[Supercryptid]

My brother had this hypothesis (likely not unique) about the structure of space-time down at the fundamental level. I've been trying to find problems with it because it sounds too rigid and classical to me and not fuzzy or "quantumy" enough. Here it is, as written by him:

Keep in mind that I have a relatively limited knowledge of quantum physics, and this was just a way for me to visualize the universe at the fundamental level.

Anyway, it all boils down to the idea that space-time is quantized.  Simple enough, and my brother here agreed that space-time would probably be quantized, but obviously I didn't realize that the accepted concept of quantization was very different.  I envisioned that space was really at the lowest level a simple grid like system.  Particles could only exist at intersections of grid lines, and the smallest unit of movement would be one quantum.

Naturally, the size of a quantum would be incredibly small.  Our current instruments wouldn't be able to detect the movement of particles as moving across quanta due to the extremely small size involved.

Particles could move around this in any way I can conceive of without causing problems as far as I know.  Moving at angles and such couldn't be the result of a transformation of a particle's grid system though, since that would result it particles possibly existing at locations not on grid lines in other grid systems from other particles.  I assume that such things would simply be like moving across pixels on a computer screen with aliasing.  My understanding of things like relativity and uncertainty is fairly limited, but I know of nothing that has contradictory evidence.  Not to say that none of you know of such evidence.

I honestly can't see the problem with it, even if it does sound too simplistic, although it almost certainly violates some sort of quantum law I'm not aware of.

I tried to use relativity to disprove this hypothesis of his, but I thought that it might still work if every observer had their own relative grid system. The way that the grid system looks to one observer might differ from that of another. I think I know a lot more than the layman about quantum physics and relativity, but I don't think I know quite enough to completely evaluate his hypothesis. Any comments?