On 4 February 2014 11:48, <[email protected]> wrote: > > Hi Liz, thanks for doing this thread, the history metaphor was also a > great help. I wasn't clear what block time was and now I've got a better > idea. >
Good, that was the point. A lot of people seemed to be attacking it on the basis of straw man arguments, so obviously not everyone "gets" it. > > I remember reading someone argue against it in terms of energy, and I > think this was thrown out by others with explanations, but can't remember > any details. Any chance you could me by the explanation of that? > I do remember that, but only very vaguely - so I can't really say what the problem or resolution was. Sorry. If anyone can remember, please let me know. (Maybe it was something similar to the fallacy that the MWI violates conservation of energy because it's constantly "creating new universes" ... ?) > > I was also able to get a good beginner foothold understanding of your > explanation how SR gives rise to blocktime via relativity of simultaneity. > Best I can I do see the implication is compelling and hard to avoid - I > can't think of any criticism directly. But then I wouldn't expect to be > able to do that from the level I am at. > I haven't been able to come up with anything. Of course any type of physics that treats time as a dimension implies block time, for example Newtonian mechanics does, as illustrated by Laplace's comment about an omniscient being that could know the past and future given the configuration of the universe at a single moment. > > But more generically speaking, would this inference for blocktime sit at > the edge of relativity or at its core. What I mean is, beyond that it is an > implication of relativity, have there been or are there any prospects for > developing blocktime as it arises from relativity to such point, > predictions get made? Or any other kind of reinforcement? Or does blocktime > go on to imply something beyond blocktime? > The idea of space-time seems to be central to SR, and even more so to GR. (It was also central to Newtonian physics, but as "space and time" which taken together have the features of a block universe.) > > If not then out of interest, what sort of strength would you personally > attach to blocktime? Say compared to the speed of light, or big bang? > Genuinelly curious. > I'm not sure what you mean about the speed of light. I'd say block time is the best interpretation of what phyics is telling us about the universe because (a) the theoretical and experimental evidence is very strong and (b) the ontological basis for it is good - it's the minimal explanation necessary. Although other variants like "presentism" are theoretically possible, they're unnecessary to explain all existing observations, and only push the problem of time back a step, since presentism just says there's an extra time dimension in which our universe is being continually created and destroyed - but of course another time dimension can also be viewed as a block universe, one step removed. If *that* time dimension is also given a time dimension in which *it's *happening, that can also be viewed as a block universe, 2 steps removed ... and so on. > > The intuitive problem I would have with blocktime would veiry much be > along the same themes as a lot of other inferences in one way or another at > the 'edge'. The same assumption seems to come into play, that nature has > infinite resources at her fingertips...is able to get those resources > pretty much anywhere she likes too. Which might be true, but I return to > that worry that, whether true or not, the explanation is always available > to us, and will always deliver this kind of resolution, regardless of > context. So long as the problem is at the edge of knowledge. > > Is that a worry for you as well? > > It might be for some things, but block time has been so uncontentious amongst the vast majority of physicists since Newton that I don't have any problems with it. It's been very well thought through by many minds, and no one has come up with a viable alternative that I'm aware of. -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
