Perhaps 'because' if the consistency did not exist then the universe would fail to exist.
There was the Big Bang, but we do not know what caused the Big Bang. But the particular Big Bang that started our particular universe may not have been the only one to occur. There could have been multiple previous Big Bangs where the 'properties' of each of those created universes may not have had the same consistency as we experience, and the inconsistency(s) could have resulted in a 'collapse' or 'destruction' of those universes.
Whereas it was just a coincidence that our Big Bang got things 'right' for the universe to continue to develop.
We could simply be experiencing survivorship bias in/with our universe.
As someone who dabbles in philosophy, and to use its language, our existence is contingent (we, and our universe, do not have to exist):
I don't know of any plausible naturalist explanation besides Many-Worlds. And that supposes for the sake of discussion that Many-Worlds is in fact naturalist.
The void in its infinite time and endless space (the same as neither existing) became bored with itself, and in its attempt to destroy itself, split and created the universe we have now. Full of endless wonders and anomalies and beauty and travesty. All for the amusement of itself as one that remembers the abyssal void.
I think the unsatisfactory feeling I get from these answers is that nobody ever tries to model worlds with different physics or different physical parameters and try to make them work.
It's one thing to know that everything will break down if parameters of this universe change slightly, but I don't think anyone ever actually seriously tried to make alternatives work, and simply assumed that the only model we know that works is the only possibility.
Of course, I understand it's hard, and we might not have the compute to properly run the simulations to see how things actually work out (without quantum computers, apparently the problem is exponentially hard on classical computers). But philosophically it feels lazy and unimaginative.
Alternative models are being explored all the time. There is incentive to do so, because coming up with better explanations is likely to win Nobel prizes. What is now called the standard model, however, so far explains the existing observations the best, despite being more complex and having a higher amount of arbitrariness than most physicists would like.
Sadly (?) the word "nothing" seems to have become overloaded, so now—depending on who you talk to—you can have the word pointing to different concepts. See "seven types/levels of nothing":
* https://rlkuhn.com/wp-content/uploads/Closer-to-Truth-Essays...
* https://closertotruth.com/news/levels-of-nothing-by-robert-l...
Could it happen while this universe is here?
What if that supermass is another(the next?) big bang forming; energy just slides around some universe space banging off here and there, forever?
It's more like: "Because we have arrived at a model that describes well most other aspect of those particles and their behavior, and has verified predictive power, and given the constrains and calculations based on that model, that's what its charge would be".
Take quantum mechanics. This came out of observations that particles exhibited wave-like behaviour. Mathematics predicts certain things when you start to apply the wave equation. These are then experimentally verified and the model is shown to be pretty good, although it has some deficiencies like not fully linking up with relativity. There are some doubts in some areas of what it predicts as well from what I understand from talking to researchers.
As the article says the original model was that protons were fundamental particles: nothing smaller. This model held up for quite some time but then observational data demonstrated it was insufficient. Same with the three quark model. Knowing the various deficiencies we might go so far as to say "the model that a proton is a +1 charge is good enough" and use that because that works for many situations and that's as much as we need. Although of course, there are always scientists looking to complete the picture.
Science is the incremental acquisition of knowledge through observation and experimentation - and there's an awful lot we haven't figured out.
i.e. it's the only combination that works. A proton is a bunch of other particles that, when combined together, balance out an electron. The 'why' is 'because that's a stable configuration' in the same way that water at 25c is liquid not gas because the 'rules' of the local environment dictate that.
I mean, why do those particles exist at all? That's really what you're asking. Why do electrons exist, why do protons 'form' from subatomic particles to balance them out? Existential kinda question.
At a certain point, the reason we like some particular wacky physical model is always going to be "it has the best combination of explanatory power and simplicity"
It’s like asking why the left engine of an aircraft happens to emit the same amount of thrust as the right engine; if that wasn’t the case, there wouldn’t be a plane to talk about in the first place, just an art piece or a flaming crash.
Which epistemic foundation in which your "why" question is answered do you consider as acceptable for you?
So by a pretty simple inferrence you could conclude the proton has a positive in it, hence the charge (it of course isn't literally like this for other reasons though).
And since we also observe antiprotons, the opposite can clearly apply.
Quantum physics has always bothered me, personally, since I find it difficult to understand reasons. Not philosophical reasons, I am fine with axioms and foundations to models, but rather intuitive reasons why it works a certain way. I know it is an extremely strong theory which makes unexpected, later confirmed, predictions, but there is a frustration that the only explanation to things is "math".
One of the ways you can calculate the probability of nuclear decay for example is to assume that the particle you expect to see is literally existent and trapped inside a potential well defined by the atomic nucleus and then calculate the probability it tunnels out of that to free space.
The thing is "why" does get pretty anthropic: protons match electrons because we observe them to, and then on top of that we observe nuclear decay causing the conversion of a proton to a neutron + a positron (within the limits of our instruments) - so our model predicts that these are in fact the same value, and we keep measuring to check that they converge in that direction (it would be a big deal, for example, if we discovered this wasn't the case - every physicist would love to find out that proton charge and electron charge are actually slightly different).
No, and the standard intuition that there are discrete things made out of smaller parts breaks down when you look closely enough. The proton is a bound state of the quark and gluon fields, but it only "contains" individual quarks and gluons in a loose heuristic sense, and positrons are a different thing entirely.
> Does it mean that their wave functions interact in some specific way?
Yes, or more precisely it means that the quark fields interact with the electron field (free electrons and positrons are different states of the same underlying bispinor field) and the W boson field in some specific way.
> Quantum physics has always bothered me, personally, since I find it difficult to understand reasons.
Ultimately, the sort of mechanistic explanations you're looking for do not exist: the universe runs on differential equations and linear algebra, not billiard balls and clockwork.
A photon turns into a (virtual) electron-positron pair. Does it mean that the photon consists of these particles?
Well, you'd need to ask a question that can be answered with science rather than philosophy, generally.
