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Is the PAST determined?

Samantha Rinne

Resident Genderfluid Writer/Artist
Is the PAST determined?

Are you familiar with the Mandela Effect discussed in the past on this forum? I am an experiencer of that effect and a believer in the effect.

To blow our minds further, it is saying the past is not even consistent (like multiple valid versions).

The line actually was "Luke, I am your father." And then it became "No. I am your father."

To make things weird, the radio version is "No. Luke, I am your father."

And to make things even weirder, in "Jedi Search" by Kevin J. Anderson (1994), Luke remembers (as does much of the audience) Vader saying, "Luke, I am your father."

To say nothing of the fact that several movies also misquote it.

I think humans can time travel to some extent (usually not consciously remembering doing it because it involves occupying a previous body). Doing so produces one of two effects:
1. Deja vu (if you made the same choices)
2. Mandela effect (if someone changed something and the public has a persistent memory)

The question being, why rewrite lines in a movie? I suspect it has less to do with the movie itself and more about a minor ripple of the events surrounding this reality. Different reality, movies have slightly different lines.
 
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Etritonakin

Well-Known Member
Many people like to ask whether the future is determined. This has relevance to issues like free will, for example.

I would like to address the reverse question: Is the *past* determined?

In other words, is the past fixed once we pass it?

Another interpretation of the problem, possibly a different spin: Given the state of the universe *now* (and I am flexible about what this means), is the entirety of the past determined? Can every event of the past be *theoretically* deduced from the information of the present?

When framed in this way, I have to say that it seems unlikely. For example, it seems quite unlikely that the weight of Casar's last drink is fixed from anything available in the universe today. It seems unlikely that the question 'was there a T-Rex standing in this spot 68 million years ago exactly' actually has an answer that is determined by the state of the universe now.

So, to what extent is the past determined? If it is NOT determined, how does that affect your views of the past? if it *is* determined, in what sense is it so?
Yes -and No. That which preceded and allows for SELF "DETERMINATION" -or "DECISION" cannot be changed. Decision has the ability to destroy its own ability to decide -but decision (reality wrapping its head around itself and becoming self-aware, etc) would 'naturally' occur again. It is NATURALLY determined. (Math, logic, natural sequence from simplicity to complexity)

If "decision" retains its ability to decide, previous states can only be recreated. The fact that previous states occurred cannot truly be nullified -but they can be effectively nullified.

It is impossible to go backward in sequence of events -but it is possible to go forward in sequence of events -in reverse order -to a previous state (given necessary position and ability to interface).

If you take a step backward -it it still a step forward in "time".

Everything which now exists has "always" existed -it has only changed configuration.

Moving the ball forward is inevitable -and advantageous -but sometimes it is beneficial to drop back twenty and punt!

..as that which now exists has always existed, we certainly have enough evidence to reverse-engineer previous states.

FURTHERMORE... TRUE DECISION is the ONLY TRUE VARIABLE. EVERYTHING was absolutely inevitable until the development of true -SELF-AWARE -decision -otherwise, NOTHING could have been OTHERWISE!

The past NO LONGER EXISTS (except as represented in memory/record if previous states are recorded).
We can not travel back in time (though it is somewhat elastic as things are presently happening), because the present is made of the same stuff as the past.
It would require that each new instant be made of new "material" -and if one person traveled back in time as seen in the movies, the present would need to become "lighter" -and the past "heavier" -which simply cannot happen.
 
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blü 2

Veteran Member
Premium Member
Many people like to ask whether the future is determined. This has relevance to issues like free will, for example.

I would like to address the reverse question: Is the *past* determined?

In other words, is the past fixed once we pass it?

Another interpretation of the problem, possibly a different spin: Given the state of the universe *now* (and I am flexible about what this means), is the entirety of the past determined? Can every event of the past be *theoretically* deduced from the information of the present?

When framed in this way, I have to say that it seems unlikely. For example, it seems quite unlikely that the weight of Casar's last drink is fixed from anything available in the universe today. It seems unlikely that the question 'was there a T-Rex standing in this spot 68 million years ago exactly' actually has an answer that is determined by the state of the universe now.

So, to what extent is the past determined? If it is NOT determined, how does that affect your views of the past? if it *is* determined, in what sense is it so?
Einstein regarded spacetime as something modern expounders can liken to a loaf of bread in 4-space, which relativity cuts into slices to illustrate what things like before, after, and simultaneous mean if general relativity is correct. It's not hard to interpret that as a claim that the past (and, relatively speaking) bits of the future are fixed.

And as you know, the present scientific approach to reasoning from retrospect takes the past to be fixed, and to be consistent in its obedience to the rules. Thus we make models from hypotheses about past states and see how well their results match the present when cranked through the model's prescribed processes. Examples are models of the universe from the Big Bang to the present distribution of galaxies &c, and models of the formation and evolution of the solar system. I have no doubt there are a great many more.

Do I agree that the past is fixed? Yes, I think our past is the past and I think the past as such can't be changed after it's happened. Certainly I see no evidence in the present that humans from the future are among us ─ and maybe if time travel were indeed possible, there'd be very good reasons not to do it.

But was the past always fixed? I recall the late Stephen Jay Gould's Wonderful Life and his argument that if you "played the tape of life again" starting at the Burgess Shales, you'd get a totally different set of animals to the ones we have, such are the sheer chances at large in evolution. This is underlined by the mechanics of human conception, where the genetic composition of the offspring depends on which specific spermatozoon forms the zygote with that particular ovum. A few seconds earlier or later, or a different positioning of the bodies, or a different month, and you'd very likely get a different result.

None of that matters if determinism is strict at all levels; but since we don't know whether random quantum events can affect macro results on a scale which would disturb such outcomes, we don't presently have a firm answer to that question.

When we enlarge the scale to look at the formation of the universe, we find its dust, rocks, rings, planets, stars, galaxies, galaxy clusters and superclusters, its dark matter and dark energy and the likelihood of more unknown unknowns, all in particular spatial relationships with each other.
Are such large-scale arrangements so big that random quantum events don't make a significant difference? If we play the universe's tape again, will we get the same entities and the same relationships? I'm not aware that we have an answer to that either.

Which is to say, although we have only one past, it may be possible ─ but we don't know how possible ─ that if we ran that tape again, we'd get a different set of relationships of the elements of the universe in both senses of the word.
 

Ponder This

Well-Known Member
Many people like to ask whether the future is determined. This has relevance to issues like free will, for example.

I would like to address the reverse question: Is the *past* determined?

In other words, is the past fixed once we pass it?

Another interpretation of the problem, possibly a different spin: Given the state of the universe *now* (and I am flexible about what this means), is the entirety of the past determined? Can every event of the past be *theoretically* deduced from the information of the present?

When framed in this way, I have to say that it seems unlikely. For example, it seems quite unlikely that the weight of Casar's last drink is fixed from anything available in the universe today. It seems unlikely that the question 'was there a T-Rex standing in this spot 68 million years ago exactly' actually has an answer that is determined by the state of the universe now.

So, to what extent is the past determined? If it is NOT determined, how does that affect your views of the past? if it *is* determined, in what sense is it so?

For example, if we add 123 to 234 and get 357,
how do we know that the result of 357 was from 123 + 234 and not from 122+235?
We would've gotten the same result of 357 from adding 122 to 235.

Well, we have memory of "past" events. What does this mean?
If we lived in a world where each moment could be the result of numerous different pasts, then wouldn't our experience of memories reflect this diversity?
But rather we remember one past instead of numerous pasts.
This suggests that the past doesn't change as we move along through present moments.
In other words, if the past behaved in the same way as the future behaved, then our experience of the past would be just like our experience of the future. Our experience of the past is not just like our experience of the past. This suggests that when we add two numbers and get a result of 357, it means that there were two particular numbers that added to 357 and not multiple different pairs of numbers that added to 357.

And yet it may still be difficult to decipher the past. Perhaps it is even not possible to determine the past based solely on information in the present.

If you believe in the Mandela effect, then perhaps you believe the past is changeable. Although it escapes me how this would actually work.
 

Brickjectivity

Turned to Stone. Now I stretch daily.
Staff member
Premium Member
I thought about what 9-10ths_Penguin mentioned about Planck length. Planck length though is part of the question, because I would imagine for the loaf bread example to work perfectly there would need be continuity from moment to moment rather than granularity. That isn't the case with current standard model at the subatomic level. Blue mentioned that maybe the past was random.

I see three questions arising from the OP: Are the past and future inextricably linked one to one such that any change in the past is met with a change in the future. Is each moment full of randomness, instead. Are both things true, and does the universe change moment to moment, past and future linked and also randomly changing with the moment. This last one seems like the OP position, with its crumbling past, looking at the present as a spotlight where everything outside of the present becomes uncertain.
 

sealchan

Well-Known Member
Many people like to ask whether the future is determined. This has relevance to issues like free will, for example.

I would like to address the reverse question: Is the *past* determined?

In other words, is the past fixed once we pass it?

Another interpretation of the problem, possibly a different spin: Given the state of the universe *now* (and I am flexible about what this means), is the entirety of the past determined? Can every event of the past be *theoretically* deduced from the information of the present?

When framed in this way, I have to say that it seems unlikely. For example, it seems quite unlikely that the weight of Casar's last drink is fixed from anything available in the universe today. It seems unlikely that the question 'was there a T-Rex standing in this spot 68 million years ago exactly' actually has an answer that is determined by the state of the universe now.

So, to what extent is the past determined? If it is NOT determined, how does that affect your views of the past? if it *is* determined, in what sense is it so?

What if you phrase the question as "was the past determined?" Then it would be a simple subset of the question "is reality determined (by cause and effect)?"

But you seem to be asking "can we effect the final outcome of what has happened?" Instead of non-getting in a car accident yesterday, we did by some method of past alteration. I think that entropy protects us against any consequential ability to do this.

Psychologically and metaphorically we can certainly change the past. But I suspect that is not what you are interested in here.
 

viole

Ontological Naturalist
Premium Member
Many people like to ask whether the future is determined. This has relevance to issues like free will, for example.

I would like to address the reverse question: Is the *past* determined?

In other words, is the past fixed once we pass it?

Another interpretation of the problem, possibly a different spin: Given the state of the universe *now* (and I am flexible about what this means), is the entirety of the past determined? Can every event of the past be *theoretically* deduced from the information of the present?

When framed in this way, I have to say that it seems unlikely. For example, it seems quite unlikely that the weight of Casar's last drink is fixed from anything available in the universe today. It seems unlikely that the question 'was there a T-Rex standing in this spot 68 million years ago exactly' actually has an answer that is determined by the state of the universe now.

So, to what extent is the past determined? If it is NOT determined, how does that affect your views of the past? if it *is* determined, in what sense is it so?

Well, according to Susskind’s -1st principle (minus first, on account of preceding all others) then it appears so. The current state can come from one and only one prior state.

I think for several reasons:

1) information is neither created nor destroyed. If we had two possible prior states, then 1 bit of information (which one we come from) would be destroyed irreversibly, and without entropy increase.

2) Reversibility is determinism with time arrow reversed. Since time direction is not fundamental, and we seem to have determinism (for the opposite reasons: new information cannot be created), then we have reversibility.

3) if we take relativity at face value, together with quantum gravity, then we probably live in a block universe. Then everything in our past, is not only determined, but still existing.

Ciao

- viole
 

Polymath257

Think & Care
Staff member
Premium Member
Well, according to Susskind’s -1st principle (minus first, on account of preceding all others) then it appears so. The current state can come from one and only one prior state.

I think for several reasons:

1) information is neither created nor destroyed. If we had two possible prior states, then 1 bit of information (which one we come from) would be destroyed irreversibly, and without entropy increase.

2) Reversibility is determinism with time arrow reversed. Since time direction is not fundamental, and we seem to have determinism (for the opposite reasons: new information cannot be created), then we have reversibility.

3) if we take relativity at face value, together with quantum gravity, then we probably live in a block universe. Then everything in our past, is not only determined, but still existing.

Ciao

- viole

Hmm...it seems we very much do NOT have determinism in the forward time direction. That is what QM is all about, after all. Since we have probabilistic development into the future, why not into the past?

But time reversal is not a symmetry of the physical laws: the weak force violates that symmetry. So, unless you also include a matter-antimatter and a parity reversal to your time reversal (CPT symmetry), this does not follow.
 

viole

Ontological Naturalist
Premium Member
Hmm...it seems we very much do NOT have determinism in the forward time direction. That is what QM is all about, after all. Since we have probabilistic development into the future, why not into the past?

But time reversal is not a symmetry of the physical laws: the weak force violates that symmetry. So, unless you also include a matter-antimatter and a parity reversal to your time reversal (CPT symmetry), this does not follow.

Well, I do not believe we have a probabilistic future. With “we”, I include all possible instances of me who make a quantistic observation.

As regard the weak force, I agree with you. Alas, I am not a physicist, so i am not sure what conservation of physical information means when we include that. I can only speculate. It could mean that the reversible combination of two not reversible things today, would entail the determined combination of those two things in the past, even if they are not reversible by themselves.

An email to Susskind? :)

Ciao

- viole
 

Milton Platt

Well-Known Member
Ahh...but how do you know all that information is preserved? In fact, don't we expect the information to gradually degrade, meaning more than one past becomes possible?

And I agree, there are a LOT of past events that *are* determined by the present. Anything from which the information hasn't decayed too much will be determined. But it seems quite unlikely that *all* past events are of that sort.

I said *in theory*
We don't expect what information to degrade? We simply don't have the information.
My point is that your question does not work as a generalization.
 

Goodman John

Active Member
I do not believe the past can be changed. We can change what we believe about the past, and we can rewrite our accounts of history, but neither of these changes the actual facts of what happened a thousand years ago or one minute ago.

The present and future do not, and cannot, change the past. The only thing that can change is our perception of the past.

(Note that this does not take into account the possibility of creating multiple parallel time lines if one *could* change the past. I'm only speaking of the events of a single time line.)
 

Daemon Sophic

Avatar in flux
Many people like to ask whether the future is determined. This has relevance to issues like free will, for example.

I would like to address the reverse question: Is the *past* determined?

In other words, is the past fixed once we pass it?

Another interpretation of the problem, possibly a different spin: Given the state of the universe *now* (and I am flexible about what this means), is the entirety of the past determined? Can every event of the past be *theoretically* deduced from the information of the present?

When framed in this way, I have to say that it seems unlikely. For example, it seems quite unlikely that the weight of Casar's last drink is fixed from anything available in the universe today. It seems unlikely that the question 'was there a T-Rex standing in this spot 68 million years ago exactly' actually has an answer that is determined by the state of the universe now.

So, to what extent is the past determined? If it is NOT determined, how does that affect your views of the past? if it *is* determined, in what sense is it so?
Yes. The past is determined and fixed once we have passed it.

Your inability to measure the past by utilizing what is here in the present is irrelevant to it having happened.
For example. I walk into a room and put my backpack on a table, and then move it to the floor. Later you walk in and see my backpack on the floor.
Just because you have an inability to know that at one point it had been on the table is irrelevant.

Taking it further....
In the OP you ask...”Can every event of the past be *theoretically* deduced from the information of the present?
Again the answer is Yes. For the backpack it’s easy. You could find molecules and atoms from the table on my backpack, and vice versa.
For Ceasar’s drink and the dinosaur, it would be a lot trickier. First you would have to be able to grasp and reverse engineer the interactions of every subatomic particle in a sphere having (at least) the radius of one light-second for each second of time that has passed since Ceasar put his beer on the counter, or that T-rex strolled on by.
*** An even easier “theoretical” method would be to put a really good telescope on the USS Enterprise (NCC 1701-D), warp out that many light-seconds, and take a look back at Earth. Ta-Daa!!

Really @Polymath257 ? I thought you were one of the bright ones here. :unamused:

I would suggest to you and warn you that your thought experiment is waxing poetic, and could lead to fools suggesting such things as “alternative facts”, or “you weren’t there, so you can’t prove it”, and other such drivel.


giphy.gif

You’re a mathematician dammit,
not some liberal arts major
.​
 

gnostic

The Lost One
If we were to alter something in the past, like just one thing, would everything change?

For example, if we were to change the Adolf Hitler’s life so that his parents never met, and they have married someone else, would we still have the same Hitler who led Nazi Germany to World War 2?
 

Polymath257

Think & Care
Staff member
Premium Member
Yes. The past is determined and fixed once we have passed it.

Now, is that only the past light cone? And if you are looking at things from that perspective, in what sense do we 'pass' a point in time?

Your inability to measure the past by utilizing what is here in the present is irrelevant to it having happened.
For example. I walk into a room and put my backpack on a table, and then move it to the floor. Later you walk in and see my backpack on the floor.
Just because you have an inability to know that at one point it had been on the table is irrelevant.

Taking it further....
In the OP you ask...”Can every event of the past be *theoretically* deduced from the information of the present?
Again the answer is Yes. For the backpack it’s easy. You could find molecules and atoms from the table on my backpack, and vice versa.
For Ceasar’s drink and the dinosaur, it would be a lot trickier. First you would have to be able to grasp and reverse engineer the interactions of every subatomic particle in a sphere having (at least) the radius of one light-second for each second of time that has passed since Ceasar put his beer on the counter, or that T-rex strolled on by.

And one of the points is that such precison in the interactions isn't even theoretically possible because of quantum effects. And that means that even theoretically, this is impossible. It *would* be possible under classical physics, but not under quantum physics.

*** An even easier “theoretical” method would be to put a really good telescope on the USS Enterprise (NCC 1701-D), warp out that many light-seconds, and take a look back at Earth. Ta-Daa!!

Well, you are assuming that the light is both detectable and hasn't interacted with enough other things so that the information is still viable.

Really @Polymath257 ? I thought you were one of the bright ones here. :unamused:

I would suggest to you and warn you that your thought experiment is waxing poetic, and could lead to fools suggesting such things as “alternative facts”, or “you weren’t there, so you can’t prove it”, and other such drivel.


giphy.gif

You’re a mathematician dammit,
not some liberal arts major
.​

Nope, this is actually a serious question. We know that the future is undetermined because of quantum effects. Why not the past? Why isn't the past probabilistic in exactly the same way as the future?
 

sayak83

Veteran Member
Staff member
Premium Member
Many people like to ask whether the future is determined. This has relevance to issues like free will, for example.

I would like to address the reverse question: Is the *past* determined?

In other words, is the past fixed once we pass it?

Another interpretation of the problem, possibly a different spin: Given the state of the universe *now* (and I am flexible about what this means), is the entirety of the past determined? Can every event of the past be *theoretically* deduced from the information of the present?

When framed in this way, I have to say that it seems unlikely. For example, it seems quite unlikely that the weight of Casar's last drink is fixed from anything available in the universe today. It seems unlikely that the question 'was there a T-Rex standing in this spot 68 million years ago exactly' actually has an answer that is determined by the state of the universe now.

So, to what extent is the past determined? If it is NOT determined, how does that affect your views of the past? if it *is* determined, in what sense is it so?
An alien civilization with a very strong telescope 66 million light years away from Earth may be able to watch what the dinosaurs were doing on earth at that time. So, in that sense the past is fixed.
 

shunyadragon

shunyadragon
Premium Member
Nope, this is actually a serious question. We know that the future is undetermined because of quantum effects. Why not the past? Why isn't the past probabilistic in exactly the same way as the future?

. . . because the time arrow is only known to go in one direction into the future.
 

Polymath257

Think & Care
Staff member
Premium Member
. . . because the time arrow is only known to go in one direction into the future.

The only time arrow (expansion, coordinate, entropy) that seems relevant is the entropy arrow and it is far from clear why that should fix the past.
 

Polymath257

Think & Care
Staff member
Premium Member
An alien civilization with a very strong telescope 66 million light years away from Earth may be able to watch what the dinosaurs were doing on earth at that time. So, in that sense the past is fixed.

But even there, there is a limit to the resolution brought on by the laws of physics, and many events would be below that resolution.
 

Polymath257

Think & Care
Staff member
Premium Member
Another aspect to consider:

In modern physics (specifically general relativity), the *whole* of spacetime is considered to be a single, geometric entity. Both the past and the future are 'determined' in GR by the properties of any single time slice. In this model, knowing everything about the present would, indeed, fix everything about both the past *and* the future.

But, GR is a deterministic (classical) theory. We *know* that the real world is probabilistic (quantum). Nonetheless, we can still consider the whole of spacetime as a probabilistic entity.

So why is the future undetermined in this model but not the past? The *whole* of spacetime is still a complete geometric entity. The only difference I can see is that there are now probabilities of certain observations instead of certainties. But why only probabilities in the future light cone?
 

Daemon Sophic

Avatar in flux
The only time arrow (expansion, coordinate, entropy) that seems relevant is the entropy arrow and it is far from clear why that should fix the past.
No. @shunyadragon is correct. Similar to what I said earlier.
In contrast, you keep claiming that “since we cannot be sure we saw it right, then we cannot say that it happened.

Another aspect to consider:

In modern physics (specifically general relativity), the *whole* of spacetime is considered to be a single, geometric entity. Both the past and the future are 'determined' in GR by the properties of any single time slice. In this model, knowing everything about the present would, indeed, fix everything about both the past *and* the future.

But, GR is a deterministic (classical) theory. We *know* that the real world is probabilistic (quantum). Nonetheless, we can still consider the whole of spacetime as a probabilistic entity.

So why is the future undetermined in this model but not the past? The *whole* of spacetime is still a complete geometric entity. The only difference I can see is that there are now probabilities of certain observations instead of certainties. But why only probabilities in the future light cone?
:rolleyes:
This is getting into the Schrodinger’s Cat nonsense. The cat is either alive OR dead. Not both. Period.
Just because you cannot perceive the cat is irrelevant. Utterly and completely irrelevant.
It is NOT both alive and dead until we open the box. It is either or.

Ceasar’s cup had X number of milligrams of liquid in it. No more. No less.
Since you allowed for “theoretical” possibilities for measurement, I used the distant telescope and the subatomic omniscience approaches, but that was just for fun, and way beyond our aspirations for knowledge (at this time). ;)

Regardless. That cup contained X amount of liquid, and that dino walked somewhere. That you cannot measure it is just too sad. Get over it. Open the box and check on the cat.
 
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