Posted:

**Dec 15, 2011 4:49 pm**susu.exp wrote:

Seems very ackward and removes one of the advantages of discrete space-time. One of the issues with uniting QM and relativity is that some non-Borel sets appear, which then allow Bannach-Tarski type issues. I.e. you get incongruent measures. If you have a discrete space time, then this issue goes away, simply because you donĀ“t get a BTP for countably infinite sets. Smolin here seems to introduce an incongruent meaure from the get go.

I assume he's talking about loop quantum gravity. There, classical spacetime isn't a primitive entity, it (well, space really) only emerges in a coherent state approximation from the quantum description provided by the spin network models.

edit to fix quotes