> If one considers bacteria as living entities — and all biologists seem to — then it is impossible to explain why mitochondria are not.
There seems to be a strange, half-hubris, half-pride vein that runs through Humanity that would see us as lesser for being hosts to benevolent bacteria, despite us very obviously being unable to survive without benevolent bacteria.
We didn't evolve to understand "self", and indeed most animals do not. There was no evolutionary pressure to do so. We're having to discover it piece by piece.
We aren't driven solely by evolutionary pressure. We can (and have) developed cultures that can easily accept that humans are "just" part of a larger system, even having a unique role, without having to be superior. Our culture isn't like that, of course. We are obviously doing a good job of being "in charge" of the planet and definitely not charging headfirst into a mass extinction event with our collective eyes closed.
There seems to be a strange, half-hubris, half-pride vein that runs through Humanity that would see us as lesser for being hosts to benevolent bacteria, despite us very obviously being unable to survive without benevolent bacteria.