What is spacetime?

[Impenitent]

existing outside of time

existing outside of having mass

consciousness moving at the speed of light...

even dark thoughts...

-Imp

[Belinda]

It depends whether you are doing maths or philosophy. For maths, it's just a set of coordinates: x, y, z and t, left or right, up or down, forward or backwards and before or after, using which you can locate any event, at least that we can engage with. Philosophically, it is the 'fabric' that the universe either exists in, or is the stuff the universe is made of, depending on your preferred flavour and assuming you believe there is a material universe. I don't pretend to know the answer, but if you're interested in my best guess, it's all in my comic book: https://willybouwman.blogspot.com/2024/ ... ation.html

Is sameness a mathematical concept, or does mathematics deal in change, or both?

I mean, if relativity is true then mathematics if it's to be used to support ideas in physics must be able to deal in change and must never be a grand tautology.

But then, if mathematics cannot deal with changelessness i.e. no time, no space. and no force then what is the use of maths?

[Will Bouwman]

It depends whether you are doing maths or philosophy. For maths, it's just a set of coordinates: x, y, z and t, left or right, up or down, forward or backwards and before or after, using which you can locate any event, at least that we can engage with. Philosophically, it is the 'fabric' that the universe either exists in, or is the stuff the universe is made of, depending on your preferred flavour and assuming you believe there is a material universe. I don't pretend to know the answer, but if you're interested in my best guess, it's all in my comic book: https://willybouwman.blogspot.com/2024/ ... ation.html

Is sameness a mathematical concept...

Well yes; that's what this = means.

...or does mathematics deal in change, or both?

+ and - are two examples of how maths deals with change.

I mean, if relativity is true then mathematics if it's to be used to support ideas in physics must be able to deal in change and must never be a grand tautology.

Physicists can measure time dilation due to different velocities and gravitational strengths to astonishing accuracy, so in that respect relativity is true. You don't have to accept the ontology of general relativity, a malleable aether like stuff, but you can't really argue with the maths which describes the changes very well.

But then, if mathematics cannot deal with changelessness i.e. no time, no space. and no force then what is the use of maths?

Well, if there were no time, space nor force we wouldn't have to worry about maths as we wouldn't be here.

[Belinda]

It depends whether you are doing maths or philosophy. For maths, it's just a set of coordinates: x, y, z and t, left or right, up or down, forward or backwards and before or after, using which you can locate any event, at least that we can engage with. Philosophically, it is the 'fabric' that the universe either exists in, or is the stuff the universe is made of, depending on your preferred flavour and assuming you believe there is a material universe. I don't pretend to know the answer, but if you're interested in my best guess, it's all in my comic book: https://willybouwman.blogspot.com/2024/ ... ation.html

Is sameness a mathematical concept...

Well yes; that's what this = means.

...or does mathematics deal in change, or both?

+ and - are two examples of how maths deals with change.

I mean, if relativity is true then mathematics if it's to be used to support ideas in physics must be able to deal in change and must never be a grand tautology.

Physicists can measure time dilation due to different velocities and gravitational strengths to astonishing accuracy, so in that respect relativity is true. You don't have to accept the ontology of general relativity, a malleable aether like stuff, but you can't really argue with the maths which describes the changes very well.

But then, if mathematics cannot deal with changelessness i.e. no time, no space. and no force then what is the use of maths?

Well, if there were no time, space nor force we wouldn't have to worry about maths as we wouldn't be here.

All okay. So is maths a specially explicit language that quantifies what physics, other sciences. and common sense tells us exists?

Does maths endorse the EPR experiment that tells us space does not exist? And please can you put into everyday language how we may reconcile that space does not exist, and that space does exist? I'm willing to accept a dual aspect theory if there is one.

If there is such a theory I reckon it would be about how we can know things, not about what exists. I am starting from assuming there is a material universe which is interpreted in many ways.

[Will Bouwman]

So is maths a specially explicit language that quantifies what physics, other sciences. and common sense tells us exists?

I'm not a mathematician nor much of an expert on the philosophy of maths, so others might have a better take on this, but from my history and philosophy of science perspective, and in fact my school experience of maths, there is pure and applied maths. Pure maths is playing with mathematical concepts just for kicks - and to potentially discover something that might have practical uses. Mostly just for kicks though; some of the mathematicians I know have no interest in practical uses, some have no practical use themselves. Anyway, there is much more pure maths than applied, the main difference being the application of physical constants which are discovered by experiment. So yes, maths is an especially explicit language, some of which quantifies science.

Does maths endorse the EPR experiment that tells us space does not exist?

That's not really what Einstein, Podolsky and Rosen were suggesting; their argument was that quantum mechanics is not a complete theory and that there must be some hidden variables to account for what appears to be faster than light communication between pairs of entangled particles.

And please can you put into everyday language how we may reconcile that space does not exist, and that space does exist? I'm willing to accept a dual aspect theory if there is one.

Short answer, no I can't. Space either exists or it doesn't, and outside of some fairly outré 'mind is all that exists' metaphysics, space exists; but since we can't totally rule out wacky metaphysics, the question is underdetermined.

If there is such a theory I reckon it would be about how we can know things, not about what exists.

Well, that's Descartes's methodological scepticism; as he showed, you can't be absolutely certain of anything other than your own experiences, which may or may not be related to an exterior world.

I am starting from assuming there is a material universe which is interpreted in many ways.

A good place to start.

[Belinda]

So is maths a specially explicit language that quantifies what physics, other sciences. and common sense tells us exists?

I'm not a mathematician nor much of an expert on the philosophy of maths, so others might have a better take on this, but from my history and philosophy of science perspective, and in fact my school experience of maths, there is pure and applied maths. Pure maths is playing with mathematical concepts just for kicks - and to potentially discover something that might have practical uses. Mostly just for kicks though; some of the mathematicians I know have no interest in practical uses, some have no practical use themselves. Anyway, there is much more pure maths than applied, the main difference being the application of physical constants which are discovered by experiment. So yes, maths is an especially explicit language, some of which quantifies science.

Does maths endorse the EPR experiment that tells us space does not exist?

That's not really what Einstein, Podolsky and Rosen were suggesting; their argument was that quantum mechanics is not a complete theory and that there must be some hidden variables to account for what appears to be faster than light communication between pairs of entangled particles.

And please can you put into everyday language how we may reconcile that space does not exist, and that space does exist? I'm willing to accept a dual aspect theory if there is one.

Short answer, no I can't. Space either exists or it doesn't, and outside of some fairly outré 'mind is all that exists' metaphysics, space exists; but since we can't totally rule out wacky metaphysics, the question is underdetermined.

If there is such a theory I reckon it would be about how we can know things, not about what exists.

Well, that's Descartes's methodological scepticism; as he showed, you can't be absolutely certain of anything other than your own experiences, which may or may not be related to an exterior world.

I am starting from assuming there is a material universe which is interpreted in many ways.

A good place to start.

Quantum computers use strange physics like superposition and entanglement, where qubits can be linked across space in ways Einstein called “spooky action at a distance” (the EPR experiment). This lets them solve certain financial problems—like optimising investments or pricing complex products—much faster than regular computers. For a good introduction to these ideas, check out the documentary Einstein’s Quantum Riddle.

from ChatGPT

I saw that documentary and was mightily impressed by it.