[roosh]

Originally Posted by Morbert

And I said it is the shape of the world lines that exhibit the relative motion we associate with observers and objects. If you're asking why we don't atemporally perceive the entire world line of ourselves, that boils down to the question of how perception manifests from things, an open question.

And again, I was asking how static worldlines can exhibit the relative motion we associate with observers and objects.

If it is indeed an open question, it is limited in its scope, and would require a fairly mystical explanation.

Originally Posted by Morbert

They are the same theory: "The Wheeler-DeWitt equation embodies a stark form of presentism: it simply tells us which states the universe can find itself in, and says nothing about any evolution through time. " Is equivalent to Julian Barbour's:"The quantum universe is likely to be static. Motion and the apparent passage of time may be nothing but very well founded illusions." I.e. They are saying the universe is an unchanging configuration space, and change is an illusion generated by the Hamiltonian. The "present" in this case, is not a single 3D hypersurface, but rather all possible hypersurfaces, and all possible configurations.

Presentism is the idea that only the present moment exists; so regardless of the configuration of hypersurfaces, the Wheeler-DeWitt equation embodies a stark form of the idea that only the present moment exists.

I'm not entirely sure about the idea of a 3D hypersurface, but, if I understand correctly, I don't have too much trouble with the idea that the universe is an unchanging configuration space and that change is an illusion.

Still, it would represent presentism though.

EDIT: it is probably worth clarifying the point about change being an illusion; change still manifests in the physical world we experience, but the physical world we experience is illusory.

[Morbert]

I am assuming the world line issue has been resolved.

Presentism is the idea that only the present moment exists; so regardless of the configuration of hypersurfaces, the Wheeler-DeWitt equation embodies a stark form of the idea that only the present moment exists.

No it doesn't. This is what I have been saying. It gives us all states the universe can be in. It says nothing about the evolution or "change" of the universe. The quote you used even says this:

"The Wheeler-DeWitt equation embodies a stark form of presentism: it simply tells us which states the universe can find itself in, and says nothing about any evolution through time."

I.e. The Hamiltonian is simply a constraint. It does not generate change. The "stark form of presentism" is presumably an allusion to the fact that a static universe exists.

I'm not entirely sure about the idea of a 3D hypersurface, but, if I understand correctly, I don't have too much trouble with the idea that the universe is an unchanging configuration space and that change is an illusion.

Still, it would represent presentism though.

EDIT: it is probably worth clarifying the point about change being an illusion; change still manifests in the physical world we experience, but the physical world we experience is illusory.

You understand that the configurations corresponding to your past and your future (and all possibilities of your past and future, permitted by the Wheeler DeWitt equation) are part of this unchanging configuration space, right?

[ClimberC]

But, but, but.... time is the fourth dimension!!

We can measure fluctuations in time, so how can we measure something that isnt there? If time didnt exist, we wouldnt be able to move. there is even a theory that time, as a dimension will cease to exist..........*twitch*

[roosh]

Originally Posted by Morbert

I am assuming the world line issue has been resolved.

No, it still remains an open question with limited scope for answer; it is therefore an underlying assumption of the theory.

Originally Posted by Morbert

No it doesn't. This is what I have been saying. It gives us all states the universe can be in. It says nothing about the evolution or "change" of the universe. The quote you used even says this:

"The Wheeler-DeWitt equation embodies a stark form of presentism: it simply tells us which states the universe can find itself in, and says nothing about any evolution through time."

I.e. The Hamiltonian is simply a constraint. It does not generate change. The "stark form of presentism" is presumably an allusion to the fact that a static universe exists.

I would presume the "stark form of presentism" refers to a stark form of presentism i.e. the idea that only the present moment exists.

Originally Posted by Morbert

You understand that the configurations corresponding to your past and your future (and all possibilities of your past and future, permitted by the Wheeler DeWitt equation) are part of this unchanging configuration space, right?

If you consider that the universe is starkly presentist, then all forms of your "past" and "future" exist within whatever form the universe takes, be that a "configuration space" or whatever; this is because there is essentially no difference between "the past" and "the present"; there is no point at which "the past" stops and the present begins; the same can be said of "the future".

So, what we label "the past" continues to exist, except that it's appearance has changed, such that we can say what we observed as "the past" no longer exists. The same is true of "the future"; what is in "the future" already exists, but not in the form that it will take "in the future".


If you take the baking process for example; you get the ingredients to bake a loaf of bread; you take the flour and make the dough, with water and eggs, or whatever. The flour, the eggs and the water don't cease to exist, they simply change form. But the intact egg, the jug of water and the loose flour, which represent the past states of the objects no longer exists.

What that dough will eventually become i.e. a loaf of bread, also already exists, just not in the form of bread; the heat in the oven already exists, even before it is turned on, just not in the same form; the oven exists, the filament in the oven exists and the electricity exists, all of which combine to give the effect we label heat.

So, "the past" and "the future" exist always, but only ever in the form of the present, or the stark present, whichever you want to call it.

[Morbert]

Originally Posted by roosh

No, it still remains an open question with limited scope for answer; it is therefore an underlying assumption of the theory.

I would presume the "stark form of presentism" refers to a stark form of presentism i.e. the idea that only the present moment exists.

If you consider that the universe is starkly presentist, then all forms of your "past" and "future" exist within whatever form the universe takes, be that a "configuration space" or whatever; this is because there is essentially no difference between "the past" and "the present"; there is no point at which "the past" stops and the present begins; the same can be said of "the future".

So, what we label "the past" continues to exist, except that it's appearance has changed, such that we can say what we observed as "the past" no longer exists. The same is true of "the future"; what is in "the future" already exists, but not in the form that it will take "in the future".


If you take the baking process for example; you get the ingredients to bake a loaf of bread; you take the flour and make the dough, with water and eggs, or whatever. The flour, the eggs and the water don't cease to exist, they simply change form. But the intact egg, the jug of water and the loose flour, which represent the past states of the objects no longer exists.

What that dough will eventually become i.e. a loaf of bread, also already exists, just not in the form of bread; the heat in the oven already exists, even before it is turned on, just not in the same form; the oven exists, the filament in the oven exists and the electricity exists, all of which combine to give the effect we label heat.

So, "the past" and "the future" exist always, but only ever in the form of the present, or the stark present, whichever you want to call it.

You are making increasingly confident statements about concepts you are unfamiliar with. This is a signature of crank thinking, and I would urge you, while you are still new to the subject, to steer away from it. For example, it is clear you do not understand what a configuration space is. It is also clear that you do not understand what people like Smolin, Barbour et al mean when they say time might not exist. It is clear that you do not understand the consequence of the Wheeler DeWitt equation. You are instead latching on to specific quotes, or phrases (I.e. "A stark form of presentism") without any deeper understanding of what they are saying.

In Lee Smolin's 7th lecture from the set you linked to in your OP, he shows that the parameter describing the foliation of 4-D spacetime into slices of 3-D "space" has nothing to do with the "change" of presentism, and is in fact in many ways arbitrary. It does not lead to any notion of the "true" present.

Similarly, the Wheeler-DeWitt equation does not produce a single present that exists. It is instead a constraint on the state space of the universe. It is a "stark form of presentism" because you have a set of all states without any time dimension. This is a form completely different to what you are arguing. You are arguing that the universe is only one state, rather than an atemporal set of states, and that this state "changes" and this "change" is where our concept of time comes from.

[roosh]

Originally Posted by Morbert

You are making increasingly confident statements about concepts you are unfamiliar with. This is a signature of crank thinking, and I would urge you, while you are still new to the subject, to steer away from it. For example, it is clear you do not understand what a configuration space is. It is also clear that you do not understand what people like Smolin, Barbour et al mean when they say time might not exist. It is clear that you do not understand the consequence of the Wheeler DeWitt equation. You are instead latching on to specific quotes, or phrases (I.e. "A stark form of presentism") without any deeper understanding of what they are saying.

In Lee Smolin's 7th lecture from the set you linked to in your OP, he shows that the parameter describing the foliation of 4-D spacetime into slices of 3-D "space" has nothing to do with the "change" of presentism, and is in fact in many ways arbitrary. It does not lead to any notion of the "true" present.

Similarly, the Wheeler-DeWitt equation does not produce a single present that exists. It is instead a constraint on the state space of the universe. It is a "stark form of presentism" because you have a set of all states without any time dimension. This is a form completely different to what you are arguing. You are arguing that the universe is only one state, rather than an atemporal set of states, and that this state "changes" and this "change" is where our concept of time comes from.

I never claimed to understand what a configuration space was, I simply offered an explanation as to how "the past" can continue to exist and how "the future" can already exist without violating a strong form of presentism.

I haven't claimed that Smolin or Barbour advocate the form of presentism that you think I'm advocating; I was simply highlighting the fact that the question of the nature of time is very much an open question.

As for the Wheeler DeWitt equation, you seem to be arguing that a "stark form of presentism" is something other than a stark form of the idea that only the present moment exists.

Again, the example given is an example of how all states of the universe can exist within a single, universal, present moment.

Any other form of the idea that the observed "past" state of the universe continues to exists, or that the yet to be observed "future" already exists, requires the assumption that the observed "past" state of the universe continues to exists, or that the yet to be observed "future" already exists.


In the absence of evidence, that doesn't require the assumption that a clock measures physical time (and even with it), I think it is fairly safe to say that there is no observer living or dead, and no will there be, who has ever experienced anything other than the present moment. That means that there can be no empirical evidence that supports the contention that observed "past" states continue to exist, or that yet-to-be observed "future" states already exist, without some underlying assumption about their existence.

[Morbert]

Originally Posted by roosh

I never claimed to understand what a configuration space was, I simply offered an explanation as to how "the past" can continue to exist and how "the future" can already exist without violating a strong form of presentism.

I haven't claimed that Smolin or Barbour advocate the form of presentism that you think I'm advocating; I was simply highlighting the fact that the question of the nature of time is very much an open question.

It is very much an open question. I am of the opinion that quantum physics is the deeper theory, and that what is physical is diffeomorphic-invariant. This means time is an open question, but it also means the "present" is also an open question. There is no reason to project our intuitive, neurologically induced framework of "past,present, and future" onto the universe a a whole.

As for the Wheeler DeWitt equation, you seem to be arguing that a "stark form of presentism" is something other than a stark form of the idea that only the present moment exists.

It is! In ordinary quantum mechanics, the Hamiltonian generates change. I.e. Our system is in a single quantum state, and that state "changes" according to the Schrodinger equation. But the Wheeler DeWitt equation is not analogous in this manner. It is a constraint, not an equation of change. Time, even as a parameter, disappears.

Again, the example given is an example of how all states of the universe can exist within a single, universal, present moment.

Any other form of the idea that the observed "past" state of the universe continues to exists, or that the yet to be observed "future" already exists, requires the assumption that the observed "past" state of the universe continues to exists, or that the yet to be observed "future" already exists.

The only difference is they are not labelled "past" or "future". They are instead part of an unchanging atemporal state space. It is not even correct to call the state space a moment.

In the absence of evidence, that doesn't require the assumption that a clock measures physical time (and even with it), I think it is fairly safe to say that there is no observer living or dead, and no will there be, who has ever experienced anything other than the present moment. That means that there can be no empirical evidence that supports the contention that observed "past" states continue to exist, or that yet-to-be observed "future" states already exist, without some underlying assumption about their existence.

And there is no observer, living or dead, who has shown that their present moment is the same throughout the universe. All we can do is observe co-incidents and inter-relationships/connections between things.

[RobertHopkins]

"Tempus Fugit" Time was an invention in a sense - well not really, but in any early stages of "life" as we know it - it was used as a form of measurement of how quickly an " earth day " from sunrise to sunset and back again.

In my opinion time is merely a convention of thought and conversation. If time actually existed, it could be measured and quantified by something that cannot be suspended. So what is "time?" Time is relativity

Someone says "yesterday," and you think of time passing. However, yesterday isn't a distance away from "now" that can be measured in an absolute that we known as "time." Now is really simply here, and yesterday is the Earth spinning. There is no one measure of time that is not dependent upon motion or decay. There is only relativity -- the amount this moves in relation to some standard of movement, such as a clock movement. For example, "one hour" means what? It means 1/24th of a day, or 1/24th of the earth's revolution from this position of the earth in relation to the sun as compared to a previous or subsequent revolution. If all the movement and radioactive decay in the universe were to suddenly stop, including the rotation of electrons, the atomic activity of stars, the revolution of moons and planets, the beating of hearts, and the breathing of breaths.... If all this movement were to suddenly stop, where would time be? In a motionless universe, would there be such a thing as time? And how do we know for certain that the entire universe didn't instantly freeze two moments ago, then sleep motionlessly for an eternity, and then instantly thaw to find us exactly here, thinking that only a second has passed? We cannot know. We have no clocks that are not merely measures of relative motion.

If the measurement of " time " didn't exist or ceased to exist - we would have know way of telling each other when to meet, or when something happened - think of it as an equation to add numbers... if nobody knew how to count - well you know what would happen there....

[roosh]

Originally Posted by Morbert

It is very much an open question. I am of the opinion that quantum physics is the deeper theory, and that what is physical is diffeomorphic-invariant. This means time is an open question, but it also means the "present" is also an open question. There is no reason to project our intuitive, neurologically induced framework of "past,present, and future" onto the universe a a whole.

Knowing as little as I do, I would still be inclined to agree with you, that QM is the deeper theory. I would also agree, to an extent, that "the present" is an open question, but I think it can be separated into two aspects; how the present manifests at the macro-level i.e. how we perceive the present; and the absolute nature of reality.

I would say that, how we perceive the physical world, at the macro-level is not necessarily what the nature of reality "looks like", but I think we can still deduce that there is a universal present moment, because that is all that can be deduced from empirical experience without recourse to an assumption about past and future states continuing to exist - in a form other than the present moment.

Originally Posted by Morbert

It is! In ordinary quantum mechanics, the Hamiltonian generates change. I.e. Our system is in a single quantum state, and that state "changes" according to the Schrodinger equation. But the Wheeler DeWitt equation is not analogous in this manner. It is a constraint, not an equation of change. Time, even as a parameter, disappears.

Our system can exist as a single quantum state, where past and future exist eternally, all within the parameter of a single, universal present moment; because what constituted the past state of the system continues to exist, but has changed its form to that of the present; and the present will change to a state which we now call "the future", but what constitutes that "future" state exists in the present moment, just in a different form.

Originally Posted by Morbert

The only difference is they are not labelled "past" or "future". They are instead part of an unchanging atemporal state space. It is not even correct to call the state space a moment.

Apologies, I don't fully follow this point.

Originally Posted by Morbert

And there is no observer, living or dead, who has shown that their present moment is the same throughout the universe. All we can do is observe co-incidents and inter-relationships/connections between things.

This is true, but for the alternative to be true that observer, and every other observer, has to assume that "the past" continues to exist and that "the future" already exists, contrary to their empirical experience.

[Morbert]

Originally Posted by roosh

Our system can exist as a single quantum state, where past and future exist eternally, all within the parameter of a single, universal present moment; because what constituted the past state of the system continues to exist, but has changed its form to that of the present; and the present will change to a state which we now call "the future", but what constitutes that "future" state exists in the present moment, just in a different form.

That is not what a configuration state is. What you are saying is "The ball was here, now it's there, but the ball always exists". A timeless, static universe says "The ball is here" and "The ball is there" both exist. They are both different "configurations" that exist in an all-encompassing space of configurations. Ontologically speaking, it gets rather messy because a quantum state is not just a configuration, but rather a function over all configurations called a "wave function". But what is important is that, in the traditional, non-relativistic, Schrodinger formalism of quantum mechanics, the universe is a single quantum state that changes. That change is described by a mathematical object called the Hamiltonian operator. This is the presentism you are talking about. Time is just a parameter of change, and all that exists is the single quantum state. In quantum cosmology, the Hamiltonian no longer describes change. Instead, it is a constraint on all configurations. Change disappears as well. All states (that are allowed) exist.

[roosh]

Originally Posted by Morbert

That is not what a configuration state is. What you are saying is "The ball was here, now it's there, but the ball always exists". A timeless, static universe says "The ball is here" and "The ball is there" both exist. They are both different "configurations" that exist in an all-encompassing space of configurations. Ontologically speaking, it gets rather messy because a quantum state is not just a configuration, but rather a function over all configurations called a "wave function". But what is important is that, in the traditional, non-relativistic, Schrodinger formalism of quantum mechanics, the universe is a single quantum state that changes. That change is described by a mathematical object called the Hamiltonian operator. This is the presentism you are talking about. Time is just a parameter of change, and all that exists is the single quantum state. In quantum cosmology, the Hamiltonian no longer describes change. Instead, it is a constraint on all configurations. Change disappears as well. All states (that are allowed) exist.

To try and be more precise about what I am saying; I am saying that the nature of reality manifested, on the macro level, as "the ball was there"; this manifestation changed to "the ball is here". There is no evidence to suggest that the manifestation of "the ball there" continues to exist, and there is no evidence to suggest that the manifestation, "the ball is already over there" (the future), already exists.

To speak about a "ball" at the quantum level is, I'm sure you'll agree, pretty imprecise. I would be more inclined to say that, the nature of reality, which manifested as "the ball was there" continues to exist - in whatever form it does - and the nature of reality, which will give rise to the "future" manifestation of "the ball is over there, exists now.

Where the nature of reality is monistic in nature, and could be potentially be classified as a "wave function".

[Morbert]

Originally Posted by roosh

To try and be more precise about what I am saying; I am saying that the nature of reality manifested, on the macro level, as "the ball was there"; this manifestation changed to "the ball is here". There is no evidence to suggest that the manifestation of "the ball there" continues to exist, and there is no evidence to suggest that the manifestation, "the ball is already over there" (the future), already exists.

To speak about a "ball" at the quantum level is, I'm sure you'll agree, pretty imprecise. I would be more inclined to say that, the nature of reality, which manifested as "the ball was there" continues to exist - in whatever form it does - and the nature of reality, which will give rise to the "future" manifestation of "the ball is over there, exists now.

Where the nature of reality is monistic in nature, and could be potentially be classified as a "wave function".

This is where we get back to relativity of simultaneity. There is evidence that the notion of a single "true" present does not exist, unless we assume there are unknown mysterious dynamics at work (which we also have no evidence for).

[roosh]

Originally Posted by Morbert

This is where we get back to relativity of simultaneity. There is evidence that the notion of a single "true" present does not exist, unless we assume there are unknown mysterious dynamics at work (which we also have no evidence for).

And this is where we get back to the question of how a clock measures physical time.


The evidence that the notion of a single "true" present does not exist is reliant on the assumption that a clock measures physical time; that there is no empirical observation of "past" and "future" points to an underlying assumption of their eternal existence.


Ultimately I think it might come back to a question on the constancy of the one-way speed of light, which is an untestable assumption in relativity i.e. the conclusion has to be assumed.

The "mysterious dynamics at work" seems to pertain to experiments on the constancy of the speed of light primarily, given that time dilation and length contraction aren't actually observed in muon experiments.

I'm just wondering, if light in a vacuum had an absolute wave length, would this account for any lack of a fringe shift, or more accurately, a negligible fringe shift, in interferometery experiments?

That question might be better suited to the physics section though.

[Morbert]

Originally Posted by roosh

And this is where we get back to the question of how a clock measures physical time.


The evidence that the notion of a single "true" present does not exist is reliant on the assumption that a clock measures physical time; that there is no empirical observation of "past" and "future" points to an underlying assumption of their eternal existence.


Ultimately I think it might come back to a question on the constancy of the one-way speed of light, which is an untestable assumption in relativity i.e. the conclusion has to be assumed.

The "mysterious dynamics at work" seems to pertain to experiments on the constancy of the speed of light primarily, given that time dilation and length contraction aren't actually observed in muon experiments.

I'm just wondering, if light in a vacuum had an absolute wave length, would this account for any lack of a fringe shift, or more accurately, a negligible fringe shift, in interferometery experiments?

That question might be better suited to the physics section though.

The mysterious dynamics pertain to explanations of the constancy of the two-way speed of light. It is not only an untestable assumption, but a large collection of unparsimonious, untestable assumptions that happen to produce Einstein's relativity. Even at my most generous, I will say that, at the very least, the notion of relativity you adopt has no fewer assumptions than the spacetime notion of relativity.

[roosh]

Originally Posted by Morbert

The mysterious dynamics pertain to explanations of the constancy of the two-way speed of light. It is not only an untestable assumption, but a large collection of unparsimonious, untestable assumptions that happen to produce Einstein's relativity. Even at my most generous, I will say that, at the very least, the notion of relativity you adopt has no fewer assumptions than the spacetime notion of relativity.

Genuinely asking; did you mean to type the emboldened bit; or am I just picking it up wrong? Did you mean to say Lorentz's relativity; because it sounds like you are saying that Einsteins relativity is based on a large collection of untestable assumptions - I'll just put it down to a freudian slip

The thing is, I think that Lorentzian relativity can be stripped of certain assumptions; I don't think it requires the assumption that an absolute reference frame exists, it simply has to allow for that possibility; which is not an assumption at all, and not contradicted by any evidence.

Of course, it can assume that an absolute reference frame doesn't actually exist, that all objects are absolutely in motion; not with respect to an absolute reference frame, but in the sense of absolute motion we've been discussing. A further assumption about the existence of time can be dropped, which would tally with the idea that an absolute frame of reference doesn't necessarily exist, and hence no "universal time".

I also suspect that defining a rest frame for units of measurement would also help to remove other assumptions.


It just strikes me that the assumptions of the spacetime notion of relativity are fundamentally untestable, and circular in nature.