Shutting up and calculate was made the norm. — Cartuna

Sean Carrol talks about that. Why don't scientists want to get to the bottom of it?

It used to be called "wavefunction reduction", and simply meant that, before measurement, we don't know if the system is in state A, B, C, etc. (or some mixture), but after measurement we know it's A so we "reduce" the description to that. — Kenosha Kid

Another complication involves the word 'where'. Where is the particle? Particles exist in quantum spacetime which is mathematically different from ordinary 4D spacetime. So what do we mean by 'where'? What location in what spacetime are we talking about? Bohr said it is meaningless to say where a particle is outside detection. Maybe he means it is nowhere. Nowhere in 4D spacetime that is. It lives in its own quantum spacetime. A 'location' arises when a particle collides with our 4D spacetime (ie a physical detection apparatus). The particle must appear to be located in our 4D spacetime because the detection apparatus is in our spacetime. But 'where' was the particle prior to detection? Nowhere!

Careers at stake, satisfaction with the status quo, no imagination, calculations (and shutting up) done within the classical framework usually do the trick of delivering, etc. Physicists really trying to go all the way down are rare, and circumstances can impede. Some simply don't have the time to think about it. Universities have policies. Etcetera. Diverging from the norm can get one in trouble. Powerplay, competition (which can be a good thing though), and simple indifference (the most common attitude: don't even try to understand the quantum apple, once bitten, though I never understood the innocence lost after the bite. Which innocence? No need for explanation?

Bohr said it is meaningless to say where a particle is outside detection. Maybe he means it is nowhere. Nowhere in 4D spacetime that is. — EnPassant

I'm quite sympathetic to the idea that, say, photons don't exist in space-time between their creation and destruction. Makes a lot of sense to me. I'm not sure how it would work for massive particles...

In the double-slit experiment, the electron is interacting with the Higgs the whole time. If we consider the electron 'not in space-time', then the Higgs field would also have to be 'not in space-time'. And if there are other electrons in the beam that it can repel, those other electrons would have to be 'not in space-time', along with the virtual photons they're exchanging to repel one another. End result being that everything is in this other realm, and our space-time starts looking rather empty (except for observations).

In the double-slit experiment, the electron is interacting with the Higgs the whole time. — Kenosha Kid

That's the question. There are more theories accounting for mass. The Higgs particle has been found. The Higgs mechanism has never been seen.

I'm quite sympathetic to the idea that, say, photons don't exist in space-time between their creation and destruction. Makes a lot of sense to me. I'm not sure how it would work for massive particles... — Kenosha Kid

I thought the speed of light was a measure of the impedance due to space-time. If it's not going through space then it shouldn't be limited to the rate of motion a thing can travel through space. No?

Photons just travel through space. They possess potential energy only. Massive particles possess real kinetic energy. Photons have potential momentum, matter spin 1/2 particles (massive or massless) have actual momentum.

I'm quite sympathetic to the idea that, say, photons don't exist in space-time between their creation and destruction. — Kenosha Kid

If they don't exist within space-time, then in what sense do they exist? There's an idea in Heisenberg that they exist as potentia - that they have a different kind or degree of existence per this article:

Werner Heisenberg, the quantum pioneer famous for his uncertainty principle, considered his quantum math to describe potential outcomes of measurements of which one would become the actual result. The quantum concept of a “probability wave,” describing the likelihood of different possible outcomes of a measurement, was a quantitative version of Aristotle’s potential, Heisenberg wrote in his well-known 1958 book Physics and Philosophy. “It introduced something standing in the middle between the idea of an event and the actual event, a strange kind of physical reality just in the middle between possibility and reality.”

I thought the speed of light was a measure of the impedance due to space-time. If it's not going through space then it shouldn't be limited to the rate of motion a thing can travel through space. No? — Cheshire

In classical electrodynamics, yes. But bear in mind that, from the photon's point of view, not distance is traversed or time elapsed between creation and destruction. There's no physical reference frame in which the photon is at rest, but if you take the limit of the distance and time between events as velocity tends toward the speed of light for a frame parallel to the photon's trajectory, that distance and time period vanish. It ends up simply being a transfer of electromagnetic energy from one system to another. Nothing empirical can be said about a photon's transit.

Does that ^ cover it?

There's no physical reference frame in which the photon is at rest, but if you take the limit of the distance and time between events as velocity tends toward the speed of light for a frame parallel to the photon's trajectory, that distance and time period vanish. It ends up simply being a transfer of electromagnetic energy from one system to another. Nothing empirical can be said about a photon's transit. — Kenosha Kid

But taking a derivative is a mathematical change, the "vanishing" isn't a measure of reality anymore than rounding. It's just a product of calculus when there is a large number(speed) and relatively small numbers. Correct? It isn't known to literally vanish.

from the photon's point of view, — Kenosha Kid

There is no photon's POV. The photon works instantaneously. But it looks to us as if it traverse space and time. Which is more or less what you stated. You can compare it with instantaneous interaction in Newtonian space. But since mass and energy must be interchangeable, c is finite.

But taking a derivative is a mathematical change, the "vanishing" isn't a measure of reality anymore than rounding. It's just a product of calculus when there is a large number(speed) and relatively small numbers. Correct? It isn't known to literally vanish. — Cheshire

As in has it been measured to do so? No, like I said, you can't transfer between frames of reference by the speed of light. But you can keep going faster and faster and watch the distance between events shrink. "Vanish" here is as it's used in mathematics and physics, e.g. "the wavefunction if the atom must vanish infinitely far from the nucleus."

Don't understand what you mean. You said that perhaps electrons exist outside space and time. And the article I linked to says that

“real” should not be restricted to “actual” objects or events in spacetime. Reality ought also be assigned to certain possibilities, or “potential” realities, that have not yet become “actual.” These potential realities do not exist in spacetime, but nevertheless are “ontological” — that is, real components of existence.

So - what do you make of it? Genuine question, not trying to trip you up or anything.

Photons (or gluons and hypergluons) are the potentiality. Matter is the actual.

I didn't think you were. I was saying I couldn't see how it would make sense for an electron to exist outside of space-time:

I'm not sure how it would work for massive particles... End result being that everything is in this other realm, and our space-time starts looking rather empty (except for observations). — Kenosha Kid

But for photons, yes, I can see how the above would work. The paths explored by the photon after creation would exist in this real realm of possibility, and only in our realm of actuality upon its destruction (by the effect it has on whatever destroyed it).

It's not quite how I picture it (my view was described at length in this thread: https://thephilosophyforum.com/discussion/9391/determinism-reversibility-decoherence-and-transaction ). As I said, I am sympathetic to it.

Thanks. My philosophical attitude to it is that reality is 'actualised' through observation, and that what exists outside of or apart from observation (in the broadest sense) is in principle incomprehensible or (better still) inchoate. That conflicts with the realist presumption that the Universe exists anyway, whether observed or not, but I see that as being a methodological presumption, which is then mistaken for a metaphysical postulate. It overlooks the sense in which the observing mind furnishes the framework within which judgements of what exists or doesn't exist are made. But this shouldn't be taken to mean that such judgements are 'merely' or 'only' subjective.

This is a recurrent theme in many discussions arising from just this experiment such as the discussion of Wheeler's views in Does the Universe Exist if we're Not Looking?

//ps// Also see physics in boxes

the "wavefunction" is a property of the maths. There is no reason one should suppose space-time has a variable effect. It's just the thing being passed through. It's not really changing. If I had a point - I lost it, but thanks for the responses. Interesting stuff that lends itself to bedazzlement.

the "wavefunction" is a property of the maths. — Cheshire

That's what you think. It could be just as well that the wavefunction is made out of non-local stuff and as such, space itself could be that stuff. What is more non-local than space? Nothing.

That's what you think. It could be just as well that the wavefunction is made out of non-local stuff and as such, space itself could be that stuff. What is more non-local than space? Nothing. — Cartuna

Pretty sure the suffix "function" denotes a mathematical model in play. Now, if you wanted to say something about the wave itself you could. Such as the wave doesn't change as a result of our calculations. Nor, do seemingly trivial parts of reality. Just because you can ignore distance and get the right answer doesn't imply distance was actually eliminated in reality. Like the centrifugal force from the earth spinning isn't factored into my luggage weight at the airport(yet); but it is still there. Are we understanding each other?

Are we understanding each other? — Cheshire

Considering the function yes. Though the wave can have the functional form (the square of it). Considering the centrifugal force and distance, yes. I fail to see why the wavefunction is connected with the two examples. What do we leave out of reality with the wavefunction?

As in has it been measured to do so? No, like I said, you can't transfer between frames of reference by the speed of light. But you can keep going faster and faster and watch the distance between events shrink. "Vanish" here is as it's used in mathematics and physics, e.g. "the wavefunction if the atom must vanish infinitely far from the nucleus." — Kenosha Kid

I think I took a wrong turn near this intersection.

Can't you drive back?

Then there's the inevitable question of what counts as 'observation'. Can Schroedinger's cat actualise his death? Can a shrimp, or a bacterium? A computer with a webcam, or some other sufficiently complex non-living human? Why not a Higgs field? And then conversely is even observation actualising anything? (the recent Wigner's friend experiments, in which it appears that collapse is local to the observer, although the "observer" in the actual experiment is just a part of the experimental apparatus.)

Then there's the inevitable question of what counts as 'observation'. — Kenosha Kid

In all of those cases you're surmising what might happen in the absence of there being an observer. But of course, we will never know that without observing at some point. In my view, 'observation' is an activity of a subject, and in the broadest sense, the subject is inextricable from what is being observed. Experiments and observations always concern some delineated object or set of objects or interaction (hence the link to the 'physics in a box' article). But at back of that, 'the observer' provides the framework within which any observation is made or conclusion is drawn. Realism wants to say that what is being observed would exist regardless whether observed or not - and in one sense that is true. But it's not true in any ultimate sense. And that is what is thrown into sharp relief by physics - the scientists dealing with quantum physics were obliged to ackowledge that they were more than simply observers, but also participants. Which is precisely the meaning of Wheeler's 'participatory universe'.

In all of those cases you're surmising what might happen in the absence of there being an observer. — Wayfarer

Rather: what might count as an observer.

But at back of that, 'the observer' provides the framework within which any observation is made or conclusion is drawn. — Wayfarer

That seems to be going too far imo. There is no physical theory afaik in which results depend on conclusion, which sniffs of sneaking human importance for the running of the universe in through the back door. In collapse and branching interpretations, observation is the catalyst. In Wigner, nothing is, except personally.

Realism wants to say that what is being observed would exist regardless whether observed or not - and in one sense that is true. But it's not true in any ultimate sense. — Wayfarer

I don't think it's true that observations are independent of being observed. If there's one thing we can definitely conclude from QM, it's that observing things affects the observed thing, at least on the elementary scale. Traditional sciences are likely unaffected by this paradigm shift because they're generally dealing with statistical ensembles, even if we didn't used to think of them that way (the classical limit).

I like Wheeler. His one-electron universe was a big influence on Feynman's representation of antimatter being matter moving in the opposite direction in time, a big influence in turn on me (and the aforementioned thread), and his it-from-bit weighs heavily on your "Is information physical?" thread. I think all of his ideas are interesting, including the PAP, without necessarily being true. I find that he and others like him blur the line between ontology and epistemology: we are not just building up a history of the universe, but actually creating that history via the same process. Fascinating, but unjustifiable.

Thanks. Very informative comments.

I'm quite sympathetic to the idea that, say, photons don't exist in space-time between their creation and destruction. Makes a lot of sense to me. I'm not sure how it would work for massive particles... — Kenosha Kid

As I understand it there are two spacetimes (from a geometric point of view that is.) If the mathematics of ordinary physical spacetime is different to the mathematics of the quantum world then we are dealing with two geometries and two spacetimes. Chairs and tables live in physical spacetime, 'particles' live in quantum spacetime.

BOTH spacetimes are here in this ontological space because space is two things. It is a geometry and it is also a positive existence. It has being. Within this positive being we call space there are two geometries (at least): quantum geometry and ordinary physical geometry or spacetime. Both of them are HERE but are geometrically distinct. When a 'particle' collides with a physical object it leaves a trace effect in physical spacetime (eg a spot on a photographic plate). We don't observe particles, we observe trace effects. These trace effects are necessarily in ordinary physical spacetime because they are physical objects. This trace effect marks a location in physical spacetime and we say the 'particle' was 'there'. But what is 'there' is really a trace effect. The particle is nowhere in physical spacetime.

We don't observe particles, we observe trace effects. — EnPassant

Then what about the screen with the spot?



The effect of measuring on a particle as Heisenberg exemplified, is a literal disturbance. This is not the kind of influence measuring the wavefunction has though. The wavefunction collapses during measurement, in both position and momentum space. The more precise you measure position the less precise momentum will be. This increased insecurity of momentum is not caused by the measuring particle adding momentum to the measured particle though. After measuring the position the wavefunction's momentum will have changed, and you don't know the momentum it had before the measurement, unless you prepare it in an ensemble of pure states. Measuring the wavefunction will change it's mean momentum through space. That's why two simultaneous measurements of position can never be made at the same time (contrary to the conjectured uncertainty relations, radiating from equal time commutation relations) which claims position and momentum cannot be measured simultaneously precisely. The relation holds for ensembles, but on a single wavefunction no two conjugate observables, like position and momentum can be made at the same time and momentum or energy need two time-separate measurements.

When a 'particle' collides with a physical object it leaves a trace effect in physical spacetime (eg a spot on a photographic plate). — EnPassant

Also a physical object consists of particles, thus the distinction makes no sense.

I have already presented the solution. Every particle and also every group of particles sees another wave function, a section of the universal wave function.

It is comparable with mankind. Every group thinks it would be the most intelligent, but universally seen all are only part of the big stupidity. :)

The bit I didn't get was after the ellipses:

If we consider the electron 'not in space-time', then the Higgs field would also have to be 'not in space-time'. And if there are other electrons in the beam that it can repel, those other electrons would have to be 'not in space-time', along with the virtual photons they're exchanging to repel one another. End result being that everything is in this other realm, and our space-time starts looking rather empty (except for observations). — Kenosha Kid