Because charge is quantized, and not splittable.

Once it interacts with something all of it gets "sucked in" to one spot, and the entire electron interacts. The exact place it does that is randomized with varying probability at different spots.

But once a place is "picked" all of the charge goes there.

It's the quantization that is fundamental, and it's the quantization that makes fields look like particles, not the other way around.

If I understand correctly, there's currently no explanation of how one electron gets picked out of all the gazillions of electrons available; am I correct? Would that just be considered a fundamental randomness in nature?

I don't understand your question, can you rephrase?

In the experiment here they fire one electron at a time, so you don't have to pick one electron. Rather the final location of that electron is what's random.

When you fire a photon on a wall and see a blip, the blip is the location of the atom that had the electron that absorbed the photons energy (The electron that interacted with the photon).

Presumably there are gazillion photons. Presumably they all want that photons energy. Presumably the photon is stretched out in space so it sort of "touches" all of them. Yet, only that one electron got lucky.

That's the question: how is the location picked?

You roll a fair die, 1-6. It lands on 4 this time. Why 4, and not 5? How was the 4 chosen? In classical mechanics, it's a horrendously complicated but fundamentally simple computation. In QM, no one knows.

Why the need for full determinism? Unlike Einstein, I have no problem with God playing dice; this allows for free will, among other things (randomness is in the [computational] eye of the beholder).

Why allows it for free will?

Consider those two situations:

A: You know everything and decide about something based on all the facts known to you

B: You know everything and decide about something based on all the facts known to you plus the result of a random generator

Why is B more "free will" than A? In B there is simply another fact which is beyond your control which modifies your decision. That doesn't makes your decision more free than A, you simply have an additional "input" to consider.

One may argue that B is more free than A because in principle another person with the same knowledge as you would know what's your decision is in A but won't know it in B because of the influence of the random generator. But that doesn't makes B more "free", it only makes it a bit more unpredictable. But in reality it's impossible to always know all facts leading to the decision in A so both have similar unpredictability.

In fact I would consider only A as real "free will" because even if your decision is only determined by (external) facts, it's still all your reasoning based on your beliefs, experiences etc while in B there is a determining factor outside your reasoning you depend on which makes your decision less free (because you may have to decide for a sub-optimal outcome because you're forced by the random generator to do so).

The Many Worlds Interpretation plus Sleeping Beauty can directly explain this.

Pilot wave theory :)

Isn't that theory rooted in the particles view of the universe? It's totally at odds with this paper, it seems to me. Is it not?

aka Bohmian mechanics, aka the de Broglie-Bohm interpretation of QM. It definitely doesn't get enough serious attention IMO.

It's been getting more and more attention especially since many recent QM simulation experiments kinda show that pilot waves are a real phenomena.

"Classical" states (a single dot on the screen instead of an interference pattern) are created through the measurement process, which involves entanglement and dephasing: The small quantum system (the electron) first becomes entangled with the macroscopic system (the photo film and everything coupled to it), then the phase coherence between the individual eigenvectors of the electron gets lost due to the coupling with a large number of degrees of freedom in the measurement system.

Exactly! But how do you explain that to the public in a way that doesn't sound like a bunch of hocus pocus?

I know, it's difficult. I wanted to write an article about this for a while, guess I have to get up and just do it.

If I understand correctly, it interacts with an electron that's more or less locked into a small place around an atom.

It doesn't just hit that one point; the blip represents the location of the atom that had the electron that absorbed the photon.

Just my two cents

Calling an electron "a particle" presumes that it is always localized somewhere, and has a defined travel path. But it doesn't; when measurement happens, it is localized at some specific point, but that's all.

Something that can be localized only at interaction points, and not elsewhere, is not a "particle", it's something else. Perhaps "field excitation", like a hot spot in a microwave.

But thats the catch 22. Macroscopic objects are only classical because they have their hand in the river of interaction non stop. Only the smallest butterfly can manage to remain coherent and uncollapsed.

Each probability field ends up interacting with a single point on the screen.

This is just the copenhagen interpretation which says nothing about the physical ontology of the light before it ends up as a point on the screen. Unless you are saying the probability amplitudes are physical things-in-themselves rather than calculational models. (side note - Feynman did not think of a probability amplitude as a physical thing-in-itself)

But did Feynman think anything as a physical thing-in-itself? Feynman repeatedly argued that that physics is whatever the instruments measure, generalized by whatever computational models match the measurements, and he was happy to analogize to metaphorize whenever convenient to describe an aspect of a phenomenon ("photons jiggling")

One good thing about Feynman was he was always clear on what was experimentally observable and is what it is and what is theory where you can make up anything that fits the experiment.