[pavel_lishin]

> primitives like "plank length" and "quark spin"

I'm going to be that guy - because I love being that guy, and I won't apologize for it - and point out that we're not even sure if those are primitives!

[fishtoaster]

Haha, yeah, I, I was considering putting some disclaimers around those. "What actually are the true, base-level primitives of physics?" has been an ongoing project for centuries. :)

[bdsa]

I'm going to be that that guy and say "plank length" is probably constant for a given plank. Planck length, on the other hand... :)