and effect. Time is what separates sequential events. So time starts at the Big Bang, or wherever you define the initial state of your universe.
The problem with cyclic universes is cycles are not stable - you loose energy which each cycle. So for example, say the universe had been in a pattern of expanding-contracting-expanding-etc... forever. Then it would loose energy on each cycle, and by now it would have stopped cycling - all the matter would be in one big black hole.
Where would the energy go? There is no other place than the universe, by definition. Energy is conserved in a closed system. Hawking dealt with this ad nauseam in "Black Holes and Baby Universes".
I have a slightly different definition of time:
And there is your problem.
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To recap what I've been saying, all systems need a initial state, else there are no subsequent states and the system cannot exist. The universe is a system, so it needs an initial state - IE the start of time.
Inversion of cause and effect. Time is what separates sequential events. So time starts at the Big Bang, or wherever you define the initial state of your universe.
The problem with cyclic universes is cycles are not stable - you loose energy which each cycle. So for example, say the universe had been in a pattern of expanding-contracting-expanding-etc... forever. Then it would loose energy on each cycle, and by now it would have stopped cycling - all the matter would be in one big black hole.
Where would the energy go? There is no other place than the universe, by definition. Energy is conserved in a closed system. Hawking dealt with this ad nauseam in "Black Holes and Baby Universes".
I have a slightly different definition of time:
And there is your problem.
OK, so you are agreeing that the universe needs an initial state? And that this is the start of time?
Energy gets converted from more usable forms to less usable forms, so I suspect a cyclic universe would run down after a while.
A cyclic universe needs repeating pattern of expansion of space followed by contraction of space. I do not think the expansion/contraction of space is part of the 'closed system' of spacetime - it is external. Something would have to power that expansion/contraction and I would not imagine it would be 'perfect' - energy would be lost on each cycle.
Also if you think about a cyclic universe with no start of time, then there is no first cycle. If there's no nth cycle, there is no nth+1 cycle. So no universe at all. So any sort of cyclic universe - if that were possible - would still actually need a start of time.
What problem do you have with my definition of time?
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Time is what separates sequential events.
Or, perhaps: difference is what separates sequential events; time is the concept we use to measure that difference.
So time starts at the Big Bang, or wherever you define the initial state of your universe.
I still have difficulty understanding how the change from “no time” to “time” can happen if there is no pre-existing time in which it can occur. Of course, if there is pre-existing time, there is no period of "no time", so the whole thing becomes an exercise in futility.
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What problem do you have with my definition of time?
Simply that it is different from everyone else's, which makes discussion impossible.
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What problem do you have with my definition of time?
Simply that it is different from everyone else's, which makes discussion impossible.
No-one reals knows what time is. There are different definitions. Mine is:
Motion requires a degree of freedom in which to express itself - if the universe was composed of 3 spacial dimensions only then there would be no motion at all - everything would be statuesque. So there must be something else in addition to the 3 spacial dimensions that allows motion and this degree of freedom is called time. So time cannot possibly be motion but we do measure time by measuring motion.
What problem do you see with this definition?
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So entropy only decreases if the system is not closed or is infinite.
The second law of thermodynamics dictates that in a closed system, entropy tends to increase, or to remain constant. In spite of the presence of the word “tends”; the assertion “it never decreases” can still be found attached to many explanations. Clearly, this should give us pause for thought.
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.....but we do measure time by measuring motion.
Would it be more correct to say that we measure motion, using the concept of time to evaluate the difference created by that motion?
There is much talk of measuring time, but what we really do is introduce arbitrary unites in order to give our measurement of change mathematical significance.
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.....but we do measure time by measuring motion.
Would it be more correct to say that we measure motion, using the concept of time to evaluate the difference created by that motion?
There is much talk of measuring time, but what we really do is introduce arbitrary unites in order to give our measurement of change mathematical significance.
I think (not quite sure) that all units of measurement of time are based on motion? I think even Planck time is based on motion (the speed of light).
So 'Time does not have a start' is equivalent to 'Movement has been taking place forever'.
In order to be moving, you have to start moving, so it seems movement cannot be eternal, so that also points to time has a start.
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In a long and involved threat it is easy to select points, piecemeal, and end up getting nowhere. Also, including too many points in a single post often leads to having salient points overlooked. Perhaps we could take a few points, one at a time, to see if we can achieve some clarity that way?
We could start with:
4) So time must have a start
If time has a start, this implies a change from “no time” (event 1) to “time” (event 2). As Alan pointed out “Our only useful definition of time is "what separates sequential events." How could the change (event 1 to event 2) occur without pre-existing time in which the change could happen?
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Can you see any way out of the above reasoning that does not involve 'timelessness'?
BTW; I'm not ignoring this. Although the direct answer is "no", I think there is a "way out", but we are not there yet.
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4) So time must have a start
If time has a start, this implies a change from “no time” (event 1) to “time” (event 2). As Alan pointed out “Our only useful definition of time is "what separates sequential events." How could the change (event 1 to event 2) occur without pre-existing time in which the change could happen?
If there is a start of time, then the change that caused time to start, must have taken place outside time somehow.
So this comes back to the question of whether a timeless wider universe that it capable of change (IE starting time) is possible?
This is where I am a little stumped. If we imagine something outside time, it has to support change somehow. But it seems it cannot be the sequential type of change we are used to in time, because that would imply a start to change and then we end up with another sort of time (which in turn requires a start).
A non-sequential organisation might be possible. If you imagine timeless changes as an unordered set of changes, it might possibly help. So there is this unordered set of timeless changes, and one of those changes is the start of time.
Timeless existence is a very old philosophical problem. No-one has made much progress with it. Best description of timelessness I've heard is 'the eternal now' - somehow everything in your life (say) would take place simultaneously (of course that word is not quite right as it implies time).
Another way to look at the problem was given by Thomas Aquinas. He assumed in his argument that the axiom: ‘can’t get something from nothing’ holds - an assumption that is supported by the law of conservation of energy.
This assumption leads to the conclusion that something must have permanent existence, IE if the universe was ever in a state of nothingness, then ‘can’t get something from nothing’ implies it would still be in a state of nothingness today - so something must have permanent existence.
But assuming time has a start then nothing can exist permanently in time (and time seems sort of transitory anyway), so the rejection of creation ex nilhilo leads us to the same conclusion - something timeless and permanent must exist outside of spacetime.
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Many of these are questions I struggled with for a long time. Welcome to the weird world of infinity/eternity. :)
Before we try to move on, may I suggest looking at https://en.wikipedia.org/wiki/Itzhak_Bars
To explain to the layman how this gauge symmetry works, Bars makes an analogy between the phenomena in the 4+2 dimensional world and events happening in a hypothetical 3 dimensional room. In this analogy the two-dimensional surfaces that makeup the boundaries of the three-dimensional room (walls, ceiling, floor) are the counterparts of the 3+1 dimensional world humans live in as observers. In this setting, if you shine light from different directions in the room, you create two-dimensional shadows of the three-dimensional events projected on the surfaces surrounding the room. The shadows and their motions on some wall will look different than those on other walls, ceiling or floor. If observers were never allowed to exist in the room but were confined to live and crawl only on the surfaces of surrounding boundaries, the two-dimensional physicist at different boundaries would then write different physics equations to describe mathematically the shadows he/she sees from those different perspectives. He/she would also believe that the shadows at different boundaries are different physical systems because their equations would not match. Since all shadows come from the unique set of events in the room, it is evident from the perspective of the room that the shadows are not independent of each other. So, there must be a definite predicted relationship between the systems of the two dimensional equations at different walls. If the two dimensional physicists are very smart, with much effort they may begin to discover this hidden information by carefully comparing equations of apparently different systems and from this indirectly understand that what appeared to be many different physical systems are really simply understood as the many shadows of a single set of tree dimensional events that happen in the room. This would look like a fantastic unification of complicated systems in two dimensions as a single simple system in three dimensions. According to Itzhak Bars, this analogy conveys the relationship between 1T-physics in 3+1 dimensions (like the physics on the boundaries of the room) and 2T-physics (like physics in the room). The requirement of only gauge-symmetric combinations of 4+2 dimensions demanded by the gauge symmetry is what forces the observers to experience all phenomena as if they live in 3+1 dimensions. Bars has provided many examples of the hidden information as predictions for 1T-physics coming from 2T-physics at all energy levels, from everyday well understood classical and quantum physics to much less understood boundaries of physics in cosmology and high energy physics. He believes that the 2T-physics approach provides powerful new tools to explore the less known aspects of the universe and build the right unified theory.
I’m not qualified to comment on Itzhak Barrs’ theory, but I think there are some possible leads towards a solution in this extract.
I would value comments, generally.
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Many of these are questions I struggled with for a long time. Welcome to the weird world of infinity/eternity. :)
Before we try to move on, may I suggest looking at https://en.wikipedia.org/wiki/Itzhak_Bars
To explain to the layman how this gauge symmetry works, Bars makes an analogy between the phenomena in the 4+2 dimensional world and events happening in a hypothetical 3 dimensional room. In this analogy the two-dimensional surfaces that makeup the boundaries of the three-dimensional room (walls, ceiling, floor) are the counterparts of the 3+1 dimensional world humans live in as observers. In this setting, if you shine light from different directions in the room, you create two-dimensional shadows of the three-dimensional events projected on the surfaces surrounding the room. The shadows and their motions on some wall will look different than those on other walls, ceiling or floor. If observers were never allowed to exist in the room but were confined to live and crawl only on the surfaces of surrounding boundaries, the two-dimensional physicist at different boundaries would then write different physics equations to describe mathematically the shadows he/she sees from those different perspectives. He/she would also believe that the shadows at different boundaries are different physical systems because their equations would not match. Since all shadows come from the unique set of events in the room, it is evident from the perspective of the room that the shadows are not independent of each other. So, there must be a definite predicted relationship between the systems of the two dimensional equations at different walls. If the two dimensional physicists are very smart, with much effort they may begin to discover this hidden information by carefully comparing equations of apparently different systems and from this indirectly understand that what appeared to be many different physical systems are really simply understood as the many shadows of a single set of tree dimensional events that happen in the room. This would look like a fantastic unification of complicated systems in two dimensions as a single simple system in three dimensions. According to Itzhak Bars, this analogy conveys the relationship between 1T-physics in 3+1 dimensions (like the physics on the boundaries of the room) and 2T-physics (like physics in the room). The requirement of only gauge-symmetric combinations of 4+2 dimensions demanded by the gauge symmetry is what forces the observers to experience all phenomena as if they live in 3+1 dimensions. Bars has provided many examples of the hidden information as predictions for 1T-physics coming from 2T-physics at all energy levels, from everyday well understood classical and quantum physics to much less understood boundaries of physics in cosmology and high energy physics. He believes that the 2T-physics approach provides powerful new tools to explore the less known aspects of the universe and build the right unified theory.
I’m not qualified to comment on Itzhak Barrs’ theory, but I think there are some possible leads towards a solution in this extract.
I would value comments, generally.
Not totally sure I get it, but sounds like an interesting idea. My understanding of what he says (correct me please if I have it wrong) is that the universe is 4 space, 2 time dimensional, but what we can see and measure in our 3 space, 1 time, dimensional reality is a projection of that 4+2 universe.
I'm not quite sure what two time dimensions imply? It might double our troubles!
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So time cannot possibly be motion but we do measure time by measuring motion.
You might, but most humans nowadays rely on the hyperfine transitions of a cesium atom.
We measure length by motion, but length isn't time. Or you can measure length by comparison with a standard stick, but the stick isn't length.
It's important in physics to distinguish between quantities (what we measure) and units (how we measure it). Time is what separates sequential events. The unit of time is the interval between sequential zeroes of the electromagnetic radiation from the cesium atom.
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if the universe was composed of 3 spacial dimensions only then there would be no motion at all
The concept of three orthogonal dimensions is entirely a human mathematical construct, and not all humans share it or find it useful. If anything, it is rather restrictive when dealing with an expanding universe.
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So time cannot possibly be motion but we do measure time by measuring motion.
You might, but most humans nowadays rely on the hyperfine transitions of a cesium atom.
'hyperfine transitions' - that sounds like some sort of motion though?
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It's a transition between quantum states. You can model it as an analog of mesoscopic movement, but it's a poor analog. The point is that it gives us a means of measuring time (units) but doesn't define time (quantity).
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Time is what separates sequential events.
Or, perhaps: difference is what separates sequential events; time is the concept we use to measure that difference.
There doesn’t have to be a difference or change (but as Alan says we do use change to measure time intervals). Take an atom which is about to decay, we can measure/observe it during the period prior to decay and will not see any change, but clearly time continues to ‘flow’ and there are an infinite number of discrete time points in that period (assuming time is not quantised). If we imaging that atom is the only one in the universe then there would be no change/differences, but clearly time would still exist as an underlying phenomenon otherwise the atom would never decay. Imagine now removing that atom from that universe, can we say that there would be no time?
I still have difficulty understanding how the change from “no time” to “time” can happen if there is no pre-existing time in which it can occur. Of course, if there is pre-existing time, there is no period of "no time", so the whole thing becomes an exercise in futility.
This is the problem with the discussion here where ‘logic’ is being constructed to try and prove a point, but many physical phenomena do not follow our limited logic eg time in relativity. Aristotle made this mistake and with all good intentions held science back for almost 2000 years.
Let’s say we define t=0 as BB, we can make a number of assumptions:
- time came into existence at that point (possibly along with space and all the energy/mass that it contains)
- time existed pre t=0, possibly in a universe where space, energy and mass also existed and we have a big crunch or some other event.
- time existed pre t=0, but there was no mass/energy which only appeared at t=0.
- the laws of physics were very different pre t=0, such that time and space may have changed ‘position’ or were the same, but conservation laws were different.
- something else we haven’t yet imagined.
The problem is that today our logic would still see a universe where one event follows another and where we cannot go back in time and change or remove an event; but that logic will never allow us to determine what happened at or prior to t=0.
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There doesn’t have to be a difference or change……. Take an atom which is about to decay, we can measure/observe it during the period prior to decay and will not see any change, but clearly time continues to ‘flow’…
You are considering only observable changes in the atom. If you make an observation, this has duration. Call the start event 1, and the finish event 2. E1 is not E2, so, however brief your observation, change has occurred.
many physical phenomena do not follow our limited logic
True; but as long as we base our logic on the best information we have at the time, it is probably the best tool we have to further our knowledge. Anything else is speculation.
Let’s say we define t=0 as BB, we can make a number of assumptions:
Great!
- time came into existence at that point (possibly along with space and all the energy/mass that it contains)
Begs the question; how could that happen without pre-existing time (PET)?
- time existed pre t=0, possibly in a universe where space, energy and mass also existed and we have a big crunch or some other event.
No argument with this, but we were looking for a way in which time might “start”, without some PET; so it does not address the question.
- time existed pre t=0, but there was no mass/energy which only appeared at t=0.
As previous comment, but with the additional complication that it appears to assume that time would have some relevance in a scenario without mass/energy.
- the laws of physics were very different pre t=0, such that time and space may have changed ‘position’ or were the same, but conservation laws were different.
Not only do we have PET, here; we also have change, for which time is “essential”.
- something else we haven’t yet imagined.
Always to be kept in mind, but to what extent do we want to let this possibility stifle our quest for understanding?
…… that logic will never allow us to determine what happened at or prior to t=0.
Granted; but applied appropriately, it might allow us to determine some things that could not have happened at or prior to t=0.
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Not totally sure I get it, but sounds like an interesting idea
I’m in much the same position :), but I was not proselytising the basic idea, just looking at the possibility that what we perceive as “reality” might be an “illusion”.
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Not totally sure I get it, but sounds like an interesting idea
I’m in much the same position :), but I was not proselytising the basic idea, just looking at the possibility that what we perceive as “reality” might be an “illusion”.
Hard to be really sure.
Life might just be some dream you are having, and you wake up in another world when you die. We cannot disprove this sort of idea. Descartes said 'I think therefore I am' and talked about being imprisoned in a made-up world by an evil demon. He could not prove that he was not and no-one has since then.
What you can actually be sure of there are a minimum of two intelligent entities in the universe:
- Your conscious self
- Others, who may all be one entity, using different voices
We are sort of snookered!
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https://knowledgenuts.com/2013/09/29/descartes-dissected-his-wifes-dog-to-prove-a-point/
French philosopher Rene Descartes didn’t believe animals had souls. To test his theory, he nailed his wife’s dog to a board and chopped it open while the poor thing was still alive.
Perhaps Descartes was the “evil demon”. BTW; any idea how that would prove it had no soul?
What you can actually be sure of there are a minimum of two intelligent entities in the universe:
- Your conscious self
- Others, who may all be one entity, using different voices
How do you know that the “others” are not figments of your imagination? Warning! This way lies silly solipsism.
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https://knowledgenuts.com/2013/09/29/descartes-dissected-his-wifes-dog-to-prove-a-point/
French philosopher Rene Descartes didn’t believe animals had souls. To test his theory, he nailed his wife’s dog to a board and chopped it open while the poor thing was still alive.
Perhaps Descartes was the “evil demon”. BTW; any idea how that would prove it had no soul?
What you can actually be sure of there are a minimum of two intelligent entities in the universe:
- Your conscious self
- Others, who may all be one entity, using different voices
How do you know that the “others” are not figments of your imagination? Warning! This way lies silly solipsism.
I did not know that! Horrific stuff. I'm not personally that desperate for knowledge! Maybe he was expecting a soul to come out of the dying dog? That one did not does not seem proof - the soul might be somehow invisible.
Others could be figments of your imagination, but then you'd have to class your imagination as a separate intellectual entity to yourself, so you end up with a minimum of two entities: you and other(s).
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Time simply passes, no need to make it any more complicated than that.
https://duckduckgo.com/?q=time+waits+for+no+one+helen+forrest&t=hk&ia=videos&iax=videos&iai=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DoW6GclIvXFo (https://duckduckgo.com/?q=time+waits+for+no+one+helen+forrest&t=hk&ia=videos&iax=videos&iai=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DoW6GclIvXFo)
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Time simply passes, no need to make it any more complicated than that.
Ah, but the question is ‘has it always passed?’
You are considering only observable changes in the atom. If you make an observation, this has duration. Call the start event 1, and the finish event 2. E1 is not E2, so, however brief your observation, change has occurred.
Ah those pesky observers.
The point I was trying to make is that the lone atom, unobserved, does not experience change between transitions, but clearly time continues to ‘flow’. I realise it is an imperfect thought experiment, but it is as if time is a stage upon which changes and events take place, perhaps an enabler rather than a stage, or maybe both. Similarities with space, where if we remove all matter and energy there is no reason to believe space ceases to exist. We know that space and time are linked via a common effect viz spacetime interval such that relative movement or gravitational potential difference means that a different ‘distance’ is ‘travelled’ through time (or space).
On the other hand, if we believe that time is inherently change/difference (rather than a vehicle/stage for change, or that change is the way we experience/measure time) we could say that a cause in creating a change also creates time, hence a start to time only requires a cause not a preexisting time period.
many physical phenomena do not follow our limited logic
True; but as long as we base our logic on the best information we have at the time, it is probably the best tool we have to further our knowledge. Anything else is speculation.
That is true as long as we ensure our logic is not false logic. To be fair, even if our logic is correct it is still speculation until we have verification (please don’t ask how we could verify!)
- time came into existence at that point (possibly along with space and all the energy/mass that it contains)
Begs the question; how could that happen without pre-existing time (PET)?
- time existed pre t=0, possibly in a universe where space, energy and mass also existed and we have a big crunch or some other event.
No argument with this, but we were looking for a way in which time might “start”, without some PET; so it does not address the question.
Agreed, they are there to indicate alternatives that fit the premise ‘all events have a preceding event’, hence time does not have a start.
- time existed pre t=0, but there was no mass/energy which only appeared at t=0.
As previous comment, but with the additional complication that it appears to assume that time would have some relevance in a scenario without mass/energy.
Is it really a complication? It depends what you mean by relevance, spacetime could exist without anything to play out on their stage. We know that in the absence of mass or energy spacetime appears to revert to being uncurved. I say revert, assuming this might be it’s natural state.
- the laws of physics were very different pre t=0, such that time and space may have changed ‘position’ or were the same, but conservation laws were different.
Not only do we have PET, here; we also have change, for which time is “essential”.
Agreed. However, there are suggestions that cause and effect might not follow the pattern we observe in our epoch/universe.
- something else we haven’t yet imagined.
Always to be kept in mind, but to what extent do we want to let this possibility stifle our quest for understanding?
We don’t, we just keep it in mind and try not to imagine that we have ‘the answer’
…… that logic will never allow us to determine what happened at or prior to t=0.
Granted; but applied appropriately, it might allow us to determine some things that could not have happened at or prior to t=0.
I might say “it might allow us to determine some things that might not have happened at or prior to t=0.
I’m in much the same position :), but I was not proselytising the basic idea, just looking at the possibility that what we perceive as “reality” might be an “illusion”.
Putting aside the observation that all reality is an illusionary projection through our senses:
It was Plato (I think) who described the observers viewing objects passing in front of a fire and projecting shadows on a cave wall, if those observers saw only the shadows they would think they were the true objects.
Interesting item from Pete in a different thread:
The text refers to the following as one of three elements of the Galilean structure
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Time - A linear mapping R^4 --> R from the vector space of parallel displacements of the real "time axis."
Even in R4 we are only seeing a projection, a timeslice, the past is indeed an illusion based on our imperfect and frequently rewritten memories and our current experience is again only in retrospect albeit in apparent simultaneous experience of the moment.
The idea of complex time (2 orthogonal T dimensions) isn’t limited to Bars, but the effect on the causal structure of spacetime allows reordering of cause/effect. That’s a tricky one, but it’s what I was referring to in my previous post regarding pre BB. If that situation exists now, then we are indeed seeing only a projection. By the way, complex time also allows the speed of light to be different in the early universe!
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Time simply passes, no need to make it any more complicated than that.
Ah, but the question is ‘has it always passed?’
If at first there was nothing, nothing could ever be, without Supernatural intervention. I'm not one to embrace the Supernatural, so the answer for me is that time has always passed. I'm considerate of those who do embrace the Supernatural; they can have it their way as long as their way is not imposed on others.
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If at first there was nothing, nothing could ever be, without Supernatural intervention. I'm not one to embrace the Supernatural, so the answer for me is that time has always passed. I'm considerate of those who do embrace the Supernatural; they can have it their way as long as their way is not imposed on others.
I will not make any claims about the supernatural. Someone who did was Thomas Aquinas:
'The third way is taken from possibility and necessity, and runs thus. We find in nature things that are possible to be and not to be, since they are found to be generated, and to corrupt, and consequently, they are possible to be and not to be. But it is impossible for these always to exist, for that which is possible not to be at some time is not. Therefore, if everything is possible not to be, then at one time there could have been nothing in existence. Now if this were true, even now there would be nothing in existence, because that which does not exist only begins to exist by something already existing. Therefore, if at one time nothing was in existence, it would have been impossible for anything to have begun to exist; and thus even now nothing would be in existence — which is absurd. Therefore, not all beings are merely possible, but there must exist something the existence of which is necessary. But every necessary thing either has its necessity caused by another, or not. Now it is impossible to go on to infinity in necessary things which have their necessity caused by another, as has been already proved in regard to efficient causes. Therefore we cannot but postulate the existence of some being having of itself its own necessity, and not receiving it from another, but rather causing in others their necessity. This all men speak of as God.' - Summa Theologica, St Thomas Aquinas.
So paraphrasing this argument:
1) We assume that the axiom: ‘can’t get something from nothing’ holds - an assumption that is supported by the law of conservation of energy.
2) This assumption leads to the conclusion that something must have permanent existence, IE if the universe was ever in a state of nothingness, then ‘can’t get something from nothing’ implies it would still be in a state of nothingness today - so something must have permanent existence.
3) But time has a start so nothing can exist permanently in time (and things in time are transitory - 2nd law of thermodynamics - it all decays with time into a sea of photons)
4) So the rejection of creation ex nilhilo leads us to the same conclusion as in earlier posts - something timeless and permanent must exist outside of spacetime.
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I disagree at #3 because I don't agree that time has to have had a start.
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Time can have a zero, and indeed whether you use the Common Calendar, the Ethiopian Calendar, or the Julian Calendar, there is always a zero date and nobody (except religious nutters) gets excited about "negative" dates. If you want an "absolute" calendar you can set zero at the Big Bang, the only unique feature being that, unlike BC/AD, right now we have no idea what (if anything) may have happened before then.
Whether the observable universe was created ex nihilo or by a spontaneous eversion of some previous universe is immaterial, If there was change when t < 0 then time existed; if not, it was irrelevant.
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I disagree at #3 because I don't agree that time has to have had a start.
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All systems require an initial state else there are no subsequent states
The universe is a system - so it requires an initial state - the start of time.
Also nothing permanent can exist in time - 2nd law of thermodynamics.
But Aquinas's argument points to something permanent - that thing must be external to time.
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1) We assume that the axiom: ‘can’t get something from nothing’ holds - an assumption that is supported by the law of conservation of energy.
Physical laws are approximations to consistent observation, that is, they are descriptive, not prescriptive, and they evolve as we discover things about the universe. It's a convenient axiom for many purposes, but contradicts the Big Bang hypothesis and its supporting observations.
Also nothing permanent can exist in time - 2nd law of thermodynamics.
I think not
The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time, and is constant if and only if all processes are reversible.
In plain language, if you don't kick it, it won't bite you.
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It's a convenient axiom for many purposes, but contradicts the Big Bang hypothesis and its supporting observations.
How does the BB contradict 'can't get something from nothing'?
Its possible that the matter of the BB came from outside spacetime.
Indeed, even the zero-energy universe hypothesis requires a seed of matter - from outside of spacetime.
Also nothing permanent can exist in time - 2nd law of thermodynamics.
I think not
Everything in time withers and dies, or wears away or decays. Something permanent is required. I don't believe anything is permanent in time.
Anyway, I'm personally convinced that time must have a start:
All systems require an initial state else there are no subsequent states.
The universe is a system - so it requires an initial state - the start of time.
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All systems require an initial state else there are no subsequent states
Changes of state occur, but they are not called initial states, they are changes to the previous state..
The universe is a system - so it requires an initial state - the start of time.
You are emphasizing the need for an initial state, when actually, what you have is a previous state. When you refer to the previous state of time as an initial state, are you invoking "something from nothing"?
Also nothing permanent can exist in time - 2nd law of thermodynamics.
If a big crunch bangs into an expanding big bang arena, quite like we see in the observable universe, won't it expand forever until the expansion is interrupted by encountering some matter or energy outside of that expanding arena?
But Aquinas's argument points to something permanent - that thing must be external to time.
I would agree that it points to something that is external to the point in time and space that the particular big bang occurred.
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Anyway, I'm personally convinced that time must have a start:
All systems require an initial state else there are no subsequent states.
The universe is a system - so it requires an initial state - the start of time.
For all the systems we are aware of which have a start, time extends back, beyond that start and forward beyond the end of the system.
No matter which way you approach this you can find arguments for and against spacetime having a start point.
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All systems require an initial state else there are no subsequent states.
Would you consider an infinite/eternal "state" to be a system?
The universe is a system - so it requires an initial state - the start of time.
Once again, we have a problem with terminology. Are you referring to the universe as all that exists, or could possibly exist; or do you mean that which (apparently) started with the BB?
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So there must be something else in addition to the 3 spacial dimensions that allows motion and this degree of freedom is called time. So time cannot possibly be motion but we do measure time by measuring motion.
You have space and time movement only when there is a present and desirable situation.
If the present and desired situation were in endless communication.
That is, if there was no gap between desire and fulfillment - movement, time and place did not exist.
why? Because time is the feeling of distance between desire and fulfillment. Which requires movement.
No gap = no movement = no time
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You have space and time movement only when there is a present and desirable situation.
If the present and desired situation were in endless communication.
That is, if there was no gap between desire and fulfillment - movement, time and place did not exist.
why? Because time is the feeling of distance between desire and fulfillment. Which requires movement.
No gap = no movement = no time
Movement is not necessary for us to experience or measure time, just a change. This can be a change of intensity rather than movement.
Time and place do not exist because of our desire or its fulfilment, they exist without us.
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All systems require an initial state else there are no subsequent states.
A rock is a system, but if it doesn't change, initial and subsequent states are irrelevant. All its properties are described by its present state.
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Movement is not necessary for us to experience or measure time, just a change. This can be a change of intensity rather than movement.
Time and place do not exist because of our desire or its fulfilment, they exist without us.
If there was no one in the universe who could measure and feel time then for whom would the time exist?
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If there was no one in the universe who could measure and feel time then for whom would the time exist?
If there were no one in the universe to enjoy the sunset on earth, then for whom would it exist?
Time and space don’t go away just because we are not here, the universe existed for billions of years before life, let alone sentient life, existed.