Earlier quoted context omitted.
The very notion of discreteness depends on subjective definitions of "objects". We take concepts of objects for granted because they make interacting with the world tractable, but it's really hard to define them outside of minds.
No, the discreetness comes from physical experiments. I do see a problem defining something outside of one’s mind or outside the universe though :)
Pronounce "lah-BORE-i-tories", obviously.