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I would like to know what orthodox physicists think of Julian Barbour's radical ideas about time. This also relates to he quantum mechanics theories that i also have a post about."Barbour argues that we live in a universe which has neither past nor future. A strange new world in which we are alive and dead in the same instant. In this eternal present, our sense of the passage of time is nothing more than a giant cosmic illusion." Discover Mag.He says that there is no time, only change.Does he have a following?
In quantum mechanics every variable (position, momentum, angular momentum, spin, energy, and many tothers) is able to be represented by a Hermitian operator ...
I can't see how to ignore times arrow? Not here and now anyway. We have the idea of quantum computers as well as how all paths are take simultaneously with only one path 'left' to us finally (by its probability) and this could maybe been seen as a 'state' of timelessness. But it's not here, we live by outcomes, and those define all physics.
Why can't we introduce the idea of "negative time" where the causal relationship is reversed? It seems to me that it is because we separate things out from one another that the concept of causality arises and at a fundamental level reality may be non-local and unified so that every event exists now and time has no meaning. Could "spooky action at a distance" be pointing to this?
How do we really know that event b is an outcome of event a?
What if, instead, events a and b are somehow "paired" together or correlated such that they are predetermined to occur within some frame of reference and that their causal relationship is just an illusion?
Commonsense has taught us that if we drop an apple it falls to earth but why should the order of these events always be from the same direction?
Why can't we introduce the idea of "negative time" where the causal relationship is reversed?
We develope laws of cause and effect by experimentation and observation. Then we postulate causes and effects. Saying that we "know" them as such gets deep into sematics and epistemology.
You're confusing the ordering of events with the causality of the events. I see no reason to do so. I'm also not clear on what you mean by negative time.
The problem with this is that when we attempt to trace such causes and effects backwards in time we find we can never find an original moment that gave rise to causality since we can always ask:"what happened before that?", which gets us into a universe with no beginning, leading to the problem of explaining where causality came from.
This model is so contradictory …..
Relativity requires that all past and future events exist within spacetime.
This is because different observers must agree on what events take place (causality) but not on when or even what sequence they take place.
Regarding the fact that entropy increases with time, it's easy to show that sequences can only be observer within systems of increasing entropy.
To observer a sequence (which is what we always do when we observe time) one needs to retain information from previous states.
Quote from: AndroidNeoxRelativity requires that all past and future events exist within spacetime.Since spacetime is actually defined as the set of all events your statement is only tautologically true.Quote from: AndroidNeoxThis is because different observers must agree on what events take place (causality) but not on when or even what sequence they take place.That does not hold true in general. The spacetime separation determines whether two events can be causally related or not.Quote from: AndroidNeoxRegarding the fact that entropy increases with time, it's easy to show that sequences can only be observer within systems of increasing entropy.Okay. Since it’s so easy please show this. Thanks.Quote from: AndroidNeox To observer a sequence (which is what we always do when we observe time) one needs to retain information from previous states.Please post an example of this.
Quote from: webplodderThe problem with this is that when we attempt to trace such causes and effects backwards in time we find we can never find an original moment that gave rise to causality since we can always ask:"what happened before that?", which gets us into a universe with no beginning, leading to the problem of explaining where causality came from.Why? Who said that we couldn’t ask what happened before the big bang? I recall when I was an undergraduate and the subject of what happened before the big bang came up one day and the often quoted response “You can’t ask that question <=” Also came up along with it. My physics advisor commented, and I’ll never forget this, that such a comment was a terrible thing to say since there’s nothing wrong with asking questions like that. People who make those kinds of statements didn’t learn from the history of physics. Now, almost 25 years later, he’s proven to be quite right! Quote from: webplodderThis model is so contradictory …..I’m going to stop right here until we clear this assertion up. Please provide your arguments as to why this is the case since I don’t see it in the least.
I'm sorry, it appears we are at cross-purposes here. I wasn't just talking about before the Big Bang but whatever gave rise to that and whatever gave rise to that and so on. The central point here is that once you accept time is a continuous flow in one direction you are forced into an infinite model of reality which throws up contradictions surrounding causality. How can cause-and-effect be valid in a universe that has no cause? No matter how far back you go it is always possible to ask what went before, so it is an exercise in futility. For this reason, I reject the idea of "the arrow of time" and am forced into the conclusion that time and space exist as a unified, unbroken whole where time and space are simply emergent properties experienced as "real" by conscious observers such as us and other sentient beings.