We are not just one being - we are a colony creature. We live only because of other animals that live in, on, and all over us. We couldn't digest our food without our symbiotic gut bacteria. We couldn't avoid being killed by fungus if not for the bacteria on our skin that constantly eats it. We couldn't avoid blindness, save for the microscopic insects that live in our eyelashes - kill them off, and people tend to lose their eyesight.

We are a world, and entire populations live and die upon, and within us. Our biome, our personal ecosystem sustains and protects us.

Yes, sometimes it can all go horribly wrong, when one faction gains an upper hand - that is true. Or if one of the species on us gets into somewhere it doesn't belong, such as if bacteria on the outside manages to get inside. But, in a very real way, we are not one creature.

If we were rendered entirely 'clean', with no cells or organisms upon or inside us of any kind, only human cells, only us, we would die from multiple reasons. It would be a race to see what failed first.

We are many.