Fermi paradox -- thoroughly explicated in this article -- explains both why we're probably alone in the universe and also why if we're not alone we'd probably be let alone by the very advanced alien races.

The Fermi Paradox - Wait But Why


On a side note, you can see where David Brin -- in his Uplift Universe series of books -- developed some of his ideas about advanced alien civilizations and their work in this galaxy and four others. They'd definitely be Type II or Type III civilizations, while we're barely at, MAYBE, point-7 (meaning, not yet to a Type I civilization). Meaning, we'd be amoebae to a Type III civilization and barely worth a passing glance to a race that could move about this universe at will, no matter the distances involved (and Isaac Asimov, in his Foundation series, discussed a means of space travel using a craft that could manipulate space-time, by folding space I guess, to get where it needed to get in the blink of an eye).

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"Politics is just show business for ugly people."

Interesting read, thanks. I'd agree on that scale that we're below a Type !. I also agree that everything beyond that is speculation. Honestly, I think it's almost like wondering if there is a god. Is there a species out there that can travel space and time?

Until our technology improves, we can look for radio waves and laser beams from freaking sharks in space, but we're not going to find them. I'd hate to have that job. That doesn't prove that we're alone.