Suspect “illusion” is used for dramatic effect in the quoted reference. Seems to me that something that might be part of a larger concept can still have an identity as well. A piece of ceramic tile is still a piece of a ceramic tile even if it is also a tiny component of a massive mosaic which is part of a wall which is part of a room which is part of a building which is …
That said, making the fundamental concept of quantum mechanics even more mind blowing might as well be an illusion for my old grey cells!
This sounds like the Von Nagle theorem that was never proven: “If a string has one end, does it also have another?” Actually, the Elephant in the room is, " If Time and Space are illusions… isn’t Matter also an illusion? " The three are interdependent and no one…or even two of them can exist without the complete trio. “Are Time and Space an Illusion?” this premise needs a LOT of work and had you presented such an incomplete thought to my Grammar School nuns… it would be ruler time… (Good thing he’s at Princeton)
Actually, untrue… I DO know that… it’s a logic problem…like geometry … ( I think you should find a new urologist…) And I understand that the concept of superimposition effectively having the same outcome as a simpler form (As the wavelengths and harmonics of a string) but those are demonstrable not an illusion. Still, they are Physicists and not English majors… (And at Princeton… can’t forget that.)