alt Hacker News> This is "expected" from theory, because all particles seem to be just various aspects of the "same things" that obey a fairly simple algebra.
But again, this is just observation, and it is consistent with the charges we measure (again, just observation). It doesn't explain why these rules must behave as they do.
> This very, very strongly hints that the fundamental particles aren't actually fundamental in some sense.
This is exactly what I am suggesting in my original comment: this "coincidence" is not a coincidence but falls out from some deeper, shared mechanism.
> this is just observation
Sure, but that's fundamental to observing the universe from the inside. We can't ever be sure of anything other than our observations because we can't step outside our universe to look at its source code.
> It doesn't explain why these rules must behave as they do.
Not yet! Once we have a a theory of everything (TOE), or just a better model of fundamental particles, we may have a satisfactory explanation.
For example, if the theory ends up being something vaguely like Wolfram's "Ruliad", then we may be able to point at some aspect of very trivial mathematical rules and say: that "the electron and proton charges pop out of that naturally, it's the only way it can be, nothing else makes sense".
We can of course never be totally certain, but that type of answer may be both good enough and the best we can do.