Manny’s Reviews > A Project to Find the Fundamental Theory of Physics > Status Update

After 420 pages, I finally reach the long-promised explanation of how general relativity emerges from a graph rewriting system with suitable properties, and am referred to an arXiv paper which gives the details. It's here. Two immediate reactions:

a) Jesus Christ, why didn't you say that earlier?

b) Are there any such systems? You haven't yet shown us one.

Now 300 pages in, and maybe fifteen of those pages were about physics. If anything, I'm being generous. Given the title of the book, I can't help feeling that 5% is a low hit rate.

Come on Wolfram. You promised me emergent general relativity and quantum mechanics, but all you've shown me so far is a zillion pretty pictures of output from rewriting systems. I feel like a twelve year old grimly trawling through Lady Chatterley in search of the sex.

"One cannot help remarking," said Holmes, "on the surprising relationship between this work and Gerard t'Hooft's The Cellular Automaton Interpretation of Quantum Mechanics."

"I fail to grasp your meaning," I said, mystified. "Wolfram's book does not even mention Professor t'Hooft."

Wow. You can't accuse this book of thinking too small.

Spoiler alert: "Loop Quantum Gravity" and "Regge calculus" both occur in the index, but when I turn to the relevant pages I find that Wolfram says his scheme is completely different. And after a bit more page-flipping, I see his minimum length differs from the LQG one by dozens of orders of magnitude. I'm now curious to find out why.

My copy just arrived. Thank you Paige!