We review Fermi's paradox (or the "Great Silence" problem), not only arguably the oldest and crucial problem for the Search for ExtraTerrestrial Intelligence (SETI), but also a conundrum of profound scientific, philosophical and cultural importance. By a simple analysis of observation selection effects, the correct resolution of Fermi's paradox is certain to tell us something about the future of humanity
... Somewhat paradoxically, it seems that the class of (neo)catastrophic hypotheses gives, on balance, the strongest justification for guarded optimism regarding our current and near-future SETI efforts.
It's long but it's worth it. The giga-scale thinking involved in Fermi's paradox is a breath of fresh air and a great antidote to spending too much time worrying about whatever tiny little details make up your tiny little life."
A complex system that works is invariably found to have evolved from a simple system that works.