ETs do exist, because if they didn't... Man will have obliterated this planet in a few thousand years, and thus will become outcast and lonely, as opposed to outcast and the laughing stock of the interstellar community. We need to address the way we're living as a society. If we discover it, it will be through hard work and diligence. We could be bargaining for ways to save our planet, or we could be the latest delicacy. Time will tell.