Mind-bending, eh? It's not too scary a though though -- taking the evolutionists point of view, there is no "underlying" reason that higher order life exists.

Mind-bending, eh? It's not too scary a though though -- taking the evolutionists point of view, there is no "underlying" reason that higher order life exists. It exists because the processes of natural selection have enabled it to exist and reproduce. If bacteria contribute to the survival and reproduction of our species (they do), then they are simply part of the process. It goes both ways. We exist and reproduce because they help us do so, and they exist because we provide a nice host. One hand washes the other...