As you go further and further down in size, we should wonder if we'll eventually reach a solid granularity in our Universe. IE, the Universe might be divided into blockules. A quantum particle can be in one blockule or another, but not in between, nor in both. It would be like pixels on a computer screen. Of course, detecting blockules would normally be impossible, because we are all moving with respect to the fabric of space time. If we find that the Universe is composed of blockules, maybe that would be a good indication that this Universe is a big computer simulation that we are all part of. Maybe it's some grad student's experiment in another dimension, and he's about to finish. Uh-oh.