Simultaneity: Relative vs Absolute

roosh

Any feedback, objections, or thoughts on this are welcomed.

Presentism
I think it might be possible to look at the question of simultaneity through the lens of presentism and see that the idea of relative simultaneity might fall foul of Occam's Razor.

If we start with one of the few undeniable facts of empirical experience, the fact that for each and every observer in the universe, the entirety of their experience of the universe occurs in their own present moment, as do all empirical observations. We don't have to assume their present moment is shared by all observers, and we don't need to assume that simultaneity is absolute; we only need to acknowledge that all of our experiences occur "in the now", or "our now".

Either, or
Now, for any given observer, it is either true that their present moment is all that exists or that more than their present moment exists; that is, their past and/or future also exist. However, any such conclusion, that their past and/or future exist, must be assumed, because they only ever experience the present moment.

So, for any observer to arrive at the conclusion that their past and/or future exist, the conclusion(s) must be assumed. However, to arrive at the conclusion that nothing more than their present moment exists, they simply have to avoid the assumptions of past and/or future - given that it's one or the other.

Presentism & Absolute simultaneity
I think that absolute simultaneity is a necessary consequence of presentism, because if there is only one moment in which events can occur then it follows that any two events which occur in that moment must be absolutely simultaneous.

Relativity of Simultaneity (RoS) , therefore, requires the assumption, on behalf of every observer, that their past and/or future exist.

Further assumptions
I think we can also highlight that RoS requires some further assumptions, by looking at the assumption, on behalf of any given observer, that more than their present moment exists.

If any observer makes the assumption that more than their present moment exists, that is, they assume that their past and/or future exist, then they don't necessarily arrive at the conclusion of Relativity of Simultaneity; it would be possible that their past and/or future exist, but that simultaneity is still absolute; this could, perhaps, be seen as the Lorentzian "interpretation" with the assumptions of past and/or future. This means that a further assumption is required in order to arrive at the conclusion of RoS.

Personally, I think that assumption is probably the assumption that a clock measures something physical called "time"; that is, the assumption that a slower ticking clock represents the slowing of "time itself". This is the assumption that "time" is the object of measurement ,a physical property to be measured, as opposed to an abstract system of measurement.


Conclusion
To arrive at the conclusion of Relativity of Simultaneity - as juxtaposed with Absolute Simultaneity - the conclusions of past and/or future must be assumed; to arrive at the conclusion of Absolute Simultaneity, observers must simply refrain from assuming that their past and/or future exist; doing so leaves them with the idea that only their present moment exists, and the necessary conclusion of Absolute Simultaneity.

Morbert

That is untrue, for reasons I mentioned in our previous discussions. Relativity of simultaneity is invoked because the speed of light is the same for all observers. If you simply "refrain from assuming" RoS, then you are left with Newtonian mechanics, and are unable to account for a universal speed of light.

citrus burst

roosh wrote: »

Any feedback, objections, or thoughts on this are welcomed.

Presentism
I think it might be possible to look at the question of simultaneity through the lens of presentism and see that the idea of relative simultaneity might fall foul of Occam's Razor.

If we start with one of the few undeniable facts of empirical experience, the fact that for each and every observer in the universe, the entirety of their experience of the universe occurs in their own present moment, as do all empirical observations. We don't have to assume their present moment is shared by all observers, and we don't need to assume that simultaneity is absolute; we only need to acknowledge that all of our experiences occur "in the now", or "our now".

Firstly I don't agree that it is an undeniable fact.

Secondly it would seem to me that everyone's own present moment should be different.

Thirdly we don't have to assume that a present moment is shared by all observers, we do however have to assume some sort of over lap in order to conserve casualty.

Fourthly we need some sort of system to agree upon so to distinguish between yesterday's now, tomorrow's now, over there's now and over here's now.

I have other problems too, such as "the entirety of their experience of the universe occurs in their own present moment." I don't really know how to interpret what you are saying, especially in the context of what you are saying.

They're just a few ideas I had while scanning through, the first paragraph.

roosh

Morbert wrote: »

That is untrue, for reasons I mentioned in our previous discussions. Relativity of simultaneity is invoked because the speed of light is the same for all observers. If you simply "refrain from assuming" RoS, then you are left with Newtonian mechanics, and are unable to account for a universal speed of light.

The conclusion above is correct. In order to arrive at the conclusion of RoS, the existence of past and future have to be assumed; which, incidentally, are the conclusions arrived at on the basis of RoS. In other words, the conclusions have to be assumed.

If the assumptions of past and future are dropped, then we have absolute simultaneity and, a set of dynamics we don't understand.

roosh

citrus burst wrote: »

Firstly I don't agree that it is an undeniable fact.

On what basis would you deny it?

citrus burst wrote: »

Secondly it would seem to me that everyone's own present moment should be different.

What everyone experiences in the present moment can be different; someone in France would have a different experience to what you are experiencing right now.

In other words, someone in Paris is experiencing something right now, and you are experiencing something different right now; if you drop the assumptions that your past and/or future exist then the simultaneity of those two events must be absolute.

citrus burst wrote: »

Thirdly we don't have to assume that a present moment is shared by all observers, we do however have to assume some sort of over lap in order to conserve casualty.

We don't even have to assume an overlap; all you have to do is acknowledge that your experience occurs in the present moment; if you drop the assumptions that your past and/or future exist, then only your present moment exists and simultaneity must be absolute.

citrus burst wrote: »

Fourthly we need some sort of system to agree upon so to distinguish between yesterday's now, tomorrow's now, over there's now and over here's now.

I don't immediately see the necessity of this.

citrus burst wrote: »

I have other problems too, such as "the entirety of their experience of the universe occurs in their own present moment." I don't really know how to interpret what you are saying, especially in the context of what you are saying.

Any experience you or I have of the universe, that is, the entirety of our experience, occurs in what we call "the present moment".

Morbert

roosh wrote: »

The conclusion above is correct.

No it is not correct, no matter how many times you say it is. This is incredibly basic logic. Ignoring your false statement about assuming conclusions, watch this:

In order to arrive at the conclusion of RoS absolute simultaneity, the existence of past and future hidden dynamics that conspire to alter all our experiments in such a way that the speed of light is always measured to be c has to be assumed..

Morbert

roosh wrote: »

We don't even have to assume an overlap; all you have to do is acknowledge that your experience occurs in the present moment; if you drop the assumptions that your past and/or future exist, then only your present moment exists and simultaneity must be absolute.

I have explained this to you explicitly. I will explain it to you again: Not assuming x is not the same as assuming x is false. Dropping the assumption that the past and future exist is not the same as assuming the past and future don't exist. Instead, if you drop the assumption, you say it may or may not be true that the past and future exist, and it may or may not be true that simultaneity is absolute.

roosh

Morbert wrote: »

No it is not correct, no matter how many times you say it is. This is incredibly basic logic. Ignoring your false statement about assuming conclusions, watch this:

The conclusions of past and future that accompany RoS must be assumed; that is pretty basic.

Morbert wrote: »

In order to arrive at the conclusion of RoS absolute simultaneity, the existence of past and future hidden dynamics that conspire to alter all our experiments in such a way that the speed of light is always measured to be c has to be assumed..

To arrive at the conclusion one simply needs to drop the assumptions of past and/or future, because absolute simultaneity would be a necessary consequence and so too would a set of dynamics that are not understood, apparently.

Assuming that past and/or future exist doesn't give us RoS though, as absolute simultaneity would still be possible in a shared present moment where past and future exist. In order to arrive at the conclusion of RoS further assumptions are required; one such assumption, I believe, is the assumption that a clock measures time.

If we drop all of those assumptions then we are left with a set of dynamics that we don't understand, which isn't an assumption, since nothing is being assumed.

Morbert wrote: »

I have explained this to you explicitly. I will explain it to you again: Not assuming x is not the same as assuming x is false. Dropping the assumption that the past and future exist is not the same as assuming the past and future don't exist. Instead, if you drop the assumption, you say it may or may not be true that the past and future exist, and it may or may not be true that simultaneity is absolute.

The issue is that it is either true that an observers present moment is all that exists, or it isn't; it must be one or the other; that is, either their present moment is all that exists, or their past and/or future exists.

For an observer to conclude that more than their present moment exists they must assume the conclusions of past and/or future; to conclude that nothing more than their present moment exists they must simply drop the assumptions of anything more existing.

Morbert

roosh wrote: »

The conclusions of past and future that accompany RoS must be assumed;

No, you are not following even your own line of thought now. You are contrasting spacetime as distinct from presentism in terms of having to make assumptions. Therefore, it is not in any slightest way sufficient for you to say "oh will this ontology requires assumptions". You have to show why this ontology requires assumptions and the alternative ontology doesn't. I am saying, on a very very fundamental level, you cannot say one ontology is assumed while the other is concluded. I have explained this many many many many many times.

To arrive at the conclusion one simply needs to drop the assumptions of past and/or future, because absolute simultaneity would be a necessary consequence and so too would a set of dynamics that are not understood, apparently.

No, absolute simultaneity would not be a necessity because not assuming relativity of simultaneity is not the same as assuming relativity of simultaneity is false. If you drop the assumption, then the strongest statement you can make is that relativity of simultaneity may or may not be true.

Assuming that past and/or future exist doesn't give us RoS though, as absolute simultaneity would still be possible in a shared present moment where past and future exist. In order to arrive at the conclusion of RoS further assumptions are required; one such assumption, I believe, is the assumption that a clock measures time.

I have explained this to you before. It is the universal speed of light for all observers that motivates postulating a Minkowski spacetime of which RoS would be a feature.

If we drop all of those assumptions then we are left with a set of dynamics that we don't understand, which isn't an assumption, since nothing is being assumed.

No. I have explained this to you before. If you drop the assumptions, you are left saying RoS may or may not be the case. In order to be left with a set of dynamics and absolute simultaneity, you have to assume RoS is false.

The issue is that it is either true that an observers present moment is all that exists, or it isn't; it must be one or the other; that is, either their present moment is all that exists, or their past and/or future exists.

No, that is not the issue. What you have said here is a dichotomy that nobody disagrees with. Instead, the issue is not assuming the past and future exist is not the same as assuming the past and future don't exist. In the same way that not assuming it will rain tomorrow is not the same as assuming it won't rain tomorrow.

For an observer to conclude that more than their present moment exists they must assume the conclusions of past and/or future; to conclude that nothing more than their present moment exists they must simply drop the assumptions of anything more existing.

No, because not assuming x is true is not the same as assuming x is false. Therefore to conclude that nothing more than their present moment exists, they have to assume the past and the future don't exist, and that all those experiments testing the speed of light were somehow warped in specific way to render the speed of light the same for all observers.

roosh

Morbert wrote: »

No, you are not following even your own line of thought now. You are contrasting spacetime as distinct from presentism in terms of having to make assumptions. Therefore, it is not in any slightest way sufficient for you to say "oh will this ontology requires assumptions". You have to show why this ontology requires assumptions and the alternative ontology doesn't. I am saying, on a very very fundamental level, you cannot say one ontology is assumed while the other is concluded. I have explained this many many many many many times.

As was mentioned previously, each observer experiences their present moment and measures the speed of light to be c. This leaves them with 3 possible options, either:
a) their present moment is all that exists and new dynamics is responsible for the constancy of c;
or b) past and future co-exist with a shared present and the new dynamics are still responsible;
or c) RoS and spacetime are the conclusions.

There are, however, certain tacit assumptions required for some of those options to be feasible. In order to reach conclusions b) and c) they have to make the assumptions of past and future; if they don't make those assumptions then b) and c) simply aren't options; without the assumptions of past and future, they are left with only one possible conclusion, option a).

Morbert wrote: »

No, absolute simultaneity would not be a necessity because not assuming relativity of simultaneity is not the same as assuming relativity of simultaneity is false. If you drop the assumption, then the strongest statement you can make is that relativity of simultaneity may or may not be true.

The strongest statement we can make is that RoS is true or it isn't, but the statement that RoS is true is not an option without assuming past and future. So, without the assumptions of past and future we are left with only one option, that RoS is not true.

Morbert wrote: »

No. I have explained this to you before. If you drop the assumptions, you are left saying RoS may or may not be the case. In order to be left with a set of dynamics and absolute simultaneity, you have to assume RoS is false.
...
No, because not assuming x is true is not the same as assuming x is false. Therefore to conclude that nothing more than their present moment exists, they have to assume the past and the future don't exist, and that all those experiments testing the speed of light were somehow warped in specific way to render the speed of light the same for all observers.

No, what we are left saying is that RoS is or isn't the case; but we can't say that RoS is the case without making the assumptions of past and future; if we drop the assumptions, RoS isn't an option.

If we look at it in terms of the assumption that past and future don't exist; dropping the assumption that past and future don't exist doesn't rule out the possibility that only the present moment exists, precisely because not assuming that past and future don't exist is not the same as assuming that they do.

An observer is left with their present moment experience and with the possible conclusions that either it is all that exists or it isn't; they don't assume that past and future don't exist, but that doesn't leave them with the conclusion that they do, so either conclusion is still open to them; either their present is all that exists or their present isn't all that exists.

If they don't assume that their past and future exist, then they cannot conclude that their past and future exist, and so they can't conclude that more than their present moment exists; that leaves only one conclusion open to them.

Morbert wrote: »

No, that is not the issue. What you have said here is a dichotomy that nobody disagrees with. Instead, the issue is not assuming the past and future exist is not the same as assuming the past and future don't exist. In the same way that not assuming it will rain tomorrow is not the same as assuming it won't rain tomorrow.

The difference here is that we have a concrete starting position, as opposed to an entirely hypothetical one. An observer experiences their present moment and the question is whether or not more than that exists. Concluding that more exists requires the assumption that more exists, while concluding that nothing more exists simply requires

Morbert wrote: »

I have explained this to you before. It is the universal speed of light for all observers that motivates postulating a Minkowski spacetime of which RoS would be a feature.

I understand where it comes from, but we can look at it in terms of some of the necessary assumptions required for Minkowksi spacetime; assumptions which appear to include the conclusions.

Morbert

roosh wrote: »

As was mentioned previously, each observer experiences their present moment and measures the speed of light to be c. This leaves them with 3 possible options, either:
a) their present moment is all that exists and new dynamics is responsible for the constancy of c;
or b) past and future co-exist with a shared present and the new dynamics are still responsible;
or c) RoS and spacetime are the conclusions.

There are, however, certain tacit assumptions required for some of those options to be feasible. In order to reach conclusions b) and c) they have to make the assumptions of past and future; if they don't make those assumptions then b) and c) simply aren't options; without the assumptions of past and future, they are left with only one possible conclusion, option a).

No. Again and again and again: Not assuming x is not the same as assuming x is false. In order for b) and c) to be ruled out, you have to assume absolute simultaneity and mysterious dynamics.

Now, you brought up that exact same point in your other thread, and my response has not changed. You can, by virtue of Occam's razor, eliminate b) because it is essentially a) with the added assumption of spacetime. So the only relevant options are a) and c).

The strongest statement we can make is that RoS is true or it isn't, but the statement that RoS is true is not an option without assuming past and future. So, without the assumptions of past and future we are left with only one option, that RoS is not true.

No, what we are left saying is that RoS is or isn't the case; but we can't say that RoS is the case without making the assumptions of past and future; if we drop the assumptions, RoS isn't an option.

If we look at it in terms of the assumption that past and future don't exist; dropping the assumption that past and future don't exist doesn't rule out the possibility that only the present moment exists, precisely because not assuming that past and future don't exist is not the same as assuming that they do.

No, because not assuming x is not the same as assuming x is false. I.e. Not assuming the existence of Minkowski spacetime is not the same as assuming Minkowski spacetime doesn't exist.

An observer is left with their present moment experience and with the possible conclusions that either it is all that exists or it isn't; they don't assume that past and future don't exist, but that doesn't leave them with the conclusion that they do, so either conclusion is still open to them; either their present is all that exists or their present isn't all that exists.

Yes. They can either assume Minkowski spacetime exists, or they can assume an absolute present + dynamics that make all our measurements of light to be c.

If they don't assume that their past and future exist special dynamics exist, then they cannot conclude that their past and future special dynamics exist, and so they can't conclude that more than their present moment special dynamics exist.

See?

The difference here is that we have a concrete starting position, as opposed to an entirely hypothetical one. An observer experiences their present moment and the question is whether or not more than that exists. Concluding that more exists requires the assumption that more exists, while concluding that nothing more exists simply requires

"the assumption that mysterious dynamics exist". Was that what you were going to say?

I understand where it comes from, but we can look at it in terms of some of the necessary assumptions required for Minkowksi spacetime dynamical relativity; assumptions which appear to include the conclusions.

See?

roosh

Morbert wrote: »

No. Again and again and again: Not assuming x is not the same as assuming x is false. In order for b) and c) to be ruled out, you have to assume absolute simultaneity and mysterious dynamics.

You are completely correct, not assuming x is not the same as assuming x is false; I just don't think it applies in the way you think it applies, in this instance.

The basic fact is, conclusions b) and c) require the assumption(s) that past and future exist; in the absence of those assumptions it is not possible to arrive at conclusions b) or c).

On the other hand, we have the assumption(s) that past and future don't exist; if we assume that past and future don't exist then we conclude a). This, I think, is where the error stems from. The issue is that it isn't necessary to assume that past and future don't exist.

If the assumption that past and future don't exist is dropped, then we are still left with the conclusions a) or b) or c), because not assuming that past and future don't exist, is not the same as assuming that they do.

This brings us back to the point that unless past and future are assumed, conclusions b) and c) are not possible, and only a) is left.

Absolute simultaneity is a necessary consequence of a) and so too, supposedly, is a set of dynamics that are not understood.

Morbert wrote: »

Now, you brought up that exact same point in your other thread, and my response has not changed. You can, by virtue of Occam's razor, eliminate b) because it is essentially a) with the added assumption of spacetime. So the only relevant options are a) and c).

Option b) isn't simply option a) with the added assumption of spacetime; option a) is the position that only the present moment exists. I think you might be thinking of the position that the present moment is shared by all observers, which of course it would be if the present moment was all that existed, but the two are not the same because the former allows for the existence of past and future, as in b), while the latter doesn't.

If Occam's razor doesn't force us to cut the assumptions from c), then I think we are justified in assuming them for b), since b) and a) are mutually exclusive.

Morbert wrote: »

No, because not assuming x is not the same as assuming x is false. I.e. Not assuming the existence of Minkowski spacetime is not the same as assuming Minkowski spacetime doesn't exist.

This is dealt with above, but just a note on the point that not assuming x is not the same as assuming x is false; I think the issue lies in the fact that X is both the assumption and the conclusion. Not assuming X is not the same as assuming X is false, but in this case not assuming X doesn't allow us to conclude that X is true.

At the same time, if we know that X exists, then we are left with the possible conclusions that X is all that exists, or X isn't all that exists, or more than X exists. If we have to assume that more than X exists in order to conclude that more than X exists, then not assuming that more than X exists necessarily leaves us with only one possible conclusion, that X is all that exists.

Morbert wrote: »

Yes. They can either assume Minkowski spacetime exists, or they can assume an absolute present + dynamics that make all our measurements of light to be c.

As above, absolute simultaneity, or an absolute present, doesn't need to be assumed, it is a necessary consequence of the position that only the present moment exists.

Morbert wrote: »

If they don't assume that their past and future exist special dynamics exist, then they cannot conclude that their past and future special dynamics exist, and so they can't conclude that more than their present moment special dynamics exist.
See?

If special dynamics are a necessary consequence of presentism, and presentism is simply the position that only the present moment exists, then not assuming past and future necessarily gives us special dynamics, or dynamics that we don't yet understand. Saying that we don't understand something isn't the same as assuming that something is the case.

Morbert wrote: »

"the assumption that mysterious dynamics exist". Was that what you were going to say?

Apologies, I don't know how I managed to neglect that. I think I cut it off when I was grouping the relevant points together.

As above, however, I was going to say that concluding that nothing more exists simply requires us to drop the assumptions that more exists, because once we drop those assumptions we are left with only one possibility, that nothing more exists.

Morbert wrote: »

See?

Dynamical relativity simply requires us to drop the assumptions of past and future. Apparently, it follows as a necessary consequence of doing so.

I admit it isn't entirely satisfactory, but it appears to be less presumptuous.

Morbert

roosh, you are saying the same thing over and over. And when you say new things, they are wholly unrelated to the topic at hand.

Here is what you consistently refuse to acknowledge: If, to make an ontology work, you have to postulate some unobservable feature, then that feature is an assumption. It is not a conclusion, it is an assumption. What is so exasperating is even presentists like Brown & Pooley, which you referenced early on, would not claim otherwise. (They, instead, argue against Minkowski spacetime on the basis of explanatory power.)

So we have two relevant ontologies pertaining to relativistic phenomena:
a) A presentist, dynamical cause.
b) A 4-dimensional locally Minkowskian spacetime structure.

For each of these ontologies, there exists a necessary feature that is not observed. a) Requires a dynamical cause inducing Lorentz invariance. b) Requires "real" Minkoswkian chronometry. You cannot argue that b)'s requirement must be assumed while a)'s requirement can be concluded. That is indeed circular reasoning.

Morbert

To illustrate the mistake you are making:

roosh wrote: »

You are completely correct, not assuming x is not the same as assuming x is false; I just don't think it applies in the way you think it applies, in this instance.

The basic fact is, conclusions b) and c) require the assumption(s) that past and future exist; in the absence of those assumptions it is not possible to arrive at conclusions b) or c).

On the other hand, we have the assumption(s) that past and future don't exist; if we assume that past and future don't exist then we conclude a). This, I think, is where the error stems from. The issue is that it isn't necessary to assume that past and future don't exist.

If the assumption that past and future don't exist is dropped, then we are still left with the conclusions a) or b) or c), because not assuming that past and future don't exist, is not the same as assuming that they do.

This brings us back to the point that unless past and future are assumed, conclusions b) and c) are not possible, and only a) is left.

Absolute simultaneity is a necessary consequence of a) and so too, supposedly, is a set of dynamics that are not understood.

Here, you completely ignore the unobserved nature of the dynamical cause. If you have to suppose an unobserved facet to preserve presentism, then you cannot insist that unobserved facet is necessarily true unless you can show that presentism must be necessarily true.

Option b) isn't simply option a) with the added assumption of spacetime; option a) is the position that only the present moment exists. I think you might be thinking of the position that the present moment is shared by all observers, which of course it would be if the present moment was all that existed, but the two are not the same because the former allows for the existence of past and future, as in b), while the latter doesn't.

If Occam's razor doesn't force us to cut the assumptions from c), then I think we are justified in assuming them for b), since b) and a) are mutually exclusive.

This is an example of something completely unrelated to what I said (I never said a) and b) were the same).

<snipped repetition>

If special dynamics are a necessary consequence of presentism, and presentism is simply the position that only the present moment exists, then not assuming past and future necessarily gives us special dynamics, or dynamics that we don't yet understand. Saying that we don't understand something isn't the same as assuming that something is the case.

Here, you forget that not assuming x is not the same as assuming x is false. I.e. Not assuming the past and future exist is not the same as assuming only the present exists.

Apologies, I don't know how I managed to neglect that. I think I cut it off when I was grouping the relevant points together.

As above, however, I was going to say that concluding that nothing more exists simply requires us to drop the assumptions that more exists, because once we drop those assumptions we are left with only one possibility, that nothing more exists.

Here, you also forget that not assuming x is not the same as assuming x is false. Once you drop the assumptions of past and future, you are not left with only one possibility. You are left with two possibilities: Spacetime exists or only the present exists.

Dynamical relativity simply requires us to drop the assumptions of past and future. Apparently, it follows as a necessary consequence of doing so.

I admit it isn't entirely satisfactory, but it appears to be less presumptuous.

No, it requires the postulate of an unobserved dynamical structure, and it requires us to assume the past and future do not exist.

citrus burst

roosh wrote: »

On what basis would you deny it?

I don't know many things that are self evident, on that basis I would be suspicious of its use as a postulate.

It should be up to you to convince me that its true, since you brought it to the plate.

roosh wrote: »

What everyone experiences in the present moment can be different; someone in France would have a different experience to what you are experiencing right now.

What I meant to say is that everyone should have a different definition of the present moment.

roosh wrote: »

In other words, someone in Paris is experiencing something right now, and you are experiencing something different right now; if you drop the assumptions that your past and/or future exist then the simultaneity of those two events must be absolute.

I don't how see this comes into play. If anything it contradicts what you are trying to prove. It really could be interpreted as everything happens at once, breaking causality.

You do raise an interesting point though, there are certain situations that would allow simultaneity to be absolute (ie Newtonian approximation), but these are the exception, rather then the rule.

roosh wrote: »

We don't even have to assume an overlap; all you have to do is acknowledge that your experience occurs in the present moment; if you drop the assumptions that your past and/or future exist, then only your present moment exists and simultaneity must be absolute.

Well you do actually. If only the present moment exists, without overlap, I could conclude that William Shakespear and dinosaurs existed at the same present moment and break causality.

roosh wrote: »

I don't immediately see the necessity of this.

See above.

roosh wrote: »

Any experience you or I have of the universe, that is, the entirety of our experience, occurs in what we call "the present moment".

Do you mean within our lives?

citrus burst

roosh wrote: »

Either, or
Now, for any given observer, it is either true that their present moment is all that exists or that more than their present moment exists; that is, their past and/or future also exist. However, any such conclusion, that their past and/or future exist, must be assumed, because they only ever experience the present moment.

Or we could just assume time exists.

roosh wrote: »

So, for any observer to arrive at the conclusion that their past and/or future exist, the conclusion(s) must be assumed. However, to arrive at the conclusion that nothing more than their present moment exists, they simply have to avoid the assumptions of past and/or future - given that it's one or the other.

Not really part of my argument, but you are assuming your conclusions? I don't really follow your logic.

I would have thought assuming something negates the need to conclude it.

roosh

Morbert wrote: »

roosh, you are saying the same thing over and over. And when you say new things, they are wholly unrelated to the topic at hand.

Here is what you consistently refuse to acknowledge: If, to make an ontology work, you have to postulate some unobservable feature, then that feature is an assumption. It is not a conclusion, it is an assumption. What is so exasperating is even presentists like Brown & Pooley, which you referenced early on, would not claim otherwise. (They, instead, argue against Minkowski spacetime on the basis of explanatory power.)

So we have two relevant ontologies pertaining to relativistic phenomena:
a) A presentist, dynamical cause.
b) A 4-dimensional locally Minkowskian spacetime structure.

For each of these ontologies, there exists a necessary feature that is not observed. a) Requires a dynamical cause inducing Lorentz invariance. b) Requires "real" Minkoswkian chronometry. You cannot argue that b)'s requirement must be assumed while a)'s requirement can be concluded. That is indeed circular reasoning.

My apologies, I was working more from a position of saying that reason for the observation of the constancy of c is not understood, or perhaps not known, in which case it would not be an assumption.

But I take your point.

Morbert wrote: »

To illustrate the mistake you are making:

Here, you completely ignore the unobserved nature of the dynamical cause. If you have to suppose an unobserved facet to preserve presentism, then you cannot insist that unobserved facet is necessarily true unless you can show that presentism must be necessarily true.

The contention wasn't that the dynamical cause is necessarily true, it's that it is a necessary condition of presentism; further, the contention wasn't that presentism is necessarily true, rather that, if the assumptions of past and future are dropped, then presentism is the only option which remains.

Morbert wrote: »

This is an example of something completely unrelated to what I said (I never said a) and b) were the same).

No, what you said was that b) was essentially a) with the added assumption of spacetime, or past and future, and so, could be dismissed on the basis of Occam's Razor; but that is incorrect, because a) is the position that only the present moment exists; this excludes the possibility of adding the assumptions of past and future to it.

Morbert wrote: »

Here, you forget that not assuming x is not the same as assuming x is false. I.e. Not assuming the past and future exist is not the same as assuming only the present exists.

That isn't, strictly speaking, the contention. The contention is that, if past and future are not assumed then the only remaining conclusion is that the present moment is all that exists.

Morbert wrote: »

Here, you also forget that not assuming x is not the same as assuming x is false. Once you drop the assumptions of past and future, you are not left with only one possibility. You are left with two possibilities: Spacetime exists or only the present exists.

I think you are forgetting that arriving at the conclusion of past and future is circular reasoning. In order to arrive at the conclusion that past and future exist, it must be assumed that they do; if it is not assumed that they do, then the conclusion cannot be reached.

If concluding X requires that X be assumed, then not assuming X means that X cannot be concluded. This is, perhaps, specific to circular reasoning.

When you say that not assuming past and future still leaves the possibility of spacetime, you are, in effect, saying, "but we could still assume past and future" - because only by assuming them can you arrive at the conclusion of spacetime. What is being said is that, if they are not assumed at all. If they are not assumed, spacetime isn't a possible conclusion.

Morbert wrote: »

No, it requires the postulate of an unobserved dynamical structure, and it requires us to assume the past and future do not exist.

Dynamical relativity doesn't require us to assume that past and future don't exist, as with option b) above, it is possible to have dynamical relativity in a universe where past and future exist, but the present moment is shared by all.

Concluding that the present moment is all that exists only requires us not to assume that past and future do exist, because without those assumptions it is the only possible conclusion.


If we start off with just the fact that either the present moment is all that exists or it isn't, then not assuming past and future leaves us with only the option of presentism and the assumption of dynamical relativity.

Assuming that past and future do exist leaves us with options b) and c) so a further assumption is required to decide between them.

Is it fair to say that presentism requires fewer assumptions?

roosh

citrus burst wrote: »

I don't know many things that are self evident, on that basis I would be suspicious of its use as a postulate.

It should be up to you to convince me that its true, since you brought it to the plate.

In order to convince you we would need to see what the objections are; but above you have laid out one, or clarified what makes you suspicious; namely, that you don't know many things that are self-evident.

That there is existence is self-evident, even if the nature of that existence isn't. With regard to experiencing existence in the present, has there ever been a moment where you've been experiencing existence that hasn't be in the present moment?

citrus burst wrote: »

What I meant to say is that everyone should have a different definition of the present moment.

I'm not certain what you mean by that; as mentioned, everyone can experience something different in the present moment. We don't need to worry about anyone else's definition, because whatever reasoning we apply to ourselves is applicable to all observers.

For example, take a hypothetical observer on a distant planet and consider the question of what they are doing right now, from your perspective. Let's say they are brushing their teeth. You don't experience them brushing their teeth, you experience something different, say reading this. So you both have quite different experiences but both are happening right now.

citrus burst wrote: »

I don't how see this comes into play. If anything it contradicts what you are trying to prove. It really could be interpreted as everything happens at once, breaking causality.

You do raise an interesting point though, there are certain situations that would allow simultaneity to be absolute (ie Newtonian approximation), but these are the exception, rather then the rule.

There are many things happening at once, but causality isn't broken. Start close and work your way out; while you are reading this your housemate might be in the bathroom; both those are happening at once, but causality isn't broken; continue to work out from your living quarters into the street, the town, the country, the continent, the planet, the solar system, and beyond, and there are many many things happening all at once, but causality is not broken. Indeed, for there not to be many things happening at once, the universe could not consist of more than yourself.

citrus burst wrote: »

Well you do actually. If only the present moment exists, without overlap, I could conclude that William Shakespear and dinosaurs existed at the same present moment and break causality.

Sorry, what I meant was that for your housemate in the bathroom, or the distant observer on another planet, you don't need to assume that your present moments overlap. If your present moment is all their is, then the idea of overlap is superfluous.

This present moment is dynamical, it is constantly changing; we observe that on a daily basis; it is our memory of a previous configuration, of the present moment, which we label "the past" and our imagining a not yet manifest configuration as "the future"; we can draw worldlines to represent this evolution of the universe where Dinosaurs and Shakespeare never share the same configuration.

citrus burst wrote: »

Do you mean within our lives?

Yes; every experience we have occurs in the present.

citrus burst wrote: »

Or we could just assume time exists.

We could assume that many things exist, but that doesn't justify the assumption.

citrus burst wrote: »

Not really part of my argument, but you are assuming your conclusions? I don't really follow your logic.

I would have thought assuming something negates the need to conclude it.

One way of describing circular reasoning is "assuming ones conclusions"; in this case in order to reach conclusion X, you have to assume X. If you don't assume X, then you can't conclude X.

This is the case with past and future. We only ever experience the present, so, in order to conclude that past and future exist, we have to assume that they do. If we don't assume that they do, then we can't conclude that they do.

The thing is though, we are in a position where we only ever experience the present; this means that there are only two possible conclusions we can reach; either the present is all that exists, or past and future also exist.

In order to conclude that past and future exist, we must assume that they do. If we don't assume that they do, then we can't conclude that they do, and there is only one conclusion left open to us.



This, of course, ignores the constancy of c, which requires an explanation; for presentism to be true it seems we are required to assume dynamical relativity. It seems to be a necessary assumption if we drop the assumptions that our past and future exist.

citrus burst

roosh wrote: »

In order to convince you we would need to see what the objections are; but above you have laid out one, or clarified what makes you suspicious; namely, that you don't know many things that are self-evident.

That there is existence is self-evident, even if the nature of that existence isn't. With regard to experiencing existence in the present, has there ever been a moment where you've been experiencing existence that hasn't be in the present moment?

I've raised an objection and challenged you to prove to me that all observations/measurements occur in the present moment. If the case is true and you can prove it in a general case, then my specific objections should be encompassed in your overall proof.

Its not a case of dealing with my specific objections, its a case for you to prove that all measurements occur in the present moment.

roosh wrote: »

I'm not certain what you mean by that; as mentioned, everyone can experience something different in the present moment. We don't need to worry about anyone else's definition, because whatever reasoning we apply to ourselves is applicable to all observers.

For example, take a hypothetical observer on a distant planet and consider the question of what they are doing right now, from your perspective. Let's say they are brushing their teeth. You don't experience them brushing their teeth, you experience something different, say reading this. So you both have quite different experiences but both are happening right now.

In order to build a general case we should have some sort of definition of what the present moment is. To say it is self evident, in my opinion is not good enough, when building a theory to explain how the universe works on most scales.

To leave the definition of the present moment as a floating parameter, would at best be inconvenient.

Again I wouldn't agree that whatever reasoning we apply to ourselves, can be reasoned to all other cases.

To take your example; technically speaking, I was dead when it was observed I was brushing my teeth by a distant observer, according to some present moment. Or vice versa the observer wasn't born when I was brushing my teeth. However it would seem to me that it is hypothetically possible for both these two to meet up at some point. These problems crop up everywhere when you introduce the idea of the present moment. These are only simple cases.

roosh wrote: »

There are many things happening at once, but causality isn't broken. Start close and work your way out; while you are reading this your housemate might be in the bathroom; both those are happening at once, but causality isn't broken; continue to work out from your living quarters into the street, the town, the country, the continent, the planet, the solar system, and beyond, and there are many many things happening all at once, but causality is not broken. Indeed, for there not to be many things happening at once, the universe could not consist of more than yourself.

And technically speaking all of these, things happened in the past, the further out you go, the longer ago something happened. Coming from the other angle, all things that you do will be observed in the future.

You did however miss my point. It could be interpreted as everything happens at one present moment. If time truly does not exist this would be the case.

I think therefore, you need to assume time, in order to have a functioning universe.

roosh wrote: »

Sorry, what I meant was that for your housemate in the bathroom, or the distant observer on another planet, you don't need to assume that your present moments overlap. If your present moment is all their is, then the idea of overlap is superfluous.

This present moment is dynamical, it is constantly changing; we observe that on a daily basis; it is our memory of a previous configuration, of the present moment, which we label "the past" and our imagining a not yet manifest configuration as "the future"; we can draw worldlines to represent this evolution of the universe where Dinosaurs and Shakespeare never share the same configuration.

But you would need to assume some connection between two present moments. "we can draw worldlines to represent this evolution of the universe where Dinosaurs and Shakespeare never share the same configuration." suggests some sort or connection and overlap.

You could just assume time, and not give it an arbitrary location ie past, present, future.

If you don't assume time, you need to assume hidden dynamics that cause the present moment to move, all of this to attach arbitrary labels that satisfy your agenda.

In terms of Occum's razor, the former is a better choice.

roosh wrote: »

Yes; every experience we have occurs in the present.

How long is the present?

roosh wrote: »

We could assume that many things exist, but that doesn't justify the assumption.

But assuming time isn't such a bad thing. Which do you think is more out there; assuming time, a measurable quantity, or assuming the present moment, an as of yet undefined, unmeasurable, dynamical, arbitrary quantity?

roosh wrote: »

One way of describing circular reasoning is "assuming ones conclusions"; in this case in order to reach conclusion X, you have to assume X. If you don't assume X, then you can't conclude X.

This is the case with past and future. We only ever experience the present, so, in order to conclude that past and future exist, we have to assume that they do. If we don't assume that they do, then we can't conclude that they do.

The thing is though, we are in a position where we only ever experience the present; this means that there are only two possible conclusions we can reach; either the present is all that exists, or past and future also exist.

In order to conclude that past and future exist, we must assume that they do. If we don't assume that they do, then we can't conclude that they do, and there is only one conclusion left open to us.



This, of course, ignores the constancy of c, which requires an explanation; for presentism to be true it seems we are required to assume dynamical relativity. It seems to be a necessary assumption if we drop the assumptions that our past and future exist.

I don't think circular reasoning lends any weight to exploring the properties of the universe, other then to serve a self fulfilling agenda. We don't gain any more insight into the universe by using it.

dlouth15

Roosh,

The idea of a past, present and future depends on there being a conscious observer present determining what is "now" and therefore dividing time up into past, present and future. If we have no conscious observers then we only have a network of causally connected events with no means to distinguish between them. There's no independent physical property of events that determine whether they are happening now.

If this is a problem, then it is a problem for all of physical science, not merely special relativity. Newtonian physics also has this problem.

If "now" must be part of a physical theory, then how do you define it independently of a conscious observer? If you can't define it in such a way then you must proceed without it.

CiDeRmAn

What an interesting discussion.
Quick question though,
Isn't time, and times direction, a function of thermodynamics, a winding down of energy into its lowest form, heat.
Everything else is therefore wrinkles, but entropy rules all?
The individual light cone of people is also irrelevant at our scale but, using the anecdote of the distant creature washing his tentacles while you read an online forum, although they be simultaneous the only way to influence each other is within said light cone, which in turn means no influence at all, depending on the scale of the distance involved. This is an un bridgeable gulf, any tool that connects these events, not only in terms of simultaneous action but even outside of the lightcone, breaks the upper information speed, C.

Sorry for butting in.

This stuff also seems for philosophy than science!

Also, the position of observer in all this is disturbing, as if the universe won't function properly without one, what gives?

roosh

citrus burst wrote: »

I've raised an objection and challenged you to prove to me that all observations/measurements occur in the present moment. If the case is true and you can prove it in a general case, then my specific objections should be encompassed in your overall proof.

Its not a case of dealing with my specific objections, its a case for you to prove that all measurements occur in the present moment.

The contention is that, for any given observer, all of their measurement occur in their own present moment; in the parlance of SR (as it is popularly categorised in programmes such as NOVAs the Fabric of the Cosmos), every observer makes their own observation in their own "now slice", or what their co-ordinate reference frame would classify as "now". This is true for relativity as it is for presentism.

citrus burst wrote: »

In order to build a general case we should have some sort of definition of what the present moment is. To say it is self evident, in my opinion is not good enough, when building a theory to explain how the universe works on most scales.

To leave the definition of the present moment as a floating parameter, would at best be inconvenient.

Again I wouldn't agree that whatever reasoning we apply to ourselves, can be reasoned to all other cases.

"The present moment" is nothing more complicated than the moment in which your experience occurs. This would be circular reasoning except that it isn't solely reasoning on which it is based, it is derived from experience.

The experience you are having as you read this is occurring in the present moment, "your present moment" if necessary. It's what is meant when we say "now".

citrus burst wrote: »

To take your example; technically speaking, I was dead when it was observed I was brushing my teeth by a distant observer, according to some present moment. Or vice versa the observer wasn't born when I was brushing my teeth. However it would seem to me that it is hypothetically possible for both these two to meet up at some point. These problems crop up everywhere when you introduce the idea of the present moment. These are only simple cases.

The problem is one of misinterpretation I think. It's not so much that you would technically be dead when the distant observer sees you brushing your teeth, it's that you would be clinically dead. What the distant observer sees is just an image of you brushing your teeth. It's like seeing a photograph of a "past" event.

citrus burst wrote: »

And technically speaking all of these, things happened in the past, the further out you go, the longer ago something happened. Coming from the other angle, all things that you do will be observed in the future.

You might be thinking of light from distant events reaching you, in your present moment. In this case, the image that you see is from an event that did happen "in the past". It must necessarily have happened "before now" if light from the event is reaching you now, given the finite speed of light

citrus burst wrote: »

You did however miss my point. It could be interpreted as everything happens at one present moment. If time truly does not exist this would be the case.

I think therefore, you need to assume time, in order to have a functioning universe.

I would say that it could be misinterpreted as everything happens at one present moment; I think it stems from interpreting the present moment as "the present moment in time", but that would be inaccurate, because the present moment isn't in time. The present moment is dynamical and constantly changing, so it is possible that things happen in sequential order, in a dynamical present moment.

Just think of yourself as you've grown older; every moment of your life has been spent in what we would call "the present moment"; when you were 10yrs old, it was "the time was now", when you were 20yrs old "the time was now", and so on. At every juncture of your existence you have occupied the present moment, yet you have aged sequentially.

citrus burst wrote: »

But you would need to assume some connection between two present moments. "we can draw worldlines to represent this evolution of the universe where Dinosaurs and Shakespeare never share the same configuration." suggests some sort or connection and overlap.

"The past" is connected to the present because it preceded it and represented the conditions that lead to the present; but just as your 10yr old self doesn't overlap with your current self the two are connected; where your 10yr old self preceded your current self.

Something to ask yourself as you go about your daily business is, that might clarify what is meant; ask yourself "is it the present moment?"; ask yourself this on a regular basis and see what the answer is.

citrus burst wrote: »

You could just assume time, and not give it an arbitrary location ie past, present, future.

If you don't assume time, you need to assume hidden dynamics that cause the present moment to move, all of this to attach arbitrary labels that satisfy your agenda.

In terms of Occum's razor, the former is a better choice.

Entropy could be used to explain an ever changing present moment; they are essentially one and the same thing.

I don't see how assuming time is more favourable to dropping the assumption that time exists.

citrus burst wrote: »

How long is the present?

It doesn't have a duration, per se. It lasts as long as there is existence.

citrus burst wrote: »

But assuming time isn't such a bad thing. Which do you think is more out there; assuming time, a measurable quantity, or assuming the present moment, an as of yet undefined, unmeasurable, dynamical, arbitrary quantity?

The issue is that "time as a measurable quantity" is just an assumption; when we examine it, we can see that time isn't actually a measurable quantity; that is, time is not the object of measurement, it is the abstract system of measurement. We would still retain a concept of time, we would just see it for what it isn't. There would still be clocks, just no physical time.

citrus burst wrote: »

I don't think circular reasoning lends any weight to exploring the properties of the universe, other then to serve a self fulfilling agenda. We don't gain any more insight into the universe by using it.

Then we should drop the assumptions that past and future exist, and that time is a physically measurable property.

roosh

dlouth15 wrote: »

Roosh,

The idea of a past, present and future depends on there being a conscious observer present determining what is "now" and therefore dividing time up into past, present and future. If we have no conscious observers then we only have a network of causally connected events with no means to distinguish between them. There's no independent physical property of events that determine whether they are happening now.

If this is a problem, then it is a problem for all of physical science, not merely special relativity. Newtonian physics also has this problem.

If "now" must be part of a physical theory, then how do you define it independently of a conscious observer? If you can't define it in such a way then you must proceed without it.

Empiricism depends on their being a conscious observer.

dlouth15

roosh wrote: »

Empiricism depends on their being a conscious observer.

That doesn't really address the points made. Would you not agree that if you didn't exist as a conscious observer, the Earth would still orbit the Sun, plants would still grow, etc., the Universe would carry on much as it does now but without you? We did not always exist as conscious observers and one day we will cease to exist as conscious observers. Therefore what we want is a description of the world that does not depend on the existence of either you or me.

roosh

CiDeRmAn wrote: »

What an interesting discussion.
Quick question though,
Isn't time, and times direction, a function of thermodynamics, a winding down of energy into its lowest form, heat.
Everything else is therefore wrinkles, but entropy rules all?
The individual light cone of people is also irrelevant at our scale but, using the anecdote of the distant creature washing his tentacles while you read an online forum, although they be simultaneous the only way to influence each other is within said light cone, which in turn means no influence at all, depending on the scale of the distance involved. This is an un bridgeable gulf, any tool that connects these events, not only in terms of simultaneous action but even outside of the lightcone, breaks the upper information speed, C.

Sorry for butting in.

This stuff also seems for philosophy than science!

Also, the position of observer in all this is disturbing, as if the universe won't function properly without one, what gives?

Hey ciderman, you're not butting in at all; such discussions can only be richer for having a wide range of perspective.

Science or Philosophy
To address the issue of it being more philosophy than science; relativity of simultaneity appears to be considered, very much, science, although if examine I think it might be found to be a philosophical interpretation of observational evidence, or a philosophical conclusion from foundational principles which carry certain tacit assumptions. To highlight this issue it is worth considering the two "rival" interpretations of the mathematics of relativity, the Einsteinian and the Lorentzian. Apparently the mathematics are the exact same, such that any experimental verification of SR to date is equally validation of the Lorentzian interpretation. The Lorentzian interpretation retains the concept of absolute simultaneity. Apparently, the difference between the two interpretations is only a matter of philosophy, so relativity of simultaneity would have to be a philosophical interpretation.

Entropy
With regard to entropy, I think the dimension of time is a superfluous concept, because we only ever observe a system extended in 3 spatial dimensions. We might make records of a system, then observe that system changing and compare the subsequent state of the system to our records and see how it has become more disordered, but, if the physical universe only ever consists of the system in a single given state, then time cannot be seen as a dimension of that system. The issue is that we only ever observe a system in a single given state, extended in 3 dimensions; to conclude that the overal structure of the universe consists of the previous confiugrations of the system, as well as the future configurations, we have to assume that they do.

Light cones
Simultantaneous events can't influence each other; this is true in relativity as any presentist interpretation. There is no need to bridge the gap.

roosh

dlouth15 wrote: »

That doesn't really address the points made. Would you not agree that if you didn't exist as a conscious observer, the Earth would still orbit the Sun, plants would still grow, etc., the Universe would carry on much as it does now but without you? We did not always exist as conscious observers and one day we will cease to exist as conscious observers. Therefore what we want is a description of the world that does not depend on the existence of either you or me.

All of the phenomena you have described above are derived from conscious observation; we cannot possibly have a description of the world that does not depend on conscious observation.

dlouth15

roosh wrote: »

All of the phenomena you have described above are derived from conscious observation; we cannot possibly have a description of the world that does not depend on conscious observation.

But what if we never existed? Would the world continue without us?

The answer, I think you will agree, is that planets would still orbit suns, nuclear fusion would still occur in the centre of those suns. Stuff would still happen.

It is true that for humans to discover the laws of physics there has to be observation, but the laws themselves don't depend on observation. It is like pebbles on a beach. I can observe or not observe a particular pebble, but the pebble has an existence regardless.

roosh

dlouth15 wrote: »

But what if we never existed? Would the world continue without us?

The answer, I think you will agree, is that planets would still orbit suns, nuclear fusion would still occur in the centre of those suns. Stuff would still happen.

It is true that for humans to discover the laws of physics there has to be observation, but the laws themselves don't depend on observation. It is like pebbles on a beach. I can observe or not observe a particular pebble, but the pebble has an existence regardless.

It's a pertinent question, whether or not planets would orbit suns; in the thread on absolute motion, in the philosophy section, the question was how could relative motion occur in a block universe; the contention was that relative motion is observed because of our capacity for memory - which is dependent on our consciousness of those memories.

Personally, I believe there would still be existence without conscious observers; whether or not what we observe as the physical universe would still be manifested, I'm not so sure.

But, that would become a moot point if there were no conscious observers to discuss it.

dlouth15

roosh wrote: »

It's a pertinent question, whether or not planets would orbit suns; in the thread on absolute motion, in the philosophy section, the question was how could relative motion occur in a block universe; the contention was that relative motion is observed because of our capacity for memory - which is dependent on our consciousness of those memories.

It is possible to define relative motion in a block universe (I take this to mean some sort four dimensional spacetime). Things like orbits and such can be represented easlily.

Personally, I believe there would still be existence without conscious observers; whether or not what we observe as the physical universe would still be manifested, I'm not so sure.

But, that would become a moot point if there were no conscious observers to discuss it.

Yet would you not agree that physics is the attempt to discover physical laws and that the default assumption is that these laws exist whether or not we are observing them. I mean, I know that I will cease to exist at some point as a conscious observer. But I also know that the world will carry on without me. Physics (and other physical sciences) don't really make sense if the laws discovered are only valid while I'm around.

It's not really a moot point either. A lot of people, for example, care about the sort of world that's going to be left to their descendants after they themselves are gone.

Morbert

roosh wrote: »

The contention wasn't that the dynamical cause is necessarily true, it's that it is a necessary condition of presentism;

That was never a contention.

further, the contention wasn't that presentism is necessarily true, rather that, if the assumptions of past and future are dropped, then presentism is the only option which remains.

And that is false. Presentism is true if and only if the past and future do not exist. Thus, if you want to argue that presentism is true, then you must establish that the past and future do not exist, or are at the very least can be assumed not to exist by Occam's razor.

No, what you said was that b) was essentially a) with the added assumption of spacetime, or past and future, and so, could be dismissed on the basis of Occam's Razor; but that is incorrect, because a) is the position that only the present moment exists; this excludes the possibility of adding the assumptions of past and future to it.

I meant ontologically. I.e. What exists according to b) is what exists according to a) plus a Newtonian spacetime. Thus, we can indeed disregard b) based on Occam's razor.

That isn't, strictly speaking, the contention. The contention is that, if past and future are not assumed then the only remaining conclusion is that the present moment is all that exists.

-

Concluding that the present moment is all that exists only requires us not to assume that past and future do exist, because without those assumptions it is the only possible conclusion.

-

If we start off with just the fact that either the present moment is all that exists or it isn't, then not assuming past and future leaves us with only the option of presentism and the assumption of dynamical relativity.

And that contention is not true, because not assuming x is not the same as assuming x is false. If we don't assume spacetime, then either a) or c) is true. We cannot conclude either.

I think you are forgetting that arriving at the conclusion of past and future a dynamical cause is circular reasoning. In order to arrive at the conclusion that past and future a dynamical cause exists, it must be assumed that it does; if it is not assumed that it does, then the conclusion cannot be reached.

If concluding X requires that X be assumed, then not assuming X means that X cannot be concluded. This is, perhaps, specific to circular reasoning.

When you say that not assuming past and future a dynamical cause still leaves the possibility of spacetime a dynamical cause, you are, in effect, saying, "but we could still assume past and future a dynamical cause" - because only by assuming it can you arrive at the conclusion of spacetime a dynamical cause. What is being said is that, if it is not assumed at all. If it is not assumed, spacetime a dynamical cause isn't a possible conclusion.

See? Nobody is arguing against what you say above. I have never said spacetime can be concluded without making assumptions. I am saying what applies to c) also applies to a). Both positions are ontological positions that hinge on assumptions.

<snipped irrelevancies>

Is it fair to say that presentism requires fewer assumptions?

No, because then we are in vague territory, where it boils down to whether or not you "like" an undetected dynamical cause, or a kinematic spacetime structure.

roosh

dlouth15 wrote: »

It is possible to define relative motion in a block universe (I take this to mean some sort four dimensional spacetime). Things like orbits and such can be represented easlily.

Defining relative motion isn't the issue, the question is how could relative motion possibly occur in a universe where objects exist as worldlines extended in 4D spacetime, where those worldlines don't move and the points on the worldlines don't move.

If you imagine two chopsticks lying on the desk in front of you, lying at angles to each other - they represent the worldlines of two objects extended in 4D spacetime - how can they give rise to what we observe as relative motion?

dlouth15 wrote: »

Yet would you not agree that physics is the attempt to discover physical laws and that the default assumption is that these laws exist whether or not we are observing them.

I would probably say that physics is the attempt to describe the laws of the physical world we observer, which would imply conscious observers.

dlouth15 wrote: »

I mean, I know that I will cease to exist at some point as a conscious observer. But I also know that the world will carry on without me. Physics (and other physical sciences) don't really make sense if the laws discovered are only valid while I'm around.

It's not really a moot point either. A lot of people, for example, care about the sort of world that's going to be left to their descendants after they themselves are gone.

I don't doubt that the universe will continue to exist when I die, but the sort of world that is going to be left to our descendents is still a universe in which there are conscious observers.


EDIT: Also, presentism isn't dependent on conscious observers; just as planets may go on orbiting stars, when conscious observers are gone, they will continue to do so in the present moment.

Morbert

roosh wrote: »

Defining relative motion isn't the issue, the question is how could relative motion possibly occur in a universe where objects exist as worldlines extended in 4D spacetime, where those worldlines don't move and the points on the worldlines don't move.

If you imagine two chopsticks lying on the desk in front of you, lying at angles to each other - they represent the worldlines of two objects extended in 4D spacetime - how can they give rise to what we observe as relative motion?

I would probably say that physics is the attempt to describe the laws of the physical world we observer, which would imply conscious observers.

I don't doubt that the universe will continue to exist when I die, but the sort of world that is going to be left to our descendents is still a universe in which there are conscious observers.

Physical theories are descriptions independent of conscious observers.

citrus burst

roosh wrote: »

The contention is that, for any given observer, all of their measurement occur in their own present moment; in the parlance of SR (as it is popularly categorised in programmes such as NOVAs the Fabric of the Cosmos), every observer makes their own observation in their own "now slice", or what their co-ordinate reference frame would classify as "now". This is true for relativity as it is for presentism.

So in other words you can't really.

roosh wrote: »

"The present moment" is nothing more complicated than the moment in which your experience occurs. This would be circular reasoning except that it isn't solely reasoning on which it is based, it is derived from experience.

This is just a hand waving argument with not much merit behind it.

roosh wrote: »

The experience you are having as you read this is occurring in the present moment, "your present moment" if necessary. It's what is meant when we say "now".

But how long is now?

roosh wrote: »

The problem is one of misinterpretation I think. It's not so much that you would technically be dead when the distant observer sees you brushing your teeth, it's that you would be clinically dead. What the distant observer sees is just an image of you brushing your teeth. It's like seeing a photograph of a "past" event.

No you would be dead (assuming you are far enough away), in all sense of the word, kaput.

Technically speaking everything we see is a photograph of a past event.

roosh wrote: »

You might be thinking of light from distant events reaching you, in your present moment. In this case, the image that you see is from an event that did happen "in the past". It must necessarily have happened "before now" if light from the event is reaching you now, given the finite speed of light

If there is any distance between two events, they occurred in the past. Even if they are part of your so called present moment.

roosh wrote: »

Entropy could be used to explain an ever changing present moment; they are essentially one and the same thing.

You still need time for entropy.

roosh wrote: »

I don't see how assuming time is more favourable to dropping the assumption that time exists.

It provides an existence free definition of the universe, along with mass, length, charge etc.

roosh wrote: »

It doesn't have a duration, per se. It lasts as long as there is existence.

Then what happens?

roosh wrote: »

The issue is that "time as a measurable quantity" is just an assumption; when we examine it, we can see that time isn't actually a measurable quantity; that is, time is not the object of measurement, it is the abstract system of measurement. We would still retain a concept of time, we would just see it for what it isn't. There would still be clocks, just no physical time.

If that was the case we could justify that all measurable quantities in the universe are redundant.

I take it you have no problems with mass or length? How are these measured?

thecornflake

roosh wrote: »

What everyone experiences in the present moment can be different; someone in France would have a different experience to what you are experiencing right now.

In other words, someone in Paris is experiencing something right now, and you are experiencing something different right now; if you drop the assumptions that your past and/or future exist then the simultaneity of those two events must be absolute.


We don't even have to assume an overlap; all you have to do is acknowledge that your experience occurs in the present moment; if you drop the assumptions that your past and/or future exist, then only your present moment exists and simultaneity must be absolute.


I don't immediately see the necessity of this.


Any experience you or I have of the universe, that is, the entirety of our experience, occurs in what we call "the present moment".

You know, I think you may be on something here.

roosh

Morbert wrote: »

That was never a contention.

The contention has been that if the assumptions of past and future are dropped then presentism is the only remaining conclusion. It's been your contention that presentism necessitates a dynamical cause, I just accepted it.

Morbert wrote: »

And that is false. Presentism is true if and only if the past and future do not exist. Thus, if you want to argue that presentism is true, then you must establish that the past and future do not exist, or are at the very least can be assumed not to exist by Occam's razor.

Again, the contention isn't necessarily that presentism is true, it's that it is the only possible conclusion of the assumptions of past and future are dropped; this is true because "not-presentism" is only a possible conclusion if the assumptions of past and future are made; if they're not made i.e. if they're dropped, then the conclusion of "not-presentism" cannot be reached; that would leave presentism as the only possible conclusion.

Morbert wrote: »

I meant ontologically. I.e. What exists according to b) is what exists according to a) plus a Newtonian spacetime. Thus, we can indeed disregard b) based on Occam's razor.

If we're justified in making the assumptions of past and future for one, then we're justified in making them for the other; but we don't necessarily need b) to be a realistic possibility, it's just helpful for highlighting that more than just the assumption of past and future is required to arrive at the conclusion of Minkowski spacetime.

Morbert wrote: »

And that contention is not true, because not assuming x is not the same as assuming x is false. If we don't assume spacetime, then either a) or c) is true. We cannot conclude either.

Again, that not assuming x is not the same as assuming x is false is not in contention, indeed, it is applied to demonstrate that presentism is the only option left when the assumptions of past and future are dropped.

It is a feature of circular reasoning that if the conclusion, X, requires the assumption X, and the assumption X is dropped, then conclusion X is not an option; that is, conclusion X is only an option with the assumption X.

When you say that either a) or c) are left as possibilities, when the assumptions of past and future are dropped, what you are, in effect, saying is that, "we can always take the assumptions up again "; because only by making the assumptions of past and future can those conclusions be reached.

Morbert wrote: »

See? Nobody is arguing against what you say above. I have never said spacetime can be concluded without making assumptions. I am saying what applies to c) also applies to a). Both positions are ontological positions that hinge on assumptions.
...
No, because then we are in vague territory, where it boils down to whether or not you "like" an undetected dynamical cause, or a kinematic spacetime structure.

This is true. I guess it could come down to the number of assumptions required by both and indeed the logical consequences of both.

As has been the topic of discussion in the thread on absolute motion, a block universe is one in which relative motion is not an objective reality but would be entirely dependent on the consciousness of an observer and their capacity for memory; it is a universe in which only a smidgen of relative motion would ever be observed by the 3D manifestation of any observer; and it is a universe in which experience of the 3D world would be limited to a single moment of time, or a single point on an observers worldline, without ever going beyond that; given that all points are fixed on an observers worldline and there is no transition to later moments.

Being manifest in the 3D world, whatever time any of us sees on the clock right now is what our experience of the 3D world should be limited to, because as the 3D manifestation of a fixed point on a wordline, which does not transition to the next moment, that is all we should experience.

roosh

Morbert wrote: »

Physical theories are descriptions independent of conscious observers.

It would seem that, from the discussion on absolute motion, that relative motion is dependent on the consciousness of observers.


With regard to presentism, it wouldn't really matter, because the present moment would not be dependent on a conscious observer; if it is all that exists then it is as much Jupiter's present moment as it is ours.

roosh

citrus burst wrote: »

So in other words you can't really.

I'm not entirely sure what it is that you're looking for.

Have you ever made an observation when it wasn't the present moment; has anyone ever made an observation when it wasn't the present moment; is it even theoretically possible to observe something when it isn't the present moment?

citrus burst wrote: »

This is just a hand waving argument with not much merit behind it.

It might be just the manner in which you are thinking about it. "The present moment", or "now" is simply a label which we apply to our experience; it's how we label the "moment" in which our experience occurs.

citrus burst wrote: »

But how long is now?

I think you might be thinking in terms of "what length of 'time' is 'now'?" I think length only applies to spatial dimensions, particularly if time doesn't exist.

citrus burst wrote: »

No you would be dead (assuming you are far enough away), in all sense of the word, kaput.

That's what I meant by "clinically".

citrus burst wrote: »

Technically speaking everything we see is a photograph of a past event.

Indeed, but just as with a photograph, we only ever observe them in the present moment.

citrus burst wrote: »

If there is any distance between two events, they occurred in the past. Even if they are part of your so called present moment.

I don't think we are in disagreement here; essentially, once the light from an event, which is separated in space, reaches you, that event - from whence the light was emitted - is necessarily in the past. We observe the image in our present moment, but that image is like a photograph of a past event.

citrus burst wrote: »

You still need time for entropy.

I don't see why; entropy would still occur in a timeless universe.

citrus burst wrote: »

It provides an existence free definition of the universe, along with mass, length, charge etc.

I don't see how it does, or how presentism doesn't. If only the present moment exist, then this is true for jupiter as it is for any conscious observer.

citrus burst wrote: »

Then what happens?

Nothing happens when existence ceases; if it ever ceases. If it were to cease then there would be nothing, and therefore no "happening".

citrus burst wrote: »

If that was the case we could justify that all measurable quantities in the universe are redundant.

That assumes that time is a measurable property.

citrus burst wrote: »

I take it you have no problems with mass or length? How are these measured?

I'm not 100% on the measurement of mass, off the top of my head, but, to give a very crude example, the spatial dimensions of object A are measurable by placing another spatially extended object, B, beside it and then the spatial dimensions of A are expressed in terms of B; where B is taken as a standard unit in which the spatial dimensions of all objects are expressed, for the purposes of comparison.

We don't measure time in the same way and we don't observe any objects as being temporally extended; we only ever view objects in a single moment.

Morbert

roosh wrote: »

The contention has been that if the assumptions of past and future are dropped then presentism is the only remaining conclusion. It's been your contention that presentism necessitates a dynamical cause, I just accepted it.

Again, the contention isn't necessarily that presentism is true, it's that it is the only possible conclusion of the assumptions of past and future are dropped; this is true because "not-presentism" is only a possible conclusion if the assumptions of past and future are made; if they're not made i.e. if they're dropped, then the conclusion of "not-presentism" cannot be reached; that would leave presentism as the only possible conclusion.

And again, yes, I agree. That is your contention. And again, I say it is false. If assumptions about the existence of past and future are dropped, presentism is not "the only possibly conclusion". Instead, presentism can not be concluded any more or less than Minkowski spacetime can be concluded.

If we're justified in making the assumptions of past and future for one, then we're justified in making them for the other; but we don't necessarily need b) to be a realistic possibility, it's just helpful for highlighting that more than just the assumption of past and future is required to arrive at the conclusion of Minkowski spacetime.

I don't understand this paragraph. But I also feel the above is a somewhat irrelevant point. If its only purpose is to argue that Minkowski spacetime is not merely the existence of past and future then sure.

Again, that not assuming x is not the same as assuming x is false is not in contention, indeed, it is applied to demonstrate that presentism is the only option left when the assumptions of past and future are dropped.

Presentism is not the only option left precisely because not assuming x is not the same as assuming x is false.

It is a feature of circular reasoning that if the conclusion, X, requires the assumption X, and the assumption X is dropped, then conclusion X is not an option; that is, conclusion X is only an option with the assumption X.

When you say that either a) or c) are left as possibilities, when the assumptions of past and future are dropped, what you are, in effect, saying is that, "we can always take the assumptions up again "; because only by making the assumptions of past and future can those conclusions be reached.

Yes, we can always, at a later stage, assume/suppose the past and future exist and, by doing so, reject b). Similarly, we can also always assume/suppose the past and future don't exist and, by doing so, reject a).

This is true. I guess it could come down to the number of assumptions required by both and indeed the logical consequences of both.

As has been the topic of discussion in the thread on absolute motion, a block universe is one in which relative motion is not an objective reality but would be entirely dependent on the consciousness of an observer and their capacity for memory; it is a universe in which only a smidgen of relative motion would ever be observed by the 3D manifestation of any observer; and it is a universe in which experience of the 3D world would be limited to a single moment of time, or a single point on an observers worldline, without ever going beyond that; given that all points are fixed on an observers worldline and there is no transition to later moments.

Being manifest in the 3D world, whatever time any of us sees on the clock right now is what our experience of the 3D world should be limited to, because as the 3D manifestation of a fixed point on a wordline, which does not transition to the next moment, that is all we should experience.

If you want to resurrect that old philosophy thread on the philosophy forum, that's fine. But for know I am going to assume the contention initially raised in this thread has been settled: I.e. Insisting spacetime is real requires an ontological assumption, independent of empirical evidence. Similarly, insisting presentism is real requires an ontological assumption, independent of empirical evidence.

roosh

Morbert wrote: »

And again, yes, I agree. That is your contention. And again, I say it is false. If assumptions about the existence of past and future are dropped, presentism is not "the only possibly conclusion". Instead, presentism can not be concluded any more or less than Minkowski spacetime can be concluded.

If the assumptions of past and future are not made, then presentism is the only possible conclusion, but it would require an additional assumption, as you point out. In the absence of all of those assumptions I think we are left with "shut up and calculate".

Morbert wrote: »

I don't understand this paragraph. But I also feel the above is a somewhat irrelevant point. If its only purpose is to argue that Minkowski spacetime is not merely the existence of past and future then sure.

The point was to highlight that Minkowski spacetime, perhaps, requires more assumptions than dynamical relativity.

Morbert wrote: »

Presentism is not the only option left precisely because not assuming x is not the same as assuming x is false.

In essence, presentism is simply the absence of past and future. Since the conclusion of "not-presentism" requires the assumptions of past and future, then dropping the assumptions of past and future leaves only presentism. However, as you point out, the conclusion of a presentist universe requires a further assumption.

Morbert wrote: »

Yes, we can always, at a later stage, assume/suppose the past and future exist and, by doing so, reject b). Similarly, we can also always assume/suppose the past and future don't exist and, by doing so, reject a).

We don't need to assume that past and future don't exist; without the assumptions of past and future, presentism is the only conclusion which can be reached; as you've pointed out though, it would require an additional assumption.

Morbert wrote: »

If you want to resurrect that old philosophy thread on the philosophy forum, that's fine. But for know I am going to assume the contention initially raised in this thread has been settled: I.e. Insisting spacetime is real requires an ontological assumption, independent of empirical evidence. Similarly, insisting presentism is real requires an ontological assumption, independent of empirical evidence.

As ever, thanks for the reasoned discussion. I think it's fair to say that it is settled, alright. The point I was trying to make wasn't as strong as I initially thought. The question of which assumption is more reasonable would be a different discussion and not one I'd be too concerned about getting into hear, particularly in the physics forum, unless anyone else were to raise it.

On the other point though, I would be interested to hear the thoughts of those who are more scientifically inclined, so I might start a thread in the physics forum.