Are Space & Time A Fundamental Property Or Emergent

[studiot]

1 hour ago, joigus said:

I understand 'emergent' as a variable that's derived from relationships among more fundamental variables, and it's not present in those variables. Very much what Swansont stated. It is derived from the overall dynamics of those variables.

I should have asked about this in my last post.

What is your opinion then, on probability in the light of the general scientific requirement of reproducibility?

IOW what do you think of a variable that might sometimes 'emerge' ?

Secondly would you consider the Himalayan monsoon emergent from the Southern Oscillation (pressurein the West Pacific)?

[joigus]

6 minutes ago, studiot said:

I should have asked about this in my last post.

What is your opinion then, on probability in the light of the general scientific requirement of reproducibility?

IOW what do you think of a variable that might sometimes 'emerge' ?

Secondly would you consider the Himalayan monsoon emergent from the Southern Oscillation (pressurein the West Pacific)?

Very interesting questions. Give me some time to ponder and then react, please, because I think an attempt at an answer to that must have to do with a subtle distinction that some people make between aprioristic probability and empirical probability. I would like to say more on that, hope we're not getting too off-topic, and would be interested to know your opinion, as well as other users'.

I would also be very interested to learn what @Eise makes of all this.

[studiot]

1 minute ago, joigus said:

aprioristic probability and empirical probability.

I make such a distinction, in fact I distinguish 3 types of probability.

[joigus]

3 hours ago, studiot said:

What is your opinion then, on probability in the light of the general scientific requirement of reproducibility?

 

I don't have a very sophisticated knowledge of this. I can distinguish two types: a priory probability (when you have a knowledge about the make-up of the system. In that case, you can predict the probabilities. Laplacian probability for the proverbial die being just one example of a system in which, from symmetry, you can infer equiprobability. Other example is quantum mechanics, in which you have a dynamical law (the Schrödinger equation) which allows you to predict the probability density. It doesn't have to be always symmetry. 

Mathematics makes all this a lot less vague, of course. In the case of pre-bigbang scenarios, the statistical hypothesis would come from extrapolations of the known physical laws that are particularly 'natural' or 'simple'. And I do know how vague terms as 'natural' or 'simple' are. But I also think you can get an idea of what I mean by that.

The other version of probability is the phenomenological one. You reproduce the experiment over and over again, and get an idea of how sound your probabilistic hypothesis is. This is the kind of concept that universe, and time itself with it, is not amenable to.

The example you mentioned of the Monsoons is one that perhaps resists a simple criterion. On the one hand, Monsoons are regularities, but OTOH, there are exceptions. We know Monsoons fail from time to time.

Now, please, tell me about the third one.

Edited July 15, 2021 by joigus
minor addition

[studiot]

2 hours ago, joigus said:

Now, please, tell me about the third one.

Let us suppose that we have declared the probability of some event E to be exactly 1, the question arises what do we mean.

So P(E) = 1

Interpretation 1.  (a priori interpretation)

E must always occur.

Interpretation 2. (empirical interpretation)

E has always occurred.
This does not imply that E will occur in the future

Interpretation 3 (subjective interpretation)

We think E will occur

But does not imply that it must occur.

 

3 hours ago, joigus said:

The example you mentioned of the Monsoons is one that perhaps resists a simple criterion. On the one hand, Monsoons are regularities, but OTOH, there are exceptions. We know Monsoons fail from time to time.

As regards the Monsoon, the example refers to the discovery of one Gilbert Walker, Statistician and Director of meteorological observatories in India.
At that time the Monsoon was widely regarded as being related to solar activieies, in particular the cycle of sunspots.
Walker collected vast amounts of data in India and also had access to data from across the British Empire.

Walker offered a discovery of amazing scope.
Not only was the Monsoon unrelated to the sunspot cycle, it was related to the pressure and temperature halfway around the world.
He could not explain how pressure and temperature in the Western Pacific affected rainfall in the Indian Ocean.
But his calculations showed that it did.
He named this connection the Southern Oscillation.

https://en.wikipedia.org/wiki/Gilbert_Walker

[joigus]

2 hours ago, studiot said:

[...]

As regards the Monsoon, the example refers to the discovery of one Gilbert Walker, Statistician and Director of meteorological observatories in India.
At that time the Monsoon was widely regarded as being related to solar activieies, in particular the cycle of sunspots.
Walker collected vast amounts of data in India and also had access to data from across the British Empire.

Walker offered a discovery of amazing scope.
Not only was the Monsoon unrelated to the sunspot cycle, it was related to the pressure and temperature halfway around the world.
He could not explain how pressure and temperature in the Western Pacific affected rainfall in the Indian Ocean.
But his calculations showed that it did.
He named this connection the Southern Oscillation.

https://en.wikipedia.org/wiki/Gilbert_Walker

I know this from a documentary by Iain Stewart.  

[trevor.white]

I struggled with this concept but generally accepted the standard patina of time as a dimension. Some 10 years ago now I was searching for an answer for what I thought was down a totally different pathway. Delving into GR to understand time and chanced on the description of gravity. That was some rabbit hole, which led to the understanding that both time & gravity were emergent from essentially the same energy contained within both matter and energy structures. Though there are strong indications that it is not simply either the HIGG's boson or the top quark but a rather the interaction of forces to create the eventual emergent properties.

As for space there is too much experimental evidence to conclude our view of distance as other than deeply flawed. Even simply moving a ruler above sea level will change it's length. As for measuring time based on the vibrations of a cesium atom, good luck with that one for it has the same problem.

 

[swansont]

4 hours ago, trevor.white said:

Even simply moving a ruler above sea level will change it's length. As for measuring time based on the vibrations of a cesium atom, good luck with that one for it has the same problem.

 

I personally have used rubidium more than cesium, but I did indeed have good luck; they have a fractional frequency stability of around 2 x 10^-13 per root tau, and haven't shown any sign of drift (all white noise down to the ~10^-18 level). People building optical transition frequency standards can do even better measurements in the short/medium term.

You can account for the frequency differences caused by differences in elevation.