The Fabric Of Spacetime. It Has To Be Something But What?

[Colmc54]

In my mind I can conceive a space that is totally empty such that however large or small it is all the possible measurements are zero. Yet if I pass a photon through it it's original electromagnetic waveform will propagate through it long after the original particle that emitted it has been left behind. I could put my imagined space of nothing close to a galaxy and see the same beam of light bending in it's course from passing through my imagined box of 'nothing'.

But that is just the tip of the iceberg of the stuff that 'nothing' does. Clearly it has to be something.

This may sound trivial but if Admiral Nelson is one day to be followed by Captain Kirk of the Starship Enterprise we really need to start to look at nothing. Nothing seems to be more important than anything.

[Khandro]

jim; Are you leaning towards a universe more of design than accident then?

[jim360]

No, I'm not -- although I hope that if the evidence does lean one way or the other than I can be persuaded to follow said evidence. Not really sure where the design argument came into my post, though -- reading too much between the lines?

It's almost certainly impossible to know how the universe came into existence. Still, it seems to me that it's entirely plausible that it was self-creating, and that since then -- or even "before" -- that natural laws are entirely sufficient to explain its form today. Accidents will happen, after all.

The point is. though, that natural laws aren't necessarily arbitrary.

[Colmc54]

jim360
Thanks for your link to the Nature article. Sounds theoretically hypothetical to me. Entanglement does seem to be real though, even though like all things quantum we can only speculate, if that, on how it works.
So spacetime is a manifestation of the original entanglement of everything with everything else that emerged from the initial singularity after the 'big bang'.
So if I could disentangle myself somehow would I float up off the surface of the planet?! I feel a preliminary experiment involving beer as my preferred disentangling agent coming on!

[Khandro]

Good on yer Colm, I'm about to light a log-fire and do the same.
Jim; I've just ordered today, 'A Beautiful Question: Finding Nature's Deep Design.' by Nobel prizewinning physicist, Frank Wilcezek. Quotes from the review of the book; "Wilczek shows that the most beautiful set of equations is repeatedly the one that turns out to be true", and, "... he hints at some cosmological flavour of design when he speaks fondly of the 'Artisan' who constructed the universe in particularly beautiful laws in the first place".

I'll keep you posted!

[Old_Geezer]

It sounds to me as if he imposes poetic descriptions on a more natural reality. One should consider intent only when all else has proven incorrect.

[Colmc54]

Yes OG they can wax lyrical and bemuse us. They can scrape their chalk across acres of blackboard. But in the end you need physical proof, at least in science, before you can claim to have discovered anything.
Without that evidence base they are no better than priests.

[Khandro]

Colmc; // But in the end you need physical proof, at least in science, before you can claim to have discovered anything.//

There isn't really any such thing as proof in science, or anywhere else.

[jim360]

Any chance you could qualify that statement? What about proof in Mathematics?

[Khandro]

Jim; I nearly put that in as an exception but kept it short. I think we can safely say in pure mathematics 1 + 1 = 2, but in the 'impure' world that really needs qualification, eg. does one cat and one dog make two?

[jomifl]

Until someone comes up with an alternative to what is accepted as proof in science then we will have carry on as we are. It does seem to work though.

[jim360]

Perhaps you ought to look into Set Theory, then, Khandro? That's meant as a recommendation rather than a patronising remark, I hope you don't mind this.

"Proof" in Science is probably best described as empirical rather than anything more solid. We make a prediction, we test the prediction against data, and see that it is right. Or, more precisely, we see that it is wrong -- but that the disagreements between prediction and result are such that they can be described as statistical fluctuations, or systematic errors in the experiment design, or incompleteness of the model -- and that the general prediction is "good enough" to say that the theory was correct.

[Khandro]

The fact is that one cannot actually prove anything to be true, one consequence of karl Popper's work with 'falsifiability' is the understanding that you never really prove a theory to be 'true'. What scientists do is instead come up with implications of the theory, make hypotheses based on those implications, and then try to prove that specific hypothesis true or false through either experiment or careful observation. If the experiment or observation matches the prediction of the hypothesis, the scientist has gained support for the hypothesis (and therefore the underlying theory), but has not proven it. It's always possible that there's another explanation for the result.

[jim360]

That's basically what I said, though.

[Khandro]

Yes I know, but I think the last sentence is important.

[jim360]

Yes, fair enough.

Can you prove that Karl Popper's falsifiability approach is the correct interpretation...?

[Khandro]

nope. :0)

[jomifl]

Truth like perfection is probably unattainable but as long as it it does the job then it is good enough. Considering what was tolerated as the 'truth' in the past we arent doing too badly. At least nowadays we can choose the truth that works rather than try to fit things to the truth even if we have to cut their legs off.

[Colmc54]

Maybe I shouldn't have used the word 'proof' as it opens up
semantic arguments about what proof means. Who would deny the evidence that has shown that Einstein's special theory of relativity and it's iconic equation E equals MC squared is actually true of nature. This been this has been demonstrated by all kinds of experimental and observational evidence which reconcile the maths with reality.

[Khandro]

There could be more to it than meets the eye though;

http://discovermagazine.com/2012/mar/09-is-einsteins-greatest-work-wrong-didnt-go-far

[jim360]

That article I found annoying as it said very little about what Barbour was actually doing. Then I looked at a paper of his. And that said loads of what he was doing but I haven't a chance in hell of following it.

Ah well. In the long run it's almost certain that Einstein's GR is not the end of the story, although it's very much on the right lines given the successes of the last century or so of testing. What will replace or update it I don't know, although at first glance Barbour's ideas appear to be interesting.