Dear Steve,
thanks for the comments and for reading my essay. As you correctly saw, I'm not a fan of Platon and his idea about the world of ideas (independent of us).
I see math as part of humanity and of our brain. Aliens will also use math but (because of their other abilities) in another fashion.
I had other the chance to read your essay and rated it high.
You took agreat circle to explain your point of view: the problem of self-referentials, causality as main part of a computation and you dismissed the infinite universe of Tegmark.
Points about which we can agree.
Good luck for the contest
Torsten