joigus

Very powerful argument! Absolutely right, in connection with Riemannian and pseudo-Riemannian geometries the word "intrinsic" means exactly that.

Yeah. To tell you the truth, I found the wikipedia article a tad ambiguous about whether it's "standalone" or it's "contributes to". @swansont had a similar point to make, besides the weakness of an only-spin source. But AFAIK too, you're right. Spinors cannot be represented by 4-vectors. After looking through the provided papers, it seems clear that none of the authors (related to such idea by the Wikipedia article) mean to say that spin be the one and only source of gravitation. Rather, they set out to find subtle effects of gravity on spin systems safely above the Plankian scale.

As said, suggested, implied: Angular momentum has energy. Energy sources gravity. Ergo, Angular momentum sources gravity. At the moment, we don't know whether the words "quantum gravity" are akin to what people once used to say: "elastic properties of the luminiferous ether". It could well be the case that these words finally have to be abandoned. There is also a spin formalism for general relativity. So, in a way, all of GR is about spin. This is because spinors are more basic objects than space-time 4-vectors (for every 4-vector, or event, there are two spinors representing it).

Aaah... This sounds more like it. Although I wouldn't call the various equations coming from the Schrödinger equation "constitutive equations". Constitutive equations in physics implement properties of the medium, while the Bohmian wave implements properties of the system under study in reaction to that medium. After all, they come from a simple change of variables in the Schrödinger equation. But maybe that's just a matter of words. I'm not surprised that the theory in its form of particle + wave does not work. That point-like particles are inconsistent with relativity has been known for a long time. So long a time that the scientific community as a whole seems to have forgotten, as the whole business painfully ground to a halt during the first decades of the 20th century. A topological scalar field consistent with local gauge invariance might do the required jobs. A point particle is hopeless.

In the De Broglie-Bohm theory the pilot wave is source of a so-called quantum potential, that must be added to all other potentials acting on the particle. This quantum potential produces infinite repulsion in places where \( R=\left|\psi\right|^{2} = 0 \) (interference), as its form is proportional to \( \frac{\nabla²R}{R} \). You are using "configuration space" in a sense that is not familiar to me. "Configuration space" in mechanics usually refers to the set of all accessible positions. I don't know what you mean by "a real constraint structure". Constraints in mechanics are obstructions to how the system can move (holonomic constraints), like a particle being forced to be at the tip of a rigid rod, etc. Your vocabulary is a bit weird, and I at least do not understand what you mean. The theory has its virtues, but makes calculations extremely awkward, not least the ones pointed out by @Mordred . Besides Pauli's objections, Einstein also seems to have said that it goes against every physical intuition to conceive of something that acts on other physical entities, but cannot be acted upon. John Bell was one of its most notorious advocates. He didn't say it must be correct. He said it must be studied. </my two cents> IMO there is the possibility that it's but a version of a more elegant idea that we haven't been able to fathom so far. Among other things, point particles cannot carry irreducible representations of the relevant space-time groups, so it could be the case that there's a generalisation of it having to do with scalars, rather than point-like densities. That seems healthier in the context of field theory. </>

For me it's number 3. I can't recall how many times I've listened to it. Especially the 3rd movement. I have no words to describe the experience. But it's all of the Brandenburg concertos really. And it's Bach. Always Bach. The cello suites, the Goldberg variations, Magnificat... There's something about Bach that makes it seem as if all of music were already in it. Haven't we had an exchange about Bach before? I've noticed exactly the same feature. I must say I lack a criterion to judge so-called generative AI. How "generative" generative AI actually is? I don't know. I've skimmed through news about some generative AI packages genuinely doing seminal work in mathematics, for example. I can't significantly commit an opinion on that, TBH.

Today I learned that "Today I Learned" can also be used to discuss whether I actually learned something or not. 🫠 Cheers! Very interesting, and impossible to watch from where I stand. Thank you.

I propose to remove the "work" bit from anything speculative coming from AI. It would be just a "frame". That is, the "framework" without the "work". "I've been given a frame to talk about this" would be at least honest.

Ditto.

I didn't say anything was or wasn't intended to set our future plans. I quite intentionally kept things quite unintentional. I said something else. Please take some time to read what I did say, or this is gonna take forever with you talking past me, instead of we talking past each other., as you claim

As @studiot pointed out, (1): This is not classical physics. And (2): "nextness" depends on the number system. There is a next number in the naturals, the integers, all the finite arithmetics, etc. There isn't in the reals or the rationals. The question of whether there is a "next point" in physical space is equivalent to whether space is discrete. Is that what you mean, @Farid ?

I don't see how setting our future goals is a religious aspiration. Religion is more about inevitability and submission. Not a whole lot to do with changing your future. Religion has no tools at all, as praying and lamenting are not tools.

The boundary conditions it would require (not just for gravitational waves, but for any full-fledged macroscopic waves of any kind to exist) would be waves starting at spatial infinity in phase. They are unphysical. And yes, the reason is entropic in nature. We need to solve the arrow-of-time problem before we can answer that question. In the famous Wheeler-Feynman problem of electrodynamics as a half-advanced, half-retarded field, the boundary conditions were totally ad hoc, as the authors were keenly aware of, that there was a perfect EM absorber at spatial infinity. It is my intuition that it would cause serious problems with causality too (what would have caused that identical physical condition infinitely far apart in the first place?), but that a story for another day. All of this IIRC.

It doesn't. Understanding whether the human species has been taming itself for the last hundred thousand years is one thing. Setting our future goals, ethically, pragmatically; and acting in such a way that those goals are achieved, is a very different one. As different as studying the history of a city and doing urban planning for that city.