What is "the fabric" of space-time?

We can let cavediver speak for himself but he already stated they had no mass, nor energy, but that these concepts are derived from these fields.In reality, these fields or whatever you want to call them are more fundamental. That's the point, and they do not conist of mass, nor energy (as defined by physics). I'd argue they do consist of energy, just not physical energy.One way to illustrate this basic immaterial aspect of the universe is the phenomenon of entanglement or non-locality. Note: this is not making an argument based on quantum uncertainty as some have suggested though the same basic QM principles demonstrate quantum uncertainty and so that is related. It's an argument based on observed, repeatable science first predicted by quantum theory. Einstein didn't like those predictions, deriding it as spooky action at a distance, but Einstein turned out to be wrong as entanglement has been amply demonstrated just as it was amply predicted.For anyone not knowing what it is, the short version is that 2 distant particles that became entangled at some point act as one system. Depending on how one observes or how a particle is observed (we can discuss that later on a different thread), the particle becomes either more wave-like or particle-like with specific characteristics within the physical universe. If we can determine it's path, it propagates in our perspective/universe in one path as if it was a particle along one path. If this information is not determinable by the way we observe it, then it propagates like a wave on all paths. The dominant interpretation of quantum physics is that until one of these observation events takes place, it doesn't exist in any discrete physical form at all, but exists as a potential for form (physicality). This process has often been referred to as collapsing the wave function, which used to be thought of as irreversible, but not necessarily now due to lab experiments.Well, grasping that takes some effort the first few times one ponders it......the next part involves the fact that how one particle collapses or becomes discrete (aka as a physical form with definite, observable properties) the other entangled particle must take on specific properties as a counterpart. That's even if the other particle is on the other side of the universe. That's why Einstein called it "spooky" because there is no observed physical connection between the entangled particles, and it's not considered possible for there to be some superluminal (faster than light speed) particle to communicate and even if there was, which is not considered possible, it would have to vary it's speed to make the collapse of both particles instant.So in summary, we have evidence that somehow differently spaced partices are connected and act as one system, but we also have strong evidence there can be no physical connection between the particles. Informationally and behaviourally, they are connected and act as one system, but physically they are separated with no ability we know of for them to be connected by another particle.What does this show?This shows that the connection is immaterial or non-physical and that it is an informational connection outside space and time.

What I am getting at is that whatever this is, it isn't nothing. It's nothing physical, sure. But it does give rise to the physical aspects of the universe, right?Call it information if you want. Call it X. It doesn't matter because I am just trying to get at what we do know about it. I think we know it's not physical, not matter and energy, but that it is potential.How would you describe it?

Cavediver, they exist as something, right? Let's go with no energy and no mass, right? But they exist as something since they can be mathematically described, right?
How would you characterize that something? As mathematical principles and design?

I would describe 'it' mathematically, and characterise that 'something' as mathematics. That is all there is.

as mathematics

That is all there is.

The spooky effect at a distance is a process outside time and space that even I can't really imagine. But I believe that quantum physics tells us something very profound about the world. And that is that the world is not the way it is independently of us. That the characteristics of the world are to a certain extent dependent on us.

I think that this illustrates your problem. You are still stuck in the thinking of classical physics. Because QM comes up with ideas that are strange to that you take it as essentially something supernatural.

I am addressing the picture. You are restricting "physical" to classical physics. And that's wrong. That isn't a quibble - it is a serious problem that invalidates your argument.

ANd that's classical physics again. QM doesn't work like that

I am addressing the picture. You are restricting "physical" to classical physics. And that's wrong. That isn't a quibble - it is a serious problem that invalidates your argument.

ANd that's classical physics again. QM doesn't work like that

ANd that's classical physics again. QM doesn't work like that

ANd that's classical physics again. QM doesn't work like that

Just a suggestion, but perhaps you should try considering how entanglement might work in the many-world model of QM ? I have.

Bars’ math suggests that the familiar world of four dimensions ” three of space, one of time ” is merely a shadow of a richer six-dimensional reality. In this view the ordinary world is like a two-dimensional wall displaying shadows of the objects in a three-dimensional room.In a similar way, the observable universe of ordinary space and time may reflect the physics of a bigger space with an extra dimension of time. In ordinary life nobody notices the second time dimension, just as nobody sees the third dimension of an object’s two-dimensional shadow on a wall.

My point is that the "event" - the measurement - effects the whole universe by forcing a "split" in reality.

The laws of physics say that the particles must be in a consistent state.

So the question of how the other particle "knows" what state it should be in is solved - not by super-luminal "communication". It is solved by the split in the universe. Whichever universe you end up in, the particles will necessarily be in a consistent state.

There is nothing but the field. Anything else that appears to exist is really just the field. There isn't anything more physical than the field, because the field is the universe.