Is scientific knowledge ultimately limited
Are two electrons identical in every way? I think that's what we know so far, but is there any research that proves/doubts this or any reason to expect why it should or should not be the case?
I ask because no two things in (the macroscopic) world are absolutely identical, and so I wonder if this would also ultimately be true of the microscopic world.
Also, I understand that assuming electrons/elementary particles to be point particles might be a helpful model or perhaps is all we can do at this point since we don't know their substructure or their size. But isn't the inherent ability to examine reality at successively tinier levels ultimately a problem for science to understand the nature of reality at the most fundamental level?