re: Gaia
"We are a way for the Cosmos to know itself." - Carl Sagan
You know how some of the dinosaurs had knots of extra special nerves to help their tiny little brains control their big bodies, well, when you have a Universe that is billions of light years across with hundreds of billions of galaxies, one intelligent species is not enough to know the whole shebang.
Of course if we are the Universe's only brain, then Zeus help the Universe!