Because of the laws of physics, I think the question of "are we alone"? is moot; and I think a lot of the space ship sitings and other anecdotes are creations of fiction . . . but harmless.
But since there is some deep thinking going on, try this one if you haven't read up on the theory yet:
https://www.quantamagazine.org/big-b...bate-20180131/