Guest Post: Garrett Lisi on Geometric Naturalness

Thanks to Sabine for inviting me to do a guest post. In her book, “Lost in Math,” I mentioned the criteria of “geometric naturalness” for
judging theories of fundamental physics. Here I would like to give a
personal definition of this and expand on it a bit.



Figure: Lowest million roots of E8+++ projected from eleven dimensions.


As physicists we unabashedly steal tools from mathematicians.