I Is Time Just a Stubborn Illusion in the Block Universe Theory?

[PeterDonis]

You still ldon't know what my point is

At this point I have no idea how to make things any clearer.

You have a 4-D spacetime manifold, which is a perfectly well-defined mathematical object. You pick an event in that manifold to represent the "present" event of an observer. Events in the past light cone of that chosen event, which is a perfectly well-defined mathematical object, are considered "fixed and certain" in the model. Events not in the past light cone of that chosen event are not.

I've already described this, and I don't see what's so hard to grasp about it.

I don't know what else to say; you keep on harping about things that aren't experimentally testable, like whether events "exist", or whether they "occur", or things that depend on a theory of consciousness, like which events are "known" or "observed", when here we're just discussing a simple physical model. At this point I think you're just never going to be satisfied with anything we say, and continuing discussion is pointless.

 

[PeterDonis]

Events in the past light cone of that chosen event, which is a perfectly well-defined mathematical object, are considered "fixed and certain" in the model.

If you insist on having "fixed and certain" unpacked, events which are fixed and certain in the model are considered "initial data", i.e., they are put into the model, not predicted from the model. Events which are not fixed and certain are predictions of the model.

 

[Ebeb]

If you insist on having "fixed and certain" unpacked, events which are fixed and certain in the model are considered "initial data", i.e., they are put into the model, not predicted from the model. Events which are not fixed and certain are predictions of the model.

I want to know where you got the 'initial data' from to put into the model.
You put data into a past lightcone but if you consider the option that events that are observed might NOT have occurred before the observation, even the past light cone model is constructed on loose sand. If you don't understand this, or consider the issues I threw up being off-topic for discussing your BU article, so be it. I consider it rather an easy way for not wanting to discuss the real issue of your BU article, but that's only a personal feeling you don't have to worry about ;-)

Shame I put in so much time writing my posts. It won't happen again.

 

[PeterDonis]

I want to know where you got the 'initial data' from to put into the model.

Um, from whatever data I am using as initial data?

I'm confused by the question because this is not a question particular to SR or to the kind of model I'm describing. Any model in physics is going to have data that's put into the model, and predictions that come out. So asking this question is tantamount to asking "how do I build a model in physics", which is much too broad a question for a PF discussion.

if you consider the option that events that are observed might NOT have occurred

If I have data about events that I am using as input for my model, how do I "consider the option whether those events might NOT have occurred"? That makes no sense. The data is the data. So this question does not look to me like a question about physics, but a question about either metaphysics or philosophy, both of which are off topic here. It certainly is not a question I need to answer in order to build a physical model and use it to make predictions. (And again, that's not anything particular to the model we're talking about here; it's true of any physical model whatsoever.)

 

[Dale]

The simple fact of making a model with an event "in the past light cone of that model" is based on the premise that the event occurred before the apex event of the light cone

Yes, of course. By definition anything in the past light cone of an event occurred before the event. That is why it is called the "past" light cone.

But do you know anything "occurred in the past"? No.

I have pretty compelling physical evidence of many things that occurred in the past.

in that article you refute solipsism, but your post #56-quote-<<More precisely, you have no way of testing by experiment whether or not the event "existed" before you observed it--because any experiment would involve observation.>> leaves the option 'solipsims' still open,

What is it with BU discussions and solipsism? It seems to be a sort of philosophical name calling or guilt by association ploy. As though by gratuitously throwing the "s-word" into the discussion you can make them back off.

Any further posts discussing solipsism will be summarily deleted. This thread is already too prone to wandering.

 

[Dale]

You put data into a past lightcone but if you consider the option that events that are observed might NOT have occurred before the observation,

You are misstating things here. This is wrong: "you consider the option that events that are observed might not have occurred before the observation". It should be: "before the observation you consider the option that events that are not observed might not have occurred"

you don't know the event happed before the event of observation.

Here is another one. This should be "before the event of observation you don't know the event happened". After the observation you know both that the observed event physically happened and that it happened before the observation

But you doubt -see quote above- whether the event occurred before it is observed

Again this should be "before it is observed you doubt whether the event occurred". You consistently misstate things this way.

Hopefully those examples are sufficient for you to clear up the confusion in your recent posts.

 

[Ebeb]

Hopefully those examples are sufficient for you to clear up the confusion in your recent posts.

They help, thanks, but unfortunately they are not sufficient to clear up the confusion.
When you write: <<"before the event of observation you don't know the event happened">>, I fully agree, in the following sense:
Let's say we discuss the event "car hits tree". I fully agree that we don't know whether the car hits the tree or not until observation of such an event. But it's not the issue I wanted to deal with. The issue is: are there (any) events outside of the light cone that are not observed yet? Whether they will be observed or not is irrelevant to the question.
Are there are 'now' events occurring outside of my light cone or not. I'm not interested in what the 'content' is of the events (what they represent, f.ex "car hits tree", "bomb explosion", or whatever). I hope you understand that's a different issue than "We know whether the car hits the tree only after observation of the event 'car hits tree'". The question is whether there happens/occurs anything at all, now, at a spatial distance (elsewhere zone) from me.

To facilitate things I'll give you a possible answer to my question:
(A) strictly speaking I don't know whether at my present now event (let's call it event 'O') there are any events outside of my lightcone. Because strictly speaking it might be possible that in the future I all of a sudden don't see any events anymore, meaning that at event 'O' there are no events in the elsewhere zone, but not knowing it yet. (I should wonder whether physics/physical laws deal with such a possibility?)

The possible answer (A) to my question means we have two options to work with:
(1) there are at my the present now event spatially separated events in the elswhere zone of my present light cone.
Or
(2) there are at my the present now event no spatially separated events in the elswhere zone of my present light cone.

Correct so far?

 

[Dale]

The issue is: are there (any) events outside of the light cone that are not observed yet?

Is there any experimental measurement which could be performed to answer the question?

If not, then it is a philosophical question rather than a physical question.

If yes, then please describe the experimental setup and analysis you have in mind.

The question is whether there happens/occurs anything at all, now, at a spatial distance (elsewhere zone) from me.

Same as above.

 

[Ebeb]

O.K. Dale.
So your answer to my "Correct so far?" would be a '"yes".
Strictly speaking it means: when during the last few seconds you saw your foot, it doesn't imply/mean you will still see it the next second, because there might all of a sudden be no foot anymore!
For millions of years human beings saw events that existed before being observed, but we are not sure there are 'now' any spatially separated events from you that you will observe in the future.
O.K. Dale, I finally got the picture. It sounds too crazy to be true, but obviously I am not allowed to tell the universe to be crazy or not ;-) And it's not what Einstein had in mind (see previous quotes of, and about, Einstein).

 

[Dale]

So your answer to my "Correct so far?" would be a '"yes".

Don't put words in my mouth.

What experiment would you propose to answer the question?

Strictly speaking it means: when during the last few seconds you saw your foot, it doesn't imply/mean you will still see it the next second, because there might all of a sudden be no foot anymore!
For millions of years human beings saw events that existed before being observed, but we are not sure there are 'now' any spatially separated events from you that you will observe in the future.
O.K. Dale, I finally got the picture. It sounds too crazy to be true, but obviously I am not allowed to tell the universe to be crazy or not ;-) And it's not what Einstein had in mind (see previous quotes of, and about, Einstein).

This is wholly irrelevant to MY position on the matter. I understand the appeal of constructing a straw man to ridicule, but that is not what I am claiming.

What I am claiming is that there is no experiment that can answer the question even in principle. Therefore the question is not physical.

 

[Boing3000]

The question is whether there happens/occurs anything at all, now, at a spatial distance (elsewhere zone) from me.

But that question can only be answered when the elsewhere cross your past cone. That's all there is to it. The question of what IS now elsewhere cannot be answered by experimental apparatus.

Nobody here denies that there is an elsewhere full of events. Actually the universe seems to be quite stubborn at blasting them with uncanny regularity(SR) toward your now. But given that you cannot even attribute to them any coordinate, before they reach you, what the point ?

For millions of years human beings saw events that existed before being observed, but we are not sure there are 'now' any spatially separated events from you that you will observe in the future.

If the speed of "seeing" was that of a snail, you would realize how much your "sureness" would reduce accordingly.

"Seeing" does not project you into the future, not event the present, but the past. If it doesn't trouble you for the Andromeda galaxy, why does it for your foot ?

 

[PeterDonis]

The thread is going around in circles and is therefore closed.